Adding upstream version 5:7.2.4.upstream/5%7.2.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 13846 insertions, 0 deletions

diff --git a/src/module.c b/src/module.c
new file mode 100644
index 0000000..ac6cbbb
--- /dev/null
+++ b/src/module.c
@@ -0,0 +1,13846 @@
+/*
+ * Copyright (c) 2016, Salvatore Sanfilippo <antirez at gmail dot com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *   * Neither the name of Redis nor the names of its contributors may be used
+ *     to endorse or promote products derived from this software without
+ *     specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/* --------------------------------------------------------------------------
+ * Modules API documentation information
+ *
+ * The comments in this file are used to generate the API documentation on the
+ * Redis website.
+ *
+ * Each function starting with RM_ and preceded by a block comment is included
+ * in the API documentation. To hide an RM_ function, put a blank line between
+ * the comment and the function definition or put the comment inside the
+ * function body.
+ *
+ * The functions are divided into sections. Each section is preceded by a
+ * documentation block, which is comment block starting with a markdown level 2
+ * heading, i.e. a line starting with ##, on the first line of the comment block
+ * (with the exception of a ----- line which can appear first). Other comment
+ * blocks, which are not intended for the modules API user, such as this comment
+ * block, do NOT start with a markdown level 2 heading, so they are included in
+ * the generated a API documentation.
+ *
+ * The documentation comments may contain markdown formatting. Some automatic
+ * replacements are done, such as the replacement of RM with RedisModule in
+ * function names. For details, see the script src/modules/gendoc.rb.
+ * -------------------------------------------------------------------------- */
+
+#include "server.h"
+#include "cluster.h"
+#include "slowlog.h"
+#include "rdb.h"
+#include "monotonic.h"
+#include "script.h"
+#include "call_reply.h"
+#include "hdr_histogram.h"
+#include <dlfcn.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <fcntl.h>
+#include <string.h>
+
+/* --------------------------------------------------------------------------
+ * Private data structures used by the modules system. Those are data
+ * structures that are never exposed to Redis Modules, if not as void
+ * pointers that have an API the module can call with them)
+ * -------------------------------------------------------------------------- */
+
+struct RedisModuleInfoCtx {
+    struct RedisModule *module;
+    dict *requested_sections;
+    sds info;           /* info string we collected so far */
+    int sections;       /* number of sections we collected so far */
+    int in_section;     /* indication if we're in an active section or not */
+    int in_dict_field;  /* indication that we're currently appending to a dict */
+};
+
+/* This represents a shared API. Shared APIs will be used to populate
+ * the server.sharedapi dictionary, mapping names of APIs exported by
+ * modules for other modules to use, to their structure specifying the
+ * function pointer that can be called. */
+struct RedisModuleSharedAPI {
+    void *func;
+    RedisModule *module;
+};
+typedef struct RedisModuleSharedAPI RedisModuleSharedAPI;
+
+dict *modules; /* Hash table of modules. SDS -> RedisModule ptr.*/
+
+/* Entries in the context->amqueue array, representing objects to free
+ * when the callback returns. */
+struct AutoMemEntry {
+    void *ptr;
+    int type;
+};
+
+/* AutoMemEntry type field values. */
+#define REDISMODULE_AM_KEY 0
+#define REDISMODULE_AM_STRING 1
+#define REDISMODULE_AM_REPLY 2
+#define REDISMODULE_AM_FREED 3 /* Explicitly freed by user already. */
+#define REDISMODULE_AM_DICT 4
+#define REDISMODULE_AM_INFO 5
+
+/* The pool allocator block. Redis Modules can allocate memory via this special
+ * allocator that will automatically release it all once the callback returns.
+ * This means that it can only be used for ephemeral allocations. However
+ * there are two advantages for modules to use this API:
+ *
+ * 1) The memory is automatically released when the callback returns.
+ * 2) This allocator is faster for many small allocations since whole blocks
+ *    are allocated, and small pieces returned to the caller just advancing
+ *    the index of the allocation.
+ *
+ * Allocations are always rounded to the size of the void pointer in order
+ * to always return aligned memory chunks. */
+
+#define REDISMODULE_POOL_ALLOC_MIN_SIZE (1024*8)
+#define REDISMODULE_POOL_ALLOC_ALIGN (sizeof(void*))
+
+typedef struct RedisModulePoolAllocBlock {
+    uint32_t size;
+    uint32_t used;
+    struct RedisModulePoolAllocBlock *next;
+    char memory[];
+} RedisModulePoolAllocBlock;
+
+/* This structure represents the context in which Redis modules operate.
+ * Most APIs module can access, get a pointer to the context, so that the API
+ * implementation can hold state across calls, or remember what to free after
+ * the call and so forth.
+ *
+ * Note that not all the context structure is always filled with actual values
+ * but only the fields needed in a given context. */
+
+struct RedisModuleBlockedClient;
+struct RedisModuleUser;
+
+struct RedisModuleCtx {
+    void *getapifuncptr;            /* NOTE: Must be the first field. */
+    struct RedisModule *module;     /* Module reference. */
+    client *client;                 /* Client calling a command. */
+    struct RedisModuleBlockedClient *blocked_client; /* Blocked client for
+                                                        thread safe context. */
+    struct AutoMemEntry *amqueue;   /* Auto memory queue of objects to free. */
+    int amqueue_len;                /* Number of slots in amqueue. */
+    int amqueue_used;               /* Number of used slots in amqueue. */
+    int flags;                      /* REDISMODULE_CTX_... flags. */
+    void **postponed_arrays;        /* To set with RM_ReplySetArrayLength(). */
+    int postponed_arrays_count;     /* Number of entries in postponed_arrays. */
+    void *blocked_privdata;         /* Privdata set when unblocking a client. */
+    RedisModuleString *blocked_ready_key; /* Key ready when the reply callback
+                                             gets called for clients blocked
+                                             on keys. */
+
+    /* Used if there is the REDISMODULE_CTX_KEYS_POS_REQUEST or 
+     * REDISMODULE_CTX_CHANNEL_POS_REQUEST flag set. */
+    getKeysResult *keys_result;
+
+    struct RedisModulePoolAllocBlock *pa_head;
+    long long next_yield_time;
+
+    const struct RedisModuleUser *user;  /* RedisModuleUser commands executed via
+                                            RM_Call should be executed as, if set */
+};
+typedef struct RedisModuleCtx RedisModuleCtx;
+
+#define REDISMODULE_CTX_NONE (0)
+#define REDISMODULE_CTX_AUTO_MEMORY (1<<0)
+#define REDISMODULE_CTX_KEYS_POS_REQUEST (1<<1)
+#define REDISMODULE_CTX_BLOCKED_REPLY (1<<2)
+#define REDISMODULE_CTX_BLOCKED_TIMEOUT (1<<3)
+#define REDISMODULE_CTX_THREAD_SAFE (1<<4)
+#define REDISMODULE_CTX_BLOCKED_DISCONNECTED (1<<5)
+#define REDISMODULE_CTX_TEMP_CLIENT (1<<6) /* Return client object to the pool
+                                              when the context is destroyed */
+#define REDISMODULE_CTX_NEW_CLIENT (1<<7)  /* Free client object when the
+                                              context is destroyed */
+#define REDISMODULE_CTX_CHANNELS_POS_REQUEST (1<<8)
+#define REDISMODULE_CTX_COMMAND (1<<9) /* Context created to serve a command from call() or AOF (which calls cmd->proc directly) */
+
+
+/* This represents a Redis key opened with RM_OpenKey(). */
+struct RedisModuleKey {
+    RedisModuleCtx *ctx;
+    redisDb *db;
+    robj *key;      /* Key name object. */
+    robj *value;    /* Value object, or NULL if the key was not found. */
+    void *iter;     /* Iterator. */
+    int mode;       /* Opening mode. */
+
+    union {
+        struct {
+            /* List, use only if value->type == OBJ_LIST */
+            listTypeEntry entry;   /* Current entry in iteration. */
+            long index;            /* Current 0-based index in iteration. */
+        } list;
+        struct {
+            /* Zset iterator, use only if value->type == OBJ_ZSET */
+            uint32_t type;         /* REDISMODULE_ZSET_RANGE_* */
+            zrangespec rs;         /* Score range. */
+            zlexrangespec lrs;     /* Lex range. */
+            uint32_t start;        /* Start pos for positional ranges. */
+            uint32_t end;          /* End pos for positional ranges. */
+            void *current;         /* Zset iterator current node. */
+            int er;                /* Zset iterator end reached flag
+                                       (true if end was reached). */
+        } zset;
+        struct {
+            /* Stream, use only if value->type == OBJ_STREAM */
+            streamID currentid;    /* Current entry while iterating. */
+            int64_t numfieldsleft; /* Fields left to fetch for current entry. */
+            int signalready;       /* Flag that signalKeyAsReady() is needed. */
+        } stream;
+    } u;
+};
+
+/* RedisModuleKey 'ztype' values. */
+#define REDISMODULE_ZSET_RANGE_NONE 0       /* This must always be 0. */
+#define REDISMODULE_ZSET_RANGE_LEX 1
+#define REDISMODULE_ZSET_RANGE_SCORE 2
+#define REDISMODULE_ZSET_RANGE_POS 3
+
+/* Function pointer type of a function representing a command inside
+ * a Redis module. */
+struct RedisModuleBlockedClient;
+typedef int (*RedisModuleCmdFunc) (RedisModuleCtx *ctx, void **argv, int argc);
+typedef int (*RedisModuleAuthCallback)(RedisModuleCtx *ctx, void *username, void *password, RedisModuleString **err);
+typedef void (*RedisModuleDisconnectFunc) (RedisModuleCtx *ctx, struct RedisModuleBlockedClient *bc);
+
+/* This struct holds the information about a command registered by a module.*/
+struct RedisModuleCommand {
+    struct RedisModule *module;
+    RedisModuleCmdFunc func;
+    struct redisCommand *rediscmd;
+};
+typedef struct RedisModuleCommand RedisModuleCommand;
+
+#define REDISMODULE_REPLYFLAG_NONE 0
+#define REDISMODULE_REPLYFLAG_TOPARSE (1<<0) /* Protocol must be parsed. */
+#define REDISMODULE_REPLYFLAG_NESTED (1<<1)  /* Nested reply object. No proto
+                                                or struct free. */
+
+/* Reply of RM_Call() function. The function is filled in a lazy
+ * way depending on the function called on the reply structure. By default
+ * only the type, proto and protolen are filled. */
+typedef struct CallReply RedisModuleCallReply;
+
+/* Structure to hold the module auth callback & the Module implementing it. */
+typedef struct RedisModuleAuthCtx {
+    struct RedisModule *module;
+    RedisModuleAuthCallback auth_cb;
+} RedisModuleAuthCtx;
+
+/* Structure representing a blocked client. We get a pointer to such
+ * an object when blocking from modules. */
+typedef struct RedisModuleBlockedClient {
+    client *client;  /* Pointer to the blocked client. or NULL if the client
+                        was destroyed during the life of this object. */
+    RedisModule *module;    /* Module blocking the client. */
+    RedisModuleCmdFunc reply_callback; /* Reply callback on normal completion.*/
+    RedisModuleAuthCallback auth_reply_cb; /* Reply callback on completing blocking
+                                                    module authentication. */
+    RedisModuleCmdFunc timeout_callback; /* Reply callback on timeout. */
+    RedisModuleDisconnectFunc disconnect_callback; /* Called on disconnection.*/
+    void (*free_privdata)(RedisModuleCtx*,void*);/* privdata cleanup callback.*/
+    void *privdata;     /* Module private data that may be used by the reply
+                           or timeout callback. It is set via the
+                           RedisModule_UnblockClient() API. */
+    client *thread_safe_ctx_client; /* Fake client to be used for thread safe
+                                       context so that no lock is required. */
+    client *reply_client;           /* Fake client used to accumulate replies
+                                       in thread safe contexts. */
+    int dbid;           /* Database number selected by the original client. */
+    int blocked_on_keys;    /* If blocked via RM_BlockClientOnKeys(). */
+    int unblocked;          /* Already on the moduleUnblocked list. */
+    monotime background_timer; /* Timer tracking the start of background work */
+    uint64_t background_duration; /* Current command background time duration.
+                                     Used for measuring latency of blocking cmds */
+} RedisModuleBlockedClient;
+
+/* This is a list of Module Auth Contexts. Each time a Module registers a callback, a new ctx is
+ * added to this list. Multiple modules can register auth callbacks and the same Module can have
+ * multiple auth callbacks. */
+static list *moduleAuthCallbacks;
+
+static pthread_mutex_t moduleUnblockedClientsMutex = PTHREAD_MUTEX_INITIALIZER;
+static list *moduleUnblockedClients;
+
+/* Pool for temporary client objects. Creating and destroying a client object is
+ * costly. We manage a pool of clients to avoid this cost. Pool expands when
+ * more clients are needed and shrinks when unused. Please see modulesCron()
+ * for more details. */
+static client **moduleTempClients;
+static size_t moduleTempClientCap = 0;
+static size_t moduleTempClientCount = 0;    /* Client count in pool */
+static size_t moduleTempClientMinCount = 0; /* Min client count in pool since
+                                               the last cron. */
+
+/* We need a mutex that is unlocked / relocked in beforeSleep() in order to
+ * allow thread safe contexts to execute commands at a safe moment. */
+static pthread_mutex_t moduleGIL = PTHREAD_MUTEX_INITIALIZER;
+
+
+/* Function pointer type for keyspace event notification subscriptions from modules. */
+typedef int (*RedisModuleNotificationFunc) (RedisModuleCtx *ctx, int type, const char *event, RedisModuleString *key);
+
+/* Function pointer type for post jobs */
+typedef void (*RedisModulePostNotificationJobFunc) (RedisModuleCtx *ctx, void *pd);
+
+/* Keyspace notification subscriber information.
+ * See RM_SubscribeToKeyspaceEvents() for more information. */
+typedef struct RedisModuleKeyspaceSubscriber {
+    /* The module subscribed to the event */
+    RedisModule *module;
+    /* Notification callback in the module*/
+    RedisModuleNotificationFunc notify_callback;
+    /* A bit mask of the events the module is interested in */
+    int event_mask;
+    /* Active flag set on entry, to avoid reentrant subscribers
+     * calling themselves */
+    int active;
+} RedisModuleKeyspaceSubscriber;
+
+typedef struct RedisModulePostExecUnitJob {
+    /* The module subscribed to the event */
+    RedisModule *module;
+    RedisModulePostNotificationJobFunc callback;
+    void *pd;
+    void (*free_pd)(void*);
+    int dbid;
+} RedisModulePostExecUnitJob;
+
+/* The module keyspace notification subscribers list */
+static list *moduleKeyspaceSubscribers;
+
+/* The module post keyspace jobs list */
+static list *modulePostExecUnitJobs;
+
+/* Data structures related to the exported dictionary data structure. */
+typedef struct RedisModuleDict {
+    rax *rax;                       /* The radix tree. */
+} RedisModuleDict;
+
+typedef struct RedisModuleDictIter {
+    RedisModuleDict *dict;
+    raxIterator ri;
+} RedisModuleDictIter;
+
+typedef struct RedisModuleCommandFilterCtx {
+    RedisModuleString **argv;
+    int argv_len;
+    int argc;
+    client *c;
+} RedisModuleCommandFilterCtx;
+
+typedef void (*RedisModuleCommandFilterFunc) (RedisModuleCommandFilterCtx *filter);
+
+typedef struct RedisModuleCommandFilter {
+    /* The module that registered the filter */
+    RedisModule *module;
+    /* Filter callback function */
+    RedisModuleCommandFilterFunc callback;
+    /* REDISMODULE_CMDFILTER_* flags */
+    int flags;
+} RedisModuleCommandFilter;
+
+/* Registered filters */
+static list *moduleCommandFilters;
+
+typedef void (*RedisModuleForkDoneHandler) (int exitcode, int bysignal, void *user_data);
+
+static struct RedisModuleForkInfo {
+    RedisModuleForkDoneHandler done_handler;
+    void* done_handler_user_data;
+} moduleForkInfo = {0};
+
+typedef struct RedisModuleServerInfoData {
+    rax *rax;                       /* parsed info data. */
+} RedisModuleServerInfoData;
+
+/* Flags for moduleCreateArgvFromUserFormat(). */
+#define REDISMODULE_ARGV_REPLICATE (1<<0)
+#define REDISMODULE_ARGV_NO_AOF (1<<1)
+#define REDISMODULE_ARGV_NO_REPLICAS (1<<2)
+#define REDISMODULE_ARGV_RESP_3 (1<<3)
+#define REDISMODULE_ARGV_RESP_AUTO (1<<4)
+#define REDISMODULE_ARGV_RUN_AS_USER (1<<5)
+#define REDISMODULE_ARGV_SCRIPT_MODE (1<<6)
+#define REDISMODULE_ARGV_NO_WRITES (1<<7)
+#define REDISMODULE_ARGV_CALL_REPLIES_AS_ERRORS (1<<8)
+#define REDISMODULE_ARGV_RESPECT_DENY_OOM (1<<9)
+#define REDISMODULE_ARGV_DRY_RUN (1<<10)
+#define REDISMODULE_ARGV_ALLOW_BLOCK (1<<11)
+
+/* Determine whether Redis should signalModifiedKey implicitly.
+ * In case 'ctx' has no 'module' member (and therefore no module->options),
+ * we assume default behavior, that is, Redis signals.
+ * (see RM_GetThreadSafeContext) */
+#define SHOULD_SIGNAL_MODIFIED_KEYS(ctx) \
+    ((ctx)->module? !((ctx)->module->options & REDISMODULE_OPTION_NO_IMPLICIT_SIGNAL_MODIFIED) : 1)
+
+/* Server events hooks data structures and defines: this modules API
+ * allow modules to subscribe to certain events in Redis, such as
+ * the start and end of an RDB or AOF save, the change of role in replication,
+ * and similar other events. */
+
+typedef struct RedisModuleEventListener {
+    RedisModule *module;
+    RedisModuleEvent event;
+    RedisModuleEventCallback callback;
+} RedisModuleEventListener;
+
+list *RedisModule_EventListeners; /* Global list of all the active events. */
+
+/* Data structures related to the redis module users */
+
+/* This is the object returned by RM_CreateModuleUser(). The module API is
+ * able to create users, set ACLs to such users, and later authenticate
+ * clients using such newly created users. */
+typedef struct RedisModuleUser {
+    user *user; /* Reference to the real redis user */
+    int free_user; /* Indicates that user should also be freed when this object is freed */
+} RedisModuleUser;
+
+/* This is a structure used to export some meta-information such as dbid to the module. */
+typedef struct RedisModuleKeyOptCtx {
+    struct redisObject *from_key, *to_key; /* Optional name of key processed, NULL when unknown. 
+                                              In most cases, only 'from_key' is valid, but in callbacks 
+                                              such as `copy2`, both 'from_key' and 'to_key' are valid. */
+    int from_dbid, to_dbid;                /* The dbid of the key being processed, -1 when unknown.
+                                              In most cases, only 'from_dbid' is valid, but in callbacks such 
+                                              as `copy2`, 'from_dbid' and 'to_dbid' are both valid. */
+} RedisModuleKeyOptCtx;
+
+/* Data structures related to redis module configurations */
+/* The function signatures for module config get callbacks. These are identical to the ones exposed in redismodule.h. */
+typedef RedisModuleString * (*RedisModuleConfigGetStringFunc)(const char *name, void *privdata);
+typedef long long (*RedisModuleConfigGetNumericFunc)(const char *name, void *privdata);
+typedef int (*RedisModuleConfigGetBoolFunc)(const char *name, void *privdata);
+typedef int (*RedisModuleConfigGetEnumFunc)(const char *name, void *privdata);
+/* The function signatures for module config set callbacks. These are identical to the ones exposed in redismodule.h. */
+typedef int (*RedisModuleConfigSetStringFunc)(const char *name, RedisModuleString *val, void *privdata, RedisModuleString **err);
+typedef int (*RedisModuleConfigSetNumericFunc)(const char *name, long long val, void *privdata, RedisModuleString **err);
+typedef int (*RedisModuleConfigSetBoolFunc)(const char *name, int val, void *privdata, RedisModuleString **err);
+typedef int (*RedisModuleConfigSetEnumFunc)(const char *name, int val, void *privdata, RedisModuleString **err);
+/* Apply signature, identical to redismodule.h */
+typedef int (*RedisModuleConfigApplyFunc)(RedisModuleCtx *ctx, void *privdata, RedisModuleString **err);
+
+/* Struct representing a module config. These are stored in a list in the module struct */
+struct ModuleConfig {
+    sds name; /* Name of config without the module name appended to the front */
+    void *privdata; /* Optional data passed into the module config callbacks */
+    union get_fn { /* The get callback specified by the module */
+        RedisModuleConfigGetStringFunc get_string;
+        RedisModuleConfigGetNumericFunc get_numeric;
+        RedisModuleConfigGetBoolFunc get_bool;
+        RedisModuleConfigGetEnumFunc get_enum;
+    } get_fn;
+    union set_fn { /* The set callback specified by the module */
+        RedisModuleConfigSetStringFunc set_string;
+        RedisModuleConfigSetNumericFunc set_numeric;
+        RedisModuleConfigSetBoolFunc set_bool;
+        RedisModuleConfigSetEnumFunc set_enum;
+    } set_fn;
+    RedisModuleConfigApplyFunc apply_fn;
+    RedisModule *module;
+};
+
+typedef struct RedisModuleAsyncRMCallPromise{
+    size_t ref_count;
+    void *private_data;
+    RedisModule *module;
+    RedisModuleOnUnblocked on_unblocked;
+    client *c;
+    RedisModuleCtx *ctx;
+} RedisModuleAsyncRMCallPromise;
+
+/* --------------------------------------------------------------------------
+ * Prototypes
+ * -------------------------------------------------------------------------- */
+
+void RM_FreeCallReply(RedisModuleCallReply *reply);
+void RM_CloseKey(RedisModuleKey *key);
+void autoMemoryCollect(RedisModuleCtx *ctx);
+robj **moduleCreateArgvFromUserFormat(const char *cmdname, const char *fmt, int *argcp, int *flags, va_list ap);
+void RM_ZsetRangeStop(RedisModuleKey *kp);
+static void zsetKeyReset(RedisModuleKey *key);
+static void moduleInitKeyTypeSpecific(RedisModuleKey *key);
+void RM_FreeDict(RedisModuleCtx *ctx, RedisModuleDict *d);
+void RM_FreeServerInfo(RedisModuleCtx *ctx, RedisModuleServerInfoData *data);
+
+/* Helpers for RM_SetCommandInfo. */
+static int moduleValidateCommandInfo(const RedisModuleCommandInfo *info);
+static int64_t moduleConvertKeySpecsFlags(int64_t flags, int from_api);
+static int moduleValidateCommandArgs(RedisModuleCommandArg *args,
+                                     const RedisModuleCommandInfoVersion *version);
+static struct redisCommandArg *moduleCopyCommandArgs(RedisModuleCommandArg *args,
+                                                     const RedisModuleCommandInfoVersion *version);
+static redisCommandArgType moduleConvertArgType(RedisModuleCommandArgType type, int *error);
+static int moduleConvertArgFlags(int flags);
+void moduleCreateContext(RedisModuleCtx *out_ctx, RedisModule *module, int ctx_flags);
+/* --------------------------------------------------------------------------
+ * ## Heap allocation raw functions
+ *
+ * Memory allocated with these functions are taken into account by Redis key
+ * eviction algorithms and are reported in Redis memory usage information.
+ * -------------------------------------------------------------------------- */
+
+/* Use like malloc(). Memory allocated with this function is reported in
+ * Redis INFO memory, used for keys eviction according to maxmemory settings
+ * and in general is taken into account as memory allocated by Redis.
+ * You should avoid using malloc().
+ * This function panics if unable to allocate enough memory. */
+void *RM_Alloc(size_t bytes) {
+    /* Use 'zmalloc_usable()' instead of 'zmalloc()' to allow the compiler
+     * to recognize the additional memory size, which means that modules can
+     * use the memory reported by 'RM_MallocUsableSize()' safely. In theory this
+     * isn't really needed since this API can't be inlined (not even for embedded
+     * modules like TLS (we use function pointers for module APIs), and the API doesn't
+     * have the malloc_size attribute, but it's hard to predict how smart future compilers
+     * will be, so better safe than sorry. */
+    return zmalloc_usable(bytes,NULL);
+}
+
+/* Similar to RM_Alloc, but returns NULL in case of allocation failure, instead
+ * of panicking. */
+void *RM_TryAlloc(size_t bytes) {
+    return ztrymalloc_usable(bytes,NULL);
+}
+
+/* Use like calloc(). Memory allocated with this function is reported in
+ * Redis INFO memory, used for keys eviction according to maxmemory settings
+ * and in general is taken into account as memory allocated by Redis.
+ * You should avoid using calloc() directly. */
+void *RM_Calloc(size_t nmemb, size_t size) {
+    return zcalloc_usable(nmemb*size,NULL);
+}
+
+/* Use like realloc() for memory obtained with RedisModule_Alloc(). */
+void* RM_Realloc(void *ptr, size_t bytes) {
+    return zrealloc_usable(ptr,bytes,NULL);
+}
+
+/* Use like free() for memory obtained by RedisModule_Alloc() and
+ * RedisModule_Realloc(). However you should never try to free with
+ * RedisModule_Free() memory allocated with malloc() inside your module. */
+void RM_Free(void *ptr) {
+    zfree(ptr);
+}
+
+/* Like strdup() but returns memory allocated with RedisModule_Alloc(). */
+char *RM_Strdup(const char *str) {
+    return zstrdup(str);
+}
+
+/* --------------------------------------------------------------------------
+ * Pool allocator
+ * -------------------------------------------------------------------------- */
+
+/* Release the chain of blocks used for pool allocations. */
+void poolAllocRelease(RedisModuleCtx *ctx) {
+    RedisModulePoolAllocBlock *head = ctx->pa_head, *next;
+
+    while(head != NULL) {
+        next = head->next;
+        zfree(head);
+        head = next;
+    }
+    ctx->pa_head = NULL;
+}
+
+/* Return heap allocated memory that will be freed automatically when the
+ * module callback function returns. Mostly suitable for small allocations
+ * that are short living and must be released when the callback returns
+ * anyway. The returned memory is aligned to the architecture word size
+ * if at least word size bytes are requested, otherwise it is just
+ * aligned to the next power of two, so for example a 3 bytes request is
+ * 4 bytes aligned while a 2 bytes request is 2 bytes aligned.
+ *
+ * There is no realloc style function since when this is needed to use the
+ * pool allocator is not a good idea.
+ *
+ * The function returns NULL if `bytes` is 0. */
+void *RM_PoolAlloc(RedisModuleCtx *ctx, size_t bytes) {
+    if (bytes == 0) return NULL;
+    RedisModulePoolAllocBlock *b = ctx->pa_head;
+    size_t left = b ? b->size - b->used : 0;
+
+    /* Fix alignment. */
+    if (left >= bytes) {
+        size_t alignment = REDISMODULE_POOL_ALLOC_ALIGN;
+        while (bytes < alignment && alignment/2 >= bytes) alignment /= 2;
+        if (b->used % alignment)
+            b->used += alignment - (b->used % alignment);
+        left = (b->used > b->size) ? 0 : b->size - b->used;
+    }
+
+    /* Create a new block if needed. */
+    if (left < bytes) {
+        size_t blocksize = REDISMODULE_POOL_ALLOC_MIN_SIZE;
+        if (blocksize < bytes) blocksize = bytes;
+        b = zmalloc(sizeof(*b) + blocksize);
+        b->size = blocksize;
+        b->used = 0;
+        b->next = ctx->pa_head;
+        ctx->pa_head = b;
+    }
+
+    char *retval = b->memory + b->used;
+    b->used += bytes;
+    return retval;
+}
+
+/* --------------------------------------------------------------------------
+ * Helpers for modules API implementation
+ * -------------------------------------------------------------------------- */
+
+client *moduleAllocTempClient(void) {
+    client *c = NULL;
+
+    if (moduleTempClientCount > 0) {
+        c = moduleTempClients[--moduleTempClientCount];
+        if (moduleTempClientCount < moduleTempClientMinCount)
+            moduleTempClientMinCount = moduleTempClientCount;
+    } else {
+        c = createClient(NULL);
+        c->flags |= CLIENT_MODULE;
+        c->user = NULL; /* Root user */
+    }
+    return c;
+}
+
+static void freeRedisModuleAsyncRMCallPromise(RedisModuleAsyncRMCallPromise *promise) {
+    if (--promise->ref_count > 0) {
+        return;
+    }
+    /* When the promise is finally freed it can not have a client attached to it.
+     * Either releasing the client or RM_CallReplyPromiseAbort would have removed it. */
+    serverAssert(!promise->c);
+    zfree(promise);
+}
+
+void moduleReleaseTempClient(client *c) {
+    if (moduleTempClientCount == moduleTempClientCap) {
+        moduleTempClientCap = moduleTempClientCap ? moduleTempClientCap*2 : 32;
+        moduleTempClients = zrealloc(moduleTempClients, sizeof(c)*moduleTempClientCap);
+    }
+    clearClientConnectionState(c);
+    listEmpty(c->reply);
+    c->reply_bytes = 0;
+    c->duration = 0;
+    resetClient(c);
+    c->bufpos = 0;
+    c->flags = CLIENT_MODULE;
+    c->user = NULL; /* Root user */
+    c->cmd = c->lastcmd = c->realcmd = NULL;
+    if (c->bstate.async_rm_call_handle) {
+        RedisModuleAsyncRMCallPromise *promise = c->bstate.async_rm_call_handle;
+        promise->c = NULL; /* Remove the client from the promise so it will no longer be possible to abort it. */
+        freeRedisModuleAsyncRMCallPromise(promise);
+        c->bstate.async_rm_call_handle = NULL;
+    }
+    moduleTempClients[moduleTempClientCount++] = c;
+}
+
+/* Create an empty key of the specified type. `key` must point to a key object
+ * opened for writing where the `.value` member is set to NULL because the
+ * key was found to be non existing.
+ *
+ * On success REDISMODULE_OK is returned and the key is populated with
+ * the value of the specified type. The function fails and returns
+ * REDISMODULE_ERR if:
+ *
+ * 1. The key is not open for writing.
+ * 2. The key is not empty.
+ * 3. The specified type is unknown.
+ */
+int moduleCreateEmptyKey(RedisModuleKey *key, int type) {
+    robj *obj;
+
+    /* The key must be open for writing and non existing to proceed. */
+    if (!(key->mode & REDISMODULE_WRITE) || key->value)
+        return REDISMODULE_ERR;
+
+    switch(type) {
+    case REDISMODULE_KEYTYPE_LIST:
+        obj = createListListpackObject();
+        break;
+    case REDISMODULE_KEYTYPE_ZSET:
+        obj = createZsetListpackObject();
+        break;
+    case REDISMODULE_KEYTYPE_HASH:
+        obj = createHashObject();
+        break;
+    case REDISMODULE_KEYTYPE_STREAM:
+        obj = createStreamObject();
+        break;
+    default: return REDISMODULE_ERR;
+    }
+    dbAdd(key->db,key->key,obj);
+    key->value = obj;
+    moduleInitKeyTypeSpecific(key);
+    return REDISMODULE_OK;
+}
+
+/* Frees key->iter and sets it to NULL. */
+static void moduleFreeKeyIterator(RedisModuleKey *key) {
+    serverAssert(key->iter != NULL);
+    switch (key->value->type) {
+    case OBJ_LIST: listTypeReleaseIterator(key->iter); break;
+    case OBJ_STREAM:
+        streamIteratorStop(key->iter);
+        zfree(key->iter);
+        break;
+    default: serverAssert(0); /* No key->iter for other types. */
+    }
+    key->iter = NULL;
+}
+
+/* Callback for listTypeTryConversion().
+ * Frees list iterator and sets it to NULL. */
+static void moduleFreeListIterator(void *data) {
+    RedisModuleKey *key = (RedisModuleKey*)data;
+    serverAssert(key->value->type == OBJ_LIST);
+    if (key->iter) moduleFreeKeyIterator(key);
+}
+
+/* This function is called in low-level API implementation functions in order
+ * to check if the value associated with the key remained empty after an
+ * operation that removed elements from an aggregate data type.
+ *
+ * If this happens, the key is deleted from the DB and the key object state
+ * is set to the right one in order to be targeted again by write operations
+ * possibly recreating the key if needed.
+ *
+ * The function returns 1 if the key value object is found empty and is
+ * deleted, otherwise 0 is returned. */
+int moduleDelKeyIfEmpty(RedisModuleKey *key) {
+    if (!(key->mode & REDISMODULE_WRITE) || key->value == NULL) return 0;
+    int isempty;
+    robj *o = key->value;
+
+    switch(o->type) {
+    case OBJ_LIST: isempty = listTypeLength(o) == 0; break;
+    case OBJ_SET: isempty = setTypeSize(o) == 0; break;
+    case OBJ_ZSET: isempty = zsetLength(o) == 0; break;
+    case OBJ_HASH: isempty = hashTypeLength(o) == 0; break;
+    case OBJ_STREAM: isempty = streamLength(o) == 0; break;
+    default: isempty = 0;
+    }
+
+    if (isempty) {
+        if (key->iter) moduleFreeKeyIterator(key);
+        dbDelete(key->db,key->key);
+        key->value = NULL;
+        return 1;
+    } else {
+        return 0;
+    }
+}
+
+/* --------------------------------------------------------------------------
+ * Service API exported to modules
+ *
+ * Note that all the exported APIs are called RM_<funcname> in the core
+ * and RedisModule_<funcname> in the module side (defined as function
+ * pointers in redismodule.h). In this way the dynamic linker does not
+ * mess with our global function pointers, overriding it with the symbols
+ * defined in the main executable having the same names.
+ * -------------------------------------------------------------------------- */
+
+int RM_GetApi(const char *funcname, void **targetPtrPtr) {
+    /* Lookup the requested module API and store the function pointer into the
+     * target pointer. The function returns REDISMODULE_ERR if there is no such
+     * named API, otherwise REDISMODULE_OK.
+     *
+     * This function is not meant to be used by modules developer, it is only
+     * used implicitly by including redismodule.h. */
+    dictEntry *he = dictFind(server.moduleapi, funcname);
+    if (!he) return REDISMODULE_ERR;
+    *targetPtrPtr = dictGetVal(he);
+    return REDISMODULE_OK;
+}
+
+void modulePostExecutionUnitOperations(void) {
+    if (server.execution_nesting)
+        return;
+
+    if (server.busy_module_yield_flags) {
+        blockingOperationEnds();
+        server.busy_module_yield_flags = BUSY_MODULE_YIELD_NONE;
+        if (server.current_client)
+            unprotectClient(server.current_client);
+        unblockPostponedClients();
+    }
+}
+
+/* Free the context after the user function was called. */
+void moduleFreeContext(RedisModuleCtx *ctx) {
+    /* See comment in moduleCreateContext */
+    if (!(ctx->flags & (REDISMODULE_CTX_THREAD_SAFE|REDISMODULE_CTX_COMMAND))) {
+        exitExecutionUnit();
+        postExecutionUnitOperations();
+    }
+    autoMemoryCollect(ctx);
+    poolAllocRelease(ctx);
+    if (ctx->postponed_arrays) {
+        zfree(ctx->postponed_arrays);
+        ctx->postponed_arrays_count = 0;
+        serverLog(LL_WARNING,
+            "API misuse detected in module %s: "
+            "RedisModule_ReplyWith*(REDISMODULE_POSTPONED_LEN) "
+            "not matched by the same number of RedisModule_SetReply*Len() "
+            "calls.",
+            ctx->module->name);
+    }
+    /* If this context has a temp client, we return it back to the pool.
+     * If this context created a new client (e.g detached context), we free it.
+     * If the client is assigned manually, e.g ctx->client = someClientInstance,
+     * none of these flags will be set and we do not attempt to free it. */
+    if (ctx->flags & REDISMODULE_CTX_TEMP_CLIENT)
+        moduleReleaseTempClient(ctx->client);
+    else if (ctx->flags & REDISMODULE_CTX_NEW_CLIENT)
+        freeClient(ctx->client);
+}
+
+static CallReply *moduleParseReply(client *c, RedisModuleCtx *ctx) {
+    /* Convert the result of the Redis command into a module reply. */
+    sds proto = sdsnewlen(c->buf,c->bufpos);
+    c->bufpos = 0;
+    while(listLength(c->reply)) {
+        clientReplyBlock *o = listNodeValue(listFirst(c->reply));
+
+        proto = sdscatlen(proto,o->buf,o->used);
+        listDelNode(c->reply,listFirst(c->reply));
+    }
+    CallReply *reply = callReplyCreate(proto, c->deferred_reply_errors, ctx);
+    c->deferred_reply_errors = NULL; /* now the responsibility of the reply object. */
+    return reply;
+}
+
+void moduleCallCommandUnblockedHandler(client *c) {
+    RedisModuleCtx ctx;
+    RedisModuleAsyncRMCallPromise *promise = c->bstate.async_rm_call_handle;
+    serverAssert(promise);
+    RedisModule *module = promise->module;
+    if (!promise->on_unblocked) {
+        moduleReleaseTempClient(c);
+        return; /* module did not set any unblock callback. */
+    }
+    moduleCreateContext(&ctx, module, REDISMODULE_CTX_TEMP_CLIENT);
+    selectDb(ctx.client, c->db->id);
+
+    CallReply *reply = moduleParseReply(c, NULL);
+    module->in_call++;
+    promise->on_unblocked(&ctx, reply, promise->private_data);
+    module->in_call--;
+
+    moduleFreeContext(&ctx);
+    moduleReleaseTempClient(c);
+}
+
+/* Create a module ctx and keep track of the nesting level.
+ *
+ * Note: When creating ctx for threads (RM_GetThreadSafeContext and
+ * RM_GetDetachedThreadSafeContext) we do not bump up the nesting level
+ * because we only need to track of nesting level in the main thread
+ * (only the main thread uses propagatePendingCommands) */
+void moduleCreateContext(RedisModuleCtx *out_ctx, RedisModule *module, int ctx_flags) {
+    memset(out_ctx, 0 ,sizeof(RedisModuleCtx));
+    out_ctx->getapifuncptr = (void*)(unsigned long)&RM_GetApi;
+    out_ctx->module = module;
+    out_ctx->flags = ctx_flags;
+    if (ctx_flags & REDISMODULE_CTX_TEMP_CLIENT)
+        out_ctx->client = moduleAllocTempClient();
+    else if (ctx_flags & REDISMODULE_CTX_NEW_CLIENT)
+        out_ctx->client = createClient(NULL);
+
+    /* Calculate the initial yield time for long blocked contexts.
+     * in loading we depend on the server hz, but in other cases we also wait
+     * for busy_reply_threshold.
+     * Note that in theory we could have started processing BUSY_MODULE_YIELD_EVENTS
+     * sooner, and only delay the processing for clients till the busy_reply_threshold,
+     * but this carries some overheads of frequently marking clients with BLOCKED_POSTPONE
+     * and releasing them, i.e. if modules only block for short periods. */
+    if (server.loading)
+        out_ctx->next_yield_time = getMonotonicUs() + 1000000 / server.hz;
+    else
+        out_ctx->next_yield_time = getMonotonicUs() + server.busy_reply_threshold * 1000;
+
+    /* Increment the execution_nesting counter (module is about to execute some code),
+     * except in the following cases:
+     * 1. We came here from cmd->proc (either call() or AOF load).
+     *    In the former, the counter has been already incremented from within
+     *    call() and in the latter we don't care about execution_nesting
+     * 2. If we are running in a thread (execution_nesting will be dealt with
+     *    when locking/unlocking the GIL) */
+    if (!(ctx_flags & (REDISMODULE_CTX_THREAD_SAFE|REDISMODULE_CTX_COMMAND))) {
+        enterExecutionUnit(1, 0);
+    }
+}
+
+/* This Redis command binds the normal Redis command invocation with commands
+ * exported by modules. */
+void RedisModuleCommandDispatcher(client *c) {
+    RedisModuleCommand *cp = c->cmd->module_cmd;
+    RedisModuleCtx ctx;
+    moduleCreateContext(&ctx, cp->module, REDISMODULE_CTX_COMMAND);
+
+    ctx.client = c;
+    cp->func(&ctx,(void**)c->argv,c->argc);
+    moduleFreeContext(&ctx);
+
+    /* In some cases processMultibulkBuffer uses sdsMakeRoomFor to
+     * expand the query buffer, and in order to avoid a big object copy
+     * the query buffer SDS may be used directly as the SDS string backing
+     * the client argument vectors: sometimes this will result in the SDS
+     * string having unused space at the end. Later if a module takes ownership
+     * of the RedisString, such space will be wasted forever. Inside the
+     * Redis core this is not a problem because tryObjectEncoding() is called
+     * before storing strings in the key space. Here we need to do it
+     * for the module. */
+    for (int i = 0; i < c->argc; i++) {
+        /* Only do the work if the module took ownership of the object:
+         * in that case the refcount is no longer 1. */
+        if (c->argv[i]->refcount > 1)
+            trimStringObjectIfNeeded(c->argv[i], 0);
+    }
+}
+
+/* This function returns the list of keys, with the same interface as the
+ * 'getkeys' function of the native commands, for module commands that exported
+ * the "getkeys-api" flag during the registration. This is done when the
+ * list of keys are not at fixed positions, so that first/last/step cannot
+ * be used.
+ *
+ * In order to accomplish its work, the module command is called, flagging
+ * the context in a way that the command can recognize this is a special
+ * "get keys" call by calling RedisModule_IsKeysPositionRequest(ctx). */
+int moduleGetCommandKeysViaAPI(struct redisCommand *cmd, robj **argv, int argc, getKeysResult *result) {
+    RedisModuleCommand *cp = cmd->module_cmd;
+    RedisModuleCtx ctx;
+    moduleCreateContext(&ctx, cp->module, REDISMODULE_CTX_KEYS_POS_REQUEST);
+
+    /* Initialize getKeysResult */
+    getKeysPrepareResult(result, MAX_KEYS_BUFFER);
+    ctx.keys_result = result;
+
+    cp->func(&ctx,(void**)argv,argc);
+    /* We currently always use the array allocated by RM_KeyAtPos() and don't try
+     * to optimize for the pre-allocated buffer.
+     */
+    moduleFreeContext(&ctx);
+    return result->numkeys;
+}
+
+/* This function returns the list of channels, with the same interface as
+ * moduleGetCommandKeysViaAPI, for modules that declare "getchannels-api"
+ * during registration. Unlike keys, this is the only way to declare channels. */
+int moduleGetCommandChannelsViaAPI(struct redisCommand *cmd, robj **argv, int argc, getKeysResult *result) {
+    RedisModuleCommand *cp = cmd->module_cmd;
+    RedisModuleCtx ctx;
+    moduleCreateContext(&ctx, cp->module, REDISMODULE_CTX_CHANNELS_POS_REQUEST);
+
+    /* Initialize getKeysResult */
+    getKeysPrepareResult(result, MAX_KEYS_BUFFER);
+    ctx.keys_result = result;
+
+    cp->func(&ctx,(void**)argv,argc);
+    /* We currently always use the array allocated by RM_RM_ChannelAtPosWithFlags() and don't try
+     * to optimize for the pre-allocated buffer. */
+    moduleFreeContext(&ctx);
+    return result->numkeys;
+}
+
+/* --------------------------------------------------------------------------
+ * ## Commands API
+ *
+ * These functions are used to implement custom Redis commands.
+ *
+ * For examples, see https://redis.io/topics/modules-intro.
+ * -------------------------------------------------------------------------- */
+
+/* Return non-zero if a module command, that was declared with the
+ * flag "getkeys-api", is called in a special way to get the keys positions
+ * and not to get executed. Otherwise zero is returned. */
+int RM_IsKeysPositionRequest(RedisModuleCtx *ctx) {
+    return (ctx->flags & REDISMODULE_CTX_KEYS_POS_REQUEST) != 0;
+}
+
+/* When a module command is called in order to obtain the position of
+ * keys, since it was flagged as "getkeys-api" during the registration,
+ * the command implementation checks for this special call using the
+ * RedisModule_IsKeysPositionRequest() API and uses this function in
+ * order to report keys.
+ *
+ * The supported flags are the ones used by RM_SetCommandInfo, see REDISMODULE_CMD_KEY_*.
+ *
+ *
+ * The following is an example of how it could be used:
+ *
+ *     if (RedisModule_IsKeysPositionRequest(ctx)) {
+ *         RedisModule_KeyAtPosWithFlags(ctx, 2, REDISMODULE_CMD_KEY_RO | REDISMODULE_CMD_KEY_ACCESS);
+ *         RedisModule_KeyAtPosWithFlags(ctx, 1, REDISMODULE_CMD_KEY_RW | REDISMODULE_CMD_KEY_UPDATE | REDISMODULE_CMD_KEY_ACCESS);
+ *     }
+ *
+ *  Note: in the example above the get keys API could have been handled by key-specs (preferred).
+ *  Implementing the getkeys-api is required only when is it not possible to declare key-specs that cover all keys.
+ *
+ */
+void RM_KeyAtPosWithFlags(RedisModuleCtx *ctx, int pos, int flags) {
+    if (!(ctx->flags & REDISMODULE_CTX_KEYS_POS_REQUEST) || !ctx->keys_result) return;
+    if (pos <= 0) return;
+
+    getKeysResult *res = ctx->keys_result;
+
+    /* Check overflow */
+    if (res->numkeys == res->size) {
+        int newsize = res->size + (res->size > 8192 ? 8192 : res->size);
+        getKeysPrepareResult(res, newsize);
+    }
+
+    res->keys[res->numkeys].pos = pos;
+    res->keys[res->numkeys].flags = moduleConvertKeySpecsFlags(flags, 1);
+    res->numkeys++;
+}
+
+/* This API existed before RM_KeyAtPosWithFlags was added, now deprecated and
+ * can be used for compatibility with older versions, before key-specs and flags
+ * were introduced. */
+void RM_KeyAtPos(RedisModuleCtx *ctx, int pos) {
+    /* Default flags require full access */
+    int flags = moduleConvertKeySpecsFlags(CMD_KEY_FULL_ACCESS, 0);
+    RM_KeyAtPosWithFlags(ctx, pos, flags);
+}
+
+/* Return non-zero if a module command, that was declared with the
+ * flag "getchannels-api", is called in a special way to get the channel positions
+ * and not to get executed. Otherwise zero is returned. */
+int RM_IsChannelsPositionRequest(RedisModuleCtx *ctx) {
+    return (ctx->flags & REDISMODULE_CTX_CHANNELS_POS_REQUEST) != 0;
+}
+
+/* When a module command is called in order to obtain the position of
+ * channels, since it was flagged as "getchannels-api" during the
+ * registration, the command implementation checks for this special call
+ * using the RedisModule_IsChannelsPositionRequest() API and uses this
+ * function in order to report the channels.
+ * 
+ * The supported flags are:
+ * * REDISMODULE_CMD_CHANNEL_SUBSCRIBE: This command will subscribe to the channel.
+ * * REDISMODULE_CMD_CHANNEL_UNSUBSCRIBE: This command will unsubscribe from this channel.
+ * * REDISMODULE_CMD_CHANNEL_PUBLISH: This command will publish to this channel.
+ * * REDISMODULE_CMD_CHANNEL_PATTERN: Instead of acting on a specific channel, will act on any 
+ *                                    channel specified by the pattern. This is the same access
+ *                                    used by the PSUBSCRIBE and PUNSUBSCRIBE commands available 
+ *                                    in Redis. Not intended to be used with PUBLISH permissions.
+ *
+ * The following is an example of how it could be used:
+ *
+ *     if (RedisModule_IsChannelsPositionRequest(ctx)) {
+ *         RedisModule_ChannelAtPosWithFlags(ctx, 1, REDISMODULE_CMD_CHANNEL_SUBSCRIBE | REDISMODULE_CMD_CHANNEL_PATTERN);
+ *         RedisModule_ChannelAtPosWithFlags(ctx, 1, REDISMODULE_CMD_CHANNEL_PUBLISH);
+ *     }
+ *
+ * Note: One usage of declaring channels is for evaluating ACL permissions. In this context,
+ * unsubscribing is always allowed, so commands will only be checked against subscribe and
+ * publish permissions. This is preferred over using RM_ACLCheckChannelPermissions, since
+ * it allows the ACLs to be checked before the command is executed. */
+void RM_ChannelAtPosWithFlags(RedisModuleCtx *ctx, int pos, int flags) {
+    if (!(ctx->flags & REDISMODULE_CTX_CHANNELS_POS_REQUEST) || !ctx->keys_result) return;
+    if (pos <= 0) return;
+
+    getKeysResult *res = ctx->keys_result;
+
+    /* Check overflow */
+    if (res->numkeys == res->size) {
+        int newsize = res->size + (res->size > 8192 ? 8192 : res->size);
+        getKeysPrepareResult(res, newsize);
+    }
+
+    int new_flags = 0;
+    if (flags & REDISMODULE_CMD_CHANNEL_SUBSCRIBE) new_flags |= CMD_CHANNEL_SUBSCRIBE;
+    if (flags & REDISMODULE_CMD_CHANNEL_UNSUBSCRIBE) new_flags |= CMD_CHANNEL_UNSUBSCRIBE;
+    if (flags & REDISMODULE_CMD_CHANNEL_PUBLISH) new_flags |= CMD_CHANNEL_PUBLISH;
+    if (flags & REDISMODULE_CMD_CHANNEL_PATTERN) new_flags |= CMD_CHANNEL_PATTERN;
+
+    res->keys[res->numkeys].pos = pos;
+    res->keys[res->numkeys].flags = new_flags;
+    res->numkeys++;
+}
+
+/* Returns 1 if name is valid, otherwise returns 0.
+ *
+ * We want to block some chars in module command names that we know can
+ * mess things up.
+ *
+ * There are these characters:
+ * ' ' (space) - issues with old inline protocol.
+ * '\r', '\n' (newline) - can mess up the protocol on acl error replies.
+ * '|' - sub-commands.
+ * '@' - ACL categories.
+ * '=', ',' - info and client list fields (':' handled by getSafeInfoString).
+ * */
+int isCommandNameValid(const char *name) {
+    const char *block_chars = " \r\n|@=,";
+
+    if (strpbrk(name, block_chars))
+        return 0;
+    return 1;
+}
+
+/* Helper for RM_CreateCommand(). Turns a string representing command
+ * flags into the command flags used by the Redis core.
+ *
+ * It returns the set of flags, or -1 if unknown flags are found. */
+int64_t commandFlagsFromString(char *s) {
+    int count, j;
+    int64_t flags = 0;
+    sds *tokens = sdssplitlen(s,strlen(s)," ",1,&count);
+    for (j = 0; j < count; j++) {
+        char *t = tokens[j];
+        if (!strcasecmp(t,"write")) flags |= CMD_WRITE;
+        else if (!strcasecmp(t,"readonly")) flags |= CMD_READONLY;
+        else if (!strcasecmp(t,"admin")) flags |= CMD_ADMIN;
+        else if (!strcasecmp(t,"deny-oom")) flags |= CMD_DENYOOM;
+        else if (!strcasecmp(t,"deny-script")) flags |= CMD_NOSCRIPT;
+        else if (!strcasecmp(t,"allow-loading")) flags |= CMD_LOADING;
+        else if (!strcasecmp(t,"pubsub")) flags |= CMD_PUBSUB;
+        else if (!strcasecmp(t,"random")) { /* Deprecated. Silently ignore. */ }
+        else if (!strcasecmp(t,"blocking")) flags |= CMD_BLOCKING;
+        else if (!strcasecmp(t,"allow-stale")) flags |= CMD_STALE;
+        else if (!strcasecmp(t,"no-monitor")) flags |= CMD_SKIP_MONITOR;
+        else if (!strcasecmp(t,"no-slowlog")) flags |= CMD_SKIP_SLOWLOG;
+        else if (!strcasecmp(t,"fast")) flags |= CMD_FAST;
+        else if (!strcasecmp(t,"no-auth")) flags |= CMD_NO_AUTH;
+        else if (!strcasecmp(t,"may-replicate")) flags |= CMD_MAY_REPLICATE;
+        else if (!strcasecmp(t,"getkeys-api")) flags |= CMD_MODULE_GETKEYS;
+        else if (!strcasecmp(t,"getchannels-api")) flags |= CMD_MODULE_GETCHANNELS;
+        else if (!strcasecmp(t,"no-cluster")) flags |= CMD_MODULE_NO_CLUSTER;
+        else if (!strcasecmp(t,"no-mandatory-keys")) flags |= CMD_NO_MANDATORY_KEYS;
+        else if (!strcasecmp(t,"allow-busy")) flags |= CMD_ALLOW_BUSY;
+        else break;
+    }
+    sdsfreesplitres(tokens,count);
+    if (j != count) return -1; /* Some token not processed correctly. */
+    return flags;
+}
+
+RedisModuleCommand *moduleCreateCommandProxy(struct RedisModule *module, sds declared_name, sds fullname, RedisModuleCmdFunc cmdfunc, int64_t flags, int firstkey, int lastkey, int keystep);
+
+/* Register a new command in the Redis server, that will be handled by
+ * calling the function pointer 'cmdfunc' using the RedisModule calling
+ * convention.
+ *
+ * The function returns REDISMODULE_ERR in these cases:
+ * - If creation of module command is called outside the RedisModule_OnLoad.
+ * - The specified command is already busy.
+ * - The command name contains some chars that are not allowed.
+ * - A set of invalid flags were passed.
+ *
+ * Otherwise REDISMODULE_OK is returned and the new command is registered.
+ *
+ * This function must be called during the initialization of the module
+ * inside the RedisModule_OnLoad() function. Calling this function outside
+ * of the initialization function is not defined.
+ *
+ * The command function type is the following:
+ *
+ *      int MyCommand_RedisCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc);
+ *
+ * And is supposed to always return REDISMODULE_OK.
+ *
+ * The set of flags 'strflags' specify the behavior of the command, and should
+ * be passed as a C string composed of space separated words, like for
+ * example "write deny-oom". The set of flags are:
+ *
+ * * **"write"**:     The command may modify the data set (it may also read
+ *                    from it).
+ * * **"readonly"**:  The command returns data from keys but never writes.
+ * * **"admin"**:     The command is an administrative command (may change
+ *                    replication or perform similar tasks).
+ * * **"deny-oom"**:  The command may use additional memory and should be
+ *                    denied during out of memory conditions.
+ * * **"deny-script"**:   Don't allow this command in Lua scripts.
+ * * **"allow-loading"**: Allow this command while the server is loading data.
+ *                        Only commands not interacting with the data set
+ *                        should be allowed to run in this mode. If not sure
+ *                        don't use this flag.
+ * * **"pubsub"**:    The command publishes things on Pub/Sub channels.
+ * * **"random"**:    The command may have different outputs even starting
+ *                    from the same input arguments and key values.
+ *                    Starting from Redis 7.0 this flag has been deprecated.
+ *                    Declaring a command as "random" can be done using
+ *                    command tips, see https://redis.io/topics/command-tips.
+ * * **"allow-stale"**: The command is allowed to run on slaves that don't
+ *                      serve stale data. Don't use if you don't know what
+ *                      this means.
+ * * **"no-monitor"**: Don't propagate the command on monitor. Use this if
+ *                     the command has sensitive data among the arguments.
+ * * **"no-slowlog"**: Don't log this command in the slowlog. Use this if
+ *                     the command has sensitive data among the arguments.
+ * * **"fast"**:      The command time complexity is not greater
+ *                    than O(log(N)) where N is the size of the collection or
+ *                    anything else representing the normal scalability
+ *                    issue with the command.
+ * * **"getkeys-api"**: The command implements the interface to return
+ *                      the arguments that are keys. Used when start/stop/step
+ *                      is not enough because of the command syntax.
+ * * **"no-cluster"**: The command should not register in Redis Cluster
+ *                     since is not designed to work with it because, for
+ *                     example, is unable to report the position of the
+ *                     keys, programmatically creates key names, or any
+ *                     other reason.
+ * * **"no-auth"**:    This command can be run by an un-authenticated client.
+ *                     Normally this is used by a command that is used
+ *                     to authenticate a client.
+ * * **"may-replicate"**: This command may generate replication traffic, even
+ *                        though it's not a write command.
+ * * **"no-mandatory-keys"**: All the keys this command may take are optional
+ * * **"blocking"**: The command has the potential to block the client.
+ * * **"allow-busy"**: Permit the command while the server is blocked either by
+ *                     a script or by a slow module command, see
+ *                     RM_Yield.
+ * * **"getchannels-api"**: The command implements the interface to return
+ *                          the arguments that are channels.
+ *
+ * The last three parameters specify which arguments of the new command are
+ * Redis keys. See https://redis.io/commands/command for more information.
+ *
+ * * `firstkey`: One-based index of the first argument that's a key.
+ *               Position 0 is always the command name itself.
+ *               0 for commands with no keys.
+ * * `lastkey`:  One-based index of the last argument that's a key.
+ *               Negative numbers refer to counting backwards from the last
+ *               argument (-1 means the last argument provided)
+ *               0 for commands with no keys.
+ * * `keystep`:  Step between first and last key indexes.
+ *               0 for commands with no keys.
+ *
+ * This information is used by ACL, Cluster and the `COMMAND` command.
+ *
+ * NOTE: The scheme described above serves a limited purpose and can
+ * only be used to find keys that exist at constant indices.
+ * For non-trivial key arguments, you may pass 0,0,0 and use
+ * RedisModule_SetCommandInfo to set key specs using a more advanced scheme and use
+ * RedisModule_SetCommandACLCategories to set Redis ACL categories of the commands. */
+int RM_CreateCommand(RedisModuleCtx *ctx, const char *name, RedisModuleCmdFunc cmdfunc, const char *strflags, int firstkey, int lastkey, int keystep) {
+    if (!ctx->module->onload)
+        return REDISMODULE_ERR;
+    int64_t flags = strflags ? commandFlagsFromString((char*)strflags) : 0;
+    if (flags == -1) return REDISMODULE_ERR;
+    if ((flags & CMD_MODULE_NO_CLUSTER) && server.cluster_enabled)
+        return REDISMODULE_ERR;
+
+    /* Check if the command name is valid. */
+    if (!isCommandNameValid(name))
+        return REDISMODULE_ERR;
+
+    /* Check if the command name is busy. */
+    if (lookupCommandByCString(name) != NULL)
+        return REDISMODULE_ERR;
+
+    sds declared_name = sdsnew(name);
+    RedisModuleCommand *cp = moduleCreateCommandProxy(ctx->module, declared_name, sdsdup(declared_name), cmdfunc, flags, firstkey, lastkey, keystep);
+    cp->rediscmd->arity = cmdfunc ? -1 : -2; /* Default value, can be changed later via dedicated API */
+
+    serverAssert(dictAdd(server.commands, sdsdup(declared_name), cp->rediscmd) == DICT_OK);
+    serverAssert(dictAdd(server.orig_commands, sdsdup(declared_name), cp->rediscmd) == DICT_OK);
+    cp->rediscmd->id = ACLGetCommandID(declared_name); /* ID used for ACL. */
+    return REDISMODULE_OK;
+}
+
+/* A proxy that help create a module command / subcommand.
+ *
+ * 'declared_name': it contains the sub_name, which is just the fullname for non-subcommands.
+ * 'fullname': sds string representing the command fullname.
+ *
+ * Function will take the ownership of both 'declared_name' and 'fullname' SDS.
+ */
+RedisModuleCommand *moduleCreateCommandProxy(struct RedisModule *module, sds declared_name, sds fullname, RedisModuleCmdFunc cmdfunc, int64_t flags, int firstkey, int lastkey, int keystep) {
+    struct redisCommand *rediscmd;
+    RedisModuleCommand *cp;
+
+    /* Create a command "proxy", which is a structure that is referenced
+     * in the command table, so that the generic command that works as
+     * binding between modules and Redis, can know what function to call
+     * and what the module is. */
+    cp = zcalloc(sizeof(*cp));
+    cp->module = module;
+    cp->func = cmdfunc;
+    cp->rediscmd = zcalloc(sizeof(*rediscmd));
+    cp->rediscmd->declared_name = declared_name; /* SDS for module commands */
+    cp->rediscmd->fullname = fullname;
+    cp->rediscmd->group = COMMAND_GROUP_MODULE;
+    cp->rediscmd->proc = RedisModuleCommandDispatcher;
+    cp->rediscmd->flags = flags | CMD_MODULE;
+    cp->rediscmd->module_cmd = cp;
+    if (firstkey != 0) {
+        cp->rediscmd->key_specs_num = 1;
+        cp->rediscmd->key_specs = zcalloc(sizeof(keySpec));
+        cp->rediscmd->key_specs[0].flags = CMD_KEY_FULL_ACCESS;
+        if (flags & CMD_MODULE_GETKEYS)
+            cp->rediscmd->key_specs[0].flags |= CMD_KEY_VARIABLE_FLAGS;
+        cp->rediscmd->key_specs[0].begin_search_type = KSPEC_BS_INDEX;
+        cp->rediscmd->key_specs[0].bs.index.pos = firstkey;
+        cp->rediscmd->key_specs[0].find_keys_type = KSPEC_FK_RANGE;
+        cp->rediscmd->key_specs[0].fk.range.lastkey = lastkey < 0 ? lastkey : (lastkey-firstkey);
+        cp->rediscmd->key_specs[0].fk.range.keystep = keystep;
+        cp->rediscmd->key_specs[0].fk.range.limit = 0;
+    } else {
+        cp->rediscmd->key_specs_num = 0;
+        cp->rediscmd->key_specs = NULL;
+    }
+    populateCommandLegacyRangeSpec(cp->rediscmd);
+    cp->rediscmd->microseconds = 0;
+    cp->rediscmd->calls = 0;
+    cp->rediscmd->rejected_calls = 0;
+    cp->rediscmd->failed_calls = 0;
+    return cp;
+}
+
+/* Get an opaque structure, representing a module command, by command name.
+ * This structure is used in some of the command-related APIs.
+ *
+ * NULL is returned in case of the following errors:
+ *
+ * * Command not found
+ * * The command is not a module command
+ * * The command doesn't belong to the calling module
+ */
+RedisModuleCommand *RM_GetCommand(RedisModuleCtx *ctx, const char *name) {
+    struct redisCommand *cmd = lookupCommandByCString(name);
+
+    if (!cmd || !(cmd->flags & CMD_MODULE))
+        return NULL;
+
+    RedisModuleCommand *cp = cmd->module_cmd;
+    if (cp->module != ctx->module)
+        return NULL;
+
+    return cp;
+}
+
+/* Very similar to RedisModule_CreateCommand except that it is used to create
+ * a subcommand, associated with another, container, command.
+ *
+ * Example: If a module has a configuration command, MODULE.CONFIG, then
+ * GET and SET should be individual subcommands, while MODULE.CONFIG is
+ * a command, but should not be registered with a valid `funcptr`:
+ *
+ *      if (RedisModule_CreateCommand(ctx,"module.config",NULL,"",0,0,0) == REDISMODULE_ERR)
+ *          return REDISMODULE_ERR;
+ *
+ *      RedisModuleCommand *parent = RedisModule_GetCommand(ctx,,"module.config");
+ *
+ *      if (RedisModule_CreateSubcommand(parent,"set",cmd_config_set,"",0,0,0) == REDISMODULE_ERR)
+ *         return REDISMODULE_ERR;
+ *
+ *      if (RedisModule_CreateSubcommand(parent,"get",cmd_config_get,"",0,0,0) == REDISMODULE_ERR)
+ *         return REDISMODULE_ERR;
+ *
+ * Returns REDISMODULE_OK on success and REDISMODULE_ERR in case of the following errors:
+ *
+ * * Error while parsing `strflags`
+ * * Command is marked as `no-cluster` but cluster mode is enabled
+ * * `parent` is already a subcommand (we do not allow more than one level of command nesting)
+ * * `parent` is a command with an implementation (RedisModuleCmdFunc) (A parent command should be a pure container of subcommands)
+ * * `parent` already has a subcommand called `name`
+ * * Creating a subcommand is called outside of RedisModule_OnLoad.
+ */
+int RM_CreateSubcommand(RedisModuleCommand *parent, const char *name, RedisModuleCmdFunc cmdfunc, const char *strflags, int firstkey, int lastkey, int keystep) {
+    if (!parent->module->onload)
+        return REDISMODULE_ERR;
+    int64_t flags = strflags ? commandFlagsFromString((char*)strflags) : 0;
+    if (flags == -1) return REDISMODULE_ERR;
+    if ((flags & CMD_MODULE_NO_CLUSTER) && server.cluster_enabled)
+        return REDISMODULE_ERR;
+
+    struct redisCommand *parent_cmd = parent->rediscmd;
+
+    if (parent_cmd->parent)
+        return REDISMODULE_ERR; /* We don't allow more than one level of subcommands */
+
+    RedisModuleCommand *parent_cp = parent_cmd->module_cmd;
+    if (parent_cp->func)
+        return REDISMODULE_ERR; /* A parent command should be a pure container of subcommands */
+
+    /* Check if the command name is valid. */
+    if (!isCommandNameValid(name))
+        return REDISMODULE_ERR;
+
+    /* Check if the command name is busy within the parent command. */
+    sds declared_name = sdsnew(name);
+    if (parent_cmd->subcommands_dict && lookupSubcommand(parent_cmd, declared_name) != NULL) {
+        sdsfree(declared_name);
+        return REDISMODULE_ERR;
+    }
+
+    sds fullname = catSubCommandFullname(parent_cmd->fullname, name);
+    RedisModuleCommand *cp = moduleCreateCommandProxy(parent->module, declared_name, fullname, cmdfunc, flags, firstkey, lastkey, keystep);
+    cp->rediscmd->arity = -2;
+
+    commandAddSubcommand(parent_cmd, cp->rediscmd, name);
+    return REDISMODULE_OK;
+}
+
+/* Accessors of array elements of structs where the element size is stored
+ * separately in the version struct. */
+static RedisModuleCommandHistoryEntry *
+moduleCmdHistoryEntryAt(const RedisModuleCommandInfoVersion *version,
+                        RedisModuleCommandHistoryEntry *entries, int index) {
+    off_t offset = index * version->sizeof_historyentry;
+    return (RedisModuleCommandHistoryEntry *)((char *)(entries) + offset);
+}
+static RedisModuleCommandKeySpec *
+moduleCmdKeySpecAt(const RedisModuleCommandInfoVersion *version,
+                   RedisModuleCommandKeySpec *keyspecs, int index) {
+    off_t offset = index * version->sizeof_keyspec;
+    return (RedisModuleCommandKeySpec *)((char *)(keyspecs) + offset);
+}
+static RedisModuleCommandArg *
+moduleCmdArgAt(const RedisModuleCommandInfoVersion *version,
+               const RedisModuleCommandArg *args, int index) {
+    off_t offset = index * version->sizeof_arg;
+    return (RedisModuleCommandArg *)((char *)(args) + offset);
+}
+
+/* Recursively populate the args structure (setting num_args to the number of
+ * subargs) and return the number of args. */
+int populateArgsStructure(struct redisCommandArg *args) {
+    if (!args)
+        return 0;
+    int count = 0;
+    while (args->name) {
+        serverAssert(count < INT_MAX);
+        args->num_args = populateArgsStructure(args->subargs);
+        count++;
+        args++;
+    }
+    return count;
+}
+
+/* Helper for categoryFlagsFromString(). Attempts to find an acl flag representing the provided flag string
+ * and adds that flag to acl_categories_flags if a match is found.
+ *
+ * Returns '1' if acl category flag is recognized or
+ * returns '0' if not recognized  */
+int matchAclCategoryFlag(char *flag, int64_t *acl_categories_flags) {
+    uint64_t this_flag = ACLGetCommandCategoryFlagByName(flag);
+    if (this_flag) {
+        *acl_categories_flags |= (int64_t) this_flag;
+        return 1;
+    }
+    return 0; /* Unrecognized */
+}
+
+/* Helper for RM_SetCommandACLCategories(). Turns a string representing acl category
+ * flags into the acl category flags used by Redis ACL which allows users to access 
+ * the module commands by acl categories.
+ * 
+ * It returns the set of acl flags, or -1 if unknown flags are found. */
+int64_t categoryFlagsFromString(char *aclflags) {
+    int count, j;
+    int64_t acl_categories_flags = 0;
+    sds *tokens = sdssplitlen(aclflags,strlen(aclflags)," ",1,&count);
+    for (j = 0; j < count; j++) {
+        char *t = tokens[j];
+        if (!matchAclCategoryFlag(t, &acl_categories_flags)) {
+            serverLog(LL_WARNING,"Unrecognized categories flag %s on module load", t);
+            break;
+        }
+    }
+    sdsfreesplitres(tokens,count);
+    if (j != count) return -1; /* Some token not processed correctly. */
+    return acl_categories_flags;
+}
+
+/* RedisModule_SetCommandACLCategories can be used to set ACL categories to module
+ * commands and subcommands. The set of ACL categories should be passed as
+ * a space separated C string 'aclflags'.
+ * 
+ * Example, the acl flags 'write slow' marks the command as part of the write and 
+ * slow ACL categories.
+ * 
+ * On success REDISMODULE_OK is returned. On error REDISMODULE_ERR is returned.
+ * 
+ * This function can only be called during the RedisModule_OnLoad function. If called
+ * outside of this function, an error is returned.
+ */
+int RM_SetCommandACLCategories(RedisModuleCommand *command, const char *aclflags) {
+    if (!command || !command->module || !command->module->onload) return REDISMODULE_ERR;
+    int64_t categories_flags = aclflags ? categoryFlagsFromString((char*)aclflags) : 0;
+    if (categories_flags == -1) return REDISMODULE_ERR;
+    struct redisCommand *rcmd = command->rediscmd;
+    rcmd->acl_categories = categories_flags; /* ACL categories flags for module command */
+    command->module->num_commands_with_acl_categories++;
+    return REDISMODULE_OK;
+}
+
+/* Set additional command information.
+ *
+ * Affects the output of `COMMAND`, `COMMAND INFO` and `COMMAND DOCS`, Cluster,
+ * ACL and is used to filter commands with the wrong number of arguments before
+ * the call reaches the module code.
+ *
+ * This function can be called after creating a command using RM_CreateCommand
+ * and fetching the command pointer using RM_GetCommand. The information can
+ * only be set once for each command and has the following structure:
+ *
+ *     typedef struct RedisModuleCommandInfo {
+ *         const RedisModuleCommandInfoVersion *version;
+ *         const char *summary;
+ *         const char *complexity;
+ *         const char *since;
+ *         RedisModuleCommandHistoryEntry *history;
+ *         const char *tips;
+ *         int arity;
+ *         RedisModuleCommandKeySpec *key_specs;
+ *         RedisModuleCommandArg *args;
+ *     } RedisModuleCommandInfo;
+ *
+ * All fields except `version` are optional. Explanation of the fields:
+ *
+ * - `version`: This field enables compatibility with different Redis versions.
+ *   Always set this field to REDISMODULE_COMMAND_INFO_VERSION.
+ *
+ * - `summary`: A short description of the command (optional).
+ *
+ * - `complexity`: Complexity description (optional).
+ *
+ * - `since`: The version where the command was introduced (optional).
+ *   Note: The version specified should be the module's, not Redis version.
+ *
+ * - `history`: An array of RedisModuleCommandHistoryEntry (optional), which is
+ *   a struct with the following fields:
+ *
+ *         const char *since;
+ *         const char *changes;
+ *
+ *     `since` is a version string and `changes` is a string describing the
+ *     changes. The array is terminated by a zeroed entry, i.e. an entry with
+ *     both strings set to NULL.
+ *
+ * - `tips`: A string of space-separated tips regarding this command, meant for
+ *   clients and proxies. See https://redis.io/topics/command-tips.
+ *
+ * - `arity`: Number of arguments, including the command name itself. A positive
+ *   number specifies an exact number of arguments and a negative number
+ *   specifies a minimum number of arguments, so use -N to say >= N. Redis
+ *   validates a call before passing it to a module, so this can replace an
+ *   arity check inside the module command implementation. A value of 0 (or an
+ *   omitted arity field) is equivalent to -2 if the command has sub commands
+ *   and -1 otherwise.
+ *
+ * - `key_specs`: An array of RedisModuleCommandKeySpec, terminated by an
+ *   element memset to zero. This is a scheme that tries to describe the
+ *   positions of key arguments better than the old RM_CreateCommand arguments
+ *   `firstkey`, `lastkey`, `keystep` and is needed if those three are not
+ *   enough to describe the key positions. There are two steps to retrieve key
+ *   positions: *begin search* (BS) in which index should find the first key and
+ *   *find keys* (FK) which, relative to the output of BS, describes how can we
+ *   will which arguments are keys. Additionally, there are key specific flags.
+ *
+ *     Key-specs cause the triplet (firstkey, lastkey, keystep) given in
+ *     RM_CreateCommand to be recomputed, but it is still useful to provide
+ *     these three parameters in RM_CreateCommand, to better support old Redis
+ *     versions where RM_SetCommandInfo is not available.
+ *
+ *     Note that key-specs don't fully replace the "getkeys-api" (see
+ *     RM_CreateCommand, RM_IsKeysPositionRequest and RM_KeyAtPosWithFlags) so
+ *     it may be a good idea to supply both key-specs and implement the
+ *     getkeys-api.
+ *
+ *     A key-spec has the following structure:
+ *
+ *         typedef struct RedisModuleCommandKeySpec {
+ *             const char *notes;
+ *             uint64_t flags;
+ *             RedisModuleKeySpecBeginSearchType begin_search_type;
+ *             union {
+ *                 struct {
+ *                     int pos;
+ *                 } index;
+ *                 struct {
+ *                     const char *keyword;
+ *                     int startfrom;
+ *                 } keyword;
+ *             } bs;
+ *             RedisModuleKeySpecFindKeysType find_keys_type;
+ *             union {
+ *                 struct {
+ *                     int lastkey;
+ *                     int keystep;
+ *                     int limit;
+ *                 } range;
+ *                 struct {
+ *                     int keynumidx;
+ *                     int firstkey;
+ *                     int keystep;
+ *                 } keynum;
+ *             } fk;
+ *         } RedisModuleCommandKeySpec;
+ *
+ *     Explanation of the fields of RedisModuleCommandKeySpec:
+ *
+ *     * `notes`: Optional notes or clarifications about this key spec.
+ *
+ *     * `flags`: A bitwise or of key-spec flags described below.
+ *
+ *     * `begin_search_type`: This describes how the first key is discovered.
+ *       There are two ways to determine the first key:
+ *
+ *         * `REDISMODULE_KSPEC_BS_UNKNOWN`: There is no way to tell where the
+ *           key args start.
+ *         * `REDISMODULE_KSPEC_BS_INDEX`: Key args start at a constant index.
+ *         * `REDISMODULE_KSPEC_BS_KEYWORD`: Key args start just after a
+ *           specific keyword.
+ *
+ *     * `bs`: This is a union in which the `index` or `keyword` branch is used
+ *       depending on the value of the `begin_search_type` field.
+ *
+ *         * `bs.index.pos`: The index from which we start the search for keys.
+ *           (`REDISMODULE_KSPEC_BS_INDEX` only.)
+ *
+ *         * `bs.keyword.keyword`: The keyword (string) that indicates the
+ *           beginning of key arguments. (`REDISMODULE_KSPEC_BS_KEYWORD` only.)
+ *
+ *         * `bs.keyword.startfrom`: An index in argv from which to start
+ *           searching. Can be negative, which means start search from the end,
+ *           in reverse. Example: -2 means to start in reverse from the
+ *           penultimate argument. (`REDISMODULE_KSPEC_BS_KEYWORD` only.)
+ *
+ *     * `find_keys_type`: After the "begin search", this describes which
+ *       arguments are keys. The strategies are:
+ *
+ *         * `REDISMODULE_KSPEC_BS_UNKNOWN`: There is no way to tell where the
+ *           key args are located.
+ *         * `REDISMODULE_KSPEC_FK_RANGE`: Keys end at a specific index (or
+ *           relative to the last argument).
+ *         * `REDISMODULE_KSPEC_FK_KEYNUM`: There's an argument that contains
+ *           the number of key args somewhere before the keys themselves.
+ *
+ *       `find_keys_type` and `fk` can be omitted if this keyspec describes
+ *       exactly one key.
+ *
+ *     * `fk`: This is a union in which the `range` or `keynum` branch is used
+ *       depending on the value of the `find_keys_type` field.
+ *
+ *         * `fk.range` (for `REDISMODULE_KSPEC_FK_RANGE`): A struct with the
+ *           following fields:
+ *
+ *             * `lastkey`: Index of the last key relative to the result of the
+ *               begin search step. Can be negative, in which case it's not
+ *               relative. -1 indicates the last argument, -2 one before the
+ *               last and so on.
+ *
+ *             * `keystep`: How many arguments should we skip after finding a
+ *               key, in order to find the next one?
+ *
+ *             * `limit`: If `lastkey` is -1, we use `limit` to stop the search
+ *               by a factor. 0 and 1 mean no limit. 2 means 1/2 of the
+ *               remaining args, 3 means 1/3, and so on.
+ *
+ *         * `fk.keynum` (for `REDISMODULE_KSPEC_FK_KEYNUM`): A struct with the
+ *           following fields:
+ *
+ *             * `keynumidx`: Index of the argument containing the number of
+ *               keys to come, relative to the result of the begin search step.
+ *
+ *             * `firstkey`: Index of the fist key relative to the result of the
+ *               begin search step. (Usually it's just after `keynumidx`, in
+ *               which case it should be set to `keynumidx + 1`.)
+ *
+ *             * `keystep`: How many arguments should we skip after finding a
+ *               key, in order to find the next one?
+ *
+ *     Key-spec flags:
+ *
+ *     The first four refer to what the command actually does with the *value or
+ *     metadata of the key*, and not necessarily the user data or how it affects
+ *     it. Each key-spec may must have exactly one of these. Any operation
+ *     that's not distinctly deletion, overwrite or read-only would be marked as
+ *     RW.
+ *
+ *     * `REDISMODULE_CMD_KEY_RO`: Read-Only. Reads the value of the key, but
+ *       doesn't necessarily return it.
+ *
+ *     * `REDISMODULE_CMD_KEY_RW`: Read-Write. Modifies the data stored in the
+ *       value of the key or its metadata.
+ *
+ *     * `REDISMODULE_CMD_KEY_OW`: Overwrite. Overwrites the data stored in the
+ *       value of the key.
+ *
+ *     * `REDISMODULE_CMD_KEY_RM`: Deletes the key.
+ *
+ *     The next four refer to *user data inside the value of the key*, not the
+ *     metadata like LRU, type, cardinality. It refers to the logical operation
+ *     on the user's data (actual input strings or TTL), being
+ *     used/returned/copied/changed. It doesn't refer to modification or
+ *     returning of metadata (like type, count, presence of data). ACCESS can be
+ *     combined with one of the write operations INSERT, DELETE or UPDATE. Any
+ *     write that's not an INSERT or a DELETE would be UPDATE.
+ *
+ *     * `REDISMODULE_CMD_KEY_ACCESS`: Returns, copies or uses the user data
+ *       from the value of the key.
+ *
+ *     * `REDISMODULE_CMD_KEY_UPDATE`: Updates data to the value, new value may
+ *       depend on the old value.
+ *
+ *     * `REDISMODULE_CMD_KEY_INSERT`: Adds data to the value with no chance of
+ *       modification or deletion of existing data.
+ *
+ *     * `REDISMODULE_CMD_KEY_DELETE`: Explicitly deletes some content from the
+ *       value of the key.
+ *
+ *     Other flags:
+ *
+ *     * `REDISMODULE_CMD_KEY_NOT_KEY`: The key is not actually a key, but 
+ *       should be routed in cluster mode as if it was a key.
+ *
+ *     * `REDISMODULE_CMD_KEY_INCOMPLETE`: The keyspec might not point out all
+ *       the keys it should cover.
+ *
+ *     * `REDISMODULE_CMD_KEY_VARIABLE_FLAGS`: Some keys might have different
+ *       flags depending on arguments.
+ *
+ * - `args`: An array of RedisModuleCommandArg, terminated by an element memset
+ *   to zero. RedisModuleCommandArg is a structure with at the fields described
+ *   below.
+ *
+ *         typedef struct RedisModuleCommandArg {
+ *             const char *name;
+ *             RedisModuleCommandArgType type;
+ *             int key_spec_index;
+ *             const char *token;
+ *             const char *summary;
+ *             const char *since;
+ *             int flags;
+ *             struct RedisModuleCommandArg *subargs;
+ *         } RedisModuleCommandArg;
+ *
+ *     Explanation of the fields:
+ *
+ *     * `name`: Name of the argument.
+ *
+ *     * `type`: The type of the argument. See below for details. The types
+ *       `REDISMODULE_ARG_TYPE_ONEOF` and `REDISMODULE_ARG_TYPE_BLOCK` require
+ *       an argument to have sub-arguments, i.e. `subargs`.
+ *
+ *     * `key_spec_index`: If the `type` is `REDISMODULE_ARG_TYPE_KEY` you must
+ *       provide the index of the key-spec associated with this argument. See
+ *       `key_specs` above. If the argument is not a key, you may specify -1.
+ *
+ *     * `token`: The token preceding the argument (optional). Example: the
+ *       argument `seconds` in `SET` has a token `EX`. If the argument consists
+ *       of only a token (for example `NX` in `SET`) the type should be
+ *       `REDISMODULE_ARG_TYPE_PURE_TOKEN` and `value` should be NULL.
+ *
+ *     * `summary`: A short description of the argument (optional).
+ *
+ *     * `since`: The first version which included this argument (optional).
+ *
+ *     * `flags`: A bitwise or of the macros `REDISMODULE_CMD_ARG_*`. See below.
+ *
+ *     * `value`: The display-value of the argument. This string is what should
+ *       be displayed when creating the command syntax from the output of
+ *       `COMMAND`. If `token` is not NULL, it should also be displayed.
+ *
+ *     Explanation of `RedisModuleCommandArgType`:
+ *
+ *     * `REDISMODULE_ARG_TYPE_STRING`: String argument.
+ *     * `REDISMODULE_ARG_TYPE_INTEGER`: Integer argument.
+ *     * `REDISMODULE_ARG_TYPE_DOUBLE`: Double-precision float argument.
+ *     * `REDISMODULE_ARG_TYPE_KEY`: String argument representing a keyname.
+ *     * `REDISMODULE_ARG_TYPE_PATTERN`: String, but regex pattern.
+ *     * `REDISMODULE_ARG_TYPE_UNIX_TIME`: Integer, but Unix timestamp.
+ *     * `REDISMODULE_ARG_TYPE_PURE_TOKEN`: Argument doesn't have a placeholder.
+ *       It's just a token without a value. Example: the `KEEPTTL` option of the
+ *       `SET` command.
+ *     * `REDISMODULE_ARG_TYPE_ONEOF`: Used when the user can choose only one of
+ *       a few sub-arguments. Requires `subargs`. Example: the `NX` and `XX`
+ *       options of `SET`.
+ *     * `REDISMODULE_ARG_TYPE_BLOCK`: Used when one wants to group together
+ *       several sub-arguments, usually to apply something on all of them, like
+ *       making the entire group "optional". Requires `subargs`. Example: the
+ *       `LIMIT offset count` parameters in `ZRANGE`.
+ *
+ *     Explanation of the command argument flags:
+ *
+ *     * `REDISMODULE_CMD_ARG_OPTIONAL`: The argument is optional (like GET in
+ *       the SET command).
+ *     * `REDISMODULE_CMD_ARG_MULTIPLE`: The argument may repeat itself (like
+ *       key in DEL).
+ *     * `REDISMODULE_CMD_ARG_MULTIPLE_TOKEN`: The argument may repeat itself,
+ *       and so does its token (like `GET pattern` in SORT).
+ *
+ * On success REDISMODULE_OK is returned. On error REDISMODULE_ERR is returned
+ * and `errno` is set to EINVAL if invalid info was provided or EEXIST if info
+ * has already been set. If the info is invalid, a warning is logged explaining
+ * which part of the info is invalid and why. */
+int RM_SetCommandInfo(RedisModuleCommand *command, const RedisModuleCommandInfo *info) {
+    if (!moduleValidateCommandInfo(info)) {
+        errno = EINVAL;
+        return REDISMODULE_ERR;
+    }
+
+    struct redisCommand *cmd = command->rediscmd;
+
+    /* Check if any info has already been set. Overwriting info involves freeing
+     * the old info, which is not implemented. */
+    if (cmd->summary || cmd->complexity || cmd->since || cmd->history ||
+        cmd->tips || cmd->args ||
+        !(cmd->key_specs_num == 0 ||
+          /* Allow key spec populated from legacy (first,last,step) to exist. */
+          (cmd->key_specs_num == 1 &&
+           cmd->key_specs[0].begin_search_type == KSPEC_BS_INDEX &&
+           cmd->key_specs[0].find_keys_type == KSPEC_FK_RANGE))) {
+        errno = EEXIST;
+        return REDISMODULE_ERR;
+    }
+
+    if (info->summary) cmd->summary = zstrdup(info->summary);
+    if (info->complexity) cmd->complexity = zstrdup(info->complexity);
+    if (info->since) cmd->since = zstrdup(info->since);
+
+    const RedisModuleCommandInfoVersion *version = info->version;
+    if (info->history) {
+        size_t count = 0;
+        while (moduleCmdHistoryEntryAt(version, info->history, count)->since)
+            count++;
+        serverAssert(count < SIZE_MAX / sizeof(commandHistory));
+        cmd->history = zmalloc(sizeof(commandHistory) * (count + 1));
+        for (size_t j = 0; j < count; j++) {
+            RedisModuleCommandHistoryEntry *entry =
+                moduleCmdHistoryEntryAt(version, info->history, j);
+            cmd->history[j].since = zstrdup(entry->since);
+            cmd->history[j].changes = zstrdup(entry->changes);
+        }
+        cmd->history[count].since = NULL;
+        cmd->history[count].changes = NULL;
+        cmd->num_history = count;
+    }
+
+    if (info->tips) {
+        int count;
+        sds *tokens = sdssplitlen(info->tips, strlen(info->tips), " ", 1, &count);
+        if (tokens) {
+            cmd->tips = zmalloc(sizeof(char *) * (count + 1));
+            for (int j = 0; j < count; j++) {
+                cmd->tips[j] = zstrdup(tokens[j]);
+            }
+            cmd->tips[count] = NULL;
+            cmd->num_tips = count;
+            sdsfreesplitres(tokens, count);
+        }
+    }
+
+    if (info->arity) cmd->arity = info->arity;
+
+    if (info->key_specs) {
+        /* Count and allocate the key specs. */
+        size_t count = 0;
+        while (moduleCmdKeySpecAt(version, info->key_specs, count)->begin_search_type)
+            count++;
+        serverAssert(count < INT_MAX);
+        zfree(cmd->key_specs);
+        cmd->key_specs = zmalloc(sizeof(keySpec) * count);
+
+        /* Copy the contents of the RedisModuleCommandKeySpec array. */
+        cmd->key_specs_num = count;
+        for (size_t j = 0; j < count; j++) {
+            RedisModuleCommandKeySpec *spec =
+                moduleCmdKeySpecAt(version, info->key_specs, j);
+            cmd->key_specs[j].notes = spec->notes ? zstrdup(spec->notes) : NULL;
+            cmd->key_specs[j].flags = moduleConvertKeySpecsFlags(spec->flags, 1);
+            switch (spec->begin_search_type) {
+            case REDISMODULE_KSPEC_BS_UNKNOWN:
+                cmd->key_specs[j].begin_search_type = KSPEC_BS_UNKNOWN;
+                break;
+            case REDISMODULE_KSPEC_BS_INDEX:
+                cmd->key_specs[j].begin_search_type = KSPEC_BS_INDEX;
+                cmd->key_specs[j].bs.index.pos = spec->bs.index.pos;
+                break;
+            case REDISMODULE_KSPEC_BS_KEYWORD:
+                cmd->key_specs[j].begin_search_type = KSPEC_BS_KEYWORD;
+                cmd->key_specs[j].bs.keyword.keyword = zstrdup(spec->bs.keyword.keyword);
+                cmd->key_specs[j].bs.keyword.startfrom = spec->bs.keyword.startfrom;
+                break;
+            default:
+                /* Can't happen; stopped in moduleValidateCommandInfo(). */
+                serverPanic("Unknown begin_search_type");
+            }
+
+            switch (spec->find_keys_type) {
+            case REDISMODULE_KSPEC_FK_OMITTED:
+                /* Omitted field is shorthand to say that it's a single key. */
+                cmd->key_specs[j].find_keys_type = KSPEC_FK_RANGE;
+                cmd->key_specs[j].fk.range.lastkey = 0;
+                cmd->key_specs[j].fk.range.keystep = 1;
+                cmd->key_specs[j].fk.range.limit = 0;
+                break;
+            case REDISMODULE_KSPEC_FK_UNKNOWN:
+                cmd->key_specs[j].find_keys_type = KSPEC_FK_UNKNOWN;
+                break;
+            case REDISMODULE_KSPEC_FK_RANGE:
+                cmd->key_specs[j].find_keys_type = KSPEC_FK_RANGE;
+                cmd->key_specs[j].fk.range.lastkey = spec->fk.range.lastkey;
+                cmd->key_specs[j].fk.range.keystep = spec->fk.range.keystep;
+                cmd->key_specs[j].fk.range.limit = spec->fk.range.limit;
+                break;
+            case REDISMODULE_KSPEC_FK_KEYNUM:
+                cmd->key_specs[j].find_keys_type = KSPEC_FK_KEYNUM;
+                cmd->key_specs[j].fk.keynum.keynumidx = spec->fk.keynum.keynumidx;
+                cmd->key_specs[j].fk.keynum.firstkey = spec->fk.keynum.firstkey;
+                cmd->key_specs[j].fk.keynum.keystep = spec->fk.keynum.keystep;
+                break;
+            default:
+                /* Can't happen; stopped in moduleValidateCommandInfo(). */
+                serverPanic("Unknown find_keys_type");
+            }
+        }
+
+        /* Update the legacy (first,last,step) spec and "movablekeys" flag used by the COMMAND command,
+         * by trying to "glue" consecutive range key specs. */
+        populateCommandLegacyRangeSpec(cmd);
+    }
+
+    if (info->args) {
+        cmd->args = moduleCopyCommandArgs(info->args, version);
+        /* Populate arg.num_args with the number of subargs, recursively */
+        cmd->num_args = populateArgsStructure(cmd->args);
+    }
+
+    /* Fields added in future versions to be added here, under conditions like
+     * `if (info->version >= 2) { access version 2 fields here }` */
+
+    return REDISMODULE_OK;
+}
+
+/* Returns 1 if v is a power of two, 0 otherwise. */
+static inline int isPowerOfTwo(uint64_t v) {
+    return v && !(v & (v - 1));
+}
+
+/* Returns 1 if the command info is valid and 0 otherwise. */
+static int moduleValidateCommandInfo(const RedisModuleCommandInfo *info) {
+    const RedisModuleCommandInfoVersion *version = info->version;
+    if (!version) {
+        serverLog(LL_WARNING, "Invalid command info: version missing");
+        return 0;
+    }
+
+    /* No validation for the fields summary, complexity, since, tips (strings or
+     * NULL) and arity (any integer). */
+
+    /* History: If since is set, changes must also be set. */
+    if (info->history) {
+        for (size_t j = 0;
+             moduleCmdHistoryEntryAt(version, info->history, j)->since;
+             j++)
+        {
+            if (!moduleCmdHistoryEntryAt(version, info->history, j)->changes) {
+                serverLog(LL_WARNING, "Invalid command info: history[%zd].changes missing", j);
+                return 0;
+            }
+        }
+    }
+
+    /* Key specs. */
+    if (info->key_specs) {
+        for (size_t j = 0;
+             moduleCmdKeySpecAt(version, info->key_specs, j)->begin_search_type;
+             j++)
+        {
+            RedisModuleCommandKeySpec *spec =
+                moduleCmdKeySpecAt(version, info->key_specs, j);
+            if (j >= INT_MAX) {
+                serverLog(LL_WARNING, "Invalid command info: Too many key specs");
+                return 0; /* redisCommand.key_specs_num is an int. */
+            }
+
+            /* Flags. Exactly one flag in a group is set if and only if the
+             * masked bits is a power of two. */
+            uint64_t key_flags =
+                REDISMODULE_CMD_KEY_RO | REDISMODULE_CMD_KEY_RW |
+                REDISMODULE_CMD_KEY_OW | REDISMODULE_CMD_KEY_RM;
+            uint64_t write_flags =
+                REDISMODULE_CMD_KEY_INSERT | REDISMODULE_CMD_KEY_DELETE |
+                REDISMODULE_CMD_KEY_UPDATE;
+            if (!isPowerOfTwo(spec->flags & key_flags)) {
+                serverLog(LL_WARNING,
+                          "Invalid command info: key_specs[%zd].flags: "
+                          "Exactly one of the flags RO, RW, OW, RM required", j);
+                return 0;
+            }
+            if ((spec->flags & write_flags) != 0 &&
+                !isPowerOfTwo(spec->flags & write_flags))
+            {
+                serverLog(LL_WARNING,
+                          "Invalid command info: key_specs[%zd].flags: "
+                          "INSERT, DELETE and UPDATE are mutually exclusive", j);
+                return 0;
+            }
+
+            switch (spec->begin_search_type) {
+            case REDISMODULE_KSPEC_BS_UNKNOWN: break;
+            case REDISMODULE_KSPEC_BS_INDEX: break;
+            case REDISMODULE_KSPEC_BS_KEYWORD:
+                if (spec->bs.keyword.keyword == NULL) {
+                    serverLog(LL_WARNING,
+                              "Invalid command info: key_specs[%zd].bs.keyword.keyword "
+                              "required when begin_search_type is KEYWORD", j);
+                    return 0;
+                }
+                break;
+            default:
+                serverLog(LL_WARNING,
+                          "Invalid command info: key_specs[%zd].begin_search_type: "
+                          "Invalid value %d", j, spec->begin_search_type);
+                return 0;
+            }
+
+            /* Validate find_keys_type. */
+            switch (spec->find_keys_type) {
+            case REDISMODULE_KSPEC_FK_OMITTED: break; /* short for RANGE {0,1,0} */
+            case REDISMODULE_KSPEC_FK_UNKNOWN: break;
+            case REDISMODULE_KSPEC_FK_RANGE: break;
+            case REDISMODULE_KSPEC_FK_KEYNUM: break;
+            default:
+                serverLog(LL_WARNING,
+                          "Invalid command info: key_specs[%zd].find_keys_type: "
+                          "Invalid value %d", j, spec->find_keys_type);
+                return 0;
+            }
+        }
+    }
+
+    /* Args, subargs (recursive) */
+    return moduleValidateCommandArgs(info->args, version);
+}
+
+/* When from_api is true, converts from REDISMODULE_CMD_KEY_* flags to CMD_KEY_* flags.
+ * When from_api is false, converts from CMD_KEY_* flags to REDISMODULE_CMD_KEY_* flags. */
+static int64_t moduleConvertKeySpecsFlags(int64_t flags, int from_api) {
+    int64_t out = 0;
+    int64_t map[][2] = {
+        {REDISMODULE_CMD_KEY_RO, CMD_KEY_RO},
+        {REDISMODULE_CMD_KEY_RW, CMD_KEY_RW},
+        {REDISMODULE_CMD_KEY_OW, CMD_KEY_OW},
+        {REDISMODULE_CMD_KEY_RM, CMD_KEY_RM},
+        {REDISMODULE_CMD_KEY_ACCESS, CMD_KEY_ACCESS},
+        {REDISMODULE_CMD_KEY_INSERT, CMD_KEY_INSERT},
+        {REDISMODULE_CMD_KEY_UPDATE, CMD_KEY_UPDATE},
+        {REDISMODULE_CMD_KEY_DELETE, CMD_KEY_DELETE},
+        {REDISMODULE_CMD_KEY_NOT_KEY, CMD_KEY_NOT_KEY},
+        {REDISMODULE_CMD_KEY_INCOMPLETE, CMD_KEY_INCOMPLETE},
+        {REDISMODULE_CMD_KEY_VARIABLE_FLAGS, CMD_KEY_VARIABLE_FLAGS},
+        {0,0}};
+
+    int from_idx = from_api ? 0 : 1, to_idx = !from_idx;
+    for (int i=0; map[i][0]; i++)
+        if (flags & map[i][from_idx]) out |= map[i][to_idx];
+    return out;
+}
+
+/* Validates an array of RedisModuleCommandArg. Returns 1 if it's valid and 0 if
+ * it's invalid. */
+static int moduleValidateCommandArgs(RedisModuleCommandArg *args,
+                                     const RedisModuleCommandInfoVersion *version) {
+    if (args == NULL) return 1; /* Missing args is OK. */
+    for (size_t j = 0; moduleCmdArgAt(version, args, j)->name != NULL; j++) {
+        RedisModuleCommandArg *arg = moduleCmdArgAt(version, args, j);
+        int arg_type_error = 0;
+        moduleConvertArgType(arg->type, &arg_type_error);
+        if (arg_type_error) {
+            serverLog(LL_WARNING,
+                      "Invalid command info: Argument \"%s\": Undefined type %d",
+                      arg->name, arg->type);
+            return 0;
+        }
+        if (arg->type == REDISMODULE_ARG_TYPE_PURE_TOKEN && !arg->token) {
+            serverLog(LL_WARNING,
+                      "Invalid command info: Argument \"%s\": "
+                      "token required when type is PURE_TOKEN", args[j].name);
+            return 0;
+        }
+
+        if (arg->type == REDISMODULE_ARG_TYPE_KEY) {
+            if (arg->key_spec_index < 0) {
+                serverLog(LL_WARNING,
+                          "Invalid command info: Argument \"%s\": "
+                          "key_spec_index required when type is KEY",
+                          arg->name);
+                return 0;
+            }
+        } else if (arg->key_spec_index != -1 && arg->key_spec_index != 0) {
+            /* 0 is allowed for convenience, to allow it to be omitted in
+             * compound struct literals on the form `.field = value`. */
+            serverLog(LL_WARNING,
+                      "Invalid command info: Argument \"%s\": "
+                      "key_spec_index specified but type isn't KEY",
+                      arg->name);
+            return 0;
+        }
+
+        if (arg->flags & ~(_REDISMODULE_CMD_ARG_NEXT - 1)) {
+            serverLog(LL_WARNING,
+                      "Invalid command info: Argument \"%s\": Invalid flags",
+                      arg->name);
+            return 0;
+        }
+
+        if (arg->type == REDISMODULE_ARG_TYPE_ONEOF ||
+            arg->type == REDISMODULE_ARG_TYPE_BLOCK)
+        {
+            if (arg->subargs == NULL) {
+                serverLog(LL_WARNING,
+                          "Invalid command info: Argument \"%s\": "
+                          "subargs required when type is ONEOF or BLOCK",
+                          arg->name);
+                return 0;
+            }
+            if (!moduleValidateCommandArgs(arg->subargs, version)) return 0;
+        } else {
+            if (arg->subargs != NULL) {
+                serverLog(LL_WARNING,
+                          "Invalid command info: Argument \"%s\": "
+                          "subargs specified but type isn't ONEOF nor BLOCK",
+                          arg->name);
+                return 0;
+            }
+        }
+    }
+    return 1;
+}
+
+/* Converts an array of RedisModuleCommandArg into a freshly allocated array of
+ * struct redisCommandArg. */
+static struct redisCommandArg *moduleCopyCommandArgs(RedisModuleCommandArg *args,
+                                                     const RedisModuleCommandInfoVersion *version) {
+    size_t count = 0;
+    while (moduleCmdArgAt(version, args, count)->name) count++;
+    serverAssert(count < SIZE_MAX / sizeof(struct redisCommandArg));
+    struct redisCommandArg *realargs = zcalloc((count+1) * sizeof(redisCommandArg));
+
+    for (size_t j = 0; j < count; j++) {
+        RedisModuleCommandArg *arg = moduleCmdArgAt(version, args, j);
+        realargs[j].name = zstrdup(arg->name);
+        realargs[j].type = moduleConvertArgType(arg->type, NULL);
+        if (arg->type == REDISMODULE_ARG_TYPE_KEY)
+            realargs[j].key_spec_index = arg->key_spec_index;
+        else
+            realargs[j].key_spec_index = -1;
+        if (arg->token) realargs[j].token = zstrdup(arg->token);
+        if (arg->summary) realargs[j].summary = zstrdup(arg->summary);
+        if (arg->since) realargs[j].since = zstrdup(arg->since);
+        if (arg->deprecated_since) realargs[j].deprecated_since = zstrdup(arg->deprecated_since);
+        if (arg->display_text) realargs[j].display_text = zstrdup(arg->display_text);
+        realargs[j].flags = moduleConvertArgFlags(arg->flags);
+        if (arg->subargs) realargs[j].subargs = moduleCopyCommandArgs(arg->subargs, version);
+    }
+    return realargs;
+}
+
+static redisCommandArgType moduleConvertArgType(RedisModuleCommandArgType type, int *error) {
+    if (error) *error = 0;
+    switch (type) {
+    case REDISMODULE_ARG_TYPE_STRING: return ARG_TYPE_STRING;
+    case REDISMODULE_ARG_TYPE_INTEGER: return ARG_TYPE_INTEGER;
+    case REDISMODULE_ARG_TYPE_DOUBLE: return ARG_TYPE_DOUBLE;
+    case REDISMODULE_ARG_TYPE_KEY: return ARG_TYPE_KEY;
+    case REDISMODULE_ARG_TYPE_PATTERN: return ARG_TYPE_PATTERN;
+    case REDISMODULE_ARG_TYPE_UNIX_TIME: return ARG_TYPE_UNIX_TIME;
+    case REDISMODULE_ARG_TYPE_PURE_TOKEN: return ARG_TYPE_PURE_TOKEN;
+    case REDISMODULE_ARG_TYPE_ONEOF: return ARG_TYPE_ONEOF;
+    case REDISMODULE_ARG_TYPE_BLOCK: return ARG_TYPE_BLOCK;
+    default:
+        if (error) *error = 1;
+        return -1;
+    }
+}
+
+static int moduleConvertArgFlags(int flags) {
+    int realflags = 0;
+    if (flags & REDISMODULE_CMD_ARG_OPTIONAL) realflags |= CMD_ARG_OPTIONAL;
+    if (flags & REDISMODULE_CMD_ARG_MULTIPLE) realflags |= CMD_ARG_MULTIPLE;
+    if (flags & REDISMODULE_CMD_ARG_MULTIPLE_TOKEN) realflags |= CMD_ARG_MULTIPLE_TOKEN;
+    return realflags;
+}
+
+/* Return `struct RedisModule *` as `void *` to avoid exposing it outside of module.c. */
+void *moduleGetHandleByName(char *modulename) {
+    return dictFetchValue(modules,modulename);
+}
+
+/* Returns 1 if `cmd` is a command of the module `modulename`. 0 otherwise. */
+int moduleIsModuleCommand(void *module_handle, struct redisCommand *cmd) {
+    if (cmd->proc != RedisModuleCommandDispatcher)
+        return 0;
+    if (module_handle == NULL)
+        return 0;
+    RedisModuleCommand *cp = cmd->module_cmd;
+    return (cp->module == module_handle);
+}
+
+/* --------------------------------------------------------------------------
+ * ## Module information and time measurement
+ * -------------------------------------------------------------------------- */
+
+int moduleListConfigMatch(void *config, void *name) {
+    return strcasecmp(((ModuleConfig *) config)->name, (char *) name) == 0;
+}
+
+void moduleListFree(void *config) {
+    ModuleConfig *module_config = (ModuleConfig *) config;
+    sdsfree(module_config->name);
+    zfree(config);
+}
+
+void RM_SetModuleAttribs(RedisModuleCtx *ctx, const char *name, int ver, int apiver) {
+    /* Called by RM_Init() to setup the `ctx->module` structure.
+     *
+     * This is an internal function, Redis modules developers don't need
+     * to use it. */
+    RedisModule *module;
+
+    if (ctx->module != NULL) return;
+    module = zmalloc(sizeof(*module));
+    module->name = sdsnew(name);
+    module->ver = ver;
+    module->apiver = apiver;
+    module->types = listCreate();
+    module->usedby = listCreate();
+    module->using = listCreate();
+    module->filters = listCreate();
+    module->module_configs = listCreate();
+    listSetMatchMethod(module->module_configs, moduleListConfigMatch);
+    listSetFreeMethod(module->module_configs, moduleListFree);
+    module->in_call = 0;
+    module->configs_initialized = 0;
+    module->in_hook = 0;
+    module->options = 0;
+    module->info_cb = 0;
+    module->defrag_cb = 0;
+    module->loadmod = NULL;
+    module->num_commands_with_acl_categories = 0;
+    module->onload = 1;
+    ctx->module = module;
+}
+
+/* Return non-zero if the module name is busy.
+ * Otherwise zero is returned. */
+int RM_IsModuleNameBusy(const char *name) {
+    sds modulename = sdsnew(name);
+    dictEntry *de = dictFind(modules,modulename);
+    sdsfree(modulename);
+    return de != NULL;
+}
+
+/* Return the current UNIX time in milliseconds. */
+mstime_t RM_Milliseconds(void) {
+    return mstime();
+}
+
+/* Return counter of micro-seconds relative to an arbitrary point in time. */
+uint64_t RM_MonotonicMicroseconds(void) {
+    return getMonotonicUs();
+}
+
+/* Return the current UNIX time in microseconds */
+ustime_t RM_Microseconds(void) {
+    return ustime();
+}
+
+/* Return the cached UNIX time in microseconds.
+ * It is updated in the server cron job and before executing a command.
+ * It is useful for complex call stacks, such as a command causing a
+ * key space notification, causing a module to execute a RedisModule_Call,
+ * causing another notification, etc.
+ * It makes sense that all this callbacks would use the same clock. */
+ustime_t RM_CachedMicroseconds(void) {
+    return server.ustime;
+}
+
+/* Mark a point in time that will be used as the start time to calculate
+ * the elapsed execution time when RM_BlockedClientMeasureTimeEnd() is called.
+ * Within the same command, you can call multiple times
+ * RM_BlockedClientMeasureTimeStart() and RM_BlockedClientMeasureTimeEnd()
+ * to accumulate independent time intervals to the background duration.
+ * This method always return REDISMODULE_OK. */
+int RM_BlockedClientMeasureTimeStart(RedisModuleBlockedClient *bc) {
+    elapsedStart(&(bc->background_timer));
+    return REDISMODULE_OK;
+}
+
+/* Mark a point in time that will be used as the end time
+ * to calculate the elapsed execution time.
+ * On success REDISMODULE_OK is returned.
+ * This method only returns REDISMODULE_ERR if no start time was
+ * previously defined ( meaning RM_BlockedClientMeasureTimeStart was not called ). */
+int RM_BlockedClientMeasureTimeEnd(RedisModuleBlockedClient *bc) {
+    // If the counter is 0 then we haven't called RM_BlockedClientMeasureTimeStart
+    if (!bc->background_timer)
+        return REDISMODULE_ERR;
+    bc->background_duration += elapsedUs(bc->background_timer);
+    return REDISMODULE_OK;
+}
+
+/* This API allows modules to let Redis process background tasks, and some
+ * commands during long blocking execution of a module command.
+ * The module can call this API periodically.
+ * The flags is a bit mask of these:
+ *
+ * - `REDISMODULE_YIELD_FLAG_NONE`: No special flags, can perform some background
+ *                                  operations, but not process client commands.
+ * - `REDISMODULE_YIELD_FLAG_CLIENTS`: Redis can also process client commands.
+ *
+ * The `busy_reply` argument is optional, and can be used to control the verbose
+ * error string after the `-BUSY` error code.
+ *
+ * When the `REDISMODULE_YIELD_FLAG_CLIENTS` is used, Redis will only start
+ * processing client commands after the time defined by the
+ * `busy-reply-threshold` config, in which case Redis will start rejecting most
+ * commands with `-BUSY` error, but allow the ones marked with the `allow-busy`
+ * flag to be executed.
+ * This API can also be used in thread safe context (while locked), and during
+ * loading (in the `rdb_load` callback, in which case it'll reject commands with
+ * the -LOADING error)
+ */
+void RM_Yield(RedisModuleCtx *ctx, int flags, const char *busy_reply) {
+    static int yield_nesting = 0;
+    /* Avoid nested calls to RM_Yield */
+    if (yield_nesting)
+        return;
+    yield_nesting++;
+
+    long long now = getMonotonicUs();
+    if (now >= ctx->next_yield_time) {
+        /* In loading mode, there's no need to handle busy_module_yield_reply,
+         * and busy_module_yield_flags, since redis is anyway rejecting all
+         * commands with -LOADING. */
+        if (server.loading) {
+            /* Let redis process events */
+            processEventsWhileBlocked();
+        } else {
+            const char *prev_busy_module_yield_reply = server.busy_module_yield_reply;
+            server.busy_module_yield_reply = busy_reply;
+            /* start the blocking operation if not already started. */
+            if (!server.busy_module_yield_flags) {
+                server.busy_module_yield_flags = BUSY_MODULE_YIELD_EVENTS;
+                blockingOperationStarts();
+                if (server.current_client)
+                    protectClient(server.current_client);
+            }
+            if (flags & REDISMODULE_YIELD_FLAG_CLIENTS)
+                server.busy_module_yield_flags |= BUSY_MODULE_YIELD_CLIENTS;
+
+            /* Let redis process events */
+            processEventsWhileBlocked();
+
+            server.busy_module_yield_reply = prev_busy_module_yield_reply;
+            /* Possibly restore the previous flags in case of two nested contexts
+             * that use this API with different flags, but keep the first bit
+             * (PROCESS_EVENTS) set, so we know to call blockingOperationEnds on time. */
+            server.busy_module_yield_flags &= ~BUSY_MODULE_YIELD_CLIENTS;
+        }
+
+        /* decide when the next event should fire. */
+        ctx->next_yield_time = now + 1000000 / server.hz;
+    }
+    yield_nesting--;
+}
+
+/* Set flags defining capabilities or behavior bit flags.
+ *
+ * REDISMODULE_OPTIONS_HANDLE_IO_ERRORS:
+ * Generally, modules don't need to bother with this, as the process will just
+ * terminate if a read error happens, however, setting this flag would allow
+ * repl-diskless-load to work if enabled.
+ * The module should use RedisModule_IsIOError after reads, before using the
+ * data that was read, and in case of error, propagate it upwards, and also be
+ * able to release the partially populated value and all it's allocations.
+ *
+ * REDISMODULE_OPTION_NO_IMPLICIT_SIGNAL_MODIFIED:
+ * See RM_SignalModifiedKey().
+ * 
+ * REDISMODULE_OPTIONS_HANDLE_REPL_ASYNC_LOAD:
+ * Setting this flag indicates module awareness of diskless async replication (repl-diskless-load=swapdb)
+ * and that redis could be serving reads during replication instead of blocking with LOADING status.
+ *
+ * REDISMODULE_OPTIONS_ALLOW_NESTED_KEYSPACE_NOTIFICATIONS:
+ * Declare that the module wants to get nested key-space notifications.
+ * By default, Redis will not fire key-space notifications that happened inside
+ * a key-space notification callback. This flag allows to change this behavior
+ * and fire nested key-space notifications. Notice: if enabled, the module
+ * should protected itself from infinite recursion. */
+void RM_SetModuleOptions(RedisModuleCtx *ctx, int options) {
+    ctx->module->options = options;
+}
+
+/* Signals that the key is modified from user's perspective (i.e. invalidate WATCH
+ * and client side caching).
+ *
+ * This is done automatically when a key opened for writing is closed, unless
+ * the option REDISMODULE_OPTION_NO_IMPLICIT_SIGNAL_MODIFIED has been set using
+ * RM_SetModuleOptions().
+*/
+int RM_SignalModifiedKey(RedisModuleCtx *ctx, RedisModuleString *keyname) {
+    signalModifiedKey(ctx->client,ctx->client->db,keyname);
+    return REDISMODULE_OK;
+}
+
+/* --------------------------------------------------------------------------
+ * ## Automatic memory management for modules
+ * -------------------------------------------------------------------------- */
+
+/* Enable automatic memory management.
+ *
+ * The function must be called as the first function of a command implementation
+ * that wants to use automatic memory.
+ *
+ * When enabled, automatic memory management tracks and automatically frees
+ * keys, call replies and Redis string objects once the command returns. In most
+ * cases this eliminates the need of calling the following functions:
+ *
+ * 1. RedisModule_CloseKey()
+ * 2. RedisModule_FreeCallReply()
+ * 3. RedisModule_FreeString()
+ *
+ * These functions can still be used with automatic memory management enabled,
+ * to optimize loops that make numerous allocations for example. */
+void RM_AutoMemory(RedisModuleCtx *ctx) {
+    ctx->flags |= REDISMODULE_CTX_AUTO_MEMORY;
+}
+
+/* Add a new object to release automatically when the callback returns. */
+void autoMemoryAdd(RedisModuleCtx *ctx, int type, void *ptr) {
+    if (!(ctx->flags & REDISMODULE_CTX_AUTO_MEMORY)) return;
+    if (ctx->amqueue_used == ctx->amqueue_len) {
+        ctx->amqueue_len *= 2;
+        if (ctx->amqueue_len < 16) ctx->amqueue_len = 16;
+        ctx->amqueue = zrealloc(ctx->amqueue,sizeof(struct AutoMemEntry)*ctx->amqueue_len);
+    }
+    ctx->amqueue[ctx->amqueue_used].type = type;
+    ctx->amqueue[ctx->amqueue_used].ptr = ptr;
+    ctx->amqueue_used++;
+}
+
+/* Mark an object as freed in the auto release queue, so that users can still
+ * free things manually if they want.
+ *
+ * The function returns 1 if the object was actually found in the auto memory
+ * pool, otherwise 0 is returned. */
+int autoMemoryFreed(RedisModuleCtx *ctx, int type, void *ptr) {
+    if (!(ctx->flags & REDISMODULE_CTX_AUTO_MEMORY)) return 0;
+
+    int count = (ctx->amqueue_used+1)/2;
+    for (int j = 0; j < count; j++) {
+        for (int side = 0; side < 2; side++) {
+            /* For side = 0 check right side of the array, for
+             * side = 1 check the left side instead (zig-zag scanning). */
+            int i = (side == 0) ? (ctx->amqueue_used - 1 - j) : j;
+            if (ctx->amqueue[i].type == type &&
+                ctx->amqueue[i].ptr == ptr)
+            {
+                ctx->amqueue[i].type = REDISMODULE_AM_FREED;
+
+                /* Switch the freed element and the last element, to avoid growing
+                 * the queue unnecessarily if we allocate/free in a loop */
+                if (i != ctx->amqueue_used-1) {
+                    ctx->amqueue[i] = ctx->amqueue[ctx->amqueue_used-1];
+                }
+
+                /* Reduce the size of the queue because we either moved the top
+                 * element elsewhere or freed it */
+                ctx->amqueue_used--;
+                return 1;
+            }
+        }
+    }
+    return 0;
+}
+
+/* Release all the objects in queue. */
+void autoMemoryCollect(RedisModuleCtx *ctx) {
+    if (!(ctx->flags & REDISMODULE_CTX_AUTO_MEMORY)) return;
+    /* Clear the AUTO_MEMORY flag from the context, otherwise the functions
+     * we call to free the resources, will try to scan the auto release
+     * queue to mark the entries as freed. */
+    ctx->flags &= ~REDISMODULE_CTX_AUTO_MEMORY;
+    int j;
+    for (j = 0; j < ctx->amqueue_used; j++) {
+        void *ptr = ctx->amqueue[j].ptr;
+        switch(ctx->amqueue[j].type) {
+        case REDISMODULE_AM_STRING: decrRefCount(ptr); break;
+        case REDISMODULE_AM_REPLY: RM_FreeCallReply(ptr); break;
+        case REDISMODULE_AM_KEY: RM_CloseKey(ptr); break;
+        case REDISMODULE_AM_DICT: RM_FreeDict(NULL,ptr); break;
+        case REDISMODULE_AM_INFO: RM_FreeServerInfo(NULL,ptr); break;
+        }
+    }
+    ctx->flags |= REDISMODULE_CTX_AUTO_MEMORY;
+    zfree(ctx->amqueue);
+    ctx->amqueue = NULL;
+    ctx->amqueue_len = 0;
+    ctx->amqueue_used = 0;
+}
+
+/* --------------------------------------------------------------------------
+ * ## String objects APIs
+ * -------------------------------------------------------------------------- */
+
+/* Create a new module string object. The returned string must be freed
+ * with RedisModule_FreeString(), unless automatic memory is enabled.
+ *
+ * The string is created by copying the `len` bytes starting
+ * at `ptr`. No reference is retained to the passed buffer.
+ *
+ * The module context 'ctx' is optional and may be NULL if you want to create
+ * a string out of the context scope. However in that case, the automatic
+ * memory management will not be available, and the string memory must be
+ * managed manually. */
+RedisModuleString *RM_CreateString(RedisModuleCtx *ctx, const char *ptr, size_t len) {
+    RedisModuleString *o = createStringObject(ptr,len);
+    if (ctx != NULL) autoMemoryAdd(ctx,REDISMODULE_AM_STRING,o);
+    return o;
+}
+
+/* Create a new module string object from a printf format and arguments.
+ * The returned string must be freed with RedisModule_FreeString(), unless
+ * automatic memory is enabled.
+ *
+ * The string is created using the sds formatter function sdscatvprintf().
+ *
+ * The passed context 'ctx' may be NULL if necessary, see the
+ * RedisModule_CreateString() documentation for more info. */
+RedisModuleString *RM_CreateStringPrintf(RedisModuleCtx *ctx, const char *fmt, ...) {
+    sds s = sdsempty();
+
+    va_list ap;
+    va_start(ap, fmt);
+    s = sdscatvprintf(s, fmt, ap);
+    va_end(ap);
+
+    RedisModuleString *o = createObject(OBJ_STRING, s);
+    if (ctx != NULL) autoMemoryAdd(ctx,REDISMODULE_AM_STRING,o);
+
+    return o;
+}
+
+
+/* Like RedisModule_CreateString(), but creates a string starting from a `long long`
+ * integer instead of taking a buffer and its length.
+ *
+ * The returned string must be released with RedisModule_FreeString() or by
+ * enabling automatic memory management.
+ *
+ * The passed context 'ctx' may be NULL if necessary, see the
+ * RedisModule_CreateString() documentation for more info. */
+RedisModuleString *RM_CreateStringFromLongLong(RedisModuleCtx *ctx, long long ll) {
+    char buf[LONG_STR_SIZE];
+    size_t len = ll2string(buf,sizeof(buf),ll);
+    return RM_CreateString(ctx,buf,len);
+}
+
+/* Like RedisModule_CreateString(), but creates a string starting from a `unsigned long long`
+ * integer instead of taking a buffer and its length.
+ *
+ * The returned string must be released with RedisModule_FreeString() or by
+ * enabling automatic memory management.
+ *
+ * The passed context 'ctx' may be NULL if necessary, see the
+ * RedisModule_CreateString() documentation for more info. */
+RedisModuleString *RM_CreateStringFromULongLong(RedisModuleCtx *ctx, unsigned long long ull) {
+    char buf[LONG_STR_SIZE];
+    size_t len = ull2string(buf,sizeof(buf),ull);
+    return RM_CreateString(ctx,buf,len);
+}
+
+/* Like RedisModule_CreateString(), but creates a string starting from a double
+ * instead of taking a buffer and its length.
+ *
+ * The returned string must be released with RedisModule_FreeString() or by
+ * enabling automatic memory management. */
+RedisModuleString *RM_CreateStringFromDouble(RedisModuleCtx *ctx, double d) {
+    char buf[MAX_D2STRING_CHARS];
+    size_t len = d2string(buf,sizeof(buf),d);
+    return RM_CreateString(ctx,buf,len);
+}
+
+/* Like RedisModule_CreateString(), but creates a string starting from a long
+ * double.
+ *
+ * The returned string must be released with RedisModule_FreeString() or by
+ * enabling automatic memory management.
+ *
+ * The passed context 'ctx' may be NULL if necessary, see the
+ * RedisModule_CreateString() documentation for more info. */
+RedisModuleString *RM_CreateStringFromLongDouble(RedisModuleCtx *ctx, long double ld, int humanfriendly) {
+    char buf[MAX_LONG_DOUBLE_CHARS];
+    size_t len = ld2string(buf,sizeof(buf),ld,
+        (humanfriendly ? LD_STR_HUMAN : LD_STR_AUTO));
+    return RM_CreateString(ctx,buf,len);
+}
+
+/* Like RedisModule_CreateString(), but creates a string starting from another
+ * RedisModuleString.
+ *
+ * The returned string must be released with RedisModule_FreeString() or by
+ * enabling automatic memory management.
+ *
+ * The passed context 'ctx' may be NULL if necessary, see the
+ * RedisModule_CreateString() documentation for more info. */
+RedisModuleString *RM_CreateStringFromString(RedisModuleCtx *ctx, const RedisModuleString *str) {
+    RedisModuleString *o = dupStringObject(str);
+    if (ctx != NULL) autoMemoryAdd(ctx,REDISMODULE_AM_STRING,o);
+    return o;
+}
+
+/* Creates a string from a stream ID. The returned string must be released with
+ * RedisModule_FreeString(), unless automatic memory is enabled.
+ *
+ * The passed context `ctx` may be NULL if necessary. See the
+ * RedisModule_CreateString() documentation for more info. */
+RedisModuleString *RM_CreateStringFromStreamID(RedisModuleCtx *ctx, const RedisModuleStreamID *id) {
+    streamID streamid = {id->ms, id->seq};
+    RedisModuleString *o = createObjectFromStreamID(&streamid);
+    if (ctx != NULL) autoMemoryAdd(ctx, REDISMODULE_AM_STRING, o);
+    return o;
+}
+
+/* Free a module string object obtained with one of the Redis modules API calls
+ * that return new string objects.
+ *
+ * It is possible to call this function even when automatic memory management
+ * is enabled. In that case the string will be released ASAP and removed
+ * from the pool of string to release at the end.
+ *
+ * If the string was created with a NULL context 'ctx', it is also possible to
+ * pass ctx as NULL when releasing the string (but passing a context will not
+ * create any issue). Strings created with a context should be freed also passing
+ * the context, so if you want to free a string out of context later, make sure
+ * to create it using a NULL context. */
+void RM_FreeString(RedisModuleCtx *ctx, RedisModuleString *str) {
+    decrRefCount(str);
+    if (ctx != NULL) autoMemoryFreed(ctx,REDISMODULE_AM_STRING,str);
+}
+
+/* Every call to this function, will make the string 'str' requiring
+ * an additional call to RedisModule_FreeString() in order to really
+ * free the string. Note that the automatic freeing of the string obtained
+ * enabling modules automatic memory management counts for one
+ * RedisModule_FreeString() call (it is just executed automatically).
+ *
+ * Normally you want to call this function when, at the same time
+ * the following conditions are true:
+ *
+ * 1. You have automatic memory management enabled.
+ * 2. You want to create string objects.
+ * 3. Those string objects you create need to live *after* the callback
+ *    function(for example a command implementation) creating them returns.
+ *
+ * Usually you want this in order to store the created string object
+ * into your own data structure, for example when implementing a new data
+ * type.
+ *
+ * Note that when memory management is turned off, you don't need
+ * any call to RetainString() since creating a string will always result
+ * into a string that lives after the callback function returns, if
+ * no FreeString() call is performed.
+ *
+ * It is possible to call this function with a NULL context.
+ *
+ * When strings are going to be retained for an extended duration, it is good
+ * practice to also call RedisModule_TrimStringAllocation() in order to
+ * optimize memory usage.
+ *
+ * Threaded modules that reference retained strings from other threads *must*
+ * explicitly trim the allocation as soon as the string is retained. Not doing
+ * so may result with automatic trimming which is not thread safe. */
+void RM_RetainString(RedisModuleCtx *ctx, RedisModuleString *str) {
+    if (ctx == NULL || !autoMemoryFreed(ctx,REDISMODULE_AM_STRING,str)) {
+        /* Increment the string reference counting only if we can't
+         * just remove the object from the list of objects that should
+         * be reclaimed. Why we do that, instead of just incrementing
+         * the refcount in any case, and let the automatic FreeString()
+         * call at the end to bring the refcount back at the desired
+         * value? Because this way we ensure that the object refcount
+         * value is 1 (instead of going to 2 to be dropped later to 1)
+         * after the call to this function. This is needed for functions
+         * like RedisModule_StringAppendBuffer() to work. */
+        incrRefCount(str);
+    }
+}
+
+/**
+* This function can be used instead of RedisModule_RetainString().
+* The main difference between the two is that this function will always
+* succeed, whereas RedisModule_RetainString() may fail because of an
+* assertion.
+*
+* The function returns a pointer to RedisModuleString, which is owned
+* by the caller. It requires a call to RedisModule_FreeString() to free
+* the string when automatic memory management is disabled for the context.
+* When automatic memory management is enabled, you can either call
+* RedisModule_FreeString() or let the automation free it.
+*
+* This function is more efficient than RedisModule_CreateStringFromString()
+* because whenever possible, it avoids copying the underlying
+* RedisModuleString. The disadvantage of using this function is that it
+* might not be possible to use RedisModule_StringAppendBuffer() on the
+* returned RedisModuleString.
+*
+* It is possible to call this function with a NULL context.
+*
+ * When strings are going to be held for an extended duration, it is good
+ * practice to also call RedisModule_TrimStringAllocation() in order to
+ * optimize memory usage.
+ *
+ * Threaded modules that reference held strings from other threads *must*
+ * explicitly trim the allocation as soon as the string is held. Not doing
+ * so may result with automatic trimming which is not thread safe. */
+RedisModuleString* RM_HoldString(RedisModuleCtx *ctx, RedisModuleString *str) {
+    if (str->refcount == OBJ_STATIC_REFCOUNT) {
+        return RM_CreateStringFromString(ctx, str);
+    }
+
+    incrRefCount(str);
+    if (ctx != NULL) {
+        /*
+         * Put the str in the auto memory management of the ctx.
+         * It might already be there, in this case, the ref count will
+         * be 2 and we will decrease the ref count twice and free the
+         * object in the auto memory free function.
+         *
+         * Why we can not do the same trick of just remove the object
+         * from the auto memory (like in RM_RetainString)?
+         * This code shows the issue:
+         *
+         * RM_AutoMemory(ctx);
+         * str1 = RM_CreateString(ctx, "test", 4);
+         * str2 = RM_HoldString(ctx, str1);
+         * RM_FreeString(str1);
+         * RM_FreeString(str2);
+         *
+         * If after the RM_HoldString we would just remove the string from
+         * the auto memory, this example will cause access to a freed memory
+         * on 'RM_FreeString(str2);' because the String will be free
+         * on 'RM_FreeString(str1);'.
+         *
+         * So it's safer to just increase the ref count
+         * and add the String to auto memory again.
+         *
+         * The limitation is that it is not possible to use RedisModule_StringAppendBuffer
+         * on the String.
+         */
+        autoMemoryAdd(ctx,REDISMODULE_AM_STRING,str);
+    }
+    return str;
+}
+
+/* Given a string module object, this function returns the string pointer
+ * and length of the string. The returned pointer and length should only
+ * be used for read only accesses and never modified. */
+const char *RM_StringPtrLen(const RedisModuleString *str, size_t *len) {
+    if (str == NULL) {
+        const char *errmsg = "(NULL string reply referenced in module)";
+        if (len) *len = strlen(errmsg);
+        return errmsg;
+    }
+    if (len) *len = sdslen(str->ptr);
+    return str->ptr;
+}
+
+/* --------------------------------------------------------------------------
+ * Higher level string operations
+ * ------------------------------------------------------------------------- */
+
+/* Convert the string into a `long long` integer, storing it at `*ll`.
+ * Returns REDISMODULE_OK on success. If the string can't be parsed
+ * as a valid, strict `long long` (no spaces before/after), REDISMODULE_ERR
+ * is returned. */
+int RM_StringToLongLong(const RedisModuleString *str, long long *ll) {
+    return string2ll(str->ptr,sdslen(str->ptr),ll) ? REDISMODULE_OK :
+                                                     REDISMODULE_ERR;
+}
+
+/* Convert the string into a `unsigned long long` integer, storing it at `*ull`.
+ * Returns REDISMODULE_OK on success. If the string can't be parsed
+ * as a valid, strict `unsigned long long` (no spaces before/after), REDISMODULE_ERR
+ * is returned. */
+int RM_StringToULongLong(const RedisModuleString *str, unsigned long long *ull) {
+    return string2ull(str->ptr,ull) ? REDISMODULE_OK : REDISMODULE_ERR;
+}
+
+/* Convert the string into a double, storing it at `*d`.
+ * Returns REDISMODULE_OK on success or REDISMODULE_ERR if the string is
+ * not a valid string representation of a double value. */
+int RM_StringToDouble(const RedisModuleString *str, double *d) {
+    int retval = getDoubleFromObject(str,d);
+    return (retval == C_OK) ? REDISMODULE_OK : REDISMODULE_ERR;
+}
+
+/* Convert the string into a long double, storing it at `*ld`.
+ * Returns REDISMODULE_OK on success or REDISMODULE_ERR if the string is
+ * not a valid string representation of a double value. */
+int RM_StringToLongDouble(const RedisModuleString *str, long double *ld) {
+    int retval = string2ld(str->ptr,sdslen(str->ptr),ld);
+    return retval ? REDISMODULE_OK : REDISMODULE_ERR;
+}
+
+/* Convert the string into a stream ID, storing it at `*id`.
+ * Returns REDISMODULE_OK on success and returns REDISMODULE_ERR if the string
+ * is not a valid string representation of a stream ID. The special IDs "+" and
+ * "-" are allowed.
+ */
+int RM_StringToStreamID(const RedisModuleString *str, RedisModuleStreamID *id) {
+    streamID streamid;
+    if (streamParseID(str, &streamid) == C_OK) {
+        id->ms = streamid.ms;
+        id->seq = streamid.seq;
+        return REDISMODULE_OK;
+    } else {
+        return REDISMODULE_ERR;
+    }
+}
+
+/* Compare two string objects, returning -1, 0 or 1 respectively if
+ * a < b, a == b, a > b. Strings are compared byte by byte as two
+ * binary blobs without any encoding care / collation attempt. */
+int RM_StringCompare(const RedisModuleString *a, const RedisModuleString *b) {
+    return compareStringObjects(a,b);
+}
+
+/* Return the (possibly modified in encoding) input 'str' object if
+ * the string is unshared, otherwise NULL is returned. */
+RedisModuleString *moduleAssertUnsharedString(RedisModuleString *str) {
+    if (str->refcount != 1) {
+        serverLog(LL_WARNING,
+            "Module attempted to use an in-place string modify operation "
+            "with a string referenced multiple times. Please check the code "
+            "for API usage correctness.");
+        return NULL;
+    }
+    if (str->encoding == OBJ_ENCODING_EMBSTR) {
+        /* Note: here we "leak" the additional allocation that was
+         * used in order to store the embedded string in the object. */
+        str->ptr = sdsnewlen(str->ptr,sdslen(str->ptr));
+        str->encoding = OBJ_ENCODING_RAW;
+    } else if (str->encoding == OBJ_ENCODING_INT) {
+        /* Convert the string from integer to raw encoding. */
+        str->ptr = sdsfromlonglong((long)str->ptr);
+        str->encoding = OBJ_ENCODING_RAW;
+    }
+    return str;
+}
+
+/* Append the specified buffer to the string 'str'. The string must be a
+ * string created by the user that is referenced only a single time, otherwise
+ * REDISMODULE_ERR is returned and the operation is not performed. */
+int RM_StringAppendBuffer(RedisModuleCtx *ctx, RedisModuleString *str, const char *buf, size_t len) {
+    UNUSED(ctx);
+    str = moduleAssertUnsharedString(str);
+    if (str == NULL) return REDISMODULE_ERR;
+    str->ptr = sdscatlen(str->ptr,buf,len);
+    return REDISMODULE_OK;
+}
+
+/* Trim possible excess memory allocated for a RedisModuleString.
+ *
+ * Sometimes a RedisModuleString may have more memory allocated for
+ * it than required, typically for argv arguments that were constructed
+ * from network buffers. This function optimizes such strings by reallocating
+ * their memory, which is useful for strings that are not short lived but
+ * retained for an extended duration.
+ *
+ * This operation is *not thread safe* and should only be called when
+ * no concurrent access to the string is guaranteed. Using it for an argv
+ * string in a module command before the string is potentially available
+ * to other threads is generally safe.
+ *
+ * Currently, Redis may also automatically trim retained strings when a
+ * module command returns. However, doing this explicitly should still be
+ * a preferred option:
+ *
+ * 1. Future versions of Redis may abandon auto-trimming.
+ * 2. Auto-trimming as currently implemented is *not thread safe*.
+ *    A background thread manipulating a recently retained string may end up
+ *    in a race condition with the auto-trim, which could result with
+ *    data corruption.
+ */
+void RM_TrimStringAllocation(RedisModuleString *str) {
+    if (!str) return;
+    trimStringObjectIfNeeded(str, 1);
+}
+
+/* --------------------------------------------------------------------------
+ * ## Reply APIs
+ *
+ * These functions are used for sending replies to the client.
+ *
+ * Most functions always return REDISMODULE_OK so you can use it with
+ * 'return' in order to return from the command implementation with:
+ *
+ *     if (... some condition ...)
+ *         return RedisModule_ReplyWithLongLong(ctx,mycount);
+ *
+ * ### Reply with collection functions
+ *
+ * After starting a collection reply, the module must make calls to other
+ * `ReplyWith*` style functions in order to emit the elements of the collection.
+ * Collection types include: Array, Map, Set and Attribute.
+ *
+ * When producing collections with a number of elements that is not known
+ * beforehand, the function can be called with a special flag
+ * REDISMODULE_POSTPONED_LEN (REDISMODULE_POSTPONED_ARRAY_LEN in the past),
+ * and the actual number of elements can be later set with RM_ReplySet*Length()
+ * call (which will set the latest "open" count if there are multiple ones).
+ * -------------------------------------------------------------------------- */
+
+/* Send an error about the number of arguments given to the command,
+ * citing the command name in the error message. Returns REDISMODULE_OK.
+ *
+ * Example:
+ *
+ *     if (argc != 3) return RedisModule_WrongArity(ctx);
+ */
+int RM_WrongArity(RedisModuleCtx *ctx) {
+    addReplyErrorArity(ctx->client);
+    return REDISMODULE_OK;
+}
+
+/* Return the client object the `RM_Reply*` functions should target.
+ * Normally this is just `ctx->client`, that is the client that called
+ * the module command, however in the case of thread safe contexts there
+ * is no directly associated client (since it would not be safe to access
+ * the client from a thread), so instead the blocked client object referenced
+ * in the thread safe context, has a fake client that we just use to accumulate
+ * the replies. Later, when the client is unblocked, the accumulated replies
+ * are appended to the actual client.
+ *
+ * The function returns the client pointer depending on the context, or
+ * NULL if there is no potential client. This happens when we are in the
+ * context of a thread safe context that was not initialized with a blocked
+ * client object. Other contexts without associated clients are the ones
+ * initialized to run the timers callbacks. */
+client *moduleGetReplyClient(RedisModuleCtx *ctx) {
+    if (ctx->flags & REDISMODULE_CTX_THREAD_SAFE) {
+        if (ctx->blocked_client)
+            return ctx->blocked_client->reply_client;
+        else
+            return NULL;
+    } else {
+        /* If this is a non thread safe context, just return the client
+         * that is running the command if any. This may be NULL as well
+         * in the case of contexts that are not executed with associated
+         * clients, like timer contexts. */
+        return ctx->client;
+    }
+}
+
+/* Send an integer reply to the client, with the specified `long long` value.
+ * The function always returns REDISMODULE_OK. */
+int RM_ReplyWithLongLong(RedisModuleCtx *ctx, long long ll) {
+    client *c = moduleGetReplyClient(ctx);
+    if (c == NULL) return REDISMODULE_OK;
+    addReplyLongLong(c,ll);
+    return REDISMODULE_OK;
+}
+
+/* Reply with the error 'err'.
+ *
+ * Note that 'err' must contain all the error, including
+ * the initial error code. The function only provides the initial "-", so
+ * the usage is, for example:
+ *
+ *     RedisModule_ReplyWithError(ctx,"ERR Wrong Type");
+ *
+ * and not just:
+ *
+ *     RedisModule_ReplyWithError(ctx,"Wrong Type");
+ *
+ * The function always returns REDISMODULE_OK.
+ */
+int RM_ReplyWithError(RedisModuleCtx *ctx, const char *err) {
+    client *c = moduleGetReplyClient(ctx);
+    if (c == NULL) return REDISMODULE_OK;
+    addReplyErrorFormat(c,"-%s",err);
+    return REDISMODULE_OK;
+}
+
+/* Reply with the error create from a printf format and arguments.
+ *
+ * Note that 'fmt' must contain all the error, including
+ * the initial error code. The function only provides the initial "-", so
+ * the usage is, for example:
+ *
+ *     RedisModule_ReplyWithErrorFormat(ctx,"ERR Wrong Type: %s",type);
+ *
+ * and not just:
+ *
+ *     RedisModule_ReplyWithErrorFormat(ctx,"Wrong Type: %s",type);
+ *
+ * The function always returns REDISMODULE_OK.
+ */
+int RM_ReplyWithErrorFormat(RedisModuleCtx *ctx, const char *fmt, ...) {
+    client *c = moduleGetReplyClient(ctx);
+    if (c == NULL) return REDISMODULE_OK;
+
+    int len = strlen(fmt) + 2; /* 1 for the \0 and 1 for the hyphen */
+    char *hyphenfmt = zmalloc(len);
+    snprintf(hyphenfmt, len, "-%s", fmt);
+
+    va_list ap;
+    va_start(ap, fmt);
+    addReplyErrorFormatInternal(c, 0, hyphenfmt, ap);
+    va_end(ap);
+
+    zfree(hyphenfmt);
+
+    return REDISMODULE_OK;
+}
+
+/* Reply with a simple string (`+... \r\n` in RESP protocol). This replies
+ * are suitable only when sending a small non-binary string with small
+ * overhead, like "OK" or similar replies.
+ *
+ * The function always returns REDISMODULE_OK. */
+int RM_ReplyWithSimpleString(RedisModuleCtx *ctx, const char *msg) {
+    client *c = moduleGetReplyClient(ctx);
+    if (c == NULL) return REDISMODULE_OK;
+    addReplyProto(c,"+",1);
+    addReplyProto(c,msg,strlen(msg));
+    addReplyProto(c,"\r\n",2);
+    return REDISMODULE_OK;
+}
+
+#define COLLECTION_REPLY_ARRAY      1
+#define COLLECTION_REPLY_MAP        2
+#define COLLECTION_REPLY_SET        3
+#define COLLECTION_REPLY_ATTRIBUTE  4
+
+int moduleReplyWithCollection(RedisModuleCtx *ctx, long len, int type) {
+    client *c = moduleGetReplyClient(ctx);
+    if (c == NULL) return REDISMODULE_OK;
+    if (len == REDISMODULE_POSTPONED_LEN) {
+        ctx->postponed_arrays = zrealloc(ctx->postponed_arrays,sizeof(void*)*
+                (ctx->postponed_arrays_count+1));
+        ctx->postponed_arrays[ctx->postponed_arrays_count] =
+            addReplyDeferredLen(c);
+        ctx->postponed_arrays_count++;
+    } else if (len == 0) {
+        switch (type) {
+        case COLLECTION_REPLY_ARRAY:
+            addReply(c, shared.emptyarray);
+            break;
+        case COLLECTION_REPLY_MAP:
+            addReply(c, shared.emptymap[c->resp]);
+            break;
+        case COLLECTION_REPLY_SET:
+            addReply(c, shared.emptyset[c->resp]);
+            break;
+        case COLLECTION_REPLY_ATTRIBUTE:
+            addReplyAttributeLen(c,len);
+            break;
+        default:
+            serverPanic("Invalid module empty reply type %d", type);        }
+    } else {
+        switch (type) {
+        case COLLECTION_REPLY_ARRAY:
+            addReplyArrayLen(c,len);
+            break;
+        case COLLECTION_REPLY_MAP:
+            addReplyMapLen(c,len);
+            break;
+        case COLLECTION_REPLY_SET:
+            addReplySetLen(c,len);
+            break;
+        case COLLECTION_REPLY_ATTRIBUTE:
+            addReplyAttributeLen(c,len);
+            break;
+        default:
+            serverPanic("Invalid module reply type %d", type);
+        }
+    }
+    return REDISMODULE_OK;
+}
+
+/* Reply with an array type of 'len' elements.
+ *
+ * After starting an array reply, the module must make `len` calls to other
+ * `ReplyWith*` style functions in order to emit the elements of the array.
+ * See Reply APIs section for more details.
+ *
+ * Use RM_ReplySetArrayLength() to set deferred length.
+ *
+ * The function always returns REDISMODULE_OK. */
+int RM_ReplyWithArray(RedisModuleCtx *ctx, long len) {
+    return moduleReplyWithCollection(ctx, len, COLLECTION_REPLY_ARRAY);
+}
+
+/* Reply with a RESP3 Map type of 'len' pairs.
+ * Visit https://github.com/antirez/RESP3/blob/master/spec.md for more info about RESP3.
+ *
+ * After starting a map reply, the module must make `len*2` calls to other
+ * `ReplyWith*` style functions in order to emit the elements of the map.
+ * See Reply APIs section for more details.
+ *
+ * If the connected client is using RESP2, the reply will be converted to a flat
+ * array.
+ * 
+ * Use RM_ReplySetMapLength() to set deferred length.
+ * 
+ * The function always returns REDISMODULE_OK. */
+int RM_ReplyWithMap(RedisModuleCtx *ctx, long len) {
+    return moduleReplyWithCollection(ctx, len, COLLECTION_REPLY_MAP);
+}
+
+/* Reply with a RESP3 Set type of 'len' elements.
+ * Visit https://github.com/antirez/RESP3/blob/master/spec.md for more info about RESP3.
+ *
+ * After starting a set reply, the module must make `len` calls to other
+ * `ReplyWith*` style functions in order to emit the elements of the set.
+ * See Reply APIs section for more details.
+ *
+ * If the connected client is using RESP2, the reply will be converted to an
+ * array type.
+ *
+ * Use RM_ReplySetSetLength() to set deferred length.
+ * 
+ * The function always returns REDISMODULE_OK. */
+int RM_ReplyWithSet(RedisModuleCtx *ctx, long len) {
+    return moduleReplyWithCollection(ctx, len, COLLECTION_REPLY_SET);
+}
+
+
+/* Add attributes (metadata) to the reply. Should be done before adding the
+ * actual reply. see https://github.com/antirez/RESP3/blob/master/spec.md#attribute-type
+ *
+ * After starting an attribute's reply, the module must make `len*2` calls to other
+ * `ReplyWith*` style functions in order to emit the elements of the attribute map.
+ * See Reply APIs section for more details.
+ *
+ * Use RM_ReplySetAttributeLength() to set deferred length.
+ * 
+ * Not supported by RESP2 and will return REDISMODULE_ERR, otherwise
+ * the function always returns REDISMODULE_OK. */
+int RM_ReplyWithAttribute(RedisModuleCtx *ctx, long len) {
+    if (ctx->client->resp == 2) return REDISMODULE_ERR;
+ 
+    return moduleReplyWithCollection(ctx, len, COLLECTION_REPLY_ATTRIBUTE);
+}
+
+/* Reply to the client with a null array, simply null in RESP3,
+ * null array in RESP2.
+ *
+ * Note: In RESP3 there's no difference between Null reply and
+ * NullArray reply, so to prevent ambiguity it's better to avoid
+ * using this API and use RedisModule_ReplyWithNull instead.
+ *
+ * The function always returns REDISMODULE_OK. */
+int RM_ReplyWithNullArray(RedisModuleCtx *ctx) {
+    client *c = moduleGetReplyClient(ctx);
+    if (c == NULL) return REDISMODULE_OK;
+    addReplyNullArray(c);
+    return REDISMODULE_OK;
+}
+
+/* Reply to the client with an empty array.
+ *
+ * The function always returns REDISMODULE_OK. */
+int RM_ReplyWithEmptyArray(RedisModuleCtx *ctx) {
+    client *c = moduleGetReplyClient(ctx);
+    if (c == NULL) return REDISMODULE_OK;
+    addReply(c,shared.emptyarray);
+    return REDISMODULE_OK;
+}
+
+void moduleReplySetCollectionLength(RedisModuleCtx *ctx, long len, int type) {
+    client *c = moduleGetReplyClient(ctx);
+    if (c == NULL) return;
+    if (ctx->postponed_arrays_count == 0) {
+        serverLog(LL_WARNING,
+            "API misuse detected in module %s: "
+            "RedisModule_ReplySet*Length() called without previous "
+            "RedisModule_ReplyWith*(ctx,REDISMODULE_POSTPONED_LEN) "
+            "call.", ctx->module->name);
+            return;
+    }
+    ctx->postponed_arrays_count--;
+    switch(type) {
+    case COLLECTION_REPLY_ARRAY:
+        setDeferredArrayLen(c,ctx->postponed_arrays[ctx->postponed_arrays_count],len);
+        break;
+    case COLLECTION_REPLY_MAP:
+        setDeferredMapLen(c,ctx->postponed_arrays[ctx->postponed_arrays_count],len);
+        break;
+    case COLLECTION_REPLY_SET:
+        setDeferredSetLen(c,ctx->postponed_arrays[ctx->postponed_arrays_count],len);
+        break;
+    case COLLECTION_REPLY_ATTRIBUTE:
+        setDeferredAttributeLen(c,ctx->postponed_arrays[ctx->postponed_arrays_count],len);
+        break;
+    default:
+        serverPanic("Invalid module reply type %d", type);
+    }
+    if (ctx->postponed_arrays_count == 0) {
+        zfree(ctx->postponed_arrays);
+        ctx->postponed_arrays = NULL;
+    }
+}
+
+/* When RedisModule_ReplyWithArray() is used with the argument
+ * REDISMODULE_POSTPONED_LEN, because we don't know beforehand the number
+ * of items we are going to output as elements of the array, this function
+ * will take care to set the array length.
+ *
+ * Since it is possible to have multiple array replies pending with unknown
+ * length, this function guarantees to always set the latest array length
+ * that was created in a postponed way.
+ *
+ * For example in order to output an array like [1,[10,20,30]] we
+ * could write:
+ *
+ *      RedisModule_ReplyWithArray(ctx,REDISMODULE_POSTPONED_LEN);
+ *      RedisModule_ReplyWithLongLong(ctx,1);
+ *      RedisModule_ReplyWithArray(ctx,REDISMODULE_POSTPONED_LEN);
+ *      RedisModule_ReplyWithLongLong(ctx,10);
+ *      RedisModule_ReplyWithLongLong(ctx,20);
+ *      RedisModule_ReplyWithLongLong(ctx,30);
+ *      RedisModule_ReplySetArrayLength(ctx,3); // Set len of 10,20,30 array.
+ *      RedisModule_ReplySetArrayLength(ctx,2); // Set len of top array
+ *
+ * Note that in the above example there is no reason to postpone the array
+ * length, since we produce a fixed number of elements, but in the practice
+ * the code may use an iterator or other ways of creating the output so
+ * that is not easy to calculate in advance the number of elements.
+ */
+void RM_ReplySetArrayLength(RedisModuleCtx *ctx, long len) {
+    moduleReplySetCollectionLength(ctx, len, COLLECTION_REPLY_ARRAY);
+}
+
+/* Very similar to RedisModule_ReplySetArrayLength except `len` should
+ * exactly half of the number of `ReplyWith*` functions called in the
+ * context of the map.
+ * Visit https://github.com/antirez/RESP3/blob/master/spec.md for more info about RESP3. */
+void RM_ReplySetMapLength(RedisModuleCtx *ctx, long len) {
+    moduleReplySetCollectionLength(ctx, len, COLLECTION_REPLY_MAP);
+}
+
+/* Very similar to RedisModule_ReplySetArrayLength
+ * Visit https://github.com/antirez/RESP3/blob/master/spec.md for more info about RESP3. */
+void RM_ReplySetSetLength(RedisModuleCtx *ctx, long len) {
+    moduleReplySetCollectionLength(ctx, len, COLLECTION_REPLY_SET);
+}
+
+/* Very similar to RedisModule_ReplySetMapLength
+ * Visit https://github.com/antirez/RESP3/blob/master/spec.md for more info about RESP3.
+ *
+ * Must not be called if RM_ReplyWithAttribute returned an error. */
+void RM_ReplySetAttributeLength(RedisModuleCtx *ctx, long len) {
+    if (ctx->client->resp == 2) return;
+    moduleReplySetCollectionLength(ctx, len, COLLECTION_REPLY_ATTRIBUTE);
+}
+
+/* Reply with a bulk string, taking in input a C buffer pointer and length.
+ *
+ * The function always returns REDISMODULE_OK. */
+int RM_ReplyWithStringBuffer(RedisModuleCtx *ctx, const char *buf, size_t len) {
+    client *c = moduleGetReplyClient(ctx);
+    if (c == NULL) return REDISMODULE_OK;
+    addReplyBulkCBuffer(c,(char*)buf,len);
+    return REDISMODULE_OK;
+}
+
+/* Reply with a bulk string, taking in input a C buffer pointer that is
+ * assumed to be null-terminated.
+ *
+ * The function always returns REDISMODULE_OK. */
+int RM_ReplyWithCString(RedisModuleCtx *ctx, const char *buf) {
+    client *c = moduleGetReplyClient(ctx);
+    if (c == NULL) return REDISMODULE_OK;
+    addReplyBulkCString(c,(char*)buf);
+    return REDISMODULE_OK;
+}
+
+/* Reply with a bulk string, taking in input a RedisModuleString object.
+ *
+ * The function always returns REDISMODULE_OK. */
+int RM_ReplyWithString(RedisModuleCtx *ctx, RedisModuleString *str) {
+    client *c = moduleGetReplyClient(ctx);
+    if (c == NULL) return REDISMODULE_OK;
+    addReplyBulk(c,str);
+    return REDISMODULE_OK;
+}
+
+/* Reply with an empty string.
+ *
+ * The function always returns REDISMODULE_OK. */
+int RM_ReplyWithEmptyString(RedisModuleCtx *ctx) {
+    client *c = moduleGetReplyClient(ctx);
+    if (c == NULL) return REDISMODULE_OK;
+    addReply(c,shared.emptybulk);
+    return REDISMODULE_OK;
+}
+
+/* Reply with a binary safe string, which should not be escaped or filtered
+ * taking in input a C buffer pointer, length and a 3 character type/extension.
+ *
+ * The function always returns REDISMODULE_OK. */
+int RM_ReplyWithVerbatimStringType(RedisModuleCtx *ctx, const char *buf, size_t len, const char *ext) {
+    client *c = moduleGetReplyClient(ctx);
+    if (c == NULL) return REDISMODULE_OK;
+    addReplyVerbatim(c, buf, len, ext);
+    return REDISMODULE_OK;
+}
+
+/* Reply with a binary safe string, which should not be escaped or filtered
+ * taking in input a C buffer pointer and length.
+ *
+ * The function always returns REDISMODULE_OK. */
+int RM_ReplyWithVerbatimString(RedisModuleCtx *ctx, const char *buf, size_t len) {
+	return RM_ReplyWithVerbatimStringType(ctx, buf, len, "txt");
+}
+
+/* Reply to the client with a NULL.
+ *
+ * The function always returns REDISMODULE_OK. */
+int RM_ReplyWithNull(RedisModuleCtx *ctx) {
+    client *c = moduleGetReplyClient(ctx);
+    if (c == NULL) return REDISMODULE_OK;
+    addReplyNull(c);
+    return REDISMODULE_OK;
+}
+
+/* Reply with a RESP3 Boolean type.
+ * Visit https://github.com/antirez/RESP3/blob/master/spec.md for more info about RESP3.
+ *
+ * In RESP3, this is boolean type
+ * In RESP2, it's a string response of "1" and "0" for true and false respectively.
+ *
+ * The function always returns REDISMODULE_OK. */
+int RM_ReplyWithBool(RedisModuleCtx *ctx, int b) {
+    client *c = moduleGetReplyClient(ctx);
+    if (c == NULL) return REDISMODULE_OK;
+    addReplyBool(c,b);
+    return REDISMODULE_OK;
+}
+
+/* Reply exactly what a Redis command returned us with RedisModule_Call().
+ * This function is useful when we use RedisModule_Call() in order to
+ * execute some command, as we want to reply to the client exactly the
+ * same reply we obtained by the command.
+ *
+ * Return:
+ * - REDISMODULE_OK on success.
+ * - REDISMODULE_ERR if the given reply is in RESP3 format but the client expects RESP2.
+ *   In case of an error, it's the module writer responsibility to translate the reply
+ *   to RESP2 (or handle it differently by returning an error). Notice that for
+ *   module writer convenience, it is possible to pass `0` as a parameter to the fmt
+ *   argument of `RM_Call` so that the RedisModuleCallReply will return in the same
+ *   protocol (RESP2 or RESP3) as set in the current client's context. */
+int RM_ReplyWithCallReply(RedisModuleCtx *ctx, RedisModuleCallReply *reply) {
+    client *c = moduleGetReplyClient(ctx);
+    if (c == NULL) return REDISMODULE_OK;
+    if (c->resp == 2 && callReplyIsResp3(reply)) {
+        /* The reply is in RESP3 format and the client is RESP2,
+         * so it isn't possible to send this reply to the client. */
+        return REDISMODULE_ERR;
+    }
+    size_t proto_len;
+    const char *proto = callReplyGetProto(reply, &proto_len);
+    addReplyProto(c, proto, proto_len);
+    /* Propagate the error list from that reply to the other client, to do some
+     * post error reply handling, like statistics.
+     * Note that if the original reply had an array with errors, and the module
+     * replied with just a portion of the original reply, and not the entire
+     * reply, the errors are currently not propagated and the errors stats
+     * will not get propagated. */
+    list *errors = callReplyDeferredErrorList(reply);
+    if (errors)
+        deferredAfterErrorReply(c, errors);
+    return REDISMODULE_OK;
+}
+
+/* Reply with a RESP3 Double type.
+ * Visit https://github.com/antirez/RESP3/blob/master/spec.md for more info about RESP3.
+ *
+ * Send a string reply obtained converting the double 'd' into a bulk string.
+ * This function is basically equivalent to converting a double into
+ * a string into a C buffer, and then calling the function
+ * RedisModule_ReplyWithStringBuffer() with the buffer and length.
+ *
+ * In RESP3 the string is tagged as a double, while in RESP2 it's just a plain string 
+ * that the user will have to parse.
+ *
+ * The function always returns REDISMODULE_OK. */
+int RM_ReplyWithDouble(RedisModuleCtx *ctx, double d) {
+    client *c = moduleGetReplyClient(ctx);
+    if (c == NULL) return REDISMODULE_OK;
+    addReplyDouble(c,d);
+    return REDISMODULE_OK;
+}
+
+/* Reply with a RESP3 BigNumber type.
+ * Visit https://github.com/antirez/RESP3/blob/master/spec.md for more info about RESP3.
+ *
+ * In RESP3, this is a string of length `len` that is tagged as a BigNumber, 
+ * however, it's up to the caller to ensure that it's a valid BigNumber.
+ * In RESP2, this is just a plain bulk string response.
+ *
+ * The function always returns REDISMODULE_OK. */
+int RM_ReplyWithBigNumber(RedisModuleCtx *ctx, const char *bignum, size_t len) {
+    client *c = moduleGetReplyClient(ctx);
+    if (c == NULL) return REDISMODULE_OK;
+    addReplyBigNum(c, bignum, len);
+    return REDISMODULE_OK;
+}
+
+/* Send a string reply obtained converting the long double 'ld' into a bulk
+ * string. This function is basically equivalent to converting a long double
+ * into a string into a C buffer, and then calling the function
+ * RedisModule_ReplyWithStringBuffer() with the buffer and length.
+ * The double string uses human readable formatting (see
+ * `addReplyHumanLongDouble` in networking.c).
+ *
+ * The function always returns REDISMODULE_OK. */
+int RM_ReplyWithLongDouble(RedisModuleCtx *ctx, long double ld) {
+    client *c = moduleGetReplyClient(ctx);
+    if (c == NULL) return REDISMODULE_OK;
+    addReplyHumanLongDouble(c, ld);
+    return REDISMODULE_OK;
+}
+
+/* --------------------------------------------------------------------------
+ * ## Commands replication API
+ * -------------------------------------------------------------------------- */
+
+/* Replicate the specified command and arguments to slaves and AOF, as effect
+ * of execution of the calling command implementation.
+ *
+ * The replicated commands are always wrapped into the MULTI/EXEC that
+ * contains all the commands replicated in a given module command
+ * execution. However the commands replicated with RedisModule_Call()
+ * are the first items, the ones replicated with RedisModule_Replicate()
+ * will all follow before the EXEC.
+ *
+ * Modules should try to use one interface or the other.
+ *
+ * This command follows exactly the same interface of RedisModule_Call(),
+ * so a set of format specifiers must be passed, followed by arguments
+ * matching the provided format specifiers.
+ *
+ * Please refer to RedisModule_Call() for more information.
+ *
+ * Using the special "A" and "R" modifiers, the caller can exclude either
+ * the AOF or the replicas from the propagation of the specified command.
+ * Otherwise, by default, the command will be propagated in both channels.
+ *
+ * #### Note about calling this function from a thread safe context:
+ *
+ * Normally when you call this function from the callback implementing a
+ * module command, or any other callback provided by the Redis Module API,
+ * Redis will accumulate all the calls to this function in the context of
+ * the callback, and will propagate all the commands wrapped in a MULTI/EXEC
+ * transaction. However when calling this function from a threaded safe context
+ * that can live an undefined amount of time, and can be locked/unlocked in
+ * at will, the behavior is different: MULTI/EXEC wrapper is not emitted
+ * and the command specified is inserted in the AOF and replication stream
+ * immediately.
+ *
+ * #### Return value
+ *
+ * The command returns REDISMODULE_ERR if the format specifiers are invalid
+ * or the command name does not belong to a known command. */
+int RM_Replicate(RedisModuleCtx *ctx, const char *cmdname, const char *fmt, ...) {
+    struct redisCommand *cmd;
+    robj **argv = NULL;
+    int argc = 0, flags = 0, j;
+    va_list ap;
+
+    cmd = lookupCommandByCString((char*)cmdname);
+    if (!cmd) return REDISMODULE_ERR;
+
+    /* Create the client and dispatch the command. */
+    va_start(ap, fmt);
+    argv = moduleCreateArgvFromUserFormat(cmdname,fmt,&argc,&flags,ap);
+    va_end(ap);
+    if (argv == NULL) return REDISMODULE_ERR;
+
+    /* Select the propagation target. Usually is AOF + replicas, however
+     * the caller can exclude one or the other using the "A" or "R"
+     * modifiers. */
+    int target = 0;
+    if (!(flags & REDISMODULE_ARGV_NO_AOF)) target |= PROPAGATE_AOF;
+    if (!(flags & REDISMODULE_ARGV_NO_REPLICAS)) target |= PROPAGATE_REPL;
+
+    alsoPropagate(ctx->client->db->id,argv,argc,target);
+
+    /* Release the argv. */
+    for (j = 0; j < argc; j++) decrRefCount(argv[j]);
+    zfree(argv);
+    server.dirty++;
+    return REDISMODULE_OK;
+}
+
+/* This function will replicate the command exactly as it was invoked
+ * by the client. Note that this function will not wrap the command into
+ * a MULTI/EXEC stanza, so it should not be mixed with other replication
+ * commands.
+ *
+ * Basically this form of replication is useful when you want to propagate
+ * the command to the slaves and AOF file exactly as it was called, since
+ * the command can just be re-executed to deterministically re-create the
+ * new state starting from the old one.
+ *
+ * The function always returns REDISMODULE_OK. */
+int RM_ReplicateVerbatim(RedisModuleCtx *ctx) {
+    alsoPropagate(ctx->client->db->id,
+        ctx->client->argv,ctx->client->argc,
+        PROPAGATE_AOF|PROPAGATE_REPL);
+    server.dirty++;
+    return REDISMODULE_OK;
+}
+
+/* --------------------------------------------------------------------------
+ * ## DB and Key APIs -- Generic API
+ * -------------------------------------------------------------------------- */
+
+/* Return the ID of the current client calling the currently active module
+ * command. The returned ID has a few guarantees:
+ *
+ * 1. The ID is different for each different client, so if the same client
+ *    executes a module command multiple times, it can be recognized as
+ *    having the same ID, otherwise the ID will be different.
+ * 2. The ID increases monotonically. Clients connecting to the server later
+ *    are guaranteed to get IDs greater than any past ID previously seen.
+ *
+ * Valid IDs are from 1 to 2^64 - 1. If 0 is returned it means there is no way
+ * to fetch the ID in the context the function was currently called.
+ *
+ * After obtaining the ID, it is possible to check if the command execution
+ * is actually happening in the context of AOF loading, using this macro:
+ *
+ *      if (RedisModule_IsAOFClient(RedisModule_GetClientId(ctx)) {
+ *          // Handle it differently.
+ *      }
+ */
+unsigned long long RM_GetClientId(RedisModuleCtx *ctx) {
+    if (ctx->client == NULL) return 0;
+    return ctx->client->id;
+}
+
+/* Return the ACL user name used by the client with the specified client ID.
+ * Client ID can be obtained with RM_GetClientId() API. If the client does not
+ * exist, NULL is returned and errno is set to ENOENT. If the client isn't
+ * using an ACL user, NULL is returned and errno is set to ENOTSUP */
+RedisModuleString *RM_GetClientUserNameById(RedisModuleCtx *ctx, uint64_t id) {
+    client *client = lookupClientByID(id);
+    if (client == NULL) {
+        errno = ENOENT;
+        return NULL;
+    }
+    
+    if (client->user == NULL) {
+        errno = ENOTSUP;
+        return NULL;
+    }
+
+    sds name = sdsnew(client->user->name);
+    robj *str = createObject(OBJ_STRING, name);
+    autoMemoryAdd(ctx, REDISMODULE_AM_STRING, str);
+    return str;
+}
+
+/* This is a helper for RM_GetClientInfoById() and other functions: given
+ * a client, it populates the client info structure with the appropriate
+ * fields depending on the version provided. If the version is not valid
+ * then REDISMODULE_ERR is returned. Otherwise the function returns
+ * REDISMODULE_OK and the structure pointed by 'ci' gets populated. */
+
+int modulePopulateClientInfoStructure(void *ci, client *client, int structver) {
+    if (structver != 1) return REDISMODULE_ERR;
+
+    RedisModuleClientInfoV1 *ci1 = ci;
+    memset(ci1,0,sizeof(*ci1));
+    ci1->version = structver;
+    if (client->flags & CLIENT_MULTI)
+        ci1->flags |= REDISMODULE_CLIENTINFO_FLAG_MULTI;
+    if (client->flags & CLIENT_PUBSUB)
+        ci1->flags |= REDISMODULE_CLIENTINFO_FLAG_PUBSUB;
+    if (client->flags & CLIENT_UNIX_SOCKET)
+        ci1->flags |= REDISMODULE_CLIENTINFO_FLAG_UNIXSOCKET;
+    if (client->flags & CLIENT_TRACKING)
+        ci1->flags |= REDISMODULE_CLIENTINFO_FLAG_TRACKING;
+    if (client->flags & CLIENT_BLOCKED)
+        ci1->flags |= REDISMODULE_CLIENTINFO_FLAG_BLOCKED;
+    if (client->conn->type == connectionTypeTls())
+        ci1->flags |= REDISMODULE_CLIENTINFO_FLAG_SSL;
+
+    int port;
+    connAddrPeerName(client->conn,ci1->addr,sizeof(ci1->addr),&port);
+    ci1->port = port;
+    ci1->db = client->db->id;
+    ci1->id = client->id;
+    return REDISMODULE_OK;
+}
+
+/* This is a helper for moduleFireServerEvent() and other functions:
+ * It populates the replication info structure with the appropriate
+ * fields depending on the version provided. If the version is not valid
+ * then REDISMODULE_ERR is returned. Otherwise the function returns
+ * REDISMODULE_OK and the structure pointed by 'ri' gets populated. */
+int modulePopulateReplicationInfoStructure(void *ri, int structver) {
+    if (structver != 1) return REDISMODULE_ERR;
+
+    RedisModuleReplicationInfoV1 *ri1 = ri;
+    memset(ri1,0,sizeof(*ri1));
+    ri1->version = structver;
+    ri1->master = server.masterhost==NULL;
+    ri1->masterhost = server.masterhost? server.masterhost: "";
+    ri1->masterport = server.masterport;
+    ri1->replid1 = server.replid;
+    ri1->replid2 = server.replid2;
+    ri1->repl1_offset = server.master_repl_offset;
+    ri1->repl2_offset = server.second_replid_offset;
+    return REDISMODULE_OK;
+}
+
+/* Return information about the client with the specified ID (that was
+ * previously obtained via the RedisModule_GetClientId() API). If the
+ * client exists, REDISMODULE_OK is returned, otherwise REDISMODULE_ERR
+ * is returned.
+ *
+ * When the client exist and the `ci` pointer is not NULL, but points to
+ * a structure of type RedisModuleClientInfoV1, previously initialized with
+ * the correct REDISMODULE_CLIENTINFO_INITIALIZER_V1, the structure is populated
+ * with the following fields:
+ *
+ *      uint64_t flags;         // REDISMODULE_CLIENTINFO_FLAG_*
+ *      uint64_t id;            // Client ID
+ *      char addr[46];          // IPv4 or IPv6 address.
+ *      uint16_t port;          // TCP port.
+ *      uint16_t db;            // Selected DB.
+ *
+ * Note: the client ID is useless in the context of this call, since we
+ *       already know, however the same structure could be used in other
+ *       contexts where we don't know the client ID, yet the same structure
+ *       is returned.
+ *
+ * With flags having the following meaning:
+ *
+ *     REDISMODULE_CLIENTINFO_FLAG_SSL          Client using SSL connection.
+ *     REDISMODULE_CLIENTINFO_FLAG_PUBSUB       Client in Pub/Sub mode.
+ *     REDISMODULE_CLIENTINFO_FLAG_BLOCKED      Client blocked in command.
+ *     REDISMODULE_CLIENTINFO_FLAG_TRACKING     Client with keys tracking on.
+ *     REDISMODULE_CLIENTINFO_FLAG_UNIXSOCKET   Client using unix domain socket.
+ *     REDISMODULE_CLIENTINFO_FLAG_MULTI        Client in MULTI state.
+ *
+ * However passing NULL is a way to just check if the client exists in case
+ * we are not interested in any additional information.
+ *
+ * This is the correct usage when we want the client info structure
+ * returned:
+ *
+ *      RedisModuleClientInfo ci = REDISMODULE_CLIENTINFO_INITIALIZER;
+ *      int retval = RedisModule_GetClientInfoById(&ci,client_id);
+ *      if (retval == REDISMODULE_OK) {
+ *          printf("Address: %s\n", ci.addr);
+ *      }
+ */
+int RM_GetClientInfoById(void *ci, uint64_t id) {
+    client *client = lookupClientByID(id);
+    if (client == NULL) return REDISMODULE_ERR;
+    if (ci == NULL) return REDISMODULE_OK;
+
+    /* Fill the info structure if passed. */
+    uint64_t structver = ((uint64_t*)ci)[0];
+    return modulePopulateClientInfoStructure(ci,client,structver);
+}
+
+/* Returns the name of the client connection with the given ID.
+ *
+ * If the client ID does not exist or if the client has no name associated with
+ * it, NULL is returned. */
+RedisModuleString *RM_GetClientNameById(RedisModuleCtx *ctx, uint64_t id) {
+    client *client = lookupClientByID(id);
+    if (client == NULL || client->name == NULL) return NULL;
+    robj *name = client->name;
+    incrRefCount(name);
+    autoMemoryAdd(ctx, REDISMODULE_AM_STRING, name);
+    return name;
+}
+
+/* Sets the name of the client with the given ID. This is equivalent to the client calling
+ * `CLIENT SETNAME name`.
+ *
+ * Returns REDISMODULE_OK on success. On failure, REDISMODULE_ERR is returned
+ * and errno is set as follows:
+ *
+ * - ENOENT if the client does not exist
+ * - EINVAL if the name contains invalid characters */
+int RM_SetClientNameById(uint64_t id, RedisModuleString *name) {
+    client *client = lookupClientByID(id);
+    if (client == NULL) {
+        errno = ENOENT;
+        return REDISMODULE_ERR;
+    }
+    if (clientSetName(client, name, NULL) == C_ERR) {
+        errno = EINVAL;
+        return REDISMODULE_ERR;
+    }
+    return REDISMODULE_OK;
+}
+
+/* Publish a message to subscribers (see PUBLISH command). */
+int RM_PublishMessage(RedisModuleCtx *ctx, RedisModuleString *channel, RedisModuleString *message) {
+    UNUSED(ctx);
+    return pubsubPublishMessageAndPropagateToCluster(channel, message, 0);
+}
+
+/* Publish a message to shard-subscribers (see SPUBLISH command). */
+int RM_PublishMessageShard(RedisModuleCtx *ctx, RedisModuleString *channel, RedisModuleString *message) {
+    UNUSED(ctx);
+    return pubsubPublishMessageAndPropagateToCluster(channel, message, 1);
+}
+
+/* Return the currently selected DB. */
+int RM_GetSelectedDb(RedisModuleCtx *ctx) {
+    return ctx->client->db->id;
+}
+
+
+/* Return the current context's flags. The flags provide information on the
+ * current request context (whether the client is a Lua script or in a MULTI),
+ * and about the Redis instance in general, i.e replication and persistence.
+ *
+ * It is possible to call this function even with a NULL context, however
+ * in this case the following flags will not be reported:
+ *
+ *  * LUA, MULTI, REPLICATED, DIRTY (see below for more info).
+ *
+ * Available flags and their meaning:
+ *
+ *  * REDISMODULE_CTX_FLAGS_LUA: The command is running in a Lua script
+ *
+ *  * REDISMODULE_CTX_FLAGS_MULTI: The command is running inside a transaction
+ *
+ *  * REDISMODULE_CTX_FLAGS_REPLICATED: The command was sent over the replication
+ *    link by the MASTER
+ *
+ *  * REDISMODULE_CTX_FLAGS_MASTER: The Redis instance is a master
+ *
+ *  * REDISMODULE_CTX_FLAGS_SLAVE: The Redis instance is a slave
+ *
+ *  * REDISMODULE_CTX_FLAGS_READONLY: The Redis instance is read-only
+ *
+ *  * REDISMODULE_CTX_FLAGS_CLUSTER: The Redis instance is in cluster mode
+ *
+ *  * REDISMODULE_CTX_FLAGS_AOF: The Redis instance has AOF enabled
+ *
+ *  * REDISMODULE_CTX_FLAGS_RDB: The instance has RDB enabled
+ *
+ *  * REDISMODULE_CTX_FLAGS_MAXMEMORY:  The instance has Maxmemory set
+ *
+ *  * REDISMODULE_CTX_FLAGS_EVICT:  Maxmemory is set and has an eviction
+ *    policy that may delete keys
+ *
+ *  * REDISMODULE_CTX_FLAGS_OOM: Redis is out of memory according to the
+ *    maxmemory setting.
+ *
+ *  * REDISMODULE_CTX_FLAGS_OOM_WARNING: Less than 25% of memory remains before
+ *                                       reaching the maxmemory level.
+ *
+ *  * REDISMODULE_CTX_FLAGS_LOADING: Server is loading RDB/AOF
+ *
+ *  * REDISMODULE_CTX_FLAGS_REPLICA_IS_STALE: No active link with the master.
+ *
+ *  * REDISMODULE_CTX_FLAGS_REPLICA_IS_CONNECTING: The replica is trying to
+ *                                                 connect with the master.
+ *
+ *  * REDISMODULE_CTX_FLAGS_REPLICA_IS_TRANSFERRING: Master -> Replica RDB
+ *                                                   transfer is in progress.
+ *
+ *  * REDISMODULE_CTX_FLAGS_REPLICA_IS_ONLINE: The replica has an active link
+ *                                             with its master. This is the
+ *                                             contrary of STALE state.
+ *
+ *  * REDISMODULE_CTX_FLAGS_ACTIVE_CHILD: There is currently some background
+ *                                        process active (RDB, AUX or module).
+ *
+ *  * REDISMODULE_CTX_FLAGS_MULTI_DIRTY: The next EXEC will fail due to dirty
+ *                                       CAS (touched keys).
+ *
+ *  * REDISMODULE_CTX_FLAGS_IS_CHILD: Redis is currently running inside
+ *                                    background child process.
+ *
+ *  * REDISMODULE_CTX_FLAGS_RESP3: Indicate the that client attached to this
+ *                                 context is using RESP3.
+ *
+ *  * REDISMODULE_CTX_FLAGS_SERVER_STARTUP: The Redis instance is starting
+ */
+int RM_GetContextFlags(RedisModuleCtx *ctx) {
+    int flags = 0;
+
+    /* Client specific flags */
+    if (ctx) {
+        if (ctx->client) {
+            if (ctx->client->flags & CLIENT_DENY_BLOCKING)
+                flags |= REDISMODULE_CTX_FLAGS_DENY_BLOCKING;
+            /* Module command received from MASTER, is replicated. */
+            if (ctx->client->flags & CLIENT_MASTER)
+                flags |= REDISMODULE_CTX_FLAGS_REPLICATED;
+            if (ctx->client->resp == 3) {
+                flags |= REDISMODULE_CTX_FLAGS_RESP3;
+            }
+        }
+
+        /* For DIRTY flags, we need the blocked client if used */
+        client *c = ctx->blocked_client ? ctx->blocked_client->client : ctx->client;
+        if (c && (c->flags & (CLIENT_DIRTY_CAS|CLIENT_DIRTY_EXEC))) {
+            flags |= REDISMODULE_CTX_FLAGS_MULTI_DIRTY;
+        }
+    }
+
+    if (scriptIsRunning())
+        flags |= REDISMODULE_CTX_FLAGS_LUA;
+
+    if (server.in_exec)
+        flags |= REDISMODULE_CTX_FLAGS_MULTI;
+
+    if (server.cluster_enabled)
+        flags |= REDISMODULE_CTX_FLAGS_CLUSTER;
+
+    if (server.async_loading)
+        flags |= REDISMODULE_CTX_FLAGS_ASYNC_LOADING;
+    else if (server.loading)
+        flags |= REDISMODULE_CTX_FLAGS_LOADING;
+
+    /* Maxmemory and eviction policy */
+    if (server.maxmemory > 0 && (!server.masterhost || !server.repl_slave_ignore_maxmemory)) {
+        flags |= REDISMODULE_CTX_FLAGS_MAXMEMORY;
+
+        if (server.maxmemory_policy != MAXMEMORY_NO_EVICTION)
+            flags |= REDISMODULE_CTX_FLAGS_EVICT;
+    }
+
+    /* Persistence flags */
+    if (server.aof_state != AOF_OFF)
+        flags |= REDISMODULE_CTX_FLAGS_AOF;
+    if (server.saveparamslen > 0)
+        flags |= REDISMODULE_CTX_FLAGS_RDB;
+
+    /* Replication flags */
+    if (server.masterhost == NULL) {
+        flags |= REDISMODULE_CTX_FLAGS_MASTER;
+    } else {
+        flags |= REDISMODULE_CTX_FLAGS_SLAVE;
+        if (server.repl_slave_ro)
+            flags |= REDISMODULE_CTX_FLAGS_READONLY;
+
+        /* Replica state flags. */
+        if (server.repl_state == REPL_STATE_CONNECT ||
+            server.repl_state == REPL_STATE_CONNECTING)
+        {
+            flags |= REDISMODULE_CTX_FLAGS_REPLICA_IS_CONNECTING;
+        } else if (server.repl_state == REPL_STATE_TRANSFER) {
+            flags |= REDISMODULE_CTX_FLAGS_REPLICA_IS_TRANSFERRING;
+        } else if (server.repl_state == REPL_STATE_CONNECTED) {
+            flags |= REDISMODULE_CTX_FLAGS_REPLICA_IS_ONLINE;
+        }
+
+        if (server.repl_state != REPL_STATE_CONNECTED)
+            flags |= REDISMODULE_CTX_FLAGS_REPLICA_IS_STALE;
+    }
+
+    /* OOM flag. */
+    float level;
+    int retval = getMaxmemoryState(NULL,NULL,NULL,&level);
+    if (retval == C_ERR) flags |= REDISMODULE_CTX_FLAGS_OOM;
+    if (level > 0.75) flags |= REDISMODULE_CTX_FLAGS_OOM_WARNING;
+
+    /* Presence of children processes. */
+    if (hasActiveChildProcess()) flags |= REDISMODULE_CTX_FLAGS_ACTIVE_CHILD;
+    if (server.in_fork_child) flags |= REDISMODULE_CTX_FLAGS_IS_CHILD;
+
+    /* Non-empty server.loadmodule_queue means that Redis is starting. */
+    if (listLength(server.loadmodule_queue) > 0)
+        flags |= REDISMODULE_CTX_FLAGS_SERVER_STARTUP;
+
+    return flags;
+}
+
+/* Returns true if a client sent the CLIENT PAUSE command to the server or
+ * if Redis Cluster does a manual failover, pausing the clients.
+ * This is needed when we have a master with replicas, and want to write,
+ * without adding further data to the replication channel, that the replicas
+ * replication offset, match the one of the master. When this happens, it is
+ * safe to failover the master without data loss.
+ *
+ * However modules may generate traffic by calling RedisModule_Call() with
+ * the "!" flag, or by calling RedisModule_Replicate(), in a context outside
+ * commands execution, for instance in timeout callbacks, threads safe
+ * contexts, and so forth. When modules will generate too much traffic, it
+ * will be hard for the master and replicas offset to match, because there
+ * is more data to send in the replication channel.
+ *
+ * So modules may want to try to avoid very heavy background work that has
+ * the effect of creating data to the replication channel, when this function
+ * returns true. This is mostly useful for modules that have background
+ * garbage collection tasks, or that do writes and replicate such writes
+ * periodically in timer callbacks or other periodic callbacks.
+ */
+int RM_AvoidReplicaTraffic(void) {
+    return !!(isPausedActionsWithUpdate(PAUSE_ACTION_REPLICA));
+}
+
+/* Change the currently selected DB. Returns an error if the id
+ * is out of range.
+ *
+ * Note that the client will retain the currently selected DB even after
+ * the Redis command implemented by the module calling this function
+ * returns.
+ *
+ * If the module command wishes to change something in a different DB and
+ * returns back to the original one, it should call RedisModule_GetSelectedDb()
+ * before in order to restore the old DB number before returning. */
+int RM_SelectDb(RedisModuleCtx *ctx, int newid) {
+    int retval = selectDb(ctx->client,newid);
+    return (retval == C_OK) ? REDISMODULE_OK : REDISMODULE_ERR;
+}
+
+/* Check if a key exists, without affecting its last access time.
+ *
+ * This is equivalent to calling RM_OpenKey with the mode REDISMODULE_READ |
+ * REDISMODULE_OPEN_KEY_NOTOUCH, then checking if NULL was returned and, if not,
+ * calling RM_CloseKey on the opened key.
+ */
+int RM_KeyExists(RedisModuleCtx *ctx, robj *keyname) {
+    robj *value = lookupKeyReadWithFlags(ctx->client->db, keyname, LOOKUP_NOTOUCH);
+    return (value != NULL);
+}
+
+/* Initialize a RedisModuleKey struct */
+static void moduleInitKey(RedisModuleKey *kp, RedisModuleCtx *ctx, robj *keyname, robj *value, int mode){
+    kp->ctx = ctx;
+    kp->db = ctx->client->db;
+    kp->key = keyname;
+    incrRefCount(keyname);
+    kp->value = value;
+    kp->iter = NULL;
+    kp->mode = mode;
+    if (kp->value) moduleInitKeyTypeSpecific(kp);
+}
+
+/* Initialize the type-specific part of the key. Only when key has a value. */
+static void moduleInitKeyTypeSpecific(RedisModuleKey *key) {
+    switch (key->value->type) {
+    case OBJ_ZSET: zsetKeyReset(key); break;
+    case OBJ_STREAM: key->u.stream.signalready = 0; break;
+    }
+}
+
+/* Return a handle representing a Redis key, so that it is possible
+ * to call other APIs with the key handle as argument to perform
+ * operations on the key.
+ *
+ * The return value is the handle representing the key, that must be
+ * closed with RM_CloseKey().
+ *
+ * If the key does not exist and REDISMODULE_WRITE mode is requested, the handle
+ * is still returned, since it is possible to perform operations on
+ * a yet not existing key (that will be created, for example, after
+ * a list push operation). If the mode is just REDISMODULE_READ instead, and the
+ * key does not exist, NULL is returned. However it is still safe to
+ * call RedisModule_CloseKey() and RedisModule_KeyType() on a NULL
+ * value.
+ *
+ * Extra flags that can be pass to the API under the mode argument:
+ * * REDISMODULE_OPEN_KEY_NOTOUCH - Avoid touching the LRU/LFU of the key when opened.
+ * * REDISMODULE_OPEN_KEY_NONOTIFY - Don't trigger keyspace event on key misses.
+ * * REDISMODULE_OPEN_KEY_NOSTATS - Don't update keyspace hits/misses counters.
+ * * REDISMODULE_OPEN_KEY_NOEXPIRE - Avoid deleting lazy expired keys.
+ * * REDISMODULE_OPEN_KEY_NOEFFECTS - Avoid any effects from fetching the key. */
+RedisModuleKey *RM_OpenKey(RedisModuleCtx *ctx, robj *keyname, int mode) {
+    RedisModuleKey *kp;
+    robj *value;
+    int flags = 0;
+    flags |= (mode & REDISMODULE_OPEN_KEY_NOTOUCH? LOOKUP_NOTOUCH: 0);
+    flags |= (mode & REDISMODULE_OPEN_KEY_NONOTIFY? LOOKUP_NONOTIFY: 0);
+    flags |= (mode & REDISMODULE_OPEN_KEY_NOSTATS? LOOKUP_NOSTATS: 0);
+    flags |= (mode & REDISMODULE_OPEN_KEY_NOEXPIRE? LOOKUP_NOEXPIRE: 0);
+    flags |= (mode & REDISMODULE_OPEN_KEY_NOEFFECTS? LOOKUP_NOEFFECTS: 0);
+
+    if (mode & REDISMODULE_WRITE) {
+        value = lookupKeyWriteWithFlags(ctx->client->db,keyname, flags);
+    } else {
+        value = lookupKeyReadWithFlags(ctx->client->db,keyname, flags);
+        if (value == NULL) {
+            return NULL;
+        }
+    }
+
+    /* Setup the key handle. */
+    kp = zmalloc(sizeof(*kp));
+    moduleInitKey(kp, ctx, keyname, value, mode);
+    autoMemoryAdd(ctx,REDISMODULE_AM_KEY,kp);
+    return kp;
+}
+
+/**
+ * Returns the full OpenKey modes mask, using the return value
+ * the module can check if a certain set of OpenKey modes are supported
+ * by the redis server version in use.
+ * Example:
+ *
+ *        int supportedMode = RM_GetOpenKeyModesAll();
+ *        if (supportedMode & REDISMODULE_OPEN_KEY_NOTOUCH) {
+ *              // REDISMODULE_OPEN_KEY_NOTOUCH is supported
+ *        } else{
+ *              // REDISMODULE_OPEN_KEY_NOTOUCH is not supported
+ *        }
+ */
+int RM_GetOpenKeyModesAll(void) {
+    return _REDISMODULE_OPEN_KEY_ALL;
+}
+
+/* Destroy a RedisModuleKey struct (freeing is the responsibility of the caller). */
+static void moduleCloseKey(RedisModuleKey *key) {
+    int signal = SHOULD_SIGNAL_MODIFIED_KEYS(key->ctx);
+    if ((key->mode & REDISMODULE_WRITE) && signal)
+        signalModifiedKey(key->ctx->client,key->db,key->key);
+    if (key->value) {
+        if (key->iter) moduleFreeKeyIterator(key);
+        switch (key->value->type) {
+        case OBJ_ZSET:
+            RM_ZsetRangeStop(key);
+            break;
+        case OBJ_STREAM:
+            if (key->u.stream.signalready)
+                /* One or more RM_StreamAdd() have been done. */
+                signalKeyAsReady(key->db, key->key, OBJ_STREAM);
+            break;
+        }
+    }
+    serverAssert(key->iter == NULL);
+    decrRefCount(key->key);
+}
+
+/* Close a key handle. */
+void RM_CloseKey(RedisModuleKey *key) {
+    if (key == NULL) return;
+    moduleCloseKey(key);
+    autoMemoryFreed(key->ctx,REDISMODULE_AM_KEY,key);
+    zfree(key);
+}
+
+/* Return the type of the key. If the key pointer is NULL then
+ * REDISMODULE_KEYTYPE_EMPTY is returned. */
+int RM_KeyType(RedisModuleKey *key) {
+    if (key == NULL || key->value ==  NULL) return REDISMODULE_KEYTYPE_EMPTY;
+    /* We map between defines so that we are free to change the internal
+     * defines as desired. */
+    switch(key->value->type) {
+    case OBJ_STRING: return REDISMODULE_KEYTYPE_STRING;
+    case OBJ_LIST: return REDISMODULE_KEYTYPE_LIST;
+    case OBJ_SET: return REDISMODULE_KEYTYPE_SET;
+    case OBJ_ZSET: return REDISMODULE_KEYTYPE_ZSET;
+    case OBJ_HASH: return REDISMODULE_KEYTYPE_HASH;
+    case OBJ_MODULE: return REDISMODULE_KEYTYPE_MODULE;
+    case OBJ_STREAM: return REDISMODULE_KEYTYPE_STREAM;
+    default: return REDISMODULE_KEYTYPE_EMPTY;
+    }
+}
+
+/* Return the length of the value associated with the key.
+ * For strings this is the length of the string. For all the other types
+ * is the number of elements (just counting keys for hashes).
+ *
+ * If the key pointer is NULL or the key is empty, zero is returned. */
+size_t RM_ValueLength(RedisModuleKey *key) {
+    if (key == NULL || key->value == NULL) return 0;
+    switch(key->value->type) {
+    case OBJ_STRING: return stringObjectLen(key->value);
+    case OBJ_LIST: return listTypeLength(key->value);
+    case OBJ_SET: return setTypeSize(key->value);
+    case OBJ_ZSET: return zsetLength(key->value);
+    case OBJ_HASH: return hashTypeLength(key->value);
+    case OBJ_STREAM: return streamLength(key->value);
+    default: return 0;
+    }
+}
+
+/* If the key is open for writing, remove it, and setup the key to
+ * accept new writes as an empty key (that will be created on demand).
+ * On success REDISMODULE_OK is returned. If the key is not open for
+ * writing REDISMODULE_ERR is returned. */
+int RM_DeleteKey(RedisModuleKey *key) {
+    if (!(key->mode & REDISMODULE_WRITE)) return REDISMODULE_ERR;
+    if (key->value) {
+        dbDelete(key->db,key->key);
+        key->value = NULL;
+    }
+    return REDISMODULE_OK;
+}
+
+/* If the key is open for writing, unlink it (that is delete it in a
+ * non-blocking way, not reclaiming memory immediately) and setup the key to
+ * accept new writes as an empty key (that will be created on demand).
+ * On success REDISMODULE_OK is returned. If the key is not open for
+ * writing REDISMODULE_ERR is returned. */
+int RM_UnlinkKey(RedisModuleKey *key) {
+    if (!(key->mode & REDISMODULE_WRITE)) return REDISMODULE_ERR;
+    if (key->value) {
+        dbAsyncDelete(key->db,key->key);
+        key->value = NULL;
+    }
+    return REDISMODULE_OK;
+}
+
+/* Return the key expire value, as milliseconds of remaining TTL.
+ * If no TTL is associated with the key or if the key is empty,
+ * REDISMODULE_NO_EXPIRE is returned. */
+mstime_t RM_GetExpire(RedisModuleKey *key) {
+    mstime_t expire = getExpire(key->db,key->key);
+    if (expire == -1 || key->value == NULL)
+        return REDISMODULE_NO_EXPIRE;
+    expire -= commandTimeSnapshot();
+    return expire >= 0 ? expire : 0;
+}
+
+/* Set a new expire for the key. If the special expire
+ * REDISMODULE_NO_EXPIRE is set, the expire is cancelled if there was
+ * one (the same as the PERSIST command).
+ *
+ * Note that the expire must be provided as a positive integer representing
+ * the number of milliseconds of TTL the key should have.
+ *
+ * The function returns REDISMODULE_OK on success or REDISMODULE_ERR if
+ * the key was not open for writing or is an empty key. */
+int RM_SetExpire(RedisModuleKey *key, mstime_t expire) {
+    if (!(key->mode & REDISMODULE_WRITE) || key->value == NULL || (expire < 0 && expire != REDISMODULE_NO_EXPIRE))
+        return REDISMODULE_ERR;
+    if (expire != REDISMODULE_NO_EXPIRE) {
+        expire += commandTimeSnapshot();
+        setExpire(key->ctx->client,key->db,key->key,expire);
+    } else {
+        removeExpire(key->db,key->key);
+    }
+    return REDISMODULE_OK;
+}
+
+/* Return the key expire value, as absolute Unix timestamp.
+ * If no TTL is associated with the key or if the key is empty,
+ * REDISMODULE_NO_EXPIRE is returned. */
+mstime_t RM_GetAbsExpire(RedisModuleKey *key) {
+    mstime_t expire = getExpire(key->db,key->key);
+    if (expire == -1 || key->value == NULL)
+        return REDISMODULE_NO_EXPIRE;
+    return expire;
+}
+
+/* Set a new expire for the key. If the special expire
+ * REDISMODULE_NO_EXPIRE is set, the expire is cancelled if there was
+ * one (the same as the PERSIST command).
+ * 
+ * Note that the expire must be provided as a positive integer representing
+ * the absolute Unix timestamp the key should have.
+ *
+ * The function returns REDISMODULE_OK on success or REDISMODULE_ERR if
+ * the key was not open for writing or is an empty key. */
+int RM_SetAbsExpire(RedisModuleKey *key, mstime_t expire) {
+    if (!(key->mode & REDISMODULE_WRITE) || key->value == NULL || (expire < 0 && expire != REDISMODULE_NO_EXPIRE))
+        return REDISMODULE_ERR;
+    if (expire != REDISMODULE_NO_EXPIRE) {
+        setExpire(key->ctx->client,key->db,key->key,expire);
+    } else {
+        removeExpire(key->db,key->key);
+    }
+    return REDISMODULE_OK;
+}
+
+/* Performs similar operation to FLUSHALL, and optionally start a new AOF file (if enabled)
+ * If restart_aof is true, you must make sure the command that triggered this call is not
+ * propagated to the AOF file.
+ * When async is set to true, db contents will be freed by a background thread. */
+void RM_ResetDataset(int restart_aof, int async) {
+    if (restart_aof && server.aof_state != AOF_OFF) stopAppendOnly();
+    flushAllDataAndResetRDB((async? EMPTYDB_ASYNC: EMPTYDB_NO_FLAGS) | EMPTYDB_NOFUNCTIONS);
+    if (server.aof_enabled && restart_aof) restartAOFAfterSYNC();
+}
+
+/* Returns the number of keys in the current db. */
+unsigned long long RM_DbSize(RedisModuleCtx *ctx) {
+    return dictSize(ctx->client->db->dict);
+}
+
+/* Returns a name of a random key, or NULL if current db is empty. */
+RedisModuleString *RM_RandomKey(RedisModuleCtx *ctx) {
+    robj *key = dbRandomKey(ctx->client->db);
+    autoMemoryAdd(ctx,REDISMODULE_AM_STRING,key);
+    return key;
+}
+
+/* Returns the name of the key currently being processed. */
+const RedisModuleString *RM_GetKeyNameFromOptCtx(RedisModuleKeyOptCtx *ctx) {
+    return ctx->from_key;
+}
+
+/* Returns the name of the target key currently being processed. */
+const RedisModuleString *RM_GetToKeyNameFromOptCtx(RedisModuleKeyOptCtx *ctx) {
+    return ctx->to_key;
+}
+
+/* Returns the dbid currently being processed. */
+int RM_GetDbIdFromOptCtx(RedisModuleKeyOptCtx *ctx) {
+    return ctx->from_dbid;
+}
+
+/* Returns the target dbid currently being processed. */
+int RM_GetToDbIdFromOptCtx(RedisModuleKeyOptCtx *ctx) {
+    return ctx->to_dbid;
+}
+/* --------------------------------------------------------------------------
+ * ## Key API for String type
+ *
+ * See also RM_ValueLength(), which returns the length of a string.
+ * -------------------------------------------------------------------------- */
+
+/* If the key is open for writing, set the specified string 'str' as the
+ * value of the key, deleting the old value if any.
+ * On success REDISMODULE_OK is returned. If the key is not open for
+ * writing or there is an active iterator, REDISMODULE_ERR is returned. */
+int RM_StringSet(RedisModuleKey *key, RedisModuleString *str) {
+    if (!(key->mode & REDISMODULE_WRITE) || key->iter) return REDISMODULE_ERR;
+    RM_DeleteKey(key);
+    setKey(key->ctx->client,key->db,key->key,str,SETKEY_NO_SIGNAL);
+    key->value = str;
+    return REDISMODULE_OK;
+}
+
+/* Prepare the key associated string value for DMA access, and returns
+ * a pointer and size (by reference), that the user can use to read or
+ * modify the string in-place accessing it directly via pointer.
+ *
+ * The 'mode' is composed by bitwise OR-ing the following flags:
+ *
+ *     REDISMODULE_READ -- Read access
+ *     REDISMODULE_WRITE -- Write access
+ *
+ * If the DMA is not requested for writing, the pointer returned should
+ * only be accessed in a read-only fashion.
+ *
+ * On error (wrong type) NULL is returned.
+ *
+ * DMA access rules:
+ *
+ * 1. No other key writing function should be called since the moment
+ * the pointer is obtained, for all the time we want to use DMA access
+ * to read or modify the string.
+ *
+ * 2. Each time RM_StringTruncate() is called, to continue with the DMA
+ * access, RM_StringDMA() should be called again to re-obtain
+ * a new pointer and length.
+ *
+ * 3. If the returned pointer is not NULL, but the length is zero, no
+ * byte can be touched (the string is empty, or the key itself is empty)
+ * so a RM_StringTruncate() call should be used if there is to enlarge
+ * the string, and later call StringDMA() again to get the pointer.
+ */
+char *RM_StringDMA(RedisModuleKey *key, size_t *len, int mode) {
+    /* We need to return *some* pointer for empty keys, we just return
+     * a string literal pointer, that is the advantage to be mapped into
+     * a read only memory page, so the module will segfault if a write
+     * attempt is performed. */
+    char *emptystring = "<dma-empty-string>";
+    if (key->value == NULL) {
+        *len = 0;
+        return emptystring;
+    }
+
+    if (key->value->type != OBJ_STRING) return NULL;
+
+    /* For write access, and even for read access if the object is encoded,
+     * we unshare the string (that has the side effect of decoding it). */
+    if ((mode & REDISMODULE_WRITE) || key->value->encoding != OBJ_ENCODING_RAW)
+        key->value = dbUnshareStringValue(key->db, key->key, key->value);
+
+    *len = sdslen(key->value->ptr);
+    return key->value->ptr;
+}
+
+/* If the key is open for writing and is of string type, resize it, padding
+ * with zero bytes if the new length is greater than the old one.
+ *
+ * After this call, RM_StringDMA() must be called again to continue
+ * DMA access with the new pointer.
+ *
+ * The function returns REDISMODULE_OK on success, and REDISMODULE_ERR on
+ * error, that is, the key is not open for writing, is not a string
+ * or resizing for more than 512 MB is requested.
+ *
+ * If the key is empty, a string key is created with the new string value
+ * unless the new length value requested is zero. */
+int RM_StringTruncate(RedisModuleKey *key, size_t newlen) {
+    if (!(key->mode & REDISMODULE_WRITE)) return REDISMODULE_ERR;
+    if (key->value && key->value->type != OBJ_STRING) return REDISMODULE_ERR;
+    if (newlen > 512*1024*1024) return REDISMODULE_ERR;
+
+    /* Empty key and new len set to 0. Just return REDISMODULE_OK without
+     * doing anything. */
+    if (key->value == NULL && newlen == 0) return REDISMODULE_OK;
+
+    if (key->value == NULL) {
+        /* Empty key: create it with the new size. */
+        robj *o = createObject(OBJ_STRING,sdsnewlen(NULL, newlen));
+        setKey(key->ctx->client,key->db,key->key,o,SETKEY_NO_SIGNAL);
+        key->value = o;
+        decrRefCount(o);
+    } else {
+        /* Unshare and resize. */
+        key->value = dbUnshareStringValue(key->db, key->key, key->value);
+        size_t curlen = sdslen(key->value->ptr);
+        if (newlen > curlen) {
+            key->value->ptr = sdsgrowzero(key->value->ptr,newlen);
+        } else if (newlen < curlen) {
+            sdssubstr(key->value->ptr,0,newlen);
+            /* If the string is too wasteful, reallocate it. */
+            if (sdslen(key->value->ptr) < sdsavail(key->value->ptr))
+                key->value->ptr = sdsRemoveFreeSpace(key->value->ptr, 0);
+        }
+    }
+    return REDISMODULE_OK;
+}
+
+/* --------------------------------------------------------------------------
+ * ## Key API for List type
+ *
+ * Many of the list functions access elements by index. Since a list is in
+ * essence a doubly-linked list, accessing elements by index is generally an
+ * O(N) operation. However, if elements are accessed sequentially or with
+ * indices close together, the functions are optimized to seek the index from
+ * the previous index, rather than seeking from the ends of the list.
+ *
+ * This enables iteration to be done efficiently using a simple for loop:
+ *
+ *     long n = RM_ValueLength(key);
+ *     for (long i = 0; i < n; i++) {
+ *         RedisModuleString *elem = RedisModule_ListGet(key, i);
+ *         // Do stuff...
+ *     }
+ *
+ * Note that after modifying a list using RM_ListPop, RM_ListSet or
+ * RM_ListInsert, the internal iterator is invalidated so the next operation
+ * will require a linear seek.
+ *
+ * Modifying a list in any another way, for example using RM_Call(), while a key
+ * is open will confuse the internal iterator and may cause trouble if the key
+ * is used after such modifications. The key must be reopened in this case.
+ *
+ * See also RM_ValueLength(), which returns the length of a list.
+ * -------------------------------------------------------------------------- */
+
+/* Seeks the key's internal list iterator to the given index. On success, 1 is
+ * returned and key->iter, key->u.list.entry and key->u.list.index are set. On
+ * failure, 0 is returned and errno is set as required by the list API
+ * functions. */
+int moduleListIteratorSeek(RedisModuleKey *key, long index, int mode) {
+    if (!key) {
+        errno = EINVAL;
+        return 0;
+    } else if (!key->value || key->value->type != OBJ_LIST) {
+        errno = ENOTSUP;
+        return 0;
+    } if (!(key->mode & mode)) {
+        errno = EBADF;
+        return 0;
+    }
+
+    long length = listTypeLength(key->value);
+    if (index < -length || index >= length) {
+        errno = EDOM; /* Invalid index */
+        return 0;
+    }
+
+    if (key->iter == NULL) {
+        /* No existing iterator. Create one. */
+        key->iter = listTypeInitIterator(key->value, index, LIST_TAIL);
+        serverAssert(key->iter != NULL);
+        serverAssert(listTypeNext(key->iter, &key->u.list.entry));
+        key->u.list.index = index;
+        return 1;
+    }
+
+    /* There's an existing iterator. Make sure the requested index has the same
+     * sign as the iterator's index. */
+    if      (index < 0 && key->u.list.index >= 0) index += length;
+    else if (index >= 0 && key->u.list.index < 0) index -= length;
+
+    if (index == key->u.list.index) return 1; /* We're done. */
+
+    /* Seek the iterator to the requested index. */
+    unsigned char dir = key->u.list.index < index ? LIST_TAIL : LIST_HEAD;
+    listTypeSetIteratorDirection(key->iter, &key->u.list.entry, dir);
+    while (key->u.list.index != index) {
+        serverAssert(listTypeNext(key->iter, &key->u.list.entry));
+        key->u.list.index += dir == LIST_HEAD ? -1 : 1;
+    }
+    return 1;
+}
+
+/* Push an element into a list, on head or tail depending on 'where' argument
+ * (REDISMODULE_LIST_HEAD or REDISMODULE_LIST_TAIL). If the key refers to an
+ * empty key opened for writing, the key is created. On success, REDISMODULE_OK
+ * is returned. On failure, REDISMODULE_ERR is returned and `errno` is set as
+ * follows:
+ *
+ * - EINVAL if key or ele is NULL.
+ * - ENOTSUP if the key is of another type than list.
+ * - EBADF if the key is not opened for writing.
+ *
+ * Note: Before Redis 7.0, `errno` was not set by this function. */
+int RM_ListPush(RedisModuleKey *key, int where, RedisModuleString *ele) {
+    if (!key || !ele) {
+        errno = EINVAL;
+        return REDISMODULE_ERR;
+    } else if (key->value != NULL && key->value->type != OBJ_LIST) {
+        errno = ENOTSUP;
+        return REDISMODULE_ERR;
+    } if (!(key->mode & REDISMODULE_WRITE)) {
+        errno = EBADF;
+        return REDISMODULE_ERR;
+    }
+
+    if (!(key->mode & REDISMODULE_WRITE)) return REDISMODULE_ERR;
+    if (key->value && key->value->type != OBJ_LIST) return REDISMODULE_ERR;
+    if (key->iter) moduleFreeKeyIterator(key);
+    if (key->value == NULL) moduleCreateEmptyKey(key,REDISMODULE_KEYTYPE_LIST);
+    listTypeTryConversionAppend(key->value, &ele, 0, 0, moduleFreeListIterator, key);
+    listTypePush(key->value, ele,
+        (where == REDISMODULE_LIST_HEAD) ? LIST_HEAD : LIST_TAIL);
+    return REDISMODULE_OK;
+}
+
+/* Pop an element from the list, and returns it as a module string object
+ * that the user should be free with RM_FreeString() or by enabling
+ * automatic memory. The `where` argument specifies if the element should be
+ * popped from the beginning or the end of the list (REDISMODULE_LIST_HEAD or
+ * REDISMODULE_LIST_TAIL). On failure, the command returns NULL and sets
+ * `errno` as follows:
+ *
+ * - EINVAL if key is NULL.
+ * - ENOTSUP if the key is empty or of another type than list.
+ * - EBADF if the key is not opened for writing.
+ *
+ * Note: Before Redis 7.0, `errno` was not set by this function. */
+RedisModuleString *RM_ListPop(RedisModuleKey *key, int where) {
+    if (!key) {
+        errno = EINVAL;
+        return NULL;
+    } else if (key->value == NULL || key->value->type != OBJ_LIST) {
+        errno = ENOTSUP;
+        return NULL;
+    } else if (!(key->mode & REDISMODULE_WRITE)) {
+        errno = EBADF;
+        return NULL;
+    }
+    if (key->iter) moduleFreeKeyIterator(key);
+    robj *ele = listTypePop(key->value,
+        (where == REDISMODULE_LIST_HEAD) ? LIST_HEAD : LIST_TAIL);
+    robj *decoded = getDecodedObject(ele);
+    decrRefCount(ele);
+    if (!moduleDelKeyIfEmpty(key))
+        listTypeTryConversion(key->value, LIST_CONV_SHRINKING, moduleFreeListIterator, key);
+    autoMemoryAdd(key->ctx,REDISMODULE_AM_STRING,decoded);
+    return decoded;
+}
+
+/* Returns the element at index `index` in the list stored at `key`, like the
+ * LINDEX command. The element should be free'd using RM_FreeString() or using
+ * automatic memory management.
+ *
+ * The index is zero-based, so 0 means the first element, 1 the second element
+ * and so on. Negative indices can be used to designate elements starting at the
+ * tail of the list. Here, -1 means the last element, -2 means the penultimate
+ * and so forth.
+ *
+ * When no value is found at the given key and index, NULL is returned and
+ * `errno` is set as follows:
+ *
+ * - EINVAL if key is NULL.
+ * - ENOTSUP if the key is not a list.
+ * - EBADF if the key is not opened for reading.
+ * - EDOM if the index is not a valid index in the list.
+ */
+RedisModuleString *RM_ListGet(RedisModuleKey *key, long index) {
+    if (moduleListIteratorSeek(key, index, REDISMODULE_READ)) {
+        robj *elem = listTypeGet(&key->u.list.entry);
+        robj *decoded = getDecodedObject(elem);
+        decrRefCount(elem);
+        autoMemoryAdd(key->ctx, REDISMODULE_AM_STRING, decoded);
+        return decoded;
+    } else {
+        return NULL;
+    }
+}
+
+/* Replaces the element at index `index` in the list stored at `key`.
+ *
+ * The index is zero-based, so 0 means the first element, 1 the second element
+ * and so on. Negative indices can be used to designate elements starting at the
+ * tail of the list. Here, -1 means the last element, -2 means the penultimate
+ * and so forth.
+ *
+ * On success, REDISMODULE_OK is returned. On failure, REDISMODULE_ERR is
+ * returned and `errno` is set as follows:
+ *
+ * - EINVAL if key or value is NULL.
+ * - ENOTSUP if the key is not a list.
+ * - EBADF if the key is not opened for writing.
+ * - EDOM if the index is not a valid index in the list.
+ */
+int RM_ListSet(RedisModuleKey *key, long index, RedisModuleString *value) {
+    if (!value) {
+        errno = EINVAL;
+        return REDISMODULE_ERR;
+    }
+    if (!key->value || key->value->type != OBJ_LIST) {
+        errno = ENOTSUP;
+        return REDISMODULE_ERR;
+    }
+    listTypeTryConversionAppend(key->value, &value, 0, 0, moduleFreeListIterator, key);
+    if (moduleListIteratorSeek(key, index, REDISMODULE_WRITE)) {
+        listTypeReplace(&key->u.list.entry, value);
+        /* A note in quicklist.c forbids use of iterator after insert, so
+         * probably also after replace. */
+        moduleFreeKeyIterator(key);
+        return REDISMODULE_OK;
+    } else {
+        return REDISMODULE_ERR;
+    }
+}
+
+/* Inserts an element at the given index.
+ *
+ * The index is zero-based, so 0 means the first element, 1 the second element
+ * and so on. Negative indices can be used to designate elements starting at the
+ * tail of the list. Here, -1 means the last element, -2 means the penultimate
+ * and so forth. The index is the element's index after inserting it.
+ *
+ * On success, REDISMODULE_OK is returned. On failure, REDISMODULE_ERR is
+ * returned and `errno` is set as follows:
+ *
+ * - EINVAL if key or value is NULL.
+ * - ENOTSUP if the key of another type than list.
+ * - EBADF if the key is not opened for writing.
+ * - EDOM if the index is not a valid index in the list.
+ */
+int RM_ListInsert(RedisModuleKey *key, long index, RedisModuleString *value) {
+    if (!value) {
+        errno = EINVAL;
+        return REDISMODULE_ERR;
+    } else if (key != NULL && key->value == NULL &&
+               (index == 0 || index == -1)) {
+        /* Insert in empty key => push. */
+        return RM_ListPush(key, REDISMODULE_LIST_TAIL, value);
+    } else if (key != NULL && key->value != NULL &&
+               key->value->type == OBJ_LIST &&
+               (index == (long)listTypeLength(key->value) || index == -1)) {
+        /* Insert after the last element => push tail. */
+        return RM_ListPush(key, REDISMODULE_LIST_TAIL, value);
+    } else if (key != NULL && key->value != NULL &&
+               key->value->type == OBJ_LIST &&
+               (index == 0 || index == -(long)listTypeLength(key->value) - 1)) {
+        /* Insert before the first element => push head. */
+        return RM_ListPush(key, REDISMODULE_LIST_HEAD, value);
+    }
+    listTypeTryConversionAppend(key->value, &value, 0, 0, moduleFreeListIterator, key);
+    if (moduleListIteratorSeek(key, index, REDISMODULE_WRITE)) {
+        int where = index < 0 ? LIST_TAIL : LIST_HEAD;
+        listTypeInsert(&key->u.list.entry, value, where);
+        /* A note in quicklist.c forbids use of iterator after insert. */
+        moduleFreeKeyIterator(key);
+        return REDISMODULE_OK;
+    } else {
+        return REDISMODULE_ERR;
+    }
+}
+
+/* Removes an element at the given index. The index is 0-based. A negative index
+ * can also be used, counting from the end of the list.
+ *
+ * On success, REDISMODULE_OK is returned. On failure, REDISMODULE_ERR is
+ * returned and `errno` is set as follows:
+ *
+ * - EINVAL if key or value is NULL.
+ * - ENOTSUP if the key is not a list.
+ * - EBADF if the key is not opened for writing.
+ * - EDOM if the index is not a valid index in the list.
+ */
+int RM_ListDelete(RedisModuleKey *key, long index) {
+    if (moduleListIteratorSeek(key, index, REDISMODULE_WRITE)) {
+        listTypeDelete(key->iter, &key->u.list.entry);
+        if (moduleDelKeyIfEmpty(key)) return REDISMODULE_OK;
+        listTypeTryConversion(key->value, LIST_CONV_SHRINKING, moduleFreeListIterator, key);
+        if (!key->iter) return REDISMODULE_OK; /* Return ASAP if iterator has been freed */
+        if (listTypeNext(key->iter, &key->u.list.entry)) {
+            /* After delete entry at position 'index', we need to update
+             * 'key->u.list.index' according to the following cases:
+             * 1) [1, 2, 3] => dir: forward, index: 0  => [2, 3] => index: still 0
+             * 2) [1, 2, 3] => dir: forward, index: -3 => [2, 3] => index: -2
+             * 3) [1, 2, 3] => dir: reverse, index: 2  => [1, 2] => index: 1
+             * 4) [1, 2, 3] => dir: reverse, index: -1 => [1, 2] => index: still -1 */
+            listTypeIterator *li = key->iter;
+            int reverse = li->direction == LIST_HEAD;
+            if (key->u.list.index < 0)
+                key->u.list.index += reverse ? 0 : 1;
+            else
+                key->u.list.index += reverse ? -1 : 0;
+        } else {
+            /* Reset list iterator if the next entry doesn't exist. */
+            moduleFreeKeyIterator(key);
+        }
+        return REDISMODULE_OK;
+    } else {
+        return REDISMODULE_ERR;
+    }
+}
+
+/* --------------------------------------------------------------------------
+ * ## Key API for Sorted Set type
+ *
+ * See also RM_ValueLength(), which returns the length of a sorted set.
+ * -------------------------------------------------------------------------- */
+
+/* Conversion from/to public flags of the Modules API and our private flags,
+ * so that we have everything decoupled. */
+int moduleZsetAddFlagsToCoreFlags(int flags) {
+    int retflags = 0;
+    if (flags & REDISMODULE_ZADD_XX) retflags |= ZADD_IN_XX;
+    if (flags & REDISMODULE_ZADD_NX) retflags |= ZADD_IN_NX;
+    if (flags & REDISMODULE_ZADD_GT) retflags |= ZADD_IN_GT;
+    if (flags & REDISMODULE_ZADD_LT) retflags |= ZADD_IN_LT;
+    return retflags;
+}
+
+/* See previous function comment. */
+int moduleZsetAddFlagsFromCoreFlags(int flags) {
+    int retflags = 0;
+    if (flags & ZADD_OUT_ADDED) retflags |= REDISMODULE_ZADD_ADDED;
+    if (flags & ZADD_OUT_UPDATED) retflags |= REDISMODULE_ZADD_UPDATED;
+    if (flags & ZADD_OUT_NOP) retflags |= REDISMODULE_ZADD_NOP;
+    return retflags;
+}
+
+/* Add a new element into a sorted set, with the specified 'score'.
+ * If the element already exists, the score is updated.
+ *
+ * A new sorted set is created at value if the key is an empty open key
+ * setup for writing.
+ *
+ * Additional flags can be passed to the function via a pointer, the flags
+ * are both used to receive input and to communicate state when the function
+ * returns. 'flagsptr' can be NULL if no special flags are used.
+ *
+ * The input flags are:
+ *
+ *     REDISMODULE_ZADD_XX: Element must already exist. Do nothing otherwise.
+ *     REDISMODULE_ZADD_NX: Element must not exist. Do nothing otherwise.
+ *     REDISMODULE_ZADD_GT: If element exists, new score must be greater than the current score. 
+ *                          Do nothing otherwise. Can optionally be combined with XX.
+ *     REDISMODULE_ZADD_LT: If element exists, new score must be less than the current score.
+ *                          Do nothing otherwise. Can optionally be combined with XX.
+ *
+ * The output flags are:
+ *
+ *     REDISMODULE_ZADD_ADDED: The new element was added to the sorted set.
+ *     REDISMODULE_ZADD_UPDATED: The score of the element was updated.
+ *     REDISMODULE_ZADD_NOP: No operation was performed because XX or NX flags.
+ *
+ * On success the function returns REDISMODULE_OK. On the following errors
+ * REDISMODULE_ERR is returned:
+ *
+ * * The key was not opened for writing.
+ * * The key is of the wrong type.
+ * * 'score' double value is not a number (NaN).
+ */
+int RM_ZsetAdd(RedisModuleKey *key, double score, RedisModuleString *ele, int *flagsptr) {
+    int in_flags = 0, out_flags = 0;
+    if (!(key->mode & REDISMODULE_WRITE)) return REDISMODULE_ERR;
+    if (key->value && key->value->type != OBJ_ZSET) return REDISMODULE_ERR;
+    if (key->value == NULL) moduleCreateEmptyKey(key,REDISMODULE_KEYTYPE_ZSET);
+    if (flagsptr) in_flags = moduleZsetAddFlagsToCoreFlags(*flagsptr);
+    if (zsetAdd(key->value,score,ele->ptr,in_flags,&out_flags,NULL) == 0) {
+        if (flagsptr) *flagsptr = 0;
+        moduleDelKeyIfEmpty(key);
+        return REDISMODULE_ERR;
+    }
+    if (flagsptr) *flagsptr = moduleZsetAddFlagsFromCoreFlags(out_flags);
+    return REDISMODULE_OK;
+}
+
+/* This function works exactly like RM_ZsetAdd(), but instead of setting
+ * a new score, the score of the existing element is incremented, or if the
+ * element does not already exist, it is added assuming the old score was
+ * zero.
+ *
+ * The input and output flags, and the return value, have the same exact
+ * meaning, with the only difference that this function will return
+ * REDISMODULE_ERR even when 'score' is a valid double number, but adding it
+ * to the existing score results into a NaN (not a number) condition.
+ *
+ * This function has an additional field 'newscore', if not NULL is filled
+ * with the new score of the element after the increment, if no error
+ * is returned. */
+int RM_ZsetIncrby(RedisModuleKey *key, double score, RedisModuleString *ele, int *flagsptr, double *newscore) {
+    int in_flags = 0, out_flags = 0;
+    if (!(key->mode & REDISMODULE_WRITE)) return REDISMODULE_ERR;
+    if (key->value && key->value->type != OBJ_ZSET) return REDISMODULE_ERR;
+    if (key->value == NULL) moduleCreateEmptyKey(key,REDISMODULE_KEYTYPE_ZSET);
+    if (flagsptr) in_flags = moduleZsetAddFlagsToCoreFlags(*flagsptr);
+    in_flags |= ZADD_IN_INCR;
+    if (zsetAdd(key->value,score,ele->ptr,in_flags,&out_flags,newscore) == 0) {
+        if (flagsptr) *flagsptr = 0;
+        moduleDelKeyIfEmpty(key);
+        return REDISMODULE_ERR;
+    }
+    if (flagsptr) *flagsptr = moduleZsetAddFlagsFromCoreFlags(out_flags);
+    return REDISMODULE_OK;
+}
+
+/* Remove the specified element from the sorted set.
+ * The function returns REDISMODULE_OK on success, and REDISMODULE_ERR
+ * on one of the following conditions:
+ *
+ * * The key was not opened for writing.
+ * * The key is of the wrong type.
+ *
+ * The return value does NOT indicate the fact the element was really
+ * removed (since it existed) or not, just if the function was executed
+ * with success.
+ *
+ * In order to know if the element was removed, the additional argument
+ * 'deleted' must be passed, that populates the integer by reference
+ * setting it to 1 or 0 depending on the outcome of the operation.
+ * The 'deleted' argument can be NULL if the caller is not interested
+ * to know if the element was really removed.
+ *
+ * Empty keys will be handled correctly by doing nothing. */
+int RM_ZsetRem(RedisModuleKey *key, RedisModuleString *ele, int *deleted) {
+    if (!(key->mode & REDISMODULE_WRITE)) return REDISMODULE_ERR;
+    if (key->value && key->value->type != OBJ_ZSET) return REDISMODULE_ERR;
+    if (key->value != NULL && zsetDel(key->value,ele->ptr)) {
+        if (deleted) *deleted = 1;
+        moduleDelKeyIfEmpty(key);
+    } else {
+        if (deleted) *deleted = 0;
+    }
+    return REDISMODULE_OK;
+}
+
+/* On success retrieve the double score associated at the sorted set element
+ * 'ele' and returns REDISMODULE_OK. Otherwise REDISMODULE_ERR is returned
+ * to signal one of the following conditions:
+ *
+ * * There is no such element 'ele' in the sorted set.
+ * * The key is not a sorted set.
+ * * The key is an open empty key.
+ */
+int RM_ZsetScore(RedisModuleKey *key, RedisModuleString *ele, double *score) {
+    if (key->value == NULL) return REDISMODULE_ERR;
+    if (key->value->type != OBJ_ZSET) return REDISMODULE_ERR;
+    if (zsetScore(key->value,ele->ptr,score) == C_ERR) return REDISMODULE_ERR;
+    return REDISMODULE_OK;
+}
+
+/* --------------------------------------------------------------------------
+ * ## Key API for Sorted Set iterator
+ * -------------------------------------------------------------------------- */
+
+void zsetKeyReset(RedisModuleKey *key) {
+    key->u.zset.type = REDISMODULE_ZSET_RANGE_NONE;
+    key->u.zset.current = NULL;
+    key->u.zset.er = 1;
+}
+
+/* Stop a sorted set iteration. */
+void RM_ZsetRangeStop(RedisModuleKey *key) {
+    if (!key->value || key->value->type != OBJ_ZSET) return;
+    /* Free resources if needed. */
+    if (key->u.zset.type == REDISMODULE_ZSET_RANGE_LEX)
+        zslFreeLexRange(&key->u.zset.lrs);
+    /* Setup sensible values so that misused iteration API calls when an
+     * iterator is not active will result into something more sensible
+     * than crashing. */
+    zsetKeyReset(key);
+}
+
+/* Return the "End of range" flag value to signal the end of the iteration. */
+int RM_ZsetRangeEndReached(RedisModuleKey *key) {
+    if (!key->value || key->value->type != OBJ_ZSET) return 1;
+    return key->u.zset.er;
+}
+
+/* Helper function for RM_ZsetFirstInScoreRange() and RM_ZsetLastInScoreRange().
+ * Setup the sorted set iteration according to the specified score range
+ * (see the functions calling it for more info). If 'first' is true the
+ * first element in the range is used as a starting point for the iterator
+ * otherwise the last. Return REDISMODULE_OK on success otherwise
+ * REDISMODULE_ERR. */
+int zsetInitScoreRange(RedisModuleKey *key, double min, double max, int minex, int maxex, int first) {
+    if (!key->value || key->value->type != OBJ_ZSET) return REDISMODULE_ERR;
+
+    RM_ZsetRangeStop(key);
+    key->u.zset.type = REDISMODULE_ZSET_RANGE_SCORE;
+    key->u.zset.er = 0;
+
+    /* Setup the range structure used by the sorted set core implementation
+     * in order to seek at the specified element. */
+    zrangespec *zrs = &key->u.zset.rs;
+    zrs->min = min;
+    zrs->max = max;
+    zrs->minex = minex;
+    zrs->maxex = maxex;
+
+    if (key->value->encoding == OBJ_ENCODING_LISTPACK) {
+        key->u.zset.current = first ? zzlFirstInRange(key->value->ptr,zrs) :
+                                      zzlLastInRange(key->value->ptr,zrs);
+    } else if (key->value->encoding == OBJ_ENCODING_SKIPLIST) {
+        zset *zs = key->value->ptr;
+        zskiplist *zsl = zs->zsl;
+        key->u.zset.current = first ? zslFirstInRange(zsl,zrs) :
+                                      zslLastInRange(zsl,zrs);
+    } else {
+        serverPanic("Unsupported zset encoding");
+    }
+    if (key->u.zset.current == NULL) key->u.zset.er = 1;
+    return REDISMODULE_OK;
+}
+
+/* Setup a sorted set iterator seeking the first element in the specified
+ * range. Returns REDISMODULE_OK if the iterator was correctly initialized
+ * otherwise REDISMODULE_ERR is returned in the following conditions:
+ *
+ * 1. The value stored at key is not a sorted set or the key is empty.
+ *
+ * The range is specified according to the two double values 'min' and 'max'.
+ * Both can be infinite using the following two macros:
+ *
+ * * REDISMODULE_POSITIVE_INFINITE for positive infinite value
+ * * REDISMODULE_NEGATIVE_INFINITE for negative infinite value
+ *
+ * 'minex' and 'maxex' parameters, if true, respectively setup a range
+ * where the min and max value are exclusive (not included) instead of
+ * inclusive. */
+int RM_ZsetFirstInScoreRange(RedisModuleKey *key, double min, double max, int minex, int maxex) {
+    return zsetInitScoreRange(key,min,max,minex,maxex,1);
+}
+
+/* Exactly like RedisModule_ZsetFirstInScoreRange() but the last element of
+ * the range is selected for the start of the iteration instead. */
+int RM_ZsetLastInScoreRange(RedisModuleKey *key, double min, double max, int minex, int maxex) {
+    return zsetInitScoreRange(key,min,max,minex,maxex,0);
+}
+
+/* Helper function for RM_ZsetFirstInLexRange() and RM_ZsetLastInLexRange().
+ * Setup the sorted set iteration according to the specified lexicographical
+ * range (see the functions calling it for more info). If 'first' is true the
+ * first element in the range is used as a starting point for the iterator
+ * otherwise the last. Return REDISMODULE_OK on success otherwise
+ * REDISMODULE_ERR.
+ *
+ * Note that this function takes 'min' and 'max' in the same form of the
+ * Redis ZRANGEBYLEX command. */
+int zsetInitLexRange(RedisModuleKey *key, RedisModuleString *min, RedisModuleString *max, int first) {
+    if (!key->value || key->value->type != OBJ_ZSET) return REDISMODULE_ERR;
+
+    RM_ZsetRangeStop(key);
+    key->u.zset.er = 0;
+
+    /* Setup the range structure used by the sorted set core implementation
+     * in order to seek at the specified element. */
+    zlexrangespec *zlrs = &key->u.zset.lrs;
+    if (zslParseLexRange(min, max, zlrs) == C_ERR) return REDISMODULE_ERR;
+
+    /* Set the range type to lex only after successfully parsing the range,
+     * otherwise we don't want the zlexrangespec to be freed. */
+    key->u.zset.type = REDISMODULE_ZSET_RANGE_LEX;
+
+    if (key->value->encoding == OBJ_ENCODING_LISTPACK) {
+        key->u.zset.current = first ? zzlFirstInLexRange(key->value->ptr,zlrs) :
+                                      zzlLastInLexRange(key->value->ptr,zlrs);
+    } else if (key->value->encoding == OBJ_ENCODING_SKIPLIST) {
+        zset *zs = key->value->ptr;
+        zskiplist *zsl = zs->zsl;
+        key->u.zset.current = first ? zslFirstInLexRange(zsl,zlrs) :
+                                      zslLastInLexRange(zsl,zlrs);
+    } else {
+        serverPanic("Unsupported zset encoding");
+    }
+    if (key->u.zset.current == NULL) key->u.zset.er = 1;
+
+    return REDISMODULE_OK;
+}
+
+/* Setup a sorted set iterator seeking the first element in the specified
+ * lexicographical range. Returns REDISMODULE_OK if the iterator was correctly
+ * initialized otherwise REDISMODULE_ERR is returned in the
+ * following conditions:
+ *
+ * 1. The value stored at key is not a sorted set or the key is empty.
+ * 2. The lexicographical range 'min' and 'max' format is invalid.
+ *
+ * 'min' and 'max' should be provided as two RedisModuleString objects
+ * in the same format as the parameters passed to the ZRANGEBYLEX command.
+ * The function does not take ownership of the objects, so they can be released
+ * ASAP after the iterator is setup. */
+int RM_ZsetFirstInLexRange(RedisModuleKey *key, RedisModuleString *min, RedisModuleString *max) {
+    return zsetInitLexRange(key,min,max,1);
+}
+
+/* Exactly like RedisModule_ZsetFirstInLexRange() but the last element of
+ * the range is selected for the start of the iteration instead. */
+int RM_ZsetLastInLexRange(RedisModuleKey *key, RedisModuleString *min, RedisModuleString *max) {
+    return zsetInitLexRange(key,min,max,0);
+}
+
+/* Return the current sorted set element of an active sorted set iterator
+ * or NULL if the range specified in the iterator does not include any
+ * element. */
+RedisModuleString *RM_ZsetRangeCurrentElement(RedisModuleKey *key, double *score) {
+    RedisModuleString *str;
+
+    if (!key->value || key->value->type != OBJ_ZSET) return NULL;
+    if (key->u.zset.current == NULL) return NULL;
+    if (key->value->encoding == OBJ_ENCODING_LISTPACK) {
+        unsigned char *eptr, *sptr;
+        eptr = key->u.zset.current;
+        sds ele = lpGetObject(eptr);
+        if (score) {
+            sptr = lpNext(key->value->ptr,eptr);
+            *score = zzlGetScore(sptr);
+        }
+        str = createObject(OBJ_STRING,ele);
+    } else if (key->value->encoding == OBJ_ENCODING_SKIPLIST) {
+        zskiplistNode *ln = key->u.zset.current;
+        if (score) *score = ln->score;
+        str = createStringObject(ln->ele,sdslen(ln->ele));
+    } else {
+        serverPanic("Unsupported zset encoding");
+    }
+    autoMemoryAdd(key->ctx,REDISMODULE_AM_STRING,str);
+    return str;
+}
+
+/* Go to the next element of the sorted set iterator. Returns 1 if there was
+ * a next element, 0 if we are already at the latest element or the range
+ * does not include any item at all. */
+int RM_ZsetRangeNext(RedisModuleKey *key) {
+    if (!key->value || key->value->type != OBJ_ZSET) return 0;
+    if (!key->u.zset.type || !key->u.zset.current) return 0; /* No active iterator. */
+
+    if (key->value->encoding == OBJ_ENCODING_LISTPACK) {
+        unsigned char *zl = key->value->ptr;
+        unsigned char *eptr = key->u.zset.current;
+        unsigned char *next;
+        next = lpNext(zl,eptr); /* Skip element. */
+        if (next) next = lpNext(zl,next); /* Skip score. */
+        if (next == NULL) {
+            key->u.zset.er = 1;
+            return 0;
+        } else {
+            /* Are we still within the range? */
+            if (key->u.zset.type == REDISMODULE_ZSET_RANGE_SCORE) {
+                /* Fetch the next element score for the
+                 * range check. */
+                unsigned char *saved_next = next;
+                next = lpNext(zl,next); /* Skip next element. */
+                double score = zzlGetScore(next); /* Obtain the next score. */
+                if (!zslValueLteMax(score,&key->u.zset.rs)) {
+                    key->u.zset.er = 1;
+                    return 0;
+                }
+                next = saved_next;
+            } else if (key->u.zset.type == REDISMODULE_ZSET_RANGE_LEX) {
+                if (!zzlLexValueLteMax(next,&key->u.zset.lrs)) {
+                    key->u.zset.er = 1;
+                    return 0;
+                }
+            }
+            key->u.zset.current = next;
+            return 1;
+        }
+    } else if (key->value->encoding == OBJ_ENCODING_SKIPLIST) {
+        zskiplistNode *ln = key->u.zset.current, *next = ln->level[0].forward;
+        if (next == NULL) {
+            key->u.zset.er = 1;
+            return 0;
+        } else {
+            /* Are we still within the range? */
+            if (key->u.zset.type == REDISMODULE_ZSET_RANGE_SCORE &&
+                !zslValueLteMax(next->score,&key->u.zset.rs))
+            {
+                key->u.zset.er = 1;
+                return 0;
+            } else if (key->u.zset.type == REDISMODULE_ZSET_RANGE_LEX) {
+                if (!zslLexValueLteMax(next->ele,&key->u.zset.lrs)) {
+                    key->u.zset.er = 1;
+                    return 0;
+                }
+            }
+            key->u.zset.current = next;
+            return 1;
+        }
+    } else {
+        serverPanic("Unsupported zset encoding");
+    }
+}
+
+/* Go to the previous element of the sorted set iterator. Returns 1 if there was
+ * a previous element, 0 if we are already at the first element or the range
+ * does not include any item at all. */
+int RM_ZsetRangePrev(RedisModuleKey *key) {
+    if (!key->value || key->value->type != OBJ_ZSET) return 0;
+    if (!key->u.zset.type || !key->u.zset.current) return 0; /* No active iterator. */
+
+    if (key->value->encoding == OBJ_ENCODING_LISTPACK) {
+        unsigned char *zl = key->value->ptr;
+        unsigned char *eptr = key->u.zset.current;
+        unsigned char *prev;
+        prev = lpPrev(zl,eptr); /* Go back to previous score. */
+        if (prev) prev = lpPrev(zl,prev); /* Back to previous ele. */
+        if (prev == NULL) {
+            key->u.zset.er = 1;
+            return 0;
+        } else {
+            /* Are we still within the range? */
+            if (key->u.zset.type == REDISMODULE_ZSET_RANGE_SCORE) {
+                /* Fetch the previous element score for the
+                 * range check. */
+                unsigned char *saved_prev = prev;
+                prev = lpNext(zl,prev); /* Skip element to get the score.*/
+                double score = zzlGetScore(prev); /* Obtain the prev score. */
+                if (!zslValueGteMin(score,&key->u.zset.rs)) {
+                    key->u.zset.er = 1;
+                    return 0;
+                }
+                prev = saved_prev;
+            } else if (key->u.zset.type == REDISMODULE_ZSET_RANGE_LEX) {
+                if (!zzlLexValueGteMin(prev,&key->u.zset.lrs)) {
+                    key->u.zset.er = 1;
+                    return 0;
+                }
+            }
+            key->u.zset.current = prev;
+            return 1;
+        }
+    } else if (key->value->encoding == OBJ_ENCODING_SKIPLIST) {
+        zskiplistNode *ln = key->u.zset.current, *prev = ln->backward;
+        if (prev == NULL) {
+            key->u.zset.er = 1;
+            return 0;
+        } else {
+            /* Are we still within the range? */
+            if (key->u.zset.type == REDISMODULE_ZSET_RANGE_SCORE &&
+                !zslValueGteMin(prev->score,&key->u.zset.rs))
+            {
+                key->u.zset.er = 1;
+                return 0;
+            } else if (key->u.zset.type == REDISMODULE_ZSET_RANGE_LEX) {
+                if (!zslLexValueGteMin(prev->ele,&key->u.zset.lrs)) {
+                    key->u.zset.er = 1;
+                    return 0;
+                }
+            }
+            key->u.zset.current = prev;
+            return 1;
+        }
+    } else {
+        serverPanic("Unsupported zset encoding");
+    }
+}
+
+/* --------------------------------------------------------------------------
+ * ## Key API for Hash type
+ *
+ * See also RM_ValueLength(), which returns the number of fields in a hash.
+ * -------------------------------------------------------------------------- */
+
+/* Set the field of the specified hash field to the specified value.
+ * If the key is an empty key open for writing, it is created with an empty
+ * hash value, in order to set the specified field.
+ *
+ * The function is variadic and the user must specify pairs of field
+ * names and values, both as RedisModuleString pointers (unless the
+ * CFIELD option is set, see later). At the end of the field/value-ptr pairs,
+ * NULL must be specified as last argument to signal the end of the arguments
+ * in the variadic function.
+ *
+ * Example to set the hash argv[1] to the value argv[2]:
+ *
+ *      RedisModule_HashSet(key,REDISMODULE_HASH_NONE,argv[1],argv[2],NULL);
+ *
+ * The function can also be used in order to delete fields (if they exist)
+ * by setting them to the specified value of REDISMODULE_HASH_DELETE:
+ *
+ *      RedisModule_HashSet(key,REDISMODULE_HASH_NONE,argv[1],
+ *                          REDISMODULE_HASH_DELETE,NULL);
+ *
+ * The behavior of the command changes with the specified flags, that can be
+ * set to REDISMODULE_HASH_NONE if no special behavior is needed.
+ *
+ *     REDISMODULE_HASH_NX: The operation is performed only if the field was not
+ *                          already existing in the hash.
+ *     REDISMODULE_HASH_XX: The operation is performed only if the field was
+ *                          already existing, so that a new value could be
+ *                          associated to an existing filed, but no new fields
+ *                          are created.
+ *     REDISMODULE_HASH_CFIELDS: The field names passed are null terminated C
+ *                               strings instead of RedisModuleString objects.
+ *     REDISMODULE_HASH_COUNT_ALL: Include the number of inserted fields in the
+ *                                 returned number, in addition to the number of
+ *                                 updated and deleted fields. (Added in Redis
+ *                                 6.2.)
+ *
+ * Unless NX is specified, the command overwrites the old field value with
+ * the new one.
+ *
+ * When using REDISMODULE_HASH_CFIELDS, field names are reported using
+ * normal C strings, so for example to delete the field "foo" the following
+ * code can be used:
+ *
+ *      RedisModule_HashSet(key,REDISMODULE_HASH_CFIELDS,"foo",
+ *                          REDISMODULE_HASH_DELETE,NULL);
+ *
+ * Return value:
+ *
+ * The number of fields existing in the hash prior to the call, which have been
+ * updated (its old value has been replaced by a new value) or deleted. If the
+ * flag REDISMODULE_HASH_COUNT_ALL is set, inserted fields not previously
+ * existing in the hash are also counted.
+ *
+ * If the return value is zero, `errno` is set (since Redis 6.2) as follows:
+ *
+ * - EINVAL if any unknown flags are set or if key is NULL.
+ * - ENOTSUP if the key is associated with a non Hash value.
+ * - EBADF if the key was not opened for writing.
+ * - ENOENT if no fields were counted as described under Return value above.
+ *   This is not actually an error. The return value can be zero if all fields
+ *   were just created and the COUNT_ALL flag was unset, or if changes were held
+ *   back due to the NX and XX flags.
+ *
+ * NOTICE: The return value semantics of this function are very different
+ * between Redis 6.2 and older versions. Modules that use it should determine
+ * the Redis version and handle it accordingly.
+ */
+int RM_HashSet(RedisModuleKey *key, int flags, ...) {
+    va_list ap;
+    if (!key || (flags & ~(REDISMODULE_HASH_NX |
+                           REDISMODULE_HASH_XX |
+                           REDISMODULE_HASH_CFIELDS |
+                           REDISMODULE_HASH_COUNT_ALL))) {
+        errno = EINVAL;
+        return 0;
+    } else if (key->value && key->value->type != OBJ_HASH) {
+        errno = ENOTSUP;
+        return 0;
+    } else if (!(key->mode & REDISMODULE_WRITE)) {
+        errno = EBADF;
+        return 0;
+    }
+    if (key->value == NULL) moduleCreateEmptyKey(key,REDISMODULE_KEYTYPE_HASH);
+
+    int count = 0;
+    va_start(ap, flags);
+    while(1) {
+        RedisModuleString *field, *value;
+        /* Get the field and value objects. */
+        if (flags & REDISMODULE_HASH_CFIELDS) {
+            char *cfield = va_arg(ap,char*);
+            if (cfield == NULL) break;
+            field = createRawStringObject(cfield,strlen(cfield));
+        } else {
+            field = va_arg(ap,RedisModuleString*);
+            if (field == NULL) break;
+        }
+        value = va_arg(ap,RedisModuleString*);
+
+        /* Handle XX and NX */
+        if (flags & (REDISMODULE_HASH_XX|REDISMODULE_HASH_NX)) {
+            int exists = hashTypeExists(key->value, field->ptr);
+            if (((flags & REDISMODULE_HASH_XX) && !exists) ||
+                ((flags & REDISMODULE_HASH_NX) && exists))
+            {
+                if (flags & REDISMODULE_HASH_CFIELDS) decrRefCount(field);
+                continue;
+            }
+        }
+
+        /* Handle deletion if value is REDISMODULE_HASH_DELETE. */
+        if (value == REDISMODULE_HASH_DELETE) {
+            count += hashTypeDelete(key->value, field->ptr);
+            if (flags & REDISMODULE_HASH_CFIELDS) decrRefCount(field);
+            continue;
+        }
+
+        int low_flags = HASH_SET_COPY;
+        /* If CFIELDS is active, we can pass the ownership of the
+         * SDS object to the low level function that sets the field
+         * to avoid a useless copy. */
+        if (flags & REDISMODULE_HASH_CFIELDS)
+            low_flags |= HASH_SET_TAKE_FIELD;
+
+        robj *argv[2] = {field,value};
+        hashTypeTryConversion(key->value,argv,0,1);
+        int updated = hashTypeSet(key->value, field->ptr, value->ptr, low_flags);
+        count += (flags & REDISMODULE_HASH_COUNT_ALL) ? 1 : updated;
+
+        /* If CFIELDS is active, SDS string ownership is now of hashTypeSet(),
+         * however we still have to release the 'field' object shell. */
+        if (flags & REDISMODULE_HASH_CFIELDS) {
+           field->ptr = NULL; /* Prevent the SDS string from being freed. */
+           decrRefCount(field);
+        }
+    }
+    va_end(ap);
+    moduleDelKeyIfEmpty(key);
+    if (count == 0) errno = ENOENT;
+    return count;
+}
+
+/* Get fields from a hash value. This function is called using a variable
+ * number of arguments, alternating a field name (as a RedisModuleString
+ * pointer) with a pointer to a RedisModuleString pointer, that is set to the
+ * value of the field if the field exists, or NULL if the field does not exist.
+ * At the end of the field/value-ptr pairs, NULL must be specified as last
+ * argument to signal the end of the arguments in the variadic function.
+ *
+ * This is an example usage:
+ *
+ *      RedisModuleString *first, *second;
+ *      RedisModule_HashGet(mykey,REDISMODULE_HASH_NONE,argv[1],&first,
+ *                          argv[2],&second,NULL);
+ *
+ * As with RedisModule_HashSet() the behavior of the command can be specified
+ * passing flags different than REDISMODULE_HASH_NONE:
+ *
+ * REDISMODULE_HASH_CFIELDS: field names as null terminated C strings.
+ *
+ * REDISMODULE_HASH_EXISTS: instead of setting the value of the field
+ * expecting a RedisModuleString pointer to pointer, the function just
+ * reports if the field exists or not and expects an integer pointer
+ * as the second element of each pair.
+ *
+ * Example of REDISMODULE_HASH_CFIELDS:
+ *
+ *      RedisModuleString *username, *hashedpass;
+ *      RedisModule_HashGet(mykey,REDISMODULE_HASH_CFIELDS,"username",&username,"hp",&hashedpass, NULL);
+ *
+ * Example of REDISMODULE_HASH_EXISTS:
+ *
+ *      int exists;
+ *      RedisModule_HashGet(mykey,REDISMODULE_HASH_EXISTS,argv[1],&exists,NULL);
+ *
+ * The function returns REDISMODULE_OK on success and REDISMODULE_ERR if
+ * the key is not a hash value.
+ *
+ * Memory management:
+ *
+ * The returned RedisModuleString objects should be released with
+ * RedisModule_FreeString(), or by enabling automatic memory management.
+ */
+int RM_HashGet(RedisModuleKey *key, int flags, ...) {
+    va_list ap;
+    if (key->value && key->value->type != OBJ_HASH) return REDISMODULE_ERR;
+
+    va_start(ap, flags);
+    while(1) {
+        RedisModuleString *field, **valueptr;
+        int *existsptr;
+        /* Get the field object and the value pointer to pointer. */
+        if (flags & REDISMODULE_HASH_CFIELDS) {
+            char *cfield = va_arg(ap,char*);
+            if (cfield == NULL) break;
+            field = createRawStringObject(cfield,strlen(cfield));
+        } else {
+            field = va_arg(ap,RedisModuleString*);
+            if (field == NULL) break;
+        }
+
+        /* Query the hash for existence or value object. */
+        if (flags & REDISMODULE_HASH_EXISTS) {
+            existsptr = va_arg(ap,int*);
+            if (key->value)
+                *existsptr = hashTypeExists(key->value,field->ptr);
+            else
+                *existsptr = 0;
+        } else {
+            valueptr = va_arg(ap,RedisModuleString**);
+            if (key->value) {
+                *valueptr = hashTypeGetValueObject(key->value,field->ptr);
+                if (*valueptr) {
+                    robj *decoded = getDecodedObject(*valueptr);
+                    decrRefCount(*valueptr);
+                    *valueptr = decoded;
+                }
+                if (*valueptr)
+                    autoMemoryAdd(key->ctx,REDISMODULE_AM_STRING,*valueptr);
+            } else {
+                *valueptr = NULL;
+            }
+        }
+
+        /* Cleanup */
+        if (flags & REDISMODULE_HASH_CFIELDS) decrRefCount(field);
+    }
+    va_end(ap);
+    return REDISMODULE_OK;
+}
+
+/* --------------------------------------------------------------------------
+ * ## Key API for Stream type
+ *
+ * For an introduction to streams, see https://redis.io/topics/streams-intro.
+ *
+ * The type RedisModuleStreamID, which is used in stream functions, is a struct
+ * with two 64-bit fields and is defined as
+ *
+ *     typedef struct RedisModuleStreamID {
+ *         uint64_t ms;
+ *         uint64_t seq;
+ *     } RedisModuleStreamID;
+ *
+ * See also RM_ValueLength(), which returns the length of a stream, and the
+ * conversion functions RM_StringToStreamID() and RM_CreateStringFromStreamID().
+ * -------------------------------------------------------------------------- */
+
+/* Adds an entry to a stream. Like XADD without trimming.
+ *
+ * - `key`: The key where the stream is (or will be) stored
+ * - `flags`: A bit field of
+ *   - `REDISMODULE_STREAM_ADD_AUTOID`: Assign a stream ID automatically, like
+ *     `*` in the XADD command.
+ * - `id`: If the `AUTOID` flag is set, this is where the assigned ID is
+ *   returned. Can be NULL if `AUTOID` is set, if you don't care to receive the
+ *   ID. If `AUTOID` is not set, this is the requested ID.
+ * - `argv`: A pointer to an array of size `numfields * 2` containing the
+ *   fields and values.
+ * - `numfields`: The number of field-value pairs in `argv`.
+ *
+ * Returns REDISMODULE_OK if an entry has been added. On failure,
+ * REDISMODULE_ERR is returned and `errno` is set as follows:
+ *
+ * - EINVAL if called with invalid arguments
+ * - ENOTSUP if the key refers to a value of a type other than stream
+ * - EBADF if the key was not opened for writing
+ * - EDOM if the given ID was 0-0 or not greater than all other IDs in the
+ *   stream (only if the AUTOID flag is unset)
+ * - EFBIG if the stream has reached the last possible ID
+ * - ERANGE if the elements are too large to be stored.
+ */
+int RM_StreamAdd(RedisModuleKey *key, int flags, RedisModuleStreamID *id, RedisModuleString **argv, long numfields) {
+    /* Validate args */
+    if (!key || (numfields != 0 && !argv) || /* invalid key or argv */
+        (flags & ~(REDISMODULE_STREAM_ADD_AUTOID)) || /* invalid flags */
+        (!(flags & REDISMODULE_STREAM_ADD_AUTOID) && !id)) { /* id required */
+        errno = EINVAL;
+        return REDISMODULE_ERR;
+    } else if (key->value && key->value->type != OBJ_STREAM) {
+        errno = ENOTSUP; /* wrong type */
+        return REDISMODULE_ERR;
+    } else if (!(key->mode & REDISMODULE_WRITE)) {
+        errno = EBADF; /* key not open for writing */
+        return REDISMODULE_ERR;
+    } else if (!(flags & REDISMODULE_STREAM_ADD_AUTOID) &&
+               id->ms == 0 && id->seq == 0) {
+        errno = EDOM; /* ID out of range */
+        return REDISMODULE_ERR;
+    }
+
+    /* Create key if necessary */
+    int created = 0;
+    if (key->value == NULL) {
+        moduleCreateEmptyKey(key, REDISMODULE_KEYTYPE_STREAM);
+        created = 1;
+    }
+
+    stream *s = key->value->ptr;
+    if (s->last_id.ms == UINT64_MAX && s->last_id.seq == UINT64_MAX) {
+        /* The stream has reached the last possible ID */
+        errno = EFBIG;
+        return REDISMODULE_ERR;
+    }
+
+    streamID added_id;
+    streamID use_id;
+    streamID *use_id_ptr = NULL;
+    if (!(flags & REDISMODULE_STREAM_ADD_AUTOID)) {
+        use_id.ms = id->ms;
+        use_id.seq = id->seq;
+        use_id_ptr = &use_id;
+    }
+
+    if (streamAppendItem(s,argv,numfields,&added_id,use_id_ptr,1) == C_ERR) {
+        /* Either the ID not greater than all existing IDs in the stream, or
+         * the elements are too large to be stored. either way, errno is already
+         * set by streamAppendItem. */
+        if (created) moduleDelKeyIfEmpty(key);
+        return REDISMODULE_ERR;
+    }
+    /* Postponed signalKeyAsReady(). Done implicitly by moduleCreateEmptyKey()
+     * so not needed if the stream has just been created. */
+    if (!created) key->u.stream.signalready = 1;
+
+    if (id != NULL) {
+        id->ms = added_id.ms;
+        id->seq = added_id.seq;
+    }
+
+    return REDISMODULE_OK;
+}
+
+/* Deletes an entry from a stream.
+ *
+ * - `key`: A key opened for writing, with no stream iterator started.
+ * - `id`: The stream ID of the entry to delete.
+ *
+ * Returns REDISMODULE_OK on success. On failure, REDISMODULE_ERR is returned
+ * and `errno` is set as follows:
+ *
+ * - EINVAL if called with invalid arguments
+ * - ENOTSUP if the key refers to a value of a type other than stream or if the
+ *   key is empty
+ * - EBADF if the key was not opened for writing or if a stream iterator is
+ *   associated with the key
+ * - ENOENT if no entry with the given stream ID exists
+ *
+ * See also RM_StreamIteratorDelete() for deleting the current entry while
+ * iterating using a stream iterator.
+ */
+int RM_StreamDelete(RedisModuleKey *key, RedisModuleStreamID *id) {
+    if (!key || !id) {
+        errno = EINVAL;
+        return REDISMODULE_ERR;
+    } else if (!key->value || key->value->type != OBJ_STREAM) {
+        errno = ENOTSUP; /* wrong type */
+        return REDISMODULE_ERR;
+    } else if (!(key->mode & REDISMODULE_WRITE) ||
+               key->iter != NULL) {
+        errno = EBADF; /* key not opened for writing or iterator started */
+        return REDISMODULE_ERR;
+    }
+    stream *s = key->value->ptr;
+    streamID streamid = {id->ms, id->seq};
+    if (streamDeleteItem(s, &streamid)) {
+        return REDISMODULE_OK;
+    } else {
+        errno = ENOENT; /* no entry with this id */
+        return REDISMODULE_ERR;
+    }
+}
+
+/* Sets up a stream iterator.
+ *
+ * - `key`: The stream key opened for reading using RedisModule_OpenKey().
+ * - `flags`:
+ *   - `REDISMODULE_STREAM_ITERATOR_EXCLUSIVE`: Don't include `start` and `end`
+ *     in the iterated range.
+ *   - `REDISMODULE_STREAM_ITERATOR_REVERSE`: Iterate in reverse order, starting
+ *     from the `end` of the range.
+ * - `start`: The lower bound of the range. Use NULL for the beginning of the
+ *   stream.
+ * - `end`: The upper bound of the range. Use NULL for the end of the stream.
+ *
+ * Returns REDISMODULE_OK on success. On failure, REDISMODULE_ERR is returned
+ * and `errno` is set as follows:
+ *
+ * - EINVAL if called with invalid arguments
+ * - ENOTSUP if the key refers to a value of a type other than stream or if the
+ *   key is empty
+ * - EBADF if the key was not opened for writing or if a stream iterator is
+ *   already associated with the key
+ * - EDOM if `start` or `end` is outside the valid range
+ *
+ * Returns REDISMODULE_OK on success and REDISMODULE_ERR if the key doesn't
+ * refer to a stream or if invalid arguments were given.
+ *
+ * The stream IDs are retrieved using RedisModule_StreamIteratorNextID() and
+ * for each stream ID, the fields and values are retrieved using
+ * RedisModule_StreamIteratorNextField(). The iterator is freed by calling
+ * RedisModule_StreamIteratorStop().
+ *
+ * Example (error handling omitted):
+ *
+ *     RedisModule_StreamIteratorStart(key, 0, startid_ptr, endid_ptr);
+ *     RedisModuleStreamID id;
+ *     long numfields;
+ *     while (RedisModule_StreamIteratorNextID(key, &id, &numfields) ==
+ *            REDISMODULE_OK) {
+ *         RedisModuleString *field, *value;
+ *         while (RedisModule_StreamIteratorNextField(key, &field, &value) ==
+ *                REDISMODULE_OK) {
+ *             //
+ *             // ... Do stuff ...
+ *             //
+ *             RedisModule_FreeString(ctx, field);
+ *             RedisModule_FreeString(ctx, value);
+ *         }
+ *     }
+ *     RedisModule_StreamIteratorStop(key);
+ */
+int RM_StreamIteratorStart(RedisModuleKey *key, int flags, RedisModuleStreamID *start, RedisModuleStreamID *end) {
+    /* check args */
+    if (!key ||
+        (flags & ~(REDISMODULE_STREAM_ITERATOR_EXCLUSIVE |
+                   REDISMODULE_STREAM_ITERATOR_REVERSE))) {
+        errno = EINVAL; /* key missing or invalid flags */
+        return REDISMODULE_ERR;
+    } else if (!key->value || key->value->type != OBJ_STREAM) {
+        errno = ENOTSUP;
+        return REDISMODULE_ERR; /* not a stream */
+    } else if (key->iter) {
+        errno = EBADF; /* iterator already started */
+        return REDISMODULE_ERR;
+    }
+
+    /* define range for streamIteratorStart() */
+    streamID lower, upper;
+    if (start) lower = (streamID){start->ms, start->seq};
+    if (end)   upper = (streamID){end->ms,   end->seq};
+    if (flags & REDISMODULE_STREAM_ITERATOR_EXCLUSIVE) {
+        if ((start && streamIncrID(&lower) != C_OK) ||
+            (end   && streamDecrID(&upper) != C_OK)) {
+            errno = EDOM; /* end is 0-0 or start is MAX-MAX? */
+            return REDISMODULE_ERR;
+        }
+    }
+
+    /* create iterator */
+    stream *s = key->value->ptr;
+    int rev = flags & REDISMODULE_STREAM_ITERATOR_REVERSE;
+    streamIterator *si = zmalloc(sizeof(*si));
+    streamIteratorStart(si, s, start ? &lower : NULL, end ? &upper : NULL, rev);
+    key->iter = si;
+    key->u.stream.currentid.ms = 0; /* for RM_StreamIteratorDelete() */
+    key->u.stream.currentid.seq = 0;
+    key->u.stream.numfieldsleft = 0; /* for RM_StreamIteratorNextField() */
+    return REDISMODULE_OK;
+}
+
+/* Stops a stream iterator created using RedisModule_StreamIteratorStart() and
+ * reclaims its memory.
+ *
+ * Returns REDISMODULE_OK on success. On failure, REDISMODULE_ERR is returned
+ * and `errno` is set as follows:
+ *
+ * - EINVAL if called with a NULL key
+ * - ENOTSUP if the key refers to a value of a type other than stream or if the
+ *   key is empty
+ * - EBADF if the key was not opened for writing or if no stream iterator is
+ *   associated with the key
+ */
+int RM_StreamIteratorStop(RedisModuleKey *key) {
+    if (!key) {
+        errno = EINVAL;
+        return REDISMODULE_ERR;
+    } else if (!key->value || key->value->type != OBJ_STREAM) {
+        errno = ENOTSUP;
+        return REDISMODULE_ERR;
+    } else if (!key->iter) {
+        errno = EBADF;
+        return REDISMODULE_ERR;
+    }
+    streamIteratorStop(key->iter);
+    zfree(key->iter);
+    key->iter = NULL;
+    return REDISMODULE_OK;
+}
+
+/* Finds the next stream entry and returns its stream ID and the number of
+ * fields.
+ *
+ * - `key`: Key for which a stream iterator has been started using
+ *   RedisModule_StreamIteratorStart().
+ * - `id`: The stream ID returned. NULL if you don't care.
+ * - `numfields`: The number of fields in the found stream entry. NULL if you
+ *   don't care.
+ *
+ * Returns REDISMODULE_OK and sets `*id` and `*numfields` if an entry was found.
+ * On failure, REDISMODULE_ERR is returned and `errno` is set as follows:
+ *
+ * - EINVAL if called with a NULL key
+ * - ENOTSUP if the key refers to a value of a type other than stream or if the
+ *   key is empty
+ * - EBADF if no stream iterator is associated with the key
+ * - ENOENT if there are no more entries in the range of the iterator
+ *
+ * In practice, if RM_StreamIteratorNextID() is called after a successful call
+ * to RM_StreamIteratorStart() and with the same key, it is safe to assume that
+ * an REDISMODULE_ERR return value means that there are no more entries.
+ *
+ * Use RedisModule_StreamIteratorNextField() to retrieve the fields and values.
+ * See the example at RedisModule_StreamIteratorStart().
+ */
+int RM_StreamIteratorNextID(RedisModuleKey *key, RedisModuleStreamID *id, long *numfields) {
+    if (!key) {
+        errno = EINVAL;
+        return REDISMODULE_ERR;
+    } else if (!key->value || key->value->type != OBJ_STREAM) {
+        errno = ENOTSUP;
+        return REDISMODULE_ERR;
+    } else if (!key->iter) {
+        errno = EBADF;
+        return REDISMODULE_ERR;
+    }
+    streamIterator *si = key->iter;
+    int64_t *num_ptr = &key->u.stream.numfieldsleft;
+    streamID *streamid_ptr = &key->u.stream.currentid;
+    if (streamIteratorGetID(si, streamid_ptr, num_ptr)) {
+        if (id) {
+            id->ms = streamid_ptr->ms;
+            id->seq = streamid_ptr->seq;
+        }
+        if (numfields) *numfields = *num_ptr;
+        return REDISMODULE_OK;
+    } else {
+        /* No entry found. */
+        key->u.stream.currentid.ms = 0; /* for RM_StreamIteratorDelete() */
+        key->u.stream.currentid.seq = 0;
+        key->u.stream.numfieldsleft = 0; /* for RM_StreamIteratorNextField() */
+        errno = ENOENT;
+        return REDISMODULE_ERR;
+    }
+}
+
+/* Retrieves the next field of the current stream ID and its corresponding value
+ * in a stream iteration. This function should be called repeatedly after calling
+ * RedisModule_StreamIteratorNextID() to fetch each field-value pair.
+ *
+ * - `key`: Key where a stream iterator has been started.
+ * - `field_ptr`: This is where the field is returned.
+ * - `value_ptr`: This is where the value is returned.
+ *
+ * Returns REDISMODULE_OK and points `*field_ptr` and `*value_ptr` to freshly
+ * allocated RedisModuleString objects. The string objects are freed
+ * automatically when the callback finishes if automatic memory is enabled. On
+ * failure, REDISMODULE_ERR is returned and `errno` is set as follows:
+ *
+ * - EINVAL if called with a NULL key
+ * - ENOTSUP if the key refers to a value of a type other than stream or if the
+ *   key is empty
+ * - EBADF if no stream iterator is associated with the key
+ * - ENOENT if there are no more fields in the current stream entry
+ *
+ * In practice, if RM_StreamIteratorNextField() is called after a successful
+ * call to RM_StreamIteratorNextID() and with the same key, it is safe to assume
+ * that an REDISMODULE_ERR return value means that there are no more fields.
+ *
+ * See the example at RedisModule_StreamIteratorStart().
+ */
+int RM_StreamIteratorNextField(RedisModuleKey *key, RedisModuleString **field_ptr, RedisModuleString **value_ptr) {
+    if (!key) {
+        errno = EINVAL;
+        return REDISMODULE_ERR;
+    } else if (!key->value || key->value->type != OBJ_STREAM) {
+        errno = ENOTSUP;
+        return REDISMODULE_ERR;
+    } else if (!key->iter) {
+        errno = EBADF;
+        return REDISMODULE_ERR;
+    } else if (key->u.stream.numfieldsleft <= 0) {
+        errno = ENOENT;
+        return REDISMODULE_ERR;
+    }
+    streamIterator *si = key->iter;
+    unsigned char *field, *value;
+    int64_t field_len, value_len;
+    streamIteratorGetField(si, &field, &value, &field_len, &value_len);
+    if (field_ptr) {
+        *field_ptr = createRawStringObject((char *)field, field_len);
+        autoMemoryAdd(key->ctx, REDISMODULE_AM_STRING, *field_ptr);
+    }
+    if (value_ptr) {
+        *value_ptr = createRawStringObject((char *)value, value_len);
+        autoMemoryAdd(key->ctx, REDISMODULE_AM_STRING, *value_ptr);
+    }
+    key->u.stream.numfieldsleft--;
+    return REDISMODULE_OK;
+}
+
+/* Deletes the current stream entry while iterating.
+ *
+ * This function can be called after RM_StreamIteratorNextID() or after any
+ * calls to RM_StreamIteratorNextField().
+ *
+ * Returns REDISMODULE_OK on success. On failure, REDISMODULE_ERR is returned
+ * and `errno` is set as follows:
+ *
+ * - EINVAL if key is NULL
+ * - ENOTSUP if the key is empty or is of another type than stream
+ * - EBADF if the key is not opened for writing, if no iterator has been started
+ * - ENOENT if the iterator has no current stream entry
+ */
+int RM_StreamIteratorDelete(RedisModuleKey *key) {
+    if (!key) {
+        errno = EINVAL;
+        return REDISMODULE_ERR;
+    } else if (!key->value || key->value->type != OBJ_STREAM) {
+        errno = ENOTSUP;
+        return REDISMODULE_ERR;
+    } else if (!(key->mode & REDISMODULE_WRITE) || !key->iter) {
+        errno = EBADF;
+        return REDISMODULE_ERR;
+    } else if (key->u.stream.currentid.ms == 0 &&
+               key->u.stream.currentid.seq == 0) {
+        errno = ENOENT;
+        return REDISMODULE_ERR;
+    }
+    streamIterator *si = key->iter;
+    streamIteratorRemoveEntry(si, &key->u.stream.currentid);
+    key->u.stream.currentid.ms = 0; /* Make sure repeated Delete() fails */
+    key->u.stream.currentid.seq = 0;
+    key->u.stream.numfieldsleft = 0; /* Make sure NextField() fails */
+    return REDISMODULE_OK;
+}
+
+/* Trim a stream by length, similar to XTRIM with MAXLEN.
+ *
+ * - `key`: Key opened for writing.
+ * - `flags`: A bitfield of
+ *   - `REDISMODULE_STREAM_TRIM_APPROX`: Trim less if it improves performance,
+ *     like XTRIM with `~`.
+ * - `length`: The number of stream entries to keep after trimming.
+ *
+ * Returns the number of entries deleted. On failure, a negative value is
+ * returned and `errno` is set as follows:
+ *
+ * - EINVAL if called with invalid arguments
+ * - ENOTSUP if the key is empty or of a type other than stream
+ * - EBADF if the key is not opened for writing
+ */
+long long RM_StreamTrimByLength(RedisModuleKey *key, int flags, long long length) {
+    if (!key || (flags & ~(REDISMODULE_STREAM_TRIM_APPROX)) || length < 0) {
+        errno = EINVAL;
+        return -1;
+    } else if (!key->value || key->value->type != OBJ_STREAM) {
+        errno = ENOTSUP;
+        return -1;
+    } else if (!(key->mode & REDISMODULE_WRITE)) {
+        errno = EBADF;
+        return -1;
+    }
+    int approx = flags & REDISMODULE_STREAM_TRIM_APPROX ? 1 : 0;
+    return streamTrimByLength((stream *)key->value->ptr, length, approx);
+}
+
+/* Trim a stream by ID, similar to XTRIM with MINID.
+ *
+ * - `key`: Key opened for writing.
+ * - `flags`: A bitfield of
+ *   - `REDISMODULE_STREAM_TRIM_APPROX`: Trim less if it improves performance,
+ *     like XTRIM with `~`.
+ * - `id`: The smallest stream ID to keep after trimming.
+ *
+ * Returns the number of entries deleted. On failure, a negative value is
+ * returned and `errno` is set as follows:
+ *
+ * - EINVAL if called with invalid arguments
+ * - ENOTSUP if the key is empty or of a type other than stream
+ * - EBADF if the key is not opened for writing
+ */
+long long RM_StreamTrimByID(RedisModuleKey *key, int flags, RedisModuleStreamID *id) {
+    if (!key || (flags & ~(REDISMODULE_STREAM_TRIM_APPROX)) || !id) {
+        errno = EINVAL;
+        return -1;
+    } else if (!key->value || key->value->type != OBJ_STREAM) {
+        errno = ENOTSUP;
+        return -1;
+    } else if (!(key->mode & REDISMODULE_WRITE)) {
+        errno = EBADF;
+        return -1;
+    }
+    int approx = flags & REDISMODULE_STREAM_TRIM_APPROX ? 1 : 0;
+    streamID minid = (streamID){id->ms, id->seq};
+    return streamTrimByID((stream *)key->value->ptr, minid, approx);
+}
+
+/* --------------------------------------------------------------------------
+ * ## Calling Redis commands from modules
+ *
+ * RM_Call() sends a command to Redis. The remaining functions handle the reply.
+ * -------------------------------------------------------------------------- */
+
+
+void moduleParseCallReply_Int(RedisModuleCallReply *reply);
+void moduleParseCallReply_BulkString(RedisModuleCallReply *reply);
+void moduleParseCallReply_SimpleString(RedisModuleCallReply *reply);
+void moduleParseCallReply_Array(RedisModuleCallReply *reply);
+
+
+
+
+/* Free a Call reply and all the nested replies it contains if it's an
+ * array. */
+void RM_FreeCallReply(RedisModuleCallReply *reply) {
+    /* This is a wrapper for the recursive free reply function. This is needed
+     * in order to have the first level function to return on nested replies,
+     * but only if called by the module API. */
+
+    RedisModuleCtx *ctx = NULL;
+    if(callReplyType(reply) == REDISMODULE_REPLY_PROMISE) {
+        RedisModuleAsyncRMCallPromise *promise = callReplyGetPrivateData(reply);
+        ctx = promise->ctx;
+        freeRedisModuleAsyncRMCallPromise(promise);
+    } else {
+        ctx = callReplyGetPrivateData(reply);
+    }
+
+    freeCallReply(reply);
+    if (ctx) {
+        autoMemoryFreed(ctx,REDISMODULE_AM_REPLY,reply);
+    }
+}
+
+/* Return the reply type as one of the following:
+ *
+ * - REDISMODULE_REPLY_UNKNOWN
+ * - REDISMODULE_REPLY_STRING
+ * - REDISMODULE_REPLY_ERROR
+ * - REDISMODULE_REPLY_INTEGER
+ * - REDISMODULE_REPLY_ARRAY
+ * - REDISMODULE_REPLY_NULL
+ * - REDISMODULE_REPLY_MAP
+ * - REDISMODULE_REPLY_SET
+ * - REDISMODULE_REPLY_BOOL
+ * - REDISMODULE_REPLY_DOUBLE
+ * - REDISMODULE_REPLY_BIG_NUMBER
+ * - REDISMODULE_REPLY_VERBATIM_STRING
+ * - REDISMODULE_REPLY_ATTRIBUTE
+ * - REDISMODULE_REPLY_PROMISE */
+int RM_CallReplyType(RedisModuleCallReply *reply) {
+    return callReplyType(reply);
+}
+
+/* Return the reply type length, where applicable. */
+size_t RM_CallReplyLength(RedisModuleCallReply *reply) {
+    return callReplyGetLen(reply);
+}
+
+/* Return the 'idx'-th nested call reply element of an array reply, or NULL
+ * if the reply type is wrong or the index is out of range. */
+RedisModuleCallReply *RM_CallReplyArrayElement(RedisModuleCallReply *reply, size_t idx) {
+    return callReplyGetArrayElement(reply, idx);
+}
+
+/* Return the `long long` of an integer reply. */
+long long RM_CallReplyInteger(RedisModuleCallReply *reply) {
+    return callReplyGetLongLong(reply);
+}
+
+/* Return the double value of a double reply. */
+double RM_CallReplyDouble(RedisModuleCallReply *reply) {
+    return callReplyGetDouble(reply);
+}
+
+/* Return the big number value of a big number reply. */
+const char *RM_CallReplyBigNumber(RedisModuleCallReply *reply, size_t *len) {
+    return callReplyGetBigNumber(reply, len);
+}
+
+/* Return the value of a verbatim string reply,
+ * An optional output argument can be given to get verbatim reply format. */
+const char *RM_CallReplyVerbatim(RedisModuleCallReply *reply, size_t *len, const char **format) {
+    return callReplyGetVerbatim(reply, len, format);
+}
+
+/* Return the Boolean value of a Boolean reply. */
+int RM_CallReplyBool(RedisModuleCallReply *reply) {
+    return callReplyGetBool(reply);
+}
+
+/* Return the 'idx'-th nested call reply element of a set reply, or NULL
+ * if the reply type is wrong or the index is out of range. */
+RedisModuleCallReply *RM_CallReplySetElement(RedisModuleCallReply *reply, size_t idx) {
+    return callReplyGetSetElement(reply, idx);
+}
+
+/* Retrieve the 'idx'-th key and value of a map reply.
+ *
+ * Returns:
+ * - REDISMODULE_OK on success.
+ * - REDISMODULE_ERR if idx out of range or if the reply type is wrong.
+ *
+ * The `key` and `value` arguments are used to return by reference, and may be
+ * NULL if not required. */
+int RM_CallReplyMapElement(RedisModuleCallReply *reply, size_t idx, RedisModuleCallReply **key, RedisModuleCallReply **val) {
+    if (callReplyGetMapElement(reply, idx, key, val) == C_OK){
+        return REDISMODULE_OK;
+    }
+    return REDISMODULE_ERR;
+}
+
+/* Return the attribute of the given reply, or NULL if no attribute exists. */
+RedisModuleCallReply *RM_CallReplyAttribute(RedisModuleCallReply *reply) {
+    return callReplyGetAttribute(reply);
+}
+
+/* Retrieve the 'idx'-th key and value of an attribute reply.
+ *
+ * Returns:
+ * - REDISMODULE_OK on success.
+ * - REDISMODULE_ERR if idx out of range or if the reply type is wrong.
+ *
+ * The `key` and `value` arguments are used to return by reference, and may be
+ * NULL if not required. */
+int RM_CallReplyAttributeElement(RedisModuleCallReply *reply, size_t idx, RedisModuleCallReply **key, RedisModuleCallReply **val) {
+    if (callReplyGetAttributeElement(reply, idx, key, val) == C_OK){
+        return REDISMODULE_OK;
+    }
+    return REDISMODULE_ERR;
+}
+
+/* Set unblock handler (callback and private data) on the given promise RedisModuleCallReply.
+ * The given reply must be of promise type (REDISMODULE_REPLY_PROMISE). */
+void RM_CallReplyPromiseSetUnblockHandler(RedisModuleCallReply *reply, RedisModuleOnUnblocked on_unblock, void *private_data) {
+    RedisModuleAsyncRMCallPromise *promise = callReplyGetPrivateData(reply);
+    promise->on_unblocked = on_unblock;
+    promise->private_data = private_data;
+}
+
+/* Abort the execution of a given promise RedisModuleCallReply.
+ * return REDMODULE_OK in case the abort was done successfully and REDISMODULE_ERR
+ * if its not possible to abort the execution (execution already finished).
+ * In case the execution was aborted (REDMODULE_OK was returned), the private_data out parameter
+ * will be set with the value of the private data that was given on 'RM_CallReplyPromiseSetUnblockHandler'
+ * so the caller will be able to release the private data.
+ *
+ * If the execution was aborted successfully, it is promised that the unblock handler will not be called.
+ * That said, it is possible that the abort operation will successes but the operation will still continue.
+ * This can happened if, for example, a module implements some blocking command and does not respect the
+ * disconnect callback. For pure Redis commands this can not happened.*/
+int RM_CallReplyPromiseAbort(RedisModuleCallReply *reply, void **private_data) {
+    RedisModuleAsyncRMCallPromise *promise = callReplyGetPrivateData(reply);
+    if (!promise->c) return REDISMODULE_ERR; /* Promise can not be aborted, either already aborted or already finished. */
+    if (!(promise->c->flags & CLIENT_BLOCKED)) return REDISMODULE_ERR; /* Client is not blocked anymore, can not abort it. */
+
+    /* Client is still blocked, remove it from any blocking state and release it. */
+    if (private_data) *private_data = promise->private_data;
+    promise->private_data = NULL;
+    promise->on_unblocked = NULL;
+    unblockClient(promise->c, 0);
+    moduleReleaseTempClient(promise->c);
+    return REDISMODULE_OK;
+}
+
+/* Return the pointer and length of a string or error reply. */
+const char *RM_CallReplyStringPtr(RedisModuleCallReply *reply, size_t *len) {
+    size_t private_len;
+    if (!len) len = &private_len;
+    return callReplyGetString(reply, len);
+}
+
+/* Return a new string object from a call reply of type string, error or
+ * integer. Otherwise (wrong reply type) return NULL. */
+RedisModuleString *RM_CreateStringFromCallReply(RedisModuleCallReply *reply) {
+    RedisModuleCtx* ctx = callReplyGetPrivateData(reply);
+    size_t len;
+    const char *str;
+    switch(callReplyType(reply)) {
+        case REDISMODULE_REPLY_STRING:
+        case REDISMODULE_REPLY_ERROR:
+            str = callReplyGetString(reply, &len);
+            return RM_CreateString(ctx, str, len);
+        case REDISMODULE_REPLY_INTEGER: {
+            char buf[64];
+            int len = ll2string(buf,sizeof(buf),callReplyGetLongLong(reply));
+            return RM_CreateString(ctx ,buf,len);
+            }
+        default:
+            return NULL;
+    }
+}
+
+/* Modifies the user that RM_Call will use (e.g. for ACL checks) */
+void RM_SetContextUser(RedisModuleCtx *ctx, const RedisModuleUser *user) {
+    ctx->user = user;
+}
+
+/* Returns an array of robj pointers, by parsing the format specifier "fmt" as described for
+ * the RM_Call(), RM_Replicate() and other module APIs. Populates *argcp with the number of
+ * items (which equals to the length of the allocated argv).
+ *
+ * The integer pointed by 'flags' is populated with flags according
+ * to special modifiers in "fmt".
+ *
+ *     "!" -> REDISMODULE_ARGV_REPLICATE
+ *     "A" -> REDISMODULE_ARGV_NO_AOF
+ *     "R" -> REDISMODULE_ARGV_NO_REPLICAS
+ *     "3" -> REDISMODULE_ARGV_RESP_3
+ *     "0" -> REDISMODULE_ARGV_RESP_AUTO
+ *     "C" -> REDISMODULE_ARGV_RUN_AS_USER
+ *     "M" -> REDISMODULE_ARGV_RESPECT_DENY_OOM
+ *     "K" -> REDISMODULE_ARGV_ALLOW_BLOCK
+ *
+ * On error (format specifier error) NULL is returned and nothing is
+ * allocated. On success the argument vector is returned. */
+robj **moduleCreateArgvFromUserFormat(const char *cmdname, const char *fmt, int *argcp, int *flags, va_list ap) {
+    int argc = 0, argv_size, j;
+    robj **argv = NULL;
+
+    /* As a first guess to avoid useless reallocations, size argv to
+     * hold one argument for each char specifier in 'fmt'. */
+    argv_size = strlen(fmt)+1; /* +1 because of the command name. */
+    argv = zrealloc(argv,sizeof(robj*)*argv_size);
+
+    /* Build the arguments vector based on the format specifier. */
+    argv[0] = createStringObject(cmdname,strlen(cmdname));
+    argc++;
+
+    /* Create the client and dispatch the command. */
+    const char *p = fmt;
+    while(*p) {
+        if (*p == 'c') {
+            char *cstr = va_arg(ap,char*);
+            argv[argc++] = createStringObject(cstr,strlen(cstr));
+        } else if (*p == 's') {
+            robj *obj = va_arg(ap,void*);
+            if (obj->refcount == OBJ_STATIC_REFCOUNT)
+                obj = createStringObject(obj->ptr,sdslen(obj->ptr));
+            else
+                incrRefCount(obj);
+            argv[argc++] = obj;
+        } else if (*p == 'b') {
+            char *buf = va_arg(ap,char*);
+            size_t len = va_arg(ap,size_t);
+            argv[argc++] = createStringObject(buf,len);
+        } else if (*p == 'l') {
+            long long ll = va_arg(ap,long long);
+            argv[argc++] = createStringObjectFromLongLongWithSds(ll);
+        } else if (*p == 'v') {
+             /* A vector of strings */
+             robj **v = va_arg(ap, void*);
+             size_t vlen = va_arg(ap, size_t);
+
+             /* We need to grow argv to hold the vector's elements.
+              * We resize by vector_len-1 elements, because we held
+              * one element in argv for the vector already */
+             argv_size += vlen-1;
+             argv = zrealloc(argv,sizeof(robj*)*argv_size);
+
+             size_t i = 0;
+             for (i = 0; i < vlen; i++) {
+                 incrRefCount(v[i]);
+                 argv[argc++] = v[i];
+             }
+        } else if (*p == '!') {
+            if (flags) (*flags) |= REDISMODULE_ARGV_REPLICATE;
+        } else if (*p == 'A') {
+            if (flags) (*flags) |= REDISMODULE_ARGV_NO_AOF;
+        } else if (*p == 'R') {
+            if (flags) (*flags) |= REDISMODULE_ARGV_NO_REPLICAS;
+        } else if (*p == '3') {
+            if (flags) (*flags) |= REDISMODULE_ARGV_RESP_3;
+        } else if (*p == '0') {
+            if (flags) (*flags) |= REDISMODULE_ARGV_RESP_AUTO;
+        } else if (*p == 'C') {
+            if (flags) (*flags) |= REDISMODULE_ARGV_RUN_AS_USER;
+        } else if (*p == 'S') {
+            if (flags) (*flags) |= REDISMODULE_ARGV_SCRIPT_MODE;
+        } else if (*p == 'W') {
+            if (flags) (*flags) |= REDISMODULE_ARGV_NO_WRITES;
+        } else if (*p == 'M') {
+            if (flags) (*flags) |= REDISMODULE_ARGV_RESPECT_DENY_OOM;
+        } else if (*p == 'E') {
+            if (flags) (*flags) |= REDISMODULE_ARGV_CALL_REPLIES_AS_ERRORS;
+        } else if (*p == 'D') {
+            if (flags) (*flags) |= (REDISMODULE_ARGV_DRY_RUN | REDISMODULE_ARGV_CALL_REPLIES_AS_ERRORS);
+        } else if (*p == 'K') {
+            if (flags) (*flags) |= REDISMODULE_ARGV_ALLOW_BLOCK;
+        } else {
+            goto fmterr;
+        }
+        p++;
+    }
+    if (argcp) *argcp = argc;
+    return argv;
+
+fmterr:
+    for (j = 0; j < argc; j++)
+        decrRefCount(argv[j]);
+    zfree(argv);
+    return NULL;
+}
+
+/* Exported API to call any Redis command from modules.
+ *
+ * * **cmdname**: The Redis command to call.
+ * * **fmt**: A format specifier string for the command's arguments. Each
+ *   of the arguments should be specified by a valid type specification. The
+ *   format specifier can also contain the modifiers `!`, `A`, `3` and `R` which
+ *   don't have a corresponding argument.
+ *
+ *     * `b` -- The argument is a buffer and is immediately followed by another
+ *              argument that is the buffer's length.
+ *     * `c` -- The argument is a pointer to a plain C string (null-terminated).
+ *     * `l` -- The argument is a `long long` integer.
+ *     * `s` -- The argument is a RedisModuleString.
+ *     * `v` -- The argument(s) is a vector of RedisModuleString.
+ *     * `!` -- Sends the Redis command and its arguments to replicas and AOF.
+ *     * `A` -- Suppress AOF propagation, send only to replicas (requires `!`).
+ *     * `R` -- Suppress replicas propagation, send only to AOF (requires `!`).
+ *     * `3` -- Return a RESP3 reply. This will change the command reply.
+ *              e.g., HGETALL returns a map instead of a flat array.
+ *     * `0` -- Return the reply in auto mode, i.e. the reply format will be the
+ *              same as the client attached to the given RedisModuleCtx. This will
+ *              probably used when you want to pass the reply directly to the client.
+ *     * `C` -- Run a command as the user attached to the context.
+ *              User is either attached automatically via the client that directly
+ *              issued the command and created the context or via RM_SetContextUser.
+ *              If the context is not directly created by an issued command (such as a
+ *              background context and no user was set on it via RM_SetContextUser,
+ *              RM_Call will fail.
+ *              Checks if the command can be executed according to ACL rules and causes
+ *              the command to run as the determined user, so that any future user
+ *              dependent activity, such as ACL checks within scripts will proceed as
+ *              expected.
+ *              Otherwise, the command will run as the Redis unrestricted user.
+ *     * `S` -- Run the command in a script mode, this means that it will raise
+ *              an error if a command which are not allowed inside a script
+ *              (flagged with the `deny-script` flag) is invoked (like SHUTDOWN).
+ *              In addition, on script mode, write commands are not allowed if there are
+ *              not enough good replicas (as configured with `min-replicas-to-write`)
+ *              or when the server is unable to persist to the disk.
+ *     * `W` -- Do not allow to run any write command (flagged with the `write` flag).
+ *     * `M` -- Do not allow `deny-oom` flagged commands when over the memory limit.
+ *     * `E` -- Return error as RedisModuleCallReply. If there is an error before
+ *              invoking the command, the error is returned using errno mechanism.
+ *              This flag allows to get the error also as an error CallReply with
+ *              relevant error message.
+ *     * 'D' -- A "Dry Run" mode. Return before executing the underlying call().
+ *              If everything succeeded, it will return with a NULL, otherwise it will
+ *              return with a CallReply object denoting the error, as if it was called with
+ *              the 'E' code.
+ *     * 'K' -- Allow running blocking commands. If enabled and the command gets blocked, a
+ *              special REDISMODULE_REPLY_PROMISE will be returned. This reply type
+ *              indicates that the command was blocked and the reply will be given asynchronously.
+ *              The module can use this reply object to set a handler which will be called when
+ *              the command gets unblocked using RedisModule_CallReplyPromiseSetUnblockHandler.
+ *              The handler must be set immediately after the command invocation (without releasing
+ *              the Redis lock in between). If the handler is not set, the blocking command will
+ *              still continue its execution but the reply will be ignored (fire and forget),
+ *              notice that this is dangerous in case of role change, as explained below.
+ *              The module can use RedisModule_CallReplyPromiseAbort to abort the command invocation
+ *              if it was not yet finished (see RedisModule_CallReplyPromiseAbort documentation for more
+ *              details). It is also the module's responsibility to abort the execution on role change, either by using
+ *              server event (to get notified when the instance becomes a replica) or relying on the disconnect
+ *              callback of the original client. Failing to do so can result in a write operation on a replica.
+ *              Unlike other call replies, promise call reply **must** be freed while the Redis GIL is locked.
+ *              Notice that on unblocking, the only promise is that the unblock handler will be called,
+ *              If the blocking RM_Call caused the module to also block some real client (using RM_BlockClient),
+ *              it is the module responsibility to unblock this client on the unblock handler.
+ *              On the unblock handler it is only allowed to perform the following:
+ *              * Calling additional Redis commands using RM_Call
+ *              * Open keys using RM_OpenKey
+ *              * Replicate data to the replica or AOF
+ *
+ *              Specifically, it is not allowed to call any Redis module API which are client related such as:
+ *              * RM_Reply* API's
+ *              * RM_BlockClient
+ *              * RM_GetCurrentUserName
+ *
+ * * **...**: The actual arguments to the Redis command.
+ *
+ * On success a RedisModuleCallReply object is returned, otherwise
+ * NULL is returned and errno is set to the following values:
+ *
+ * * EBADF: wrong format specifier.
+ * * EINVAL: wrong command arity.
+ * * ENOENT: command does not exist.
+ * * EPERM: operation in Cluster instance with key in non local slot.
+ * * EROFS: operation in Cluster instance when a write command is sent
+ *          in a readonly state.
+ * * ENETDOWN: operation in Cluster instance when cluster is down.
+ * * ENOTSUP: No ACL user for the specified module context
+ * * EACCES: Command cannot be executed, according to ACL rules
+ * * ENOSPC: Write or deny-oom command is not allowed
+ * * ESPIPE: Command not allowed on script mode
+ *
+ * Example code fragment:
+ *
+ *      reply = RedisModule_Call(ctx,"INCRBY","sc",argv[1],"10");
+ *      if (RedisModule_CallReplyType(reply) == REDISMODULE_REPLY_INTEGER) {
+ *        long long myval = RedisModule_CallReplyInteger(reply);
+ *        // Do something with myval.
+ *      }
+ *
+ * This API is documented here: https://redis.io/topics/modules-intro
+ */
+RedisModuleCallReply *RM_Call(RedisModuleCtx *ctx, const char *cmdname, const char *fmt, ...) {
+    client *c = NULL;
+    robj **argv = NULL;
+    int argc = 0, flags = 0;
+    va_list ap;
+    RedisModuleCallReply *reply = NULL;
+    int replicate = 0; /* Replicate this command? */
+    int error_as_call_replies = 0; /* return errors as RedisModuleCallReply object */
+    uint64_t cmd_flags;
+
+    /* Handle arguments. */
+    va_start(ap, fmt);
+    argv = moduleCreateArgvFromUserFormat(cmdname,fmt,&argc,&flags,ap);
+    replicate = flags & REDISMODULE_ARGV_REPLICATE;
+    error_as_call_replies = flags & REDISMODULE_ARGV_CALL_REPLIES_AS_ERRORS;
+    va_end(ap);
+
+    c = moduleAllocTempClient();
+
+    if (!(flags & REDISMODULE_ARGV_ALLOW_BLOCK)) {
+        /* We do not want to allow block, the module do not expect it */
+        c->flags |= CLIENT_DENY_BLOCKING;
+    }
+    c->db = ctx->client->db;
+    c->argv = argv;
+    /* We have to assign argv_len, which is equal to argc in that case (RM_Call)
+     * because we may be calling a command that uses rewriteClientCommandArgument */
+    c->argc = c->argv_len = argc;
+    c->resp = 2;
+    if (flags & REDISMODULE_ARGV_RESP_3) {
+        c->resp = 3;
+    } else if (flags & REDISMODULE_ARGV_RESP_AUTO) {
+        /* Auto mode means to take the same protocol as the ctx client. */
+        c->resp = ctx->client->resp;
+    }
+    if (ctx->module) ctx->module->in_call++;
+
+    user *user = NULL;
+    if (flags & REDISMODULE_ARGV_RUN_AS_USER) {
+        user = ctx->user ? ctx->user->user : ctx->client->user;
+        if (!user) {
+            errno = ENOTSUP;
+            if (error_as_call_replies) {
+                sds msg = sdsnew("cannot run as user, no user directly attached to context or context's client");
+                reply = callReplyCreateError(msg, ctx);
+            }
+            goto cleanup;
+        }
+        c->user = user;
+    }
+
+    /* We handle the above format error only when the client is setup so that
+     * we can free it normally. */
+    if (argv == NULL) {
+        /* We do not return a call reply here this is an error that should only
+         * be catch by the module indicating wrong fmt was given, the module should
+         * handle this error and decide how to continue. It is not an error that
+         * should be propagated to the user. */
+        errno = EBADF;
+        goto cleanup;
+    }
+
+    /* Call command filters */
+    moduleCallCommandFilters(c);
+
+    /* Lookup command now, after filters had a chance to make modifications
+     * if necessary.
+     */
+    c->cmd = c->lastcmd = c->realcmd = lookupCommand(c->argv,c->argc);
+    sds err;
+    if (!commandCheckExistence(c, error_as_call_replies? &err : NULL)) {
+        errno = ENOENT;
+        if (error_as_call_replies)
+            reply = callReplyCreateError(err, ctx);
+        goto cleanup;
+    }
+    if (!commandCheckArity(c, error_as_call_replies? &err : NULL)) {
+        errno = EINVAL;
+        if (error_as_call_replies)
+            reply = callReplyCreateError(err, ctx);
+        goto cleanup;
+    }
+
+    cmd_flags = getCommandFlags(c);
+
+    if (flags & REDISMODULE_ARGV_SCRIPT_MODE) {
+        /* Basically on script mode we want to only allow commands that can
+         * be executed on scripts (CMD_NOSCRIPT is not set on the command flags) */
+        if (cmd_flags & CMD_NOSCRIPT) {
+            errno = ESPIPE;
+            if (error_as_call_replies) {
+                sds msg = sdscatfmt(sdsempty(), "command '%S' is not allowed on script mode", c->cmd->fullname);
+                reply = callReplyCreateError(msg, ctx);
+            }
+            goto cleanup;
+        }
+    }
+
+    if (flags & REDISMODULE_ARGV_RESPECT_DENY_OOM && server.maxmemory) {
+        if (cmd_flags & CMD_DENYOOM) {
+            int oom_state;
+            if (ctx->flags & REDISMODULE_CTX_THREAD_SAFE) {
+                /* On background thread we can not count on server.pre_command_oom_state.
+                 * Because it is only set on the main thread, in such case we will check
+                 * the actual memory usage. */
+                oom_state = (getMaxmemoryState(NULL,NULL,NULL,NULL) == C_ERR);
+            } else {
+                oom_state = server.pre_command_oom_state;
+            }
+            if (oom_state) {
+                errno = ENOSPC;
+                if (error_as_call_replies) {
+                    sds msg = sdsdup(shared.oomerr->ptr);
+                    reply = callReplyCreateError(msg, ctx);
+                }
+                goto cleanup;
+            }
+        }
+    } else {
+        /* if we aren't OOM checking in RM_Call, we want further executions from this client to also not fail on OOM */
+        c->flags |= CLIENT_ALLOW_OOM;
+    }
+
+    if (flags & REDISMODULE_ARGV_NO_WRITES) {
+        if (cmd_flags & CMD_WRITE) {
+            errno = ENOSPC;
+            if (error_as_call_replies) {
+                sds msg = sdscatfmt(sdsempty(), "Write command '%S' was "
+                                                "called while write is not allowed.", c->cmd->fullname);
+                reply = callReplyCreateError(msg, ctx);
+            }
+            goto cleanup;
+        }
+    }
+
+    /* Script mode tests */
+    if (flags & REDISMODULE_ARGV_SCRIPT_MODE) {
+        if (cmd_flags & CMD_WRITE) {
+            /* on script mode, if a command is a write command,
+             * We will not run it if we encounter disk error
+             * or we do not have enough replicas */
+
+            if (!checkGoodReplicasStatus()) {
+                errno = ESPIPE;
+                if (error_as_call_replies) {
+                    sds msg = sdsdup(shared.noreplicaserr->ptr);
+                    reply = callReplyCreateError(msg, ctx);
+                }
+                goto cleanup;
+            }
+
+            int deny_write_type = writeCommandsDeniedByDiskError();
+            int obey_client = (server.current_client && mustObeyClient(server.current_client));
+
+            if (deny_write_type != DISK_ERROR_TYPE_NONE && !obey_client) {
+                errno = ESPIPE;
+                if (error_as_call_replies) {
+                    sds msg = writeCommandsGetDiskErrorMessage(deny_write_type);
+                    reply = callReplyCreateError(msg, ctx);
+                }
+                goto cleanup;
+            }
+
+            if (server.masterhost && server.repl_slave_ro && !obey_client) {
+                errno = ESPIPE;
+                if (error_as_call_replies) {
+                    sds msg = sdsdup(shared.roslaveerr->ptr);
+                    reply = callReplyCreateError(msg, ctx);
+                }
+                goto cleanup;
+            }
+        }
+
+        if (server.masterhost && server.repl_state != REPL_STATE_CONNECTED &&
+            server.repl_serve_stale_data == 0 && !(cmd_flags & CMD_STALE)) {
+            errno = ESPIPE;
+            if (error_as_call_replies) {
+                sds msg = sdsdup(shared.masterdownerr->ptr);
+                reply = callReplyCreateError(msg, ctx);
+            }
+            goto cleanup;
+        }
+    }
+
+    /* Check if the user can run this command according to the current
+     * ACLs.
+     *
+     * If RM_SetContextUser has set a user, that user is used, otherwise
+     * use the attached client's user. If there is no attached client user and no manually
+     * set user, an error will be returned */
+    if (flags & REDISMODULE_ARGV_RUN_AS_USER) {
+        int acl_errpos;
+        int acl_retval;
+
+        acl_retval = ACLCheckAllUserCommandPerm(user,c->cmd,c->argv,c->argc,&acl_errpos);
+        if (acl_retval != ACL_OK) {
+            sds object = (acl_retval == ACL_DENIED_CMD) ? sdsdup(c->cmd->fullname) : sdsdup(c->argv[acl_errpos]->ptr);
+            addACLLogEntry(ctx->client, acl_retval, ACL_LOG_CTX_MODULE, -1, c->user->name, object);
+            if (error_as_call_replies) {
+                /* verbosity should be same as processCommand() in server.c */
+                sds acl_msg = getAclErrorMessage(acl_retval, c->user, c->cmd, c->argv[acl_errpos]->ptr, 0);
+                sds msg = sdscatfmt(sdsempty(), "-NOPERM %S\r\n", acl_msg);
+                sdsfree(acl_msg);
+                reply = callReplyCreateError(msg, ctx);
+            }
+            errno = EACCES;
+            goto cleanup;
+        }
+    }
+
+    /* If this is a Redis Cluster node, we need to make sure the module is not
+     * trying to access non-local keys, with the exception of commands
+     * received from our master. */
+    if (server.cluster_enabled && !mustObeyClient(ctx->client)) {
+        int error_code;
+        /* Duplicate relevant flags in the module client. */
+        c->flags &= ~(CLIENT_READONLY|CLIENT_ASKING);
+        c->flags |= ctx->client->flags & (CLIENT_READONLY|CLIENT_ASKING);
+        if (getNodeByQuery(c,c->cmd,c->argv,c->argc,NULL,&error_code) !=
+                           server.cluster->myself)
+        {
+            sds msg = NULL;
+            if (error_code == CLUSTER_REDIR_DOWN_RO_STATE) {
+                if (error_as_call_replies) {
+                    msg = sdscatfmt(sdsempty(), "Can not execute a write command '%S' while the cluster is down and readonly", c->cmd->fullname);
+                }
+                errno = EROFS;
+            } else if (error_code == CLUSTER_REDIR_DOWN_STATE) {
+                if (error_as_call_replies) {
+                    msg = sdscatfmt(sdsempty(), "Can not execute a command '%S' while the cluster is down", c->cmd->fullname);
+                }
+                errno = ENETDOWN;
+            } else {
+                if (error_as_call_replies) {
+                    msg = sdsnew("Attempted to access a non local key in a cluster node");
+                }
+                errno = EPERM;
+            }
+            if (msg) {
+                reply = callReplyCreateError(msg, ctx);
+            }
+            goto cleanup;
+        }
+    }
+
+    if (flags & REDISMODULE_ARGV_DRY_RUN) {
+        goto cleanup;
+    }
+
+    /* We need to use a global replication_allowed flag in order to prevent
+     * replication of nested RM_Calls. Example:
+     * 1. module1.foo does RM_Call of module2.bar without replication (i.e. no '!')
+     * 2. module2.bar internally calls RM_Call of INCR with '!'
+     * 3. at the end of module1.foo we call RM_ReplicateVerbatim
+     * We want the replica/AOF to see only module1.foo and not the INCR from module2.bar */
+    int prev_replication_allowed = server.replication_allowed;
+    server.replication_allowed = replicate && server.replication_allowed;
+
+    /* Run the command */
+    int call_flags = CMD_CALL_FROM_MODULE;
+    if (replicate) {
+        if (!(flags & REDISMODULE_ARGV_NO_AOF))
+            call_flags |= CMD_CALL_PROPAGATE_AOF;
+        if (!(flags & REDISMODULE_ARGV_NO_REPLICAS))
+            call_flags |= CMD_CALL_PROPAGATE_REPL;
+    }
+    call(c,call_flags);
+    server.replication_allowed = prev_replication_allowed;
+
+    if (c->flags & CLIENT_BLOCKED) {
+        serverAssert(flags & REDISMODULE_ARGV_ALLOW_BLOCK);
+        serverAssert(ctx->module);
+        RedisModuleAsyncRMCallPromise *promise = zmalloc(sizeof(RedisModuleAsyncRMCallPromise));
+        *promise = (RedisModuleAsyncRMCallPromise) {
+                /* We start with ref_count value of 2 because this object is held
+                 * by the promise CallReply and the fake client that was used to execute the command. */
+                .ref_count = 2,
+                .module = ctx->module,
+                .on_unblocked = NULL,
+                .private_data = NULL,
+                .c = c,
+                .ctx = (ctx->flags & REDISMODULE_CTX_AUTO_MEMORY) ? ctx : NULL,
+        };
+        reply = callReplyCreatePromise(promise);
+        c->bstate.async_rm_call_handle = promise;
+        if (!(call_flags & CMD_CALL_PROPAGATE_AOF)) {
+            /* No need for AOF propagation, set the relevant flags of the client */
+            c->flags |= CLIENT_MODULE_PREVENT_AOF_PROP;
+        }
+        if (!(call_flags & CMD_CALL_PROPAGATE_REPL)) {
+            /* No need for replication propagation, set the relevant flags of the client */
+            c->flags |= CLIENT_MODULE_PREVENT_REPL_PROP;
+        }
+        c = NULL; /* Make sure not to free the client */
+    } else {
+        reply = moduleParseReply(c, (ctx->flags & REDISMODULE_CTX_AUTO_MEMORY) ? ctx : NULL);
+    }
+
+cleanup:
+    if (reply) autoMemoryAdd(ctx,REDISMODULE_AM_REPLY,reply);
+    if (ctx->module) ctx->module->in_call--;
+    if (c) moduleReleaseTempClient(c);
+    return reply;
+}
+
+/* Return a pointer, and a length, to the protocol returned by the command
+ * that returned the reply object. */
+const char *RM_CallReplyProto(RedisModuleCallReply *reply, size_t *len) {
+    return callReplyGetProto(reply, len);
+}
+
+/* --------------------------------------------------------------------------
+ * ## Modules data types
+ *
+ * When String DMA or using existing data structures is not enough, it is
+ * possible to create new data types from scratch and export them to
+ * Redis. The module must provide a set of callbacks for handling the
+ * new values exported (for example in order to provide RDB saving/loading,
+ * AOF rewrite, and so forth). In this section we define this API.
+ * -------------------------------------------------------------------------- */
+
+/* Turn a 9 chars name in the specified charset and a 10 bit encver into
+ * a single 64 bit unsigned integer that represents this exact module name
+ * and version. This final number is called a "type ID" and is used when
+ * writing module exported values to RDB files, in order to re-associate the
+ * value to the right module to load them during RDB loading.
+ *
+ * If the string is not of the right length or the charset is wrong, or
+ * if encver is outside the unsigned 10 bit integer range, 0 is returned,
+ * otherwise the function returns the right type ID.
+ *
+ * The resulting 64 bit integer is composed as follows:
+ *
+ *     (high order bits) 6|6|6|6|6|6|6|6|6|10 (low order bits)
+ *
+ * The first 6 bits value is the first character, name[0], while the last
+ * 6 bits value, immediately before the 10 bits integer, is name[8].
+ * The last 10 bits are the encoding version.
+ *
+ * Note that a name and encver combo of "AAAAAAAAA" and 0, will produce
+ * zero as return value, that is the same we use to signal errors, thus
+ * this combination is invalid, and also useless since type names should
+ * try to be vary to avoid collisions. */
+
+const char *ModuleTypeNameCharSet =
+             "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+             "abcdefghijklmnopqrstuvwxyz"
+             "0123456789-_";
+
+uint64_t moduleTypeEncodeId(const char *name, int encver) {
+    /* We use 64 symbols so that we can map each character into 6 bits
+     * of the final output. */
+    const char *cset = ModuleTypeNameCharSet;
+    if (strlen(name) != 9) return 0;
+    if (encver < 0 || encver > 1023) return 0;
+
+    uint64_t id = 0;
+    for (int j = 0; j < 9; j++) {
+        char *p = strchr(cset,name[j]);
+        if (!p) return 0;
+        unsigned long pos = p-cset;
+        id = (id << 6) | pos;
+    }
+    id = (id << 10) | encver;
+    return id;
+}
+
+/* Search, in the list of exported data types of all the modules registered,
+ * a type with the same name as the one given. Returns the moduleType
+ * structure pointer if such a module is found, or NULL otherwise. */
+moduleType *moduleTypeLookupModuleByNameInternal(const char *name, int ignore_case) {
+    dictIterator *di = dictGetIterator(modules);
+    dictEntry *de;
+
+    while ((de = dictNext(di)) != NULL) {
+        struct RedisModule *module = dictGetVal(de);
+        listIter li;
+        listNode *ln;
+
+        listRewind(module->types,&li);
+        while((ln = listNext(&li))) {
+            moduleType *mt = ln->value;
+            if ((!ignore_case && memcmp(name,mt->name,sizeof(mt->name)) == 0)
+                || (ignore_case && !strcasecmp(name, mt->name)))
+            {
+                dictReleaseIterator(di);
+                return mt;
+            }
+        }
+    }
+    dictReleaseIterator(di);
+    return NULL;
+}
+/* Search all registered modules by name, and name is case sensitive */
+moduleType *moduleTypeLookupModuleByName(const char *name) {
+    return moduleTypeLookupModuleByNameInternal(name, 0);
+}
+
+/* Search all registered modules by name, but case insensitive */
+moduleType *moduleTypeLookupModuleByNameIgnoreCase(const char *name) {
+    return moduleTypeLookupModuleByNameInternal(name, 1);
+}
+
+/* Lookup a module by ID, with caching. This function is used during RDB
+ * loading. Modules exporting data types should never be able to unload, so
+ * our cache does not need to expire. */
+#define MODULE_LOOKUP_CACHE_SIZE 3
+
+moduleType *moduleTypeLookupModuleByID(uint64_t id) {
+    static struct {
+        uint64_t id;
+        moduleType *mt;
+    } cache[MODULE_LOOKUP_CACHE_SIZE];
+
+    /* Search in cache to start. */
+    int j;
+    for (j = 0; j < MODULE_LOOKUP_CACHE_SIZE && cache[j].mt != NULL; j++)
+        if (cache[j].id == id) return cache[j].mt;
+
+    /* Slow module by module lookup. */
+    moduleType *mt = NULL;
+    dictIterator *di = dictGetIterator(modules);
+    dictEntry *de;
+
+    while ((de = dictNext(di)) != NULL && mt == NULL) {
+        struct RedisModule *module = dictGetVal(de);
+        listIter li;
+        listNode *ln;
+
+        listRewind(module->types,&li);
+        while((ln = listNext(&li))) {
+            moduleType *this_mt = ln->value;
+            /* Compare only the 54 bit module identifier and not the
+             * encoding version. */
+            if (this_mt->id >> 10 == id >> 10) {
+                mt = this_mt;
+                break;
+            }
+        }
+    }
+    dictReleaseIterator(di);
+
+    /* Add to cache if possible. */
+    if (mt && j < MODULE_LOOKUP_CACHE_SIZE) {
+        cache[j].id = id;
+        cache[j].mt = mt;
+    }
+    return mt;
+}
+
+/* Turn an (unresolved) module ID into a type name, to show the user an
+ * error when RDB files contain module data we can't load.
+ * The buffer pointed by 'name' must be 10 bytes at least. The function will
+ * fill it with a null terminated module name. */
+void moduleTypeNameByID(char *name, uint64_t moduleid) {
+    const char *cset = ModuleTypeNameCharSet;
+
+    name[9] = '\0';
+    char *p = name+8;
+    moduleid >>= 10;
+    for (int j = 0; j < 9; j++) {
+        *p-- = cset[moduleid & 63];
+        moduleid >>= 6;
+    }
+}
+
+/* Return the name of the module that owns the specified moduleType. */
+const char *moduleTypeModuleName(moduleType *mt) {
+    if (!mt || !mt->module) return NULL;
+    return mt->module->name;
+}
+
+/* Return the module name from a module command */
+const char *moduleNameFromCommand(struct redisCommand *cmd) {
+    serverAssert(cmd->proc == RedisModuleCommandDispatcher);
+
+    RedisModuleCommand *cp = cmd->module_cmd;
+    return cp->module->name;
+}
+
+/* Create a copy of a module type value using the copy callback. If failed
+ * or not supported, produce an error reply and return NULL.
+ */
+robj *moduleTypeDupOrReply(client *c, robj *fromkey, robj *tokey, int todb, robj *value) {
+    moduleValue *mv = value->ptr;
+    moduleType *mt = mv->type;
+    if (!mt->copy && !mt->copy2) {
+        addReplyError(c, "not supported for this module key");
+        return NULL;
+    }
+    void *newval = NULL;
+    if (mt->copy2 != NULL) {
+        RedisModuleKeyOptCtx ctx = {fromkey, tokey, c->db->id, todb};
+        newval = mt->copy2(&ctx, mv->value);
+    } else {
+        newval = mt->copy(fromkey, tokey, mv->value);
+    }
+     
+    if (!newval) {
+        addReplyError(c, "module key failed to copy");
+        return NULL;
+    }
+    return createModuleObject(mt, newval);
+}
+
+/* Register a new data type exported by the module. The parameters are the
+ * following. Please for in depth documentation check the modules API
+ * documentation, especially https://redis.io/topics/modules-native-types.
+ *
+ * * **name**: A 9 characters data type name that MUST be unique in the Redis
+ *   Modules ecosystem. Be creative... and there will be no collisions. Use
+ *   the charset A-Z a-z 9-0, plus the two "-_" characters. A good
+ *   idea is to use, for example `<typename>-<vendor>`. For example
+ *   "tree-AntZ" may mean "Tree data structure by @antirez". To use both
+ *   lower case and upper case letters helps in order to prevent collisions.
+ * * **encver**: Encoding version, which is, the version of the serialization
+ *   that a module used in order to persist data. As long as the "name"
+ *   matches, the RDB loading will be dispatched to the type callbacks
+ *   whatever 'encver' is used, however the module can understand if
+ *   the encoding it must load are of an older version of the module.
+ *   For example the module "tree-AntZ" initially used encver=0. Later
+ *   after an upgrade, it started to serialize data in a different format
+ *   and to register the type with encver=1. However this module may
+ *   still load old data produced by an older version if the rdb_load
+ *   callback is able to check the encver value and act accordingly.
+ *   The encver must be a positive value between 0 and 1023.
+ *
+ * * **typemethods_ptr** is a pointer to a RedisModuleTypeMethods structure
+ *   that should be populated with the methods callbacks and structure
+ *   version, like in the following example:
+ *
+ *         RedisModuleTypeMethods tm = {
+ *             .version = REDISMODULE_TYPE_METHOD_VERSION,
+ *             .rdb_load = myType_RDBLoadCallBack,
+ *             .rdb_save = myType_RDBSaveCallBack,
+ *             .aof_rewrite = myType_AOFRewriteCallBack,
+ *             .free = myType_FreeCallBack,
+ *
+ *             // Optional fields
+ *             .digest = myType_DigestCallBack,
+ *             .mem_usage = myType_MemUsageCallBack,
+ *             .aux_load = myType_AuxRDBLoadCallBack,
+ *             .aux_save = myType_AuxRDBSaveCallBack,
+ *             .free_effort = myType_FreeEffortCallBack,
+ *             .unlink = myType_UnlinkCallBack,
+ *             .copy = myType_CopyCallback,
+ *             .defrag = myType_DefragCallback
+ * 
+ *             // Enhanced optional fields
+ *             .mem_usage2 = myType_MemUsageCallBack2,
+ *             .free_effort2 = myType_FreeEffortCallBack2,
+ *             .unlink2 = myType_UnlinkCallBack2,
+ *             .copy2 = myType_CopyCallback2,
+ *         }
+ *
+ * * **rdb_load**: A callback function pointer that loads data from RDB files.
+ * * **rdb_save**: A callback function pointer that saves data to RDB files.
+ * * **aof_rewrite**: A callback function pointer that rewrites data as commands.
+ * * **digest**: A callback function pointer that is used for `DEBUG DIGEST`.
+ * * **free**: A callback function pointer that can free a type value.
+ * * **aux_save**: A callback function pointer that saves out of keyspace data to RDB files.
+ *   'when' argument is either REDISMODULE_AUX_BEFORE_RDB or REDISMODULE_AUX_AFTER_RDB.
+ * * **aux_load**: A callback function pointer that loads out of keyspace data from RDB files.
+ *   Similar to aux_save, returns REDISMODULE_OK on success, and ERR otherwise.
+ * * **free_effort**: A callback function pointer that used to determine whether the module's
+ *   memory needs to be lazy reclaimed. The module should return the complexity involved by
+ *   freeing the value. for example: how many pointers are gonna be freed. Note that if it 
+ *   returns 0, we'll always do an async free.
+ * * **unlink**: A callback function pointer that used to notifies the module that the key has 
+ *   been removed from the DB by redis, and may soon be freed by a background thread. Note that 
+ *   it won't be called on FLUSHALL/FLUSHDB (both sync and async), and the module can use the 
+ *   RedisModuleEvent_FlushDB to hook into that.
+ * * **copy**: A callback function pointer that is used to make a copy of the specified key.
+ *   The module is expected to perform a deep copy of the specified value and return it.
+ *   In addition, hints about the names of the source and destination keys is provided.
+ *   A NULL return value is considered an error and the copy operation fails.
+ *   Note: if the target key exists and is being overwritten, the copy callback will be
+ *   called first, followed by a free callback to the value that is being replaced.
+ * 
+ * * **defrag**: A callback function pointer that is used to request the module to defrag
+ *   a key. The module should then iterate pointers and call the relevant RM_Defrag*()
+ *   functions to defragment pointers or complex types. The module should continue
+ *   iterating as long as RM_DefragShouldStop() returns a zero value, and return a
+ *   zero value if finished or non-zero value if more work is left to be done. If more work
+ *   needs to be done, RM_DefragCursorSet() and RM_DefragCursorGet() can be used to track
+ *   this work across different calls.
+ *   Normally, the defrag mechanism invokes the callback without a time limit, so
+ *   RM_DefragShouldStop() always returns zero. The "late defrag" mechanism which has
+ *   a time limit and provides cursor support is used only for keys that are determined
+ *   to have significant internal complexity. To determine this, the defrag mechanism
+ *   uses the free_effort callback and the 'active-defrag-max-scan-fields' config directive.
+ *   NOTE: The value is passed as a `void**` and the function is expected to update the
+ *   pointer if the top-level value pointer is defragmented and consequently changes.
+ *
+ * * **mem_usage2**: Similar to `mem_usage`, but provides the `RedisModuleKeyOptCtx` parameter
+ *   so that meta information such as key name and db id can be obtained, and
+ *   the `sample_size` for size estimation (see MEMORY USAGE command).
+ * * **free_effort2**: Similar to `free_effort`, but provides the `RedisModuleKeyOptCtx` parameter
+ *   so that meta information such as key name and db id can be obtained.
+ * * **unlink2**: Similar to `unlink`, but provides the `RedisModuleKeyOptCtx` parameter
+ *   so that meta information such as key name and db id can be obtained.
+ * * **copy2**: Similar to `copy`, but provides the `RedisModuleKeyOptCtx` parameter
+ *   so that meta information such as key names and db ids can be obtained.
+ * * **aux_save2**: Similar to `aux_save`, but with small semantic change, if the module
+ *   saves nothing on this callback then no data about this aux field will be written to the
+ *   RDB and it will be possible to load the RDB even if the module is not loaded.
+ * 
+ * Note: the module name "AAAAAAAAA" is reserved and produces an error, it
+ * happens to be pretty lame as well.
+ *
+ * If RedisModule_CreateDataType() is called outside of RedisModule_OnLoad() function,
+ * there is already a module registering a type with the same name,
+ * or if the module name or encver is invalid, NULL is returned.
+ * Otherwise the new type is registered into Redis, and a reference of
+ * type RedisModuleType is returned: the caller of the function should store
+ * this reference into a global variable to make future use of it in the
+ * modules type API, since a single module may register multiple types.
+ * Example code fragment:
+ *
+ *      static RedisModuleType *BalancedTreeType;
+ *
+ *      int RedisModule_OnLoad(RedisModuleCtx *ctx) {
+ *          // some code here ...
+ *          BalancedTreeType = RM_CreateDataType(...);
+ *      }
+ */
+moduleType *RM_CreateDataType(RedisModuleCtx *ctx, const char *name, int encver, void *typemethods_ptr) {
+    if (!ctx->module->onload)
+        return NULL;
+    uint64_t id = moduleTypeEncodeId(name,encver);
+    if (id == 0) return NULL;
+    if (moduleTypeLookupModuleByName(name) != NULL) return NULL;
+
+    long typemethods_version = ((long*)typemethods_ptr)[0];
+    if (typemethods_version == 0) return NULL;
+
+    struct typemethods {
+        uint64_t version;
+        moduleTypeLoadFunc rdb_load;
+        moduleTypeSaveFunc rdb_save;
+        moduleTypeRewriteFunc aof_rewrite;
+        moduleTypeMemUsageFunc mem_usage;
+        moduleTypeDigestFunc digest;
+        moduleTypeFreeFunc free;
+        struct {
+            moduleTypeAuxLoadFunc aux_load;
+            moduleTypeAuxSaveFunc aux_save;
+            int aux_save_triggers;
+        } v2;
+        struct {
+            moduleTypeFreeEffortFunc free_effort;
+            moduleTypeUnlinkFunc unlink;
+            moduleTypeCopyFunc copy;
+            moduleTypeDefragFunc defrag;
+        } v3;
+        struct {
+            moduleTypeMemUsageFunc2 mem_usage2;
+            moduleTypeFreeEffortFunc2 free_effort2;
+            moduleTypeUnlinkFunc2 unlink2;
+            moduleTypeCopyFunc2 copy2;
+        } v4;
+        struct {
+            moduleTypeAuxSaveFunc aux_save2;
+        } v5;
+    } *tms = (struct typemethods*) typemethods_ptr;
+
+    moduleType *mt = zcalloc(sizeof(*mt));
+    mt->id = id;
+    mt->module = ctx->module;
+    mt->rdb_load = tms->rdb_load;
+    mt->rdb_save = tms->rdb_save;
+    mt->aof_rewrite = tms->aof_rewrite;
+    mt->mem_usage = tms->mem_usage;
+    mt->digest = tms->digest;
+    mt->free = tms->free;
+    if (tms->version >= 2) {
+        mt->aux_load = tms->v2.aux_load;
+        mt->aux_save = tms->v2.aux_save;
+        mt->aux_save_triggers = tms->v2.aux_save_triggers;
+    }
+    if (tms->version >= 3) {
+        mt->free_effort = tms->v3.free_effort;
+        mt->unlink = tms->v3.unlink;
+        mt->copy = tms->v3.copy;
+        mt->defrag = tms->v3.defrag;
+    }
+    if (tms->version >= 4) {
+        mt->mem_usage2 = tms->v4.mem_usage2;
+        mt->unlink2 = tms->v4.unlink2;
+        mt->free_effort2 = tms->v4.free_effort2;
+        mt->copy2 = tms->v4.copy2;
+    }
+    if (tms->version >= 5) {
+        mt->aux_save2 = tms->v5.aux_save2;
+    }
+    memcpy(mt->name,name,sizeof(mt->name));
+    listAddNodeTail(ctx->module->types,mt);
+    return mt;
+}
+
+/* If the key is open for writing, set the specified module type object
+ * as the value of the key, deleting the old value if any.
+ * On success REDISMODULE_OK is returned. If the key is not open for
+ * writing or there is an active iterator, REDISMODULE_ERR is returned. */
+int RM_ModuleTypeSetValue(RedisModuleKey *key, moduleType *mt, void *value) {
+    if (!(key->mode & REDISMODULE_WRITE) || key->iter) return REDISMODULE_ERR;
+    RM_DeleteKey(key);
+    robj *o = createModuleObject(mt,value);
+    setKey(key->ctx->client,key->db,key->key,o,SETKEY_NO_SIGNAL);
+    decrRefCount(o);
+    key->value = o;
+    return REDISMODULE_OK;
+}
+
+/* Assuming RedisModule_KeyType() returned REDISMODULE_KEYTYPE_MODULE on
+ * the key, returns the module type pointer of the value stored at key.
+ *
+ * If the key is NULL, is not associated with a module type, or is empty,
+ * then NULL is returned instead. */
+moduleType *RM_ModuleTypeGetType(RedisModuleKey *key) {
+    if (key == NULL ||
+        key->value == NULL ||
+        RM_KeyType(key) != REDISMODULE_KEYTYPE_MODULE) return NULL;
+    moduleValue *mv = key->value->ptr;
+    return mv->type;
+}
+
+/* Assuming RedisModule_KeyType() returned REDISMODULE_KEYTYPE_MODULE on
+ * the key, returns the module type low-level value stored at key, as
+ * it was set by the user via RedisModule_ModuleTypeSetValue().
+ *
+ * If the key is NULL, is not associated with a module type, or is empty,
+ * then NULL is returned instead. */
+void *RM_ModuleTypeGetValue(RedisModuleKey *key) {
+    if (key == NULL ||
+        key->value == NULL ||
+        RM_KeyType(key) != REDISMODULE_KEYTYPE_MODULE) return NULL;
+    moduleValue *mv = key->value->ptr;
+    return mv->value;
+}
+
+/* --------------------------------------------------------------------------
+ * ## RDB loading and saving functions
+ * -------------------------------------------------------------------------- */
+
+/* Called when there is a load error in the context of a module. On some
+ * modules this cannot be recovered, but if the module declared capability
+ * to handle errors, we'll raise a flag rather than exiting. */
+void moduleRDBLoadError(RedisModuleIO *io) {
+    if (io->type->module->options & REDISMODULE_OPTIONS_HANDLE_IO_ERRORS) {
+        io->error = 1;
+        return;
+    }
+    serverPanic(
+        "Error loading data from RDB (short read or EOF). "
+        "Read performed by module '%s' about type '%s' "
+        "after reading '%llu' bytes of a value "
+        "for key named: '%s'.",
+        io->type->module->name,
+        io->type->name,
+        (unsigned long long)io->bytes,
+        io->key? (char*)io->key->ptr: "(null)");
+}
+
+/* Returns 0 if there's at least one registered data type that did not declare
+ * REDISMODULE_OPTIONS_HANDLE_IO_ERRORS, in which case diskless loading should
+ * be avoided since it could cause data loss. */
+int moduleAllDatatypesHandleErrors(void) {
+    dictIterator *di = dictGetIterator(modules);
+    dictEntry *de;
+
+    while ((de = dictNext(di)) != NULL) {
+        struct RedisModule *module = dictGetVal(de);
+        if (listLength(module->types) &&
+            !(module->options & REDISMODULE_OPTIONS_HANDLE_IO_ERRORS))
+        {
+            dictReleaseIterator(di);
+            return 0;
+        }
+    }
+    dictReleaseIterator(di);
+    return 1;
+}
+
+/* Returns 0 if module did not declare REDISMODULE_OPTIONS_HANDLE_REPL_ASYNC_LOAD, in which case
+ * diskless async loading should be avoided because module doesn't know there can be traffic during
+ * database full resynchronization. */
+int moduleAllModulesHandleReplAsyncLoad(void) {
+    dictIterator *di = dictGetIterator(modules);
+    dictEntry *de;
+
+    while ((de = dictNext(di)) != NULL) {
+        struct RedisModule *module = dictGetVal(de);
+        if (!(module->options & REDISMODULE_OPTIONS_HANDLE_REPL_ASYNC_LOAD)) {
+            dictReleaseIterator(di);
+            return 0;
+        }
+    }
+    dictReleaseIterator(di);
+    return 1;
+}
+
+/* Returns true if any previous IO API failed.
+ * for `Load*` APIs the REDISMODULE_OPTIONS_HANDLE_IO_ERRORS flag must be set with
+ * RedisModule_SetModuleOptions first. */
+int RM_IsIOError(RedisModuleIO *io) {
+    return io->error;
+}
+
+static int flushRedisModuleIOBuffer(RedisModuleIO *io) {
+    if (!io->pre_flush_buffer) return 0;
+
+    /* We have data that must be flushed before saving the current data.
+     * Lets flush it. */
+    sds pre_flush_buffer = io->pre_flush_buffer;
+    io->pre_flush_buffer = NULL;
+    ssize_t retval = rdbWriteRaw(io->rio, pre_flush_buffer, sdslen(pre_flush_buffer));
+    sdsfree(pre_flush_buffer);
+    if (retval >= 0) io->bytes += retval;
+    return retval;
+}
+
+/* Save an unsigned 64 bit value into the RDB file. This function should only
+ * be called in the context of the rdb_save method of modules implementing new
+ * data types. */
+void RM_SaveUnsigned(RedisModuleIO *io, uint64_t value) {
+    if (io->error) return;
+    if (flushRedisModuleIOBuffer(io) == -1) goto saveerr;
+    /* Save opcode. */
+    int retval = rdbSaveLen(io->rio, RDB_MODULE_OPCODE_UINT);
+    if (retval == -1) goto saveerr;
+    io->bytes += retval;
+    /* Save value. */
+    retval = rdbSaveLen(io->rio, value);
+    if (retval == -1) goto saveerr;
+    io->bytes += retval;
+    return;
+
+saveerr:
+    io->error = 1;
+}
+
+/* Load an unsigned 64 bit value from the RDB file. This function should only
+ * be called in the context of the `rdb_load` method of modules implementing
+ * new data types. */
+uint64_t RM_LoadUnsigned(RedisModuleIO *io) {
+    if (io->error) return 0;
+    uint64_t opcode = rdbLoadLen(io->rio,NULL);
+    if (opcode != RDB_MODULE_OPCODE_UINT) goto loaderr;
+    uint64_t value;
+    int retval = rdbLoadLenByRef(io->rio, NULL, &value);
+    if (retval == -1) goto loaderr;
+    return value;
+
+loaderr:
+    moduleRDBLoadError(io);
+    return 0;
+}
+
+/* Like RedisModule_SaveUnsigned() but for signed 64 bit values. */
+void RM_SaveSigned(RedisModuleIO *io, int64_t value) {
+    union {uint64_t u; int64_t i;} conv;
+    conv.i = value;
+    RM_SaveUnsigned(io,conv.u);
+}
+
+/* Like RedisModule_LoadUnsigned() but for signed 64 bit values. */
+int64_t RM_LoadSigned(RedisModuleIO *io) {
+    union {uint64_t u; int64_t i;} conv;
+    conv.u = RM_LoadUnsigned(io);
+    return conv.i;
+}
+
+/* In the context of the rdb_save method of a module type, saves a
+ * string into the RDB file taking as input a RedisModuleString.
+ *
+ * The string can be later loaded with RedisModule_LoadString() or
+ * other Load family functions expecting a serialized string inside
+ * the RDB file. */
+void RM_SaveString(RedisModuleIO *io, RedisModuleString *s) {
+    if (io->error) return;
+    if (flushRedisModuleIOBuffer(io) == -1) goto saveerr;
+    /* Save opcode. */
+    ssize_t retval = rdbSaveLen(io->rio, RDB_MODULE_OPCODE_STRING);
+    if (retval == -1) goto saveerr;
+    io->bytes += retval;
+    /* Save value. */
+    retval = rdbSaveStringObject(io->rio, s);
+    if (retval == -1) goto saveerr;
+    io->bytes += retval;
+    return;
+
+saveerr:
+    io->error = 1;
+}
+
+/* Like RedisModule_SaveString() but takes a raw C pointer and length
+ * as input. */
+void RM_SaveStringBuffer(RedisModuleIO *io, const char *str, size_t len) {
+    if (io->error) return;
+    if (flushRedisModuleIOBuffer(io) == -1) goto saveerr;
+    /* Save opcode. */
+    ssize_t retval = rdbSaveLen(io->rio, RDB_MODULE_OPCODE_STRING);
+    if (retval == -1) goto saveerr;
+    io->bytes += retval;
+    /* Save value. */
+    retval = rdbSaveRawString(io->rio, (unsigned char*)str,len);
+    if (retval == -1) goto saveerr;
+    io->bytes += retval;
+    return;
+
+saveerr:
+    io->error = 1;
+}
+
+/* Implements RM_LoadString() and RM_LoadStringBuffer() */
+void *moduleLoadString(RedisModuleIO *io, int plain, size_t *lenptr) {
+    if (io->error) return NULL;
+    uint64_t opcode = rdbLoadLen(io->rio,NULL);
+    if (opcode != RDB_MODULE_OPCODE_STRING) goto loaderr;
+    void *s = rdbGenericLoadStringObject(io->rio,
+              plain ? RDB_LOAD_PLAIN : RDB_LOAD_NONE, lenptr);
+    if (s == NULL) goto loaderr;
+    return s;
+
+loaderr:
+    moduleRDBLoadError(io);
+    return NULL;
+}
+
+/* In the context of the rdb_load method of a module data type, loads a string
+ * from the RDB file, that was previously saved with RedisModule_SaveString()
+ * functions family.
+ *
+ * The returned string is a newly allocated RedisModuleString object, and
+ * the user should at some point free it with a call to RedisModule_FreeString().
+ *
+ * If the data structure does not store strings as RedisModuleString objects,
+ * the similar function RedisModule_LoadStringBuffer() could be used instead. */
+RedisModuleString *RM_LoadString(RedisModuleIO *io) {
+    return moduleLoadString(io,0,NULL);
+}
+
+/* Like RedisModule_LoadString() but returns a heap allocated string that
+ * was allocated with RedisModule_Alloc(), and can be resized or freed with
+ * RedisModule_Realloc() or RedisModule_Free().
+ *
+ * The size of the string is stored at '*lenptr' if not NULL.
+ * The returned string is not automatically NULL terminated, it is loaded
+ * exactly as it was stored inside the RDB file. */
+char *RM_LoadStringBuffer(RedisModuleIO *io, size_t *lenptr) {
+    return moduleLoadString(io,1,lenptr);
+}
+
+/* In the context of the rdb_save method of a module data type, saves a double
+ * value to the RDB file. The double can be a valid number, a NaN or infinity.
+ * It is possible to load back the value with RedisModule_LoadDouble(). */
+void RM_SaveDouble(RedisModuleIO *io, double value) {
+    if (io->error) return;
+    if (flushRedisModuleIOBuffer(io) == -1) goto saveerr;
+    /* Save opcode. */
+    int retval = rdbSaveLen(io->rio, RDB_MODULE_OPCODE_DOUBLE);
+    if (retval == -1) goto saveerr;
+    io->bytes += retval;
+    /* Save value. */
+    retval = rdbSaveBinaryDoubleValue(io->rio, value);
+    if (retval == -1) goto saveerr;
+    io->bytes += retval;
+    return;
+
+saveerr:
+    io->error = 1;
+}
+
+/* In the context of the rdb_save method of a module data type, loads back the
+ * double value saved by RedisModule_SaveDouble(). */
+double RM_LoadDouble(RedisModuleIO *io) {
+    if (io->error) return 0;
+    uint64_t opcode = rdbLoadLen(io->rio,NULL);
+    if (opcode != RDB_MODULE_OPCODE_DOUBLE) goto loaderr;
+    double value;
+    int retval = rdbLoadBinaryDoubleValue(io->rio, &value);
+    if (retval == -1) goto loaderr;
+    return value;
+
+loaderr:
+    moduleRDBLoadError(io);
+    return 0;
+}
+
+/* In the context of the rdb_save method of a module data type, saves a float
+ * value to the RDB file. The float can be a valid number, a NaN or infinity.
+ * It is possible to load back the value with RedisModule_LoadFloat(). */
+void RM_SaveFloat(RedisModuleIO *io, float value) {
+    if (io->error) return;
+    if (flushRedisModuleIOBuffer(io) == -1) goto saveerr;
+    /* Save opcode. */
+    int retval = rdbSaveLen(io->rio, RDB_MODULE_OPCODE_FLOAT);
+    if (retval == -1) goto saveerr;
+    io->bytes += retval;
+    /* Save value. */
+    retval = rdbSaveBinaryFloatValue(io->rio, value);
+    if (retval == -1) goto saveerr;
+    io->bytes += retval;
+    return;
+
+saveerr:
+    io->error = 1;
+}
+
+/* In the context of the rdb_save method of a module data type, loads back the
+ * float value saved by RedisModule_SaveFloat(). */
+float RM_LoadFloat(RedisModuleIO *io) {
+    if (io->error) return 0;
+    uint64_t opcode = rdbLoadLen(io->rio,NULL);
+    if (opcode != RDB_MODULE_OPCODE_FLOAT) goto loaderr;
+    float value;
+    int retval = rdbLoadBinaryFloatValue(io->rio, &value);
+    if (retval == -1) goto loaderr;
+    return value;
+
+loaderr:
+    moduleRDBLoadError(io);
+    return 0;
+}
+
+/* In the context of the rdb_save method of a module data type, saves a long double
+ * value to the RDB file. The double can be a valid number, a NaN or infinity.
+ * It is possible to load back the value with RedisModule_LoadLongDouble(). */
+void RM_SaveLongDouble(RedisModuleIO *io, long double value) {
+    if (io->error) return;
+    char buf[MAX_LONG_DOUBLE_CHARS];
+    /* Long double has different number of bits in different platforms, so we
+     * save it as a string type. */
+    size_t len = ld2string(buf,sizeof(buf),value,LD_STR_HEX);
+    RM_SaveStringBuffer(io,buf,len);
+}
+
+/* In the context of the rdb_save method of a module data type, loads back the
+ * long double value saved by RedisModule_SaveLongDouble(). */
+long double RM_LoadLongDouble(RedisModuleIO *io) {
+    if (io->error) return 0;
+    long double value;
+    size_t len;
+    char* str = RM_LoadStringBuffer(io,&len);
+    if (!str) return 0;
+    string2ld(str,len,&value);
+    RM_Free(str);
+    return value;
+}
+
+/* Iterate over modules, and trigger rdb aux saving for the ones modules types
+ * who asked for it. */
+ssize_t rdbSaveModulesAux(rio *rdb, int when) {
+    size_t total_written = 0;
+    dictIterator *di = dictGetIterator(modules);
+    dictEntry *de;
+
+    while ((de = dictNext(di)) != NULL) {
+        struct RedisModule *module = dictGetVal(de);
+        listIter li;
+        listNode *ln;
+
+        listRewind(module->types,&li);
+        while((ln = listNext(&li))) {
+            moduleType *mt = ln->value;
+            if ((!mt->aux_save && !mt->aux_save2) || !(mt->aux_save_triggers & when))
+                continue;
+            ssize_t ret = rdbSaveSingleModuleAux(rdb, when, mt);
+            if (ret==-1) {
+                dictReleaseIterator(di);
+                return -1;
+            }
+            total_written += ret;
+        }
+    }
+
+    dictReleaseIterator(di);
+    return total_written;
+}
+
+/* --------------------------------------------------------------------------
+ * ## Key digest API (DEBUG DIGEST interface for modules types)
+ * -------------------------------------------------------------------------- */
+
+/* Add a new element to the digest. This function can be called multiple times
+ * one element after the other, for all the elements that constitute a given
+ * data structure. The function call must be followed by the call to
+ * `RedisModule_DigestEndSequence` eventually, when all the elements that are
+ * always in a given order are added. See the Redis Modules data types
+ * documentation for more info. However this is a quick example that uses Redis
+ * data types as an example.
+ *
+ * To add a sequence of unordered elements (for example in the case of a Redis
+ * Set), the pattern to use is:
+ *
+ *     foreach element {
+ *         AddElement(element);
+ *         EndSequence();
+ *     }
+ *
+ * Because Sets are not ordered, so every element added has a position that
+ * does not depend from the other. However if instead our elements are
+ * ordered in pairs, like field-value pairs of a Hash, then one should
+ * use:
+ *
+ *     foreach key,value {
+ *         AddElement(key);
+ *         AddElement(value);
+ *         EndSequence();
+ *     }
+ *
+ * Because the key and value will be always in the above order, while instead
+ * the single key-value pairs, can appear in any position into a Redis hash.
+ *
+ * A list of ordered elements would be implemented with:
+ *
+ *     foreach element {
+ *         AddElement(element);
+ *     }
+ *     EndSequence();
+ *
+ */
+void RM_DigestAddStringBuffer(RedisModuleDigest *md, const char *ele, size_t len) {
+    mixDigest(md->o,ele,len);
+}
+
+/* Like `RedisModule_DigestAddStringBuffer()` but takes a `long long` as input
+ * that gets converted into a string before adding it to the digest. */
+void RM_DigestAddLongLong(RedisModuleDigest *md, long long ll) {
+    char buf[LONG_STR_SIZE];
+    size_t len = ll2string(buf,sizeof(buf),ll);
+    mixDigest(md->o,buf,len);
+}
+
+/* See the documentation for `RedisModule_DigestAddElement()`. */
+void RM_DigestEndSequence(RedisModuleDigest *md) {
+    xorDigest(md->x,md->o,sizeof(md->o));
+    memset(md->o,0,sizeof(md->o));
+}
+
+/* Decode a serialized representation of a module data type 'mt', in a specific encoding version 'encver'
+ * from string 'str' and return a newly allocated value, or NULL if decoding failed.
+ *
+ * This call basically reuses the 'rdb_load' callback which module data types
+ * implement in order to allow a module to arbitrarily serialize/de-serialize
+ * keys, similar to how the Redis 'DUMP' and 'RESTORE' commands are implemented.
+ *
+ * Modules should generally use the REDISMODULE_OPTIONS_HANDLE_IO_ERRORS flag and
+ * make sure the de-serialization code properly checks and handles IO errors
+ * (freeing allocated buffers and returning a NULL).
+ *
+ * If this is NOT done, Redis will handle corrupted (or just truncated) serialized
+ * data by producing an error message and terminating the process.
+ */
+void *RM_LoadDataTypeFromStringEncver(const RedisModuleString *str, const moduleType *mt, int encver) {
+    rio payload;
+    RedisModuleIO io;
+    void *ret;
+
+    rioInitWithBuffer(&payload, str->ptr);
+    moduleInitIOContext(io,(moduleType *)mt,&payload,NULL,-1);
+
+    /* All RM_Save*() calls always write a version 2 compatible format, so we
+     * need to make sure we read the same.
+     */
+    ret = mt->rdb_load(&io,encver);
+    if (io.ctx) {
+        moduleFreeContext(io.ctx);
+        zfree(io.ctx);
+    }
+    return ret;
+}
+
+/* Similar to RM_LoadDataTypeFromStringEncver, original version of the API, kept
+ * for backward compatibility. 
+ */
+void *RM_LoadDataTypeFromString(const RedisModuleString *str, const moduleType *mt) {
+    return RM_LoadDataTypeFromStringEncver(str, mt, 0);
+}
+
+/* Encode a module data type 'mt' value 'data' into serialized form, and return it
+ * as a newly allocated RedisModuleString.
+ *
+ * This call basically reuses the 'rdb_save' callback which module data types
+ * implement in order to allow a module to arbitrarily serialize/de-serialize
+ * keys, similar to how the Redis 'DUMP' and 'RESTORE' commands are implemented.
+ */
+RedisModuleString *RM_SaveDataTypeToString(RedisModuleCtx *ctx, void *data, const moduleType *mt) {
+    rio payload;
+    RedisModuleIO io;
+
+    rioInitWithBuffer(&payload,sdsempty());
+    moduleInitIOContext(io,(moduleType *)mt,&payload,NULL,-1);
+    mt->rdb_save(&io,data);
+    if (io.ctx) {
+        moduleFreeContext(io.ctx);
+        zfree(io.ctx);
+    }
+    if (io.error) {
+        return NULL;
+    } else {
+        robj *str = createObject(OBJ_STRING,payload.io.buffer.ptr);
+        if (ctx != NULL) autoMemoryAdd(ctx,REDISMODULE_AM_STRING,str);
+        return str;
+    }
+}
+
+/* Returns the name of the key currently being processed. */
+const RedisModuleString *RM_GetKeyNameFromDigest(RedisModuleDigest *dig) {
+    return dig->key;
+}
+
+/* Returns the database id of the key currently being processed. */
+int RM_GetDbIdFromDigest(RedisModuleDigest *dig) {
+    return dig->dbid;
+}
+/* --------------------------------------------------------------------------
+ * ## AOF API for modules data types
+ * -------------------------------------------------------------------------- */
+
+/* Emits a command into the AOF during the AOF rewriting process. This function
+ * is only called in the context of the aof_rewrite method of data types exported
+ * by a module. The command works exactly like RedisModule_Call() in the way
+ * the parameters are passed, but it does not return anything as the error
+ * handling is performed by Redis itself. */
+void RM_EmitAOF(RedisModuleIO *io, const char *cmdname, const char *fmt, ...) {
+    if (io->error) return;
+    struct redisCommand *cmd;
+    robj **argv = NULL;
+    int argc = 0, flags = 0, j;
+    va_list ap;
+
+    cmd = lookupCommandByCString((char*)cmdname);
+    if (!cmd) {
+        serverLog(LL_WARNING,
+            "Fatal: AOF method for module data type '%s' tried to "
+            "emit unknown command '%s'",
+            io->type->name, cmdname);
+        io->error = 1;
+        errno = EINVAL;
+        return;
+    }
+
+    /* Emit the arguments into the AOF in Redis protocol format. */
+    va_start(ap, fmt);
+    argv = moduleCreateArgvFromUserFormat(cmdname,fmt,&argc,&flags,ap);
+    va_end(ap);
+    if (argv == NULL) {
+        serverLog(LL_WARNING,
+            "Fatal: AOF method for module data type '%s' tried to "
+            "call RedisModule_EmitAOF() with wrong format specifiers '%s'",
+            io->type->name, fmt);
+        io->error = 1;
+        errno = EINVAL;
+        return;
+    }
+
+    /* Bulk count. */
+    if (!io->error && rioWriteBulkCount(io->rio,'*',argc) == 0)
+        io->error = 1;
+
+    /* Arguments. */
+    for (j = 0; j < argc; j++) {
+        if (!io->error && rioWriteBulkObject(io->rio,argv[j]) == 0)
+            io->error = 1;
+        decrRefCount(argv[j]);
+    }
+    zfree(argv);
+    return;
+}
+
+/* --------------------------------------------------------------------------
+ * ## IO context handling
+ * -------------------------------------------------------------------------- */
+
+RedisModuleCtx *RM_GetContextFromIO(RedisModuleIO *io) {
+    if (io->ctx) return io->ctx; /* Can't have more than one... */
+    io->ctx = zmalloc(sizeof(RedisModuleCtx));
+    moduleCreateContext(io->ctx, io->type->module, REDISMODULE_CTX_NONE);
+    return io->ctx;
+}
+
+/* Returns the name of the key currently being processed.
+ * There is no guarantee that the key name is always available, so this may return NULL.
+ */
+const RedisModuleString *RM_GetKeyNameFromIO(RedisModuleIO *io) {
+    return io->key;
+}
+
+/* Returns a RedisModuleString with the name of the key from RedisModuleKey. */
+const RedisModuleString *RM_GetKeyNameFromModuleKey(RedisModuleKey *key) {
+    return key ? key->key : NULL;
+}
+
+/* Returns a database id of the key from RedisModuleKey. */
+int RM_GetDbIdFromModuleKey(RedisModuleKey *key) {
+    return key ? key->db->id : -1;
+}
+
+/* Returns the database id of the key currently being processed.
+ * There is no guarantee that this info is always available, so this may return -1.
+ */
+int RM_GetDbIdFromIO(RedisModuleIO *io) {
+    return io->dbid;
+}
+
+/* --------------------------------------------------------------------------
+ * ## Logging
+ * -------------------------------------------------------------------------- */
+
+/* This is the low level function implementing both:
+ *
+ *      RM_Log()
+ *      RM_LogIOError()
+ *
+ */
+void moduleLogRaw(RedisModule *module, const char *levelstr, const char *fmt, va_list ap) {
+    char msg[LOG_MAX_LEN];
+    size_t name_len;
+    int level;
+
+    if (!strcasecmp(levelstr,"debug")) level = LL_DEBUG;
+    else if (!strcasecmp(levelstr,"verbose")) level = LL_VERBOSE;
+    else if (!strcasecmp(levelstr,"notice")) level = LL_NOTICE;
+    else if (!strcasecmp(levelstr,"warning")) level = LL_WARNING;
+    else level = LL_VERBOSE; /* Default. */
+
+    if (level < server.verbosity) return;
+
+    name_len = snprintf(msg, sizeof(msg),"<%s> ", module? module->name: "module");
+    vsnprintf(msg + name_len, sizeof(msg) - name_len, fmt, ap);
+    serverLogRaw(level,msg);
+}
+
+/* Produces a log message to the standard Redis log, the format accepts
+ * printf-alike specifiers, while level is a string describing the log
+ * level to use when emitting the log, and must be one of the following:
+ *
+ * * "debug" (`REDISMODULE_LOGLEVEL_DEBUG`)
+ * * "verbose" (`REDISMODULE_LOGLEVEL_VERBOSE`)
+ * * "notice" (`REDISMODULE_LOGLEVEL_NOTICE`)
+ * * "warning" (`REDISMODULE_LOGLEVEL_WARNING`)
+ *
+ * If the specified log level is invalid, verbose is used by default.
+ * There is a fixed limit to the length of the log line this function is able
+ * to emit, this limit is not specified but is guaranteed to be more than
+ * a few lines of text.
+ *
+ * The ctx argument may be NULL if cannot be provided in the context of the
+ * caller for instance threads or callbacks, in which case a generic "module"
+ * will be used instead of the module name.
+ */
+void RM_Log(RedisModuleCtx *ctx, const char *levelstr, const char *fmt, ...) {
+    va_list ap;
+    va_start(ap, fmt);
+    moduleLogRaw(ctx? ctx->module: NULL,levelstr,fmt,ap);
+    va_end(ap);
+}
+
+/* Log errors from RDB / AOF serialization callbacks.
+ *
+ * This function should be used when a callback is returning a critical
+ * error to the caller since cannot load or save the data for some
+ * critical reason. */
+void RM_LogIOError(RedisModuleIO *io, const char *levelstr, const char *fmt, ...) {
+    va_list ap;
+    va_start(ap, fmt);
+    moduleLogRaw(io->type->module,levelstr,fmt,ap);
+    va_end(ap);
+}
+
+/* Redis-like assert function.
+ *
+ * The macro `RedisModule_Assert(expression)` is recommended, rather than
+ * calling this function directly.
+ *
+ * A failed assertion will shut down the server and produce logging information
+ * that looks identical to information generated by Redis itself.
+ */
+void RM__Assert(const char *estr, const char *file, int line) {
+    _serverAssert(estr, file, line);
+}
+
+/* Allows adding event to the latency monitor to be observed by the LATENCY
+ * command. The call is skipped if the latency is smaller than the configured
+ * latency-monitor-threshold. */
+void RM_LatencyAddSample(const char *event, mstime_t latency) {
+    if (latency >= server.latency_monitor_threshold)
+        latencyAddSample(event, latency);
+}
+
+/* --------------------------------------------------------------------------
+ * ## Blocking clients from modules
+ *
+ * For a guide about blocking commands in modules, see
+ * https://redis.io/topics/modules-blocking-ops.
+ * -------------------------------------------------------------------------- */
+
+/* This is called from blocked.c in order to unblock a client: may be called
+ * for multiple reasons while the client is in the middle of being blocked
+ * because the client is terminated, but is also called for cleanup when a
+ * client is unblocked in a clean way after replaying.
+ *
+ * What we do here is just to set the client to NULL in the redis module
+ * blocked client handle. This way if the client is terminated while there
+ * is a pending threaded operation involving the blocked client, we'll know
+ * that the client no longer exists and no reply callback should be called.
+ *
+ * The structure RedisModuleBlockedClient will be always deallocated when
+ * running the list of clients blocked by a module that need to be unblocked. */
+void unblockClientFromModule(client *c) {
+    RedisModuleBlockedClient *bc = c->bstate.module_blocked_handle;
+
+    /* Call the disconnection callback if any. Note that
+     * bc->disconnect_callback is set to NULL if the client gets disconnected
+     * by the module itself or because of a timeout, so the callback will NOT
+     * get called if this is not an actual disconnection event. */
+    if (bc->disconnect_callback) {
+        RedisModuleCtx ctx;
+        moduleCreateContext(&ctx, bc->module, REDISMODULE_CTX_NONE);
+        ctx.blocked_privdata = bc->privdata;
+        ctx.client = bc->client;
+        bc->disconnect_callback(&ctx,bc);
+        moduleFreeContext(&ctx);
+    }
+
+    /* If we made it here and client is still blocked it means that the command
+     * timed-out, client was killed or disconnected and disconnect_callback was
+     * not implemented (or it was, but RM_UnblockClient was not called from
+     * within it, as it should).
+     * We must call moduleUnblockClient in order to free privdata and
+     * RedisModuleBlockedClient.
+     *
+     * Note that we only do that for clients that are blocked on keys, for which
+     * the contract is that the module should not call RM_UnblockClient under
+     * normal circumstances.
+     * Clients implementing threads and working with private data should be
+     * aware that calling RM_UnblockClient for every blocked client is their
+     * responsibility, and if they fail to do so memory may leak. Ideally they
+     * should implement the disconnect and timeout callbacks and call
+     * RM_UnblockClient, but any other way is also acceptable. */
+    if (bc->blocked_on_keys && !bc->unblocked)
+        moduleUnblockClient(c);
+
+    bc->client = NULL;
+}
+
+/* Block a client in the context of a module: this function implements both
+ * RM_BlockClient() and RM_BlockClientOnKeys() depending on the fact the
+ * keys are passed or not.
+ *
+ * When not blocking for keys, the keys, numkeys, and privdata parameters are
+ * not needed. The privdata in that case must be NULL, since later is
+ * RM_UnblockClient() that will provide some private data that the reply
+ * callback will receive.
+ *
+ * Instead when blocking for keys, normally RM_UnblockClient() will not be
+ * called (because the client will unblock when the key is modified), so
+ * 'privdata' should be provided in that case, so that once the client is
+ * unlocked and the reply callback is called, it will receive its associated
+ * private data.
+ *
+ * Even when blocking on keys, RM_UnblockClient() can be called however, but
+ * in that case the privdata argument is disregarded, because we pass the
+ * reply callback the privdata that is set here while blocking.
+ *
+ */
+RedisModuleBlockedClient *moduleBlockClient(RedisModuleCtx *ctx, RedisModuleCmdFunc reply_callback,
+                                            RedisModuleAuthCallback auth_reply_callback,
+                                            RedisModuleCmdFunc timeout_callback, void (*free_privdata)(RedisModuleCtx*,void*),
+                                            long long timeout_ms, RedisModuleString **keys, int numkeys, void *privdata,
+                                            int flags) {
+    client *c = ctx->client;
+    int islua = scriptIsRunning();
+    int ismulti = server.in_exec;
+
+    c->bstate.module_blocked_handle = zmalloc(sizeof(RedisModuleBlockedClient));
+    RedisModuleBlockedClient *bc = c->bstate.module_blocked_handle;
+    ctx->module->blocked_clients++;
+
+    /* We need to handle the invalid operation of calling modules blocking
+     * commands from Lua or MULTI. We actually create an already aborted
+     * (client set to NULL) blocked client handle, and actually reply with
+     * an error. */
+    bc->client = (islua || ismulti) ? NULL : c;
+    bc->module = ctx->module;
+    bc->reply_callback = reply_callback;
+    bc->auth_reply_cb = auth_reply_callback;
+    bc->timeout_callback = timeout_callback;
+    bc->disconnect_callback = NULL; /* Set by RM_SetDisconnectCallback() */
+    bc->free_privdata = free_privdata;
+    bc->privdata = privdata;
+    bc->reply_client = moduleAllocTempClient();
+    bc->thread_safe_ctx_client = moduleAllocTempClient();
+    if (bc->client)
+        bc->reply_client->resp = bc->client->resp;
+    bc->dbid = c->db->id;
+    bc->blocked_on_keys = keys != NULL;
+    bc->unblocked = 0;
+    bc->background_timer = 0;
+    bc->background_duration = 0;
+
+    c->bstate.timeout = 0;
+    if (timeout_ms) {
+        mstime_t now = mstime();
+        if  (timeout_ms > LLONG_MAX - now) {
+            c->bstate.module_blocked_handle = NULL;
+            addReplyError(c, "timeout is out of range"); /* 'timeout_ms+now' would overflow */
+            return bc;
+        }
+        c->bstate.timeout = timeout_ms + now;
+    }
+
+    if (islua || ismulti) {
+        c->bstate.module_blocked_handle = NULL;
+        addReplyError(c, islua ?
+            "Blocking module command called from Lua script" :
+            "Blocking module command called from transaction");
+    } else if (ctx->flags & REDISMODULE_CTX_BLOCKED_REPLY) {
+        c->bstate.module_blocked_handle = NULL;
+        addReplyError(c, "Blocking module command called from a Reply callback context");
+    } else if (!auth_reply_callback && clientHasModuleAuthInProgress(c)) {
+        c->bstate.module_blocked_handle = NULL;
+        addReplyError(c, "Clients undergoing module based authentication can only be blocked on auth");
+    } else {
+        if (keys) {
+            blockForKeys(c,BLOCKED_MODULE,keys,numkeys,c->bstate.timeout,flags&REDISMODULE_BLOCK_UNBLOCK_DELETED);
+        } else {
+            blockClient(c,BLOCKED_MODULE);
+        }
+    }
+    return bc;
+}
+
+/* This API registers a callback to execute in addition to normal password based authentication.
+ * Multiple callbacks can be registered across different modules. When a Module is unloaded, all the
+ * auth callbacks registered by it are unregistered.
+ * The callbacks are attempted (in the order of most recently registered first) when the AUTH/HELLO
+ * (with AUTH field provided) commands are called.
+ * The callbacks will be called with a module context along with a username and a password, and are
+ * expected to take one of the following actions:
+ * (1) Authenticate - Use the RM_AuthenticateClient* API and return REDISMODULE_AUTH_HANDLED.
+ * This will immediately end the auth chain as successful and add the OK reply.
+ * (2) Deny Authentication - Return REDISMODULE_AUTH_HANDLED without authenticating or blocking the
+ * client. Optionally, `err` can be set to a custom error message and `err` will be automatically
+ * freed by the server.
+ * This will immediately end the auth chain as unsuccessful and add the ERR reply.
+ * (3) Block a client on authentication - Use the RM_BlockClientOnAuth API and return
+ * REDISMODULE_AUTH_HANDLED. Here, the client will be blocked until the RM_UnblockClient API is used
+ * which will trigger the auth reply callback (provided through the RM_BlockClientOnAuth).
+ * In this reply callback, the Module should authenticate, deny or skip handling authentication.
+ * (4) Skip handling Authentication - Return REDISMODULE_AUTH_NOT_HANDLED without blocking the
+ * client. This will allow the engine to attempt the next module auth callback.
+ * If none of the callbacks authenticate or deny auth, then password based auth is attempted and
+ * will authenticate or add failure logs and reply to the clients accordingly.
+ *
+ * Note: If a client is disconnected while it was in the middle of blocking module auth, that
+ * occurrence of the AUTH or HELLO command will not be tracked in the INFO command stats.
+ *
+ * The following is an example of how non-blocking module based authentication can be used:
+ *
+ *      int auth_cb(RedisModuleCtx *ctx, RedisModuleString *username, RedisModuleString *password, RedisModuleString **err) {
+ *          const char *user = RedisModule_StringPtrLen(username, NULL);
+ *          const char *pwd = RedisModule_StringPtrLen(password, NULL);
+ *          if (!strcmp(user,"foo") && !strcmp(pwd,"valid_password")) {
+ *              RedisModule_AuthenticateClientWithACLUser(ctx, "foo", 3, NULL, NULL, NULL);
+ *              return REDISMODULE_AUTH_HANDLED;
+ *          }
+ *
+ *          else if (!strcmp(user,"foo") && !strcmp(pwd,"wrong_password")) {
+ *              RedisModuleString *log = RedisModule_CreateString(ctx, "Module Auth", 11);
+ *              RedisModule_ACLAddLogEntryByUserName(ctx, username, log, REDISMODULE_ACL_LOG_AUTH);
+ *              RedisModule_FreeString(ctx, log);
+ *              const char *err_msg = "Auth denied by Misc Module.";
+ *              *err = RedisModule_CreateString(ctx, err_msg, strlen(err_msg));
+ *              return REDISMODULE_AUTH_HANDLED;
+ *          }
+ *          return REDISMODULE_AUTH_NOT_HANDLED;
+ *       }
+ *
+ *      int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
+ *          if (RedisModule_Init(ctx,"authmodule",1,REDISMODULE_APIVER_1)== REDISMODULE_ERR)
+ *              return REDISMODULE_ERR;
+ *          RedisModule_RegisterAuthCallback(ctx, auth_cb);
+ *          return REDISMODULE_OK;
+ *      }
+ */
+void RM_RegisterAuthCallback(RedisModuleCtx *ctx, RedisModuleAuthCallback cb) {
+    RedisModuleAuthCtx *auth_ctx = zmalloc(sizeof(RedisModuleAuthCtx));
+    auth_ctx->module = ctx->module;
+    auth_ctx->auth_cb = cb;
+    listAddNodeHead(moduleAuthCallbacks, auth_ctx);
+}
+
+/* Helper function to invoke the free private data callback of a Module blocked client. */
+void moduleInvokeFreePrivDataCallback(client *c, RedisModuleBlockedClient *bc) {
+    if (bc->privdata && bc->free_privdata) {
+        RedisModuleCtx ctx;
+        int ctx_flags = c == NULL ? REDISMODULE_CTX_BLOCKED_DISCONNECTED : REDISMODULE_CTX_NONE;
+        moduleCreateContext(&ctx, bc->module, ctx_flags);
+        ctx.blocked_privdata = bc->privdata;
+        ctx.client = bc->client;
+        bc->free_privdata(&ctx,bc->privdata);
+        moduleFreeContext(&ctx);
+    }
+}
+
+/* Unregisters all the module auth callbacks that have been registered by this Module. */
+void moduleUnregisterAuthCBs(RedisModule *module) {
+    listIter li;
+    listNode *ln;
+    listRewind(moduleAuthCallbacks, &li);
+    while ((ln = listNext(&li))) {
+        RedisModuleAuthCtx *ctx = listNodeValue(ln);
+        if (ctx->module == module) {
+            listDelNode(moduleAuthCallbacks, ln);
+            zfree(ctx);
+        }
+    }
+}
+
+/* Search for & attempt next module auth callback after skipping the ones already attempted.
+ * Returns the result of the module auth callback. */
+int attemptNextAuthCb(client *c, robj *username, robj *password, robj **err) {
+    int handle_next_callback = c->module_auth_ctx == NULL;
+    RedisModuleAuthCtx *cur_auth_ctx = NULL;
+    listNode *ln;
+    listIter li;
+    listRewind(moduleAuthCallbacks, &li);
+    int result = REDISMODULE_AUTH_NOT_HANDLED;
+    while((ln = listNext(&li))) {
+        cur_auth_ctx = listNodeValue(ln);
+        /* Skip over the previously attempted auth contexts. */
+        if (!handle_next_callback) {
+            handle_next_callback = cur_auth_ctx == c->module_auth_ctx;
+            continue;
+        }
+        /* Remove the module auth complete flag before we attempt the next cb. */
+        c->flags &= ~CLIENT_MODULE_AUTH_HAS_RESULT;
+        RedisModuleCtx ctx;
+        moduleCreateContext(&ctx, cur_auth_ctx->module, REDISMODULE_CTX_NONE);
+        ctx.client = c;
+        *err = NULL;
+        c->module_auth_ctx = cur_auth_ctx;
+        result = cur_auth_ctx->auth_cb(&ctx, username, password, err);
+        moduleFreeContext(&ctx);
+        if (result == REDISMODULE_AUTH_HANDLED) break;
+        /* If Auth was not handled (allowed/denied/blocked) by the Module, try the next auth cb. */
+    }
+    return result;
+}
+
+/* Helper function to handle a reprocessed unblocked auth client.
+ * Returns REDISMODULE_AUTH_NOT_HANDLED if the client was not reprocessed after a blocking module
+ * auth operation.
+ * Otherwise, we attempt the auth reply callback & the free priv data callback, update fields and
+ * return the result of the reply callback. */
+int attemptBlockedAuthReplyCallback(client *c, robj *username, robj *password, robj **err) {
+    int result = REDISMODULE_AUTH_NOT_HANDLED;
+    if (!c->module_blocked_client) return result;
+    RedisModuleBlockedClient *bc = (RedisModuleBlockedClient *) c->module_blocked_client;
+    bc->client = c;
+    if (bc->auth_reply_cb) {
+        RedisModuleCtx ctx;
+        moduleCreateContext(&ctx, bc->module, REDISMODULE_CTX_BLOCKED_REPLY);
+        ctx.blocked_privdata = bc->privdata;
+        ctx.blocked_ready_key = NULL;
+        ctx.client = bc->client;
+        ctx.blocked_client = bc;
+        result = bc->auth_reply_cb(&ctx, username, password, err);
+        moduleFreeContext(&ctx);
+    }
+    moduleInvokeFreePrivDataCallback(c, bc);
+    c->module_blocked_client = NULL;
+    c->lastcmd->microseconds += bc->background_duration;
+    bc->module->blocked_clients--;
+    zfree(bc);
+    return result;
+}
+
+/* Helper function to attempt Module based authentication through module auth callbacks.
+ * Here, the Module is expected to authenticate the client using the RedisModule APIs and to add ACL
+ * logs in case of errors.
+ * Returns one of the following codes:
+ * AUTH_OK - Indicates that a module handled and authenticated the client.
+ * AUTH_ERR - Indicates that a module handled and denied authentication for this client.
+ * AUTH_NOT_HANDLED - Indicates that authentication was not handled by any Module and that
+ * normal password based authentication can be attempted next.
+ * AUTH_BLOCKED - Indicates module authentication is in progress through a blocking implementation.
+ * In this case, authentication is handled here again after the client is unblocked / reprocessed. */
+int checkModuleAuthentication(client *c, robj *username, robj *password, robj **err) {
+    if (!listLength(moduleAuthCallbacks)) return AUTH_NOT_HANDLED;
+    int result = attemptBlockedAuthReplyCallback(c, username, password, err);
+    if (result == REDISMODULE_AUTH_NOT_HANDLED) {
+        result = attemptNextAuthCb(c, username, password, err);
+    }
+    if (c->flags & CLIENT_BLOCKED) {
+        /* Modules are expected to return REDISMODULE_AUTH_HANDLED when blocking clients. */
+        serverAssert(result == REDISMODULE_AUTH_HANDLED);
+        return AUTH_BLOCKED;
+    }
+    c->module_auth_ctx = NULL;
+    if (result == REDISMODULE_AUTH_NOT_HANDLED) {
+        c->flags &= ~CLIENT_MODULE_AUTH_HAS_RESULT;
+        return AUTH_NOT_HANDLED;
+    }
+    if (c->flags & CLIENT_MODULE_AUTH_HAS_RESULT) {
+        c->flags &= ~CLIENT_MODULE_AUTH_HAS_RESULT;
+        if (c->authenticated) return AUTH_OK;
+    }
+    return AUTH_ERR;
+}
+
+/* This function is called from module.c in order to check if a module
+ * blocked for BLOCKED_MODULE and subtype 'on keys' (bc->blocked_on_keys true)
+ * can really be unblocked, since the module was able to serve the client.
+ * If the callback returns REDISMODULE_OK, then the client can be unblocked,
+ * otherwise the client remains blocked and we'll retry again when one of
+ * the keys it blocked for becomes "ready" again.
+ * This function returns 1 if client was served (and should be unblocked) */
+int moduleTryServeClientBlockedOnKey(client *c, robj *key) {
+    int served = 0;
+    RedisModuleBlockedClient *bc = c->bstate.module_blocked_handle;
+
+    /* Protect against re-processing: don't serve clients that are already
+     * in the unblocking list for any reason (including RM_UnblockClient()
+     * explicit call). See #6798. */
+    if (bc->unblocked) return 0;
+
+    RedisModuleCtx ctx;
+    moduleCreateContext(&ctx, bc->module, REDISMODULE_CTX_BLOCKED_REPLY);
+    ctx.blocked_ready_key = key;
+    ctx.blocked_privdata = bc->privdata;
+    ctx.client = bc->client;
+    ctx.blocked_client = bc;
+    if (bc->reply_callback(&ctx,(void**)c->argv,c->argc) == REDISMODULE_OK)
+        served = 1;
+    moduleFreeContext(&ctx);
+    return served;
+}
+
+/* Block a client in the context of a blocking command, returning a handle
+ * which will be used, later, in order to unblock the client with a call to
+ * RedisModule_UnblockClient(). The arguments specify callback functions
+ * and a timeout after which the client is unblocked.
+ *
+ * The callbacks are called in the following contexts:
+ *
+ *     reply_callback:   called after a successful RedisModule_UnblockClient()
+ *                       call in order to reply to the client and unblock it.
+ *
+ *     timeout_callback: called when the timeout is reached or if `CLIENT UNBLOCK`
+ *                       is invoked, in order to send an error to the client.
+ *
+ *     free_privdata:    called in order to free the private data that is passed
+ *                       by RedisModule_UnblockClient() call.
+ *
+ * Note: RedisModule_UnblockClient should be called for every blocked client,
+ *       even if client was killed, timed-out or disconnected. Failing to do so
+ *       will result in memory leaks.
+ *
+ * There are some cases where RedisModule_BlockClient() cannot be used:
+ *
+ * 1. If the client is a Lua script.
+ * 2. If the client is executing a MULTI block.
+ *
+ * In these cases, a call to RedisModule_BlockClient() will **not** block the
+ * client, but instead produce a specific error reply.
+ *
+ * A module that registers a timeout_callback function can also be unblocked
+ * using the `CLIENT UNBLOCK` command, which will trigger the timeout callback.
+ * If a callback function is not registered, then the blocked client will be
+ * treated as if it is not in a blocked state and `CLIENT UNBLOCK` will return
+ * a zero value.
+ *
+ * Measuring background time: By default the time spent in the blocked command
+ * is not account for the total command duration. To include such time you should
+ * use RM_BlockedClientMeasureTimeStart() and RM_BlockedClientMeasureTimeEnd() one,
+ * or multiple times within the blocking command background work.
+ */
+RedisModuleBlockedClient *RM_BlockClient(RedisModuleCtx *ctx, RedisModuleCmdFunc reply_callback,
+                                         RedisModuleCmdFunc timeout_callback, void (*free_privdata)(RedisModuleCtx*,void*),
+                                         long long timeout_ms) {
+    return moduleBlockClient(ctx,reply_callback,NULL,timeout_callback,free_privdata,timeout_ms, NULL,0,NULL,0);
+}
+
+/* Block the current client for module authentication in the background. If module auth is not in
+ * progress on the client, the API returns NULL. Otherwise, the client is blocked and the RM_BlockedClient
+ * is returned similar to the RM_BlockClient API.
+ * Note: Only use this API from the context of a module auth callback. */
+RedisModuleBlockedClient *RM_BlockClientOnAuth(RedisModuleCtx *ctx, RedisModuleAuthCallback reply_callback,
+                                               void (*free_privdata)(RedisModuleCtx*,void*)) {
+    if (!clientHasModuleAuthInProgress(ctx->client)) {
+        addReplyError(ctx->client, "Module blocking client on auth when not currently undergoing module authentication");
+        return NULL;
+    }
+    RedisModuleBlockedClient *bc = moduleBlockClient(ctx,NULL,reply_callback,NULL,free_privdata,0, NULL,0,NULL,0);
+    if (ctx->client->flags & CLIENT_BLOCKED) {
+        ctx->client->flags |= CLIENT_PENDING_COMMAND;
+    }
+    return bc;
+}
+
+/* Get the private data that was previusely set on a blocked client */
+void *RM_BlockClientGetPrivateData(RedisModuleBlockedClient *blocked_client) {
+    return blocked_client->privdata;
+}
+
+/* Set private data on a blocked client */
+void RM_BlockClientSetPrivateData(RedisModuleBlockedClient *blocked_client, void *private_data) {
+    blocked_client->privdata = private_data;
+}
+
+/* This call is similar to RedisModule_BlockClient(), however in this case we
+ * don't just block the client, but also ask Redis to unblock it automatically
+ * once certain keys become "ready", that is, contain more data.
+ *
+ * Basically this is similar to what a typical Redis command usually does,
+ * like BLPOP or BZPOPMAX: the client blocks if it cannot be served ASAP,
+ * and later when the key receives new data (a list push for instance), the
+ * client is unblocked and served.
+ *
+ * However in the case of this module API, when the client is unblocked?
+ *
+ * 1. If you block on a key of a type that has blocking operations associated,
+ *    like a list, a sorted set, a stream, and so forth, the client may be
+ *    unblocked once the relevant key is targeted by an operation that normally
+ *    unblocks the native blocking operations for that type. So if we block
+ *    on a list key, an RPUSH command may unblock our client and so forth.
+ * 2. If you are implementing your native data type, or if you want to add new
+ *    unblocking conditions in addition to "1", you can call the modules API
+ *    RedisModule_SignalKeyAsReady().
+ *
+ * Anyway we can't be sure if the client should be unblocked just because the
+ * key is signaled as ready: for instance a successive operation may change the
+ * key, or a client in queue before this one can be served, modifying the key
+ * as well and making it empty again. So when a client is blocked with
+ * RedisModule_BlockClientOnKeys() the reply callback is not called after
+ * RM_UnblockClient() is called, but every time a key is signaled as ready:
+ * if the reply callback can serve the client, it returns REDISMODULE_OK
+ * and the client is unblocked, otherwise it will return REDISMODULE_ERR
+ * and we'll try again later.
+ *
+ * The reply callback can access the key that was signaled as ready by
+ * calling the API RedisModule_GetBlockedClientReadyKey(), that returns
+ * just the string name of the key as a RedisModuleString object.
+ *
+ * Thanks to this system we can setup complex blocking scenarios, like
+ * unblocking a client only if a list contains at least 5 items or other
+ * more fancy logics.
+ *
+ * Note that another difference with RedisModule_BlockClient(), is that here
+ * we pass the private data directly when blocking the client: it will
+ * be accessible later in the reply callback. Normally when blocking with
+ * RedisModule_BlockClient() the private data to reply to the client is
+ * passed when calling RedisModule_UnblockClient() but here the unblocking
+ * is performed by Redis itself, so we need to have some private data before
+ * hand. The private data is used to store any information about the specific
+ * unblocking operation that you are implementing. Such information will be
+ * freed using the free_privdata callback provided by the user.
+ *
+ * However the reply callback will be able to access the argument vector of
+ * the command, so the private data is often not needed.
+ *
+ * Note: Under normal circumstances RedisModule_UnblockClient should not be
+ *       called for clients that are blocked on keys (Either the key will
+ *       become ready or a timeout will occur). If for some reason you do want
+ *       to call RedisModule_UnblockClient it is possible: Client will be
+ *       handled as if it were timed-out (You must implement the timeout
+ *       callback in that case).
+ */
+RedisModuleBlockedClient *RM_BlockClientOnKeys(RedisModuleCtx *ctx, RedisModuleCmdFunc reply_callback,
+                                               RedisModuleCmdFunc timeout_callback, void (*free_privdata)(RedisModuleCtx*,void*),
+                                               long long timeout_ms, RedisModuleString **keys, int numkeys, void *privdata) {
+    return moduleBlockClient(ctx,reply_callback,NULL,timeout_callback,free_privdata,timeout_ms, keys,numkeys,privdata,0);
+}
+
+/* Same as RedisModule_BlockClientOnKeys, but can take REDISMODULE_BLOCK_* flags
+ * Can be either REDISMODULE_BLOCK_UNBLOCK_DEFAULT, which means default behavior (same
+ * as calling RedisModule_BlockClientOnKeys)
+ *
+ * The flags is a bit mask of these:
+ *
+ * - `REDISMODULE_BLOCK_UNBLOCK_DELETED`: The clients should to be awakened in case any of `keys` are deleted.
+ *                                        Mostly useful for commands that require the key to exist (like XREADGROUP)
+ */
+RedisModuleBlockedClient *RM_BlockClientOnKeysWithFlags(RedisModuleCtx *ctx, RedisModuleCmdFunc reply_callback,
+                                                        RedisModuleCmdFunc timeout_callback, void (*free_privdata)(RedisModuleCtx*,void*),
+                                                        long long timeout_ms, RedisModuleString **keys, int numkeys, void *privdata,
+                                                        int flags) {
+    return moduleBlockClient(ctx,reply_callback,NULL,timeout_callback,free_privdata,timeout_ms, keys,numkeys,privdata,flags);
+}
+
+/* This function is used in order to potentially unblock a client blocked
+ * on keys with RedisModule_BlockClientOnKeys(). When this function is called,
+ * all the clients blocked for this key will get their reply_callback called. */
+void RM_SignalKeyAsReady(RedisModuleCtx *ctx, RedisModuleString *key) {
+    signalKeyAsReady(ctx->client->db, key, OBJ_MODULE);
+}
+
+/* Implements RM_UnblockClient() and moduleUnblockClient(). */
+int moduleUnblockClientByHandle(RedisModuleBlockedClient *bc, void *privdata) {
+    pthread_mutex_lock(&moduleUnblockedClientsMutex);
+    if (!bc->blocked_on_keys) bc->privdata = privdata;
+    bc->unblocked = 1;
+    if (listLength(moduleUnblockedClients) == 0) {
+        if (write(server.module_pipe[1],"A",1) != 1) {
+            /* Ignore the error, this is best-effort. */
+        }
+    }
+    listAddNodeTail(moduleUnblockedClients,bc);
+    pthread_mutex_unlock(&moduleUnblockedClientsMutex);
+    return REDISMODULE_OK;
+}
+
+/* This API is used by the Redis core to unblock a client that was blocked
+ * by a module. */
+void moduleUnblockClient(client *c) {
+    RedisModuleBlockedClient *bc = c->bstate.module_blocked_handle;
+    moduleUnblockClientByHandle(bc,NULL);
+}
+
+/* Return true if the client 'c' was blocked by a module using
+ * RM_BlockClientOnKeys(). */
+int moduleClientIsBlockedOnKeys(client *c) {
+    RedisModuleBlockedClient *bc = c->bstate.module_blocked_handle;
+    return bc->blocked_on_keys;
+}
+
+/* Unblock a client blocked by `RedisModule_BlockedClient`. This will trigger
+ * the reply callbacks to be called in order to reply to the client.
+ * The 'privdata' argument will be accessible by the reply callback, so
+ * the caller of this function can pass any value that is needed in order to
+ * actually reply to the client.
+ *
+ * A common usage for 'privdata' is a thread that computes something that
+ * needs to be passed to the client, included but not limited some slow
+ * to compute reply or some reply obtained via networking.
+ *
+ * Note 1: this function can be called from threads spawned by the module.
+ *
+ * Note 2: when we unblock a client that is blocked for keys using the API
+ * RedisModule_BlockClientOnKeys(), the privdata argument here is not used.
+ * Unblocking a client that was blocked for keys using this API will still
+ * require the client to get some reply, so the function will use the
+ * "timeout" handler in order to do so (The privdata provided in
+ * RedisModule_BlockClientOnKeys() is accessible from the timeout
+ * callback via RM_GetBlockedClientPrivateData). */
+int RM_UnblockClient(RedisModuleBlockedClient *bc, void *privdata) {
+    if (bc->blocked_on_keys) {
+        /* In theory the user should always pass the timeout handler as an
+         * argument, but better to be safe than sorry. */
+        if (bc->timeout_callback == NULL) return REDISMODULE_ERR;
+        if (bc->unblocked) return REDISMODULE_OK;
+        if (bc->client) moduleBlockedClientTimedOut(bc->client);
+    }
+    moduleUnblockClientByHandle(bc,privdata);
+    return REDISMODULE_OK;
+}
+
+/* Abort a blocked client blocking operation: the client will be unblocked
+ * without firing any callback. */
+int RM_AbortBlock(RedisModuleBlockedClient *bc) {
+    bc->reply_callback = NULL;
+    bc->disconnect_callback = NULL;
+    bc->auth_reply_cb = NULL;
+    return RM_UnblockClient(bc,NULL);
+}
+
+/* Set a callback that will be called if a blocked client disconnects
+ * before the module has a chance to call RedisModule_UnblockClient()
+ *
+ * Usually what you want to do there, is to cleanup your module state
+ * so that you can call RedisModule_UnblockClient() safely, otherwise
+ * the client will remain blocked forever if the timeout is large.
+ *
+ * Notes:
+ *
+ * 1. It is not safe to call Reply* family functions here, it is also
+ *    useless since the client is gone.
+ *
+ * 2. This callback is not called if the client disconnects because of
+ *    a timeout. In such a case, the client is unblocked automatically
+ *    and the timeout callback is called.
+ */
+void RM_SetDisconnectCallback(RedisModuleBlockedClient *bc, RedisModuleDisconnectFunc callback) {
+    bc->disconnect_callback = callback;
+}
+
+/* This function will check the moduleUnblockedClients queue in order to
+ * call the reply callback and really unblock the client.
+ *
+ * Clients end into this list because of calls to RM_UnblockClient(),
+ * however it is possible that while the module was doing work for the
+ * blocked client, it was terminated by Redis (for timeout or other reasons).
+ * When this happens the RedisModuleBlockedClient structure in the queue
+ * will have the 'client' field set to NULL. */
+void moduleHandleBlockedClients(void) {
+    listNode *ln;
+    RedisModuleBlockedClient *bc;
+
+    pthread_mutex_lock(&moduleUnblockedClientsMutex);
+    while (listLength(moduleUnblockedClients)) {
+        ln = listFirst(moduleUnblockedClients);
+        bc = ln->value;
+        client *c = bc->client;
+        listDelNode(moduleUnblockedClients,ln);
+        pthread_mutex_unlock(&moduleUnblockedClientsMutex);
+
+        /* Release the lock during the loop, as long as we don't
+         * touch the shared list. */
+
+        /* Call the reply callback if the client is valid and we have
+         * any callback. However the callback is not called if the client
+         * was blocked on keys (RM_BlockClientOnKeys()), because we already
+         * called such callback in moduleTryServeClientBlockedOnKey() when
+         * the key was signaled as ready. */
+        long long prev_error_replies = server.stat_total_error_replies;
+        uint64_t reply_us = 0;
+        if (c && !bc->blocked_on_keys && bc->reply_callback) {
+            RedisModuleCtx ctx;
+            moduleCreateContext(&ctx, bc->module, REDISMODULE_CTX_BLOCKED_REPLY);
+            ctx.blocked_privdata = bc->privdata;
+            ctx.blocked_ready_key = NULL;
+            ctx.client = bc->client;
+            ctx.blocked_client = bc;
+            monotime replyTimer;
+            elapsedStart(&replyTimer);
+            bc->reply_callback(&ctx,(void**)c->argv,c->argc);
+            reply_us = elapsedUs(replyTimer);
+            moduleFreeContext(&ctx);
+        }
+        /* Hold onto the blocked client if module auth is in progress. The reply callback is invoked
+         * when the client is reprocessed. */
+        if (c && clientHasModuleAuthInProgress(c)) {
+            c->module_blocked_client = bc;
+        } else {
+            /* Free privdata if any. */
+            moduleInvokeFreePrivDataCallback(c, bc);
+        }
+
+        /* It is possible that this blocked client object accumulated
+         * replies to send to the client in a thread safe context.
+         * We need to glue such replies to the client output buffer and
+         * free the temporary client we just used for the replies. */
+        if (c) AddReplyFromClient(c, bc->reply_client);
+        moduleReleaseTempClient(bc->reply_client);
+        moduleReleaseTempClient(bc->thread_safe_ctx_client);
+
+        /* Update stats now that we've finished the blocking operation.
+         * This needs to be out of the reply callback above given that a
+         * module might not define any callback and still do blocking ops.
+         */
+        if (c && !clientHasModuleAuthInProgress(c) && !bc->blocked_on_keys) {
+            updateStatsOnUnblock(c, bc->background_duration, reply_us, server.stat_total_error_replies != prev_error_replies);
+        }
+
+        if (c != NULL) {
+            /* Before unblocking the client, set the disconnect callback
+             * to NULL, because if we reached this point, the client was
+             * properly unblocked by the module. */
+            bc->disconnect_callback = NULL;
+            unblockClient(c, 1);
+
+            /* Update the wait offset, we don't know if this blocked client propagated anything,
+             * currently we rather not add any API for that, so we just assume it did. */
+            c->woff = server.master_repl_offset;
+
+            /* Put the client in the list of clients that need to write
+             * if there are pending replies here. This is needed since
+             * during a non blocking command the client may receive output. */
+            if (!clientHasModuleAuthInProgress(c) && clientHasPendingReplies(c) &&
+                !(c->flags & CLIENT_PENDING_WRITE))
+            {
+                c->flags |= CLIENT_PENDING_WRITE;
+                listLinkNodeHead(server.clients_pending_write, &c->clients_pending_write_node);
+            }
+        }
+
+        /* Free 'bc' only after unblocking the client, since it is
+         * referenced in the client blocking context, and must be valid
+         * when calling unblockClient(). */
+        if (!(c && clientHasModuleAuthInProgress(c))) {
+            bc->module->blocked_clients--;
+            zfree(bc);
+        }
+
+        /* Lock again before to iterate the loop. */
+        pthread_mutex_lock(&moduleUnblockedClientsMutex);
+    }
+    pthread_mutex_unlock(&moduleUnblockedClientsMutex);
+}
+
+/* Check if the specified client can be safely timed out using
+ * moduleBlockedClientTimedOut().
+ */
+int moduleBlockedClientMayTimeout(client *c) {
+    if (c->bstate.btype != BLOCKED_MODULE)
+        return 1;
+
+    RedisModuleBlockedClient *bc = c->bstate.module_blocked_handle;
+    return (bc && bc->timeout_callback != NULL);
+}
+
+/* Called when our client timed out. After this function unblockClient()
+ * is called, and it will invalidate the blocked client. So this function
+ * does not need to do any cleanup. Eventually the module will call the
+ * API to unblock the client and the memory will be released. */
+void moduleBlockedClientTimedOut(client *c) {
+    RedisModuleBlockedClient *bc = c->bstate.module_blocked_handle;
+
+    /* Protect against re-processing: don't serve clients that are already
+     * in the unblocking list for any reason (including RM_UnblockClient()
+     * explicit call). See #6798. */
+    if (bc->unblocked) return;
+
+    RedisModuleCtx ctx;
+    moduleCreateContext(&ctx, bc->module, REDISMODULE_CTX_BLOCKED_TIMEOUT);
+    ctx.client = bc->client;
+    ctx.blocked_client = bc;
+    ctx.blocked_privdata = bc->privdata;
+    long long prev_error_replies = server.stat_total_error_replies;
+    bc->timeout_callback(&ctx,(void**)c->argv,c->argc);
+    moduleFreeContext(&ctx);
+    updateStatsOnUnblock(c, bc->background_duration, 0, server.stat_total_error_replies != prev_error_replies);
+
+    /* For timeout events, we do not want to call the disconnect callback,
+     * because the blocked client will be automatically disconnected in
+     * this case, and the user can still hook using the timeout callback. */
+    bc->disconnect_callback = NULL;
+}
+
+/* Return non-zero if a module command was called in order to fill the
+ * reply for a blocked client. */
+int RM_IsBlockedReplyRequest(RedisModuleCtx *ctx) {
+    return (ctx->flags & REDISMODULE_CTX_BLOCKED_REPLY) != 0;
+}
+
+/* Return non-zero if a module command was called in order to fill the
+ * reply for a blocked client that timed out. */
+int RM_IsBlockedTimeoutRequest(RedisModuleCtx *ctx) {
+    return (ctx->flags & REDISMODULE_CTX_BLOCKED_TIMEOUT) != 0;
+}
+
+/* Get the private data set by RedisModule_UnblockClient() */
+void *RM_GetBlockedClientPrivateData(RedisModuleCtx *ctx) {
+    return ctx->blocked_privdata;
+}
+
+/* Get the key that is ready when the reply callback is called in the context
+ * of a client blocked by RedisModule_BlockClientOnKeys(). */
+RedisModuleString *RM_GetBlockedClientReadyKey(RedisModuleCtx *ctx) {
+    return ctx->blocked_ready_key;
+}
+
+/* Get the blocked client associated with a given context.
+ * This is useful in the reply and timeout callbacks of blocked clients,
+ * before sometimes the module has the blocked client handle references
+ * around, and wants to cleanup it. */
+RedisModuleBlockedClient *RM_GetBlockedClientHandle(RedisModuleCtx *ctx) {
+    return ctx->blocked_client;
+}
+
+/* Return true if when the free callback of a blocked client is called,
+ * the reason for the client to be unblocked is that it disconnected
+ * while it was blocked. */
+int RM_BlockedClientDisconnected(RedisModuleCtx *ctx) {
+    return (ctx->flags & REDISMODULE_CTX_BLOCKED_DISCONNECTED) != 0;
+}
+
+/* --------------------------------------------------------------------------
+ * ## Thread Safe Contexts
+ * -------------------------------------------------------------------------- */
+
+/* Return a context which can be used inside threads to make Redis context
+ * calls with certain modules APIs. If 'bc' is not NULL then the module will
+ * be bound to a blocked client, and it will be possible to use the
+ * `RedisModule_Reply*` family of functions to accumulate a reply for when the
+ * client will be unblocked. Otherwise the thread safe context will be
+ * detached by a specific client.
+ *
+ * To call non-reply APIs, the thread safe context must be prepared with:
+ *
+ *     RedisModule_ThreadSafeContextLock(ctx);
+ *     ... make your call here ...
+ *     RedisModule_ThreadSafeContextUnlock(ctx);
+ *
+ * This is not needed when using `RedisModule_Reply*` functions, assuming
+ * that a blocked client was used when the context was created, otherwise
+ * no RedisModule_Reply* call should be made at all.
+ *
+ * NOTE: If you're creating a detached thread safe context (bc is NULL),
+ * consider using `RM_GetDetachedThreadSafeContext` which will also retain
+ * the module ID and thus be more useful for logging. */
+RedisModuleCtx *RM_GetThreadSafeContext(RedisModuleBlockedClient *bc) {
+    RedisModuleCtx *ctx = zmalloc(sizeof(*ctx));
+    RedisModule *module = bc ? bc->module : NULL;
+    int flags = REDISMODULE_CTX_THREAD_SAFE;
+
+    /* Creating a new client object is costly. To avoid that, we have an
+     * internal pool of client objects. In blockClient(), a client object is
+     * assigned to bc->thread_safe_ctx_client to be used for the thread safe
+     * context.
+     * For detached thread safe contexts, we create a new client object.
+     * Otherwise, as this function can be called from different threads, we
+     * would need to synchronize access to internal pool of client objects.
+     * Assuming creating detached context is rare and not that performance
+     * critical, we avoid synchronizing access to the client pool by creating
+     * a new client */
+    if (!bc) flags |= REDISMODULE_CTX_NEW_CLIENT;
+    moduleCreateContext(ctx, module, flags);
+    /* Even when the context is associated with a blocked client, we can't
+     * access it safely from another thread, so we use a fake client here
+     * in order to keep things like the currently selected database and similar
+     * things. */
+    if (bc) {
+        ctx->blocked_client = bc;
+        ctx->client = bc->thread_safe_ctx_client;
+        selectDb(ctx->client,bc->dbid);
+        if (bc->client) {
+            ctx->client->id = bc->client->id;
+            ctx->client->resp = bc->client->resp;
+        }
+    }
+    return ctx;
+}
+
+/* Return a detached thread safe context that is not associated with any
+ * specific blocked client, but is associated with the module's context.
+ *
+ * This is useful for modules that wish to hold a global context over
+ * a long term, for purposes such as logging. */
+RedisModuleCtx *RM_GetDetachedThreadSafeContext(RedisModuleCtx *ctx) {
+    RedisModuleCtx *new_ctx = zmalloc(sizeof(*new_ctx));
+    /* We create a new client object for the detached context.
+     * See RM_GetThreadSafeContext() for more information */
+    moduleCreateContext(new_ctx, ctx->module,
+                        REDISMODULE_CTX_THREAD_SAFE|REDISMODULE_CTX_NEW_CLIENT);
+    return new_ctx;
+}
+
+/* Release a thread safe context. */
+void RM_FreeThreadSafeContext(RedisModuleCtx *ctx) {
+    moduleFreeContext(ctx);
+    zfree(ctx);
+}
+
+void moduleGILAfterLock(void) {
+    /* We should never get here if we already inside a module
+     * code block which already opened a context. */
+    serverAssert(server.execution_nesting == 0);
+    /* Bump up the nesting level to prevent immediate propagation
+     * of possible RM_Call from th thread */
+    enterExecutionUnit(1, 0);
+}
+
+/* Acquire the server lock before executing a thread safe API call.
+ * This is not needed for `RedisModule_Reply*` calls when there is
+ * a blocked client connected to the thread safe context. */
+void RM_ThreadSafeContextLock(RedisModuleCtx *ctx) {
+    UNUSED(ctx);
+    moduleAcquireGIL();
+    moduleGILAfterLock();
+}
+
+/* Similar to RM_ThreadSafeContextLock but this function
+ * would not block if the server lock is already acquired.
+ *
+ * If successful (lock acquired) REDISMODULE_OK is returned,
+ * otherwise REDISMODULE_ERR is returned and errno is set
+ * accordingly. */
+int RM_ThreadSafeContextTryLock(RedisModuleCtx *ctx) {
+    UNUSED(ctx);
+
+    int res = moduleTryAcquireGIL();
+    if(res != 0) {
+        errno = res;
+        return REDISMODULE_ERR;
+    }
+    moduleGILAfterLock();
+    return REDISMODULE_OK;
+}
+
+void moduleGILBeforeUnlock(void) {
+    /* We should never get here if we already inside a module
+     * code block which already opened a context, except
+     * the bump-up from moduleGILAcquired. */
+    serverAssert(server.execution_nesting == 1);
+    /* Restore nesting level and propagate pending commands
+     * (because it's unclear when thread safe contexts are
+     * released we have to propagate here). */
+    exitExecutionUnit();
+    postExecutionUnitOperations();
+}
+
+/* Release the server lock after a thread safe API call was executed. */
+void RM_ThreadSafeContextUnlock(RedisModuleCtx *ctx) {
+    UNUSED(ctx);
+    moduleGILBeforeUnlock();
+    moduleReleaseGIL();
+}
+
+void moduleAcquireGIL(void) {
+    pthread_mutex_lock(&moduleGIL);
+}
+
+int moduleTryAcquireGIL(void) {
+    return pthread_mutex_trylock(&moduleGIL);
+}
+
+void moduleReleaseGIL(void) {
+    pthread_mutex_unlock(&moduleGIL);
+}
+
+
+/* --------------------------------------------------------------------------
+ * ## Module Keyspace Notifications API
+ * -------------------------------------------------------------------------- */
+
+/* Subscribe to keyspace notifications. This is a low-level version of the
+ * keyspace-notifications API. A module can register callbacks to be notified
+ * when keyspace events occur.
+ *
+ * Notification events are filtered by their type (string events, set events,
+ * etc), and the subscriber callback receives only events that match a specific
+ * mask of event types.
+ *
+ * When subscribing to notifications with RedisModule_SubscribeToKeyspaceEvents
+ * the module must provide an event type-mask, denoting the events the subscriber
+ * is interested in. This can be an ORed mask of any of the following flags:
+ *
+ *  - REDISMODULE_NOTIFY_GENERIC: Generic commands like DEL, EXPIRE, RENAME
+ *  - REDISMODULE_NOTIFY_STRING: String events
+ *  - REDISMODULE_NOTIFY_LIST: List events
+ *  - REDISMODULE_NOTIFY_SET: Set events
+ *  - REDISMODULE_NOTIFY_HASH: Hash events
+ *  - REDISMODULE_NOTIFY_ZSET: Sorted Set events
+ *  - REDISMODULE_NOTIFY_EXPIRED: Expiration events
+ *  - REDISMODULE_NOTIFY_EVICTED: Eviction events
+ *  - REDISMODULE_NOTIFY_STREAM: Stream events
+ *  - REDISMODULE_NOTIFY_MODULE: Module types events
+ *  - REDISMODULE_NOTIFY_KEYMISS: Key-miss events
+ *                                Notice, key-miss event is the only type
+ *                                of event that is fired from within a read command.
+ *                                Performing RM_Call with a write command from within
+ *                                this notification is wrong and discourage. It will
+ *                                cause the read command that trigger the event to be
+ *                                replicated to the AOF/Replica.
+ *  - REDISMODULE_NOTIFY_ALL: All events (Excluding REDISMODULE_NOTIFY_KEYMISS)
+ *  - REDISMODULE_NOTIFY_LOADED: A special notification available only for modules,
+ *                               indicates that the key was loaded from persistence.
+ *                               Notice, when this event fires, the given key
+ *                               can not be retained, use RM_CreateStringFromString
+ *                               instead.
+ *
+ * We do not distinguish between key events and keyspace events, and it is up
+ * to the module to filter the actions taken based on the key.
+ *
+ * The subscriber signature is:
+ *
+ *     int (*RedisModuleNotificationFunc) (RedisModuleCtx *ctx, int type,
+ *                                         const char *event,
+ *                                         RedisModuleString *key);
+ *
+ * `type` is the event type bit, that must match the mask given at registration
+ * time. The event string is the actual command being executed, and key is the
+ * relevant Redis key.
+ *
+ * Notification callback gets executed with a redis context that can not be
+ * used to send anything to the client, and has the db number where the event
+ * occurred as its selected db number.
+ *
+ * Notice that it is not necessary to enable notifications in redis.conf for
+ * module notifications to work.
+ *
+ * Warning: the notification callbacks are performed in a synchronous manner,
+ * so notification callbacks must to be fast, or they would slow Redis down.
+ * If you need to take long actions, use threads to offload them.
+ *
+ * Moreover, the fact that the notification is executed synchronously means
+ * that the notification code will be executed in the middle on Redis logic
+ * (commands logic, eviction, expire). Changing the key space while the logic
+ * runs is dangerous and discouraged. In order to react to key space events with
+ * write actions, please refer to `RM_AddPostNotificationJob`.
+ *
+ * See https://redis.io/topics/notifications for more information.
+ */
+int RM_SubscribeToKeyspaceEvents(RedisModuleCtx *ctx, int types, RedisModuleNotificationFunc callback) {
+    RedisModuleKeyspaceSubscriber *sub = zmalloc(sizeof(*sub));
+    sub->module = ctx->module;
+    sub->event_mask = types;
+    sub->notify_callback = callback;
+    sub->active = 0;
+
+    listAddNodeTail(moduleKeyspaceSubscribers, sub);
+    return REDISMODULE_OK;
+}
+
+void firePostExecutionUnitJobs(void) {
+    /* Avoid propagation of commands.
+     * In that way, postExecutionUnitOperations will prevent
+     * recursive calls to firePostExecutionUnitJobs.
+     * This is a special case where we need to increase 'execution_nesting'
+     * but we do not want to update the cached time */
+    enterExecutionUnit(0, 0);
+    while (listLength(modulePostExecUnitJobs) > 0) {
+        listNode *ln = listFirst(modulePostExecUnitJobs);
+        RedisModulePostExecUnitJob *job = listNodeValue(ln);
+        listDelNode(modulePostExecUnitJobs, ln);
+
+        RedisModuleCtx ctx;
+        moduleCreateContext(&ctx, job->module, REDISMODULE_CTX_TEMP_CLIENT);
+        selectDb(ctx.client, job->dbid);
+
+        job->callback(&ctx, job->pd);
+        if (job->free_pd) job->free_pd(job->pd);
+
+        moduleFreeContext(&ctx);
+        zfree(job);
+    }
+    exitExecutionUnit();
+}
+
+/* When running inside a key space notification callback, it is dangerous and highly discouraged to perform any write
+ * operation (See `RM_SubscribeToKeyspaceEvents`). In order to still perform write actions in this scenario,
+ * Redis provides `RM_AddPostNotificationJob` API. The API allows to register a job callback which Redis will call
+ * when the following condition are promised to be fulfilled:
+ * 1. It is safe to perform any write operation.
+ * 2. The job will be called atomically along side the key space notification.
+ *
+ * Notice, one job might trigger key space notifications that will trigger more jobs.
+ * This raises a concerns of entering an infinite loops, we consider infinite loops
+ * as a logical bug that need to be fixed in the module, an attempt to protect against
+ * infinite loops by halting the execution could result in violation of the feature correctness
+ * and so Redis will make no attempt to protect the module from infinite loops.
+ *
+ * 'free_pd' can be NULL and in such case will not be used.
+ *
+ * Return REDISMODULE_OK on success and REDISMODULE_ERR if was called while loading data from disk (AOF or RDB) or
+ * if the instance is a readonly replica. */
+int RM_AddPostNotificationJob(RedisModuleCtx *ctx, RedisModulePostNotificationJobFunc callback, void *privdata, void (*free_privdata)(void*)) {
+    if (server.loading|| (server.masterhost && server.repl_slave_ro)) {
+        return REDISMODULE_ERR;
+    }
+    RedisModulePostExecUnitJob *job = zmalloc(sizeof(*job));
+    job->module = ctx->module;
+    job->callback = callback;
+    job->pd = privdata;
+    job->free_pd = free_privdata;
+    job->dbid = ctx->client->db->id;
+
+    listAddNodeTail(modulePostExecUnitJobs, job);
+    return REDISMODULE_OK;
+}
+
+/* Get the configured bitmap of notify-keyspace-events (Could be used
+ * for additional filtering in RedisModuleNotificationFunc) */
+int RM_GetNotifyKeyspaceEvents(void) {
+    return server.notify_keyspace_events;
+}
+
+/* Expose notifyKeyspaceEvent to modules */
+int RM_NotifyKeyspaceEvent(RedisModuleCtx *ctx, int type, const char *event, RedisModuleString *key) {
+    if (!ctx || !ctx->client)
+        return REDISMODULE_ERR;
+    notifyKeyspaceEvent(type, (char *)event, key, ctx->client->db->id);
+    return REDISMODULE_OK;
+}
+
+/* Dispatcher for keyspace notifications to module subscriber functions.
+ * This gets called  only if at least one module requested to be notified on
+ * keyspace notifications */
+void moduleNotifyKeyspaceEvent(int type, const char *event, robj *key, int dbid) {
+    /* Don't do anything if there aren't any subscribers */
+    if (listLength(moduleKeyspaceSubscribers) == 0) return;
+
+    /* Ugly hack to handle modules which use write commands from within
+     * notify_callback, which they should NOT do!
+     * Modules should use RedisModules_AddPostNotificationJob instead.
+     *
+     * Anyway, we want any propagated commands from within notify_callback
+     * to be propagated inside a MULTI/EXEC together with the original
+     * command that caused the KSN.
+     * Note that it's only relevant for KSNs which are not generated from within
+     * call(), for example active-expiry and eviction (because anyway
+     * execution_nesting is incremented from within call())
+     *
+     * In order to do that we increment the execution_nesting counter, thus
+     * preventing postExecutionUnitOperations (from within moduleFreeContext)
+     * from propagating commands from CB.
+     *
+     * This is a special case where we need to increase 'execution_nesting'
+     * but we do not want to update the cached time */
+    enterExecutionUnit(0, 0);
+
+    listIter li;
+    listNode *ln;
+    listRewind(moduleKeyspaceSubscribers,&li);
+
+    /* Remove irrelevant flags from the type mask */
+    type &= ~(NOTIFY_KEYEVENT | NOTIFY_KEYSPACE);
+
+    while((ln = listNext(&li))) {
+        RedisModuleKeyspaceSubscriber *sub = ln->value;
+        /* Only notify subscribers on events matching the registration,
+         * and avoid subscribers triggering themselves */
+        if ((sub->event_mask & type) &&
+            (sub->active == 0 || (sub->module->options & REDISMODULE_OPTIONS_ALLOW_NESTED_KEYSPACE_NOTIFICATIONS))) {
+            RedisModuleCtx ctx;
+            moduleCreateContext(&ctx, sub->module, REDISMODULE_CTX_TEMP_CLIENT);
+            selectDb(ctx.client, dbid);
+
+            /* mark the handler as active to avoid reentrant loops.
+             * If the subscriber performs an action triggering itself,
+             * it will not be notified about it. */
+            sub->active = 1;
+            server.lazy_expire_disabled++;
+            sub->notify_callback(&ctx, type, event, key);
+            server.lazy_expire_disabled--;
+            sub->active = 0;
+            moduleFreeContext(&ctx);
+        }
+    }
+
+    exitExecutionUnit();
+}
+
+/* Unsubscribe any notification subscribers this module has upon unloading */
+void moduleUnsubscribeNotifications(RedisModule *module) {
+    listIter li;
+    listNode *ln;
+    listRewind(moduleKeyspaceSubscribers,&li);
+    while((ln = listNext(&li))) {
+        RedisModuleKeyspaceSubscriber *sub = ln->value;
+        if (sub->module == module) {
+            listDelNode(moduleKeyspaceSubscribers, ln);
+            zfree(sub);
+        }
+    }
+}
+
+/* --------------------------------------------------------------------------
+ * ## Modules Cluster API
+ * -------------------------------------------------------------------------- */
+
+/* The Cluster message callback function pointer type. */
+typedef void (*RedisModuleClusterMessageReceiver)(RedisModuleCtx *ctx, const char *sender_id, uint8_t type, const unsigned char *payload, uint32_t len);
+
+/* This structure identifies a registered caller: it must match a given module
+ * ID, for a given message type. The callback function is just the function
+ * that was registered as receiver. */
+typedef struct moduleClusterReceiver {
+    uint64_t module_id;
+    RedisModuleClusterMessageReceiver callback;
+    struct RedisModule *module;
+    struct moduleClusterReceiver *next;
+} moduleClusterReceiver;
+
+typedef struct moduleClusterNodeInfo {
+    int flags;
+    char ip[NET_IP_STR_LEN];
+    int port;
+    char master_id[40]; /* Only if flags & REDISMODULE_NODE_MASTER is true. */
+} mdouleClusterNodeInfo;
+
+/* We have an array of message types: each bucket is a linked list of
+ * configured receivers. */
+static moduleClusterReceiver *clusterReceivers[UINT8_MAX];
+
+/* Dispatch the message to the right module receiver. */
+void moduleCallClusterReceivers(const char *sender_id, uint64_t module_id, uint8_t type, const unsigned char *payload, uint32_t len) {
+    moduleClusterReceiver *r = clusterReceivers[type];
+    while(r) {
+        if (r->module_id == module_id) {
+            RedisModuleCtx ctx;
+            moduleCreateContext(&ctx, r->module, REDISMODULE_CTX_TEMP_CLIENT);
+            r->callback(&ctx,sender_id,type,payload,len);
+            moduleFreeContext(&ctx);
+            return;
+        }
+        r = r->next;
+    }
+}
+
+/* Register a callback receiver for cluster messages of type 'type'. If there
+ * was already a registered callback, this will replace the callback function
+ * with the one provided, otherwise if the callback is set to NULL and there
+ * is already a callback for this function, the callback is unregistered
+ * (so this API call is also used in order to delete the receiver). */
+void RM_RegisterClusterMessageReceiver(RedisModuleCtx *ctx, uint8_t type, RedisModuleClusterMessageReceiver callback) {
+    if (!server.cluster_enabled) return;
+
+    uint64_t module_id = moduleTypeEncodeId(ctx->module->name,0);
+    moduleClusterReceiver *r = clusterReceivers[type], *prev = NULL;
+    while(r) {
+        if (r->module_id == module_id) {
+            /* Found! Set or delete. */
+            if (callback) {
+                r->callback = callback;
+            } else {
+                /* Delete the receiver entry if the user is setting
+                 * it to NULL. Just unlink the receiver node from the
+                 * linked list. */
+                if (prev)
+                    prev->next = r->next;
+                else
+                    clusterReceivers[type]->next = r->next;
+                zfree(r);
+            }
+            return;
+        }
+        prev = r;
+        r = r->next;
+    }
+
+    /* Not found, let's add it. */
+    if (callback) {
+        r = zmalloc(sizeof(*r));
+        r->module_id = module_id;
+        r->module = ctx->module;
+        r->callback = callback;
+        r->next = clusterReceivers[type];
+        clusterReceivers[type] = r;
+    }
+}
+
+/* Send a message to all the nodes in the cluster if `target` is NULL, otherwise
+ * at the specified target, which is a REDISMODULE_NODE_ID_LEN bytes node ID, as
+ * returned by the receiver callback or by the nodes iteration functions.
+ *
+ * The function returns REDISMODULE_OK if the message was successfully sent,
+ * otherwise if the node is not connected or such node ID does not map to any
+ * known cluster node, REDISMODULE_ERR is returned. */
+int RM_SendClusterMessage(RedisModuleCtx *ctx, const char *target_id, uint8_t type, const char *msg, uint32_t len) {
+    if (!server.cluster_enabled) return REDISMODULE_ERR;
+    uint64_t module_id = moduleTypeEncodeId(ctx->module->name,0);
+    if (clusterSendModuleMessageToTarget(target_id,module_id,type,msg,len) == C_OK)
+        return REDISMODULE_OK;
+    else
+        return REDISMODULE_ERR;
+}
+
+/* Return an array of string pointers, each string pointer points to a cluster
+ * node ID of exactly REDISMODULE_NODE_ID_LEN bytes (without any null term).
+ * The number of returned node IDs is stored into `*numnodes`.
+ * However if this function is called by a module not running an a Redis
+ * instance with Redis Cluster enabled, NULL is returned instead.
+ *
+ * The IDs returned can be used with RedisModule_GetClusterNodeInfo() in order
+ * to get more information about single node.
+ *
+ * The array returned by this function must be freed using the function
+ * RedisModule_FreeClusterNodesList().
+ *
+ * Example:
+ *
+ *     size_t count, j;
+ *     char **ids = RedisModule_GetClusterNodesList(ctx,&count);
+ *     for (j = 0; j < count; j++) {
+ *         RedisModule_Log(ctx,"notice","Node %.*s",
+ *             REDISMODULE_NODE_ID_LEN,ids[j]);
+ *     }
+ *     RedisModule_FreeClusterNodesList(ids);
+ */
+char **RM_GetClusterNodesList(RedisModuleCtx *ctx, size_t *numnodes) {
+    UNUSED(ctx);
+
+    if (!server.cluster_enabled) return NULL;
+    size_t count = dictSize(server.cluster->nodes);
+    char **ids = zmalloc((count+1)*REDISMODULE_NODE_ID_LEN);
+    dictIterator *di = dictGetIterator(server.cluster->nodes);
+    dictEntry *de;
+    int j = 0;
+    while((de = dictNext(di)) != NULL) {
+        clusterNode *node = dictGetVal(de);
+        if (node->flags & (CLUSTER_NODE_NOADDR|CLUSTER_NODE_HANDSHAKE)) continue;
+        ids[j] = zmalloc(REDISMODULE_NODE_ID_LEN);
+        memcpy(ids[j],node->name,REDISMODULE_NODE_ID_LEN);
+        j++;
+    }
+    *numnodes = j;
+    ids[j] = NULL; /* Null term so that FreeClusterNodesList does not need
+                    * to also get the count argument. */
+    dictReleaseIterator(di);
+    return ids;
+}
+
+/* Free the node list obtained with RedisModule_GetClusterNodesList. */
+void RM_FreeClusterNodesList(char **ids) {
+    if (ids == NULL) return;
+    for (int j = 0; ids[j]; j++) zfree(ids[j]);
+    zfree(ids);
+}
+
+/* Return this node ID (REDISMODULE_CLUSTER_ID_LEN bytes) or NULL if the cluster
+ * is disabled. */
+const char *RM_GetMyClusterID(void) {
+    if (!server.cluster_enabled) return NULL;
+    return server.cluster->myself->name;
+}
+
+/* Return the number of nodes in the cluster, regardless of their state
+ * (handshake, noaddress, ...) so that the number of active nodes may actually
+ * be smaller, but not greater than this number. If the instance is not in
+ * cluster mode, zero is returned. */
+size_t RM_GetClusterSize(void) {
+    if (!server.cluster_enabled) return 0;
+    return dictSize(server.cluster->nodes);
+}
+
+/* Populate the specified info for the node having as ID the specified 'id',
+ * then returns REDISMODULE_OK. Otherwise if the format of node ID is invalid
+ * or the node ID does not exist from the POV of this local node, REDISMODULE_ERR
+ * is returned.
+ *
+ * The arguments `ip`, `master_id`, `port` and `flags` can be NULL in case we don't
+ * need to populate back certain info. If an `ip` and `master_id` (only populated
+ * if the instance is a slave) are specified, they point to buffers holding
+ * at least REDISMODULE_NODE_ID_LEN bytes. The strings written back as `ip`
+ * and `master_id` are not null terminated.
+ *
+ * The list of flags reported is the following:
+ *
+ * * REDISMODULE_NODE_MYSELF:       This node
+ * * REDISMODULE_NODE_MASTER:       The node is a master
+ * * REDISMODULE_NODE_SLAVE:        The node is a replica
+ * * REDISMODULE_NODE_PFAIL:        We see the node as failing
+ * * REDISMODULE_NODE_FAIL:         The cluster agrees the node is failing
+ * * REDISMODULE_NODE_NOFAILOVER:   The slave is configured to never failover
+ */
+int RM_GetClusterNodeInfo(RedisModuleCtx *ctx, const char *id, char *ip, char *master_id, int *port, int *flags) {
+    UNUSED(ctx);
+
+    clusterNode *node = clusterLookupNode(id, strlen(id));
+    if (node == NULL ||
+        node->flags & (CLUSTER_NODE_NOADDR|CLUSTER_NODE_HANDSHAKE))
+    {
+        return REDISMODULE_ERR;
+    }
+
+    if (ip) redis_strlcpy(ip,node->ip,NET_IP_STR_LEN);
+
+    if (master_id) {
+        /* If the information is not available, the function will set the
+         * field to zero bytes, so that when the field can't be populated the
+         * function kinda remains predictable. */
+        if (node->flags & CLUSTER_NODE_SLAVE && node->slaveof)
+            memcpy(master_id,node->slaveof->name,REDISMODULE_NODE_ID_LEN);
+        else
+            memset(master_id,0,REDISMODULE_NODE_ID_LEN);
+    }
+    if (port) *port = getNodeDefaultClientPort(node);
+
+    /* As usually we have to remap flags for modules, in order to ensure
+     * we can provide binary compatibility. */
+    if (flags) {
+        *flags = 0;
+        if (node->flags & CLUSTER_NODE_MYSELF) *flags |= REDISMODULE_NODE_MYSELF;
+        if (node->flags & CLUSTER_NODE_MASTER) *flags |= REDISMODULE_NODE_MASTER;
+        if (node->flags & CLUSTER_NODE_SLAVE) *flags |= REDISMODULE_NODE_SLAVE;
+        if (node->flags & CLUSTER_NODE_PFAIL) *flags |= REDISMODULE_NODE_PFAIL;
+        if (node->flags & CLUSTER_NODE_FAIL) *flags |= REDISMODULE_NODE_FAIL;
+        if (node->flags & CLUSTER_NODE_NOFAILOVER) *flags |= REDISMODULE_NODE_NOFAILOVER;
+    }
+    return REDISMODULE_OK;
+}
+
+/* Set Redis Cluster flags in order to change the normal behavior of
+ * Redis Cluster, especially with the goal of disabling certain functions.
+ * This is useful for modules that use the Cluster API in order to create
+ * a different distributed system, but still want to use the Redis Cluster
+ * message bus. Flags that can be set:
+ *
+ * * CLUSTER_MODULE_FLAG_NO_FAILOVER
+ * * CLUSTER_MODULE_FLAG_NO_REDIRECTION
+ *
+ * With the following effects:
+ *
+ * * NO_FAILOVER: prevent Redis Cluster slaves from failing over a dead master.
+ *                Also disables the replica migration feature.
+ *
+ * * NO_REDIRECTION: Every node will accept any key, without trying to perform
+ *                   partitioning according to the Redis Cluster algorithm.
+ *                   Slots information will still be propagated across the
+ *                   cluster, but without effect. */
+void RM_SetClusterFlags(RedisModuleCtx *ctx, uint64_t flags) {
+    UNUSED(ctx);
+    if (flags & REDISMODULE_CLUSTER_FLAG_NO_FAILOVER)
+        server.cluster_module_flags |= CLUSTER_MODULE_FLAG_NO_FAILOVER;
+    if (flags & REDISMODULE_CLUSTER_FLAG_NO_REDIRECTION)
+        server.cluster_module_flags |= CLUSTER_MODULE_FLAG_NO_REDIRECTION;
+}
+
+/* --------------------------------------------------------------------------
+ * ## Modules Timers API
+ *
+ * Module timers are a high precision "green timers" abstraction where
+ * every module can register even millions of timers without problems, even if
+ * the actual event loop will just have a single timer that is used to awake the
+ * module timers subsystem in order to process the next event.
+ *
+ * All the timers are stored into a radix tree, ordered by expire time, when
+ * the main Redis event loop timer callback is called, we try to process all
+ * the timers already expired one after the other. Then we re-enter the event
+ * loop registering a timer that will expire when the next to process module
+ * timer will expire.
+ *
+ * Every time the list of active timers drops to zero, we unregister the
+ * main event loop timer, so that there is no overhead when such feature is
+ * not used.
+ * -------------------------------------------------------------------------- */
+
+static rax *Timers;     /* The radix tree of all the timers sorted by expire. */
+long long aeTimer = -1; /* Main event loop (ae.c) timer identifier. */
+
+typedef void (*RedisModuleTimerProc)(RedisModuleCtx *ctx, void *data);
+
+/* The timer descriptor, stored as value in the radix tree. */
+typedef struct RedisModuleTimer {
+    RedisModule *module;                /* Module reference. */
+    RedisModuleTimerProc callback;      /* The callback to invoke on expire. */
+    void *data;                         /* Private data for the callback. */
+    int dbid;                           /* Database number selected by the original client. */
+} RedisModuleTimer;
+
+/* This is the timer handler that is called by the main event loop. We schedule
+ * this timer to be called when the nearest of our module timers will expire. */
+int moduleTimerHandler(struct aeEventLoop *eventLoop, long long id, void *clientData) {
+    UNUSED(eventLoop);
+    UNUSED(id);
+    UNUSED(clientData);
+
+    /* To start let's try to fire all the timers already expired. */
+    raxIterator ri;
+    raxStart(&ri,Timers);
+    uint64_t now = ustime();
+    long long next_period = 0;
+    while(1) {
+        raxSeek(&ri,"^",NULL,0);
+        if (!raxNext(&ri)) break;
+        uint64_t expiretime;
+        memcpy(&expiretime,ri.key,sizeof(expiretime));
+        expiretime = ntohu64(expiretime);
+        if (now >= expiretime) {
+            RedisModuleTimer *timer = ri.data;
+            RedisModuleCtx ctx;
+            moduleCreateContext(&ctx,timer->module,REDISMODULE_CTX_TEMP_CLIENT);
+            selectDb(ctx.client, timer->dbid);
+            timer->callback(&ctx,timer->data);
+            moduleFreeContext(&ctx);
+            raxRemove(Timers,(unsigned char*)ri.key,ri.key_len,NULL);
+            zfree(timer);
+        } else {
+            /* We call ustime() again instead of using the cached 'now' so that
+             * 'next_period' isn't affected by the time it took to execute
+             * previous calls to 'callback.
+             * We need to cast 'expiretime' so that the compiler will not treat
+             * the difference as unsigned (Causing next_period to be huge) in
+             * case expiretime < ustime() */
+            next_period = ((long long)expiretime-ustime())/1000; /* Scale to milliseconds. */
+            break;
+        }
+    }
+    raxStop(&ri);
+
+    /* Reschedule the next timer or cancel it. */
+    if (next_period <= 0) next_period = 1;
+    if (raxSize(Timers) > 0) {
+        return next_period;
+    } else {
+        aeTimer = -1;
+        return AE_NOMORE;
+    }
+}
+
+/* Create a new timer that will fire after `period` milliseconds, and will call
+ * the specified function using `data` as argument. The returned timer ID can be
+ * used to get information from the timer or to stop it before it fires.
+ * Note that for the common use case of a repeating timer (Re-registration
+ * of the timer inside the RedisModuleTimerProc callback) it matters when
+ * this API is called:
+ * If it is called at the beginning of 'callback' it means
+ * the event will triggered every 'period'.
+ * If it is called at the end of 'callback' it means
+ * there will 'period' milliseconds gaps between events.
+ * (If the time it takes to execute 'callback' is negligible the two
+ * statements above mean the same) */
+RedisModuleTimerID RM_CreateTimer(RedisModuleCtx *ctx, mstime_t period, RedisModuleTimerProc callback, void *data) {
+    RedisModuleTimer *timer = zmalloc(sizeof(*timer));
+    timer->module = ctx->module;
+    timer->callback = callback;
+    timer->data = data;
+    timer->dbid = ctx->client ? ctx->client->db->id : 0;
+    uint64_t expiretime = ustime()+period*1000;
+    uint64_t key;
+
+    while(1) {
+        key = htonu64(expiretime);
+        if (raxFind(Timers, (unsigned char*)&key,sizeof(key)) == raxNotFound) {
+            raxInsert(Timers,(unsigned char*)&key,sizeof(key),timer,NULL);
+            break;
+        } else {
+            expiretime++;
+        }
+    }
+
+    /* We need to install the main event loop timer if it's not already
+     * installed, or we may need to refresh its period if we just installed
+     * a timer that will expire sooner than any other else (i.e. the timer
+     * we just installed is the first timer in the Timers rax). */
+    if (aeTimer != -1) {
+        raxIterator ri;
+        raxStart(&ri,Timers);
+        raxSeek(&ri,"^",NULL,0);
+        raxNext(&ri);
+        if (memcmp(ri.key,&key,sizeof(key)) == 0) {
+            /* This is the first key, we need to re-install the timer according
+             * to the just added event. */
+            aeDeleteTimeEvent(server.el,aeTimer);
+            aeTimer = -1;
+        }
+        raxStop(&ri);
+    }
+
+    /* If we have no main timer (the old one was invalidated, or this is the
+     * first module timer we have), install one. */
+    if (aeTimer == -1)
+        aeTimer = aeCreateTimeEvent(server.el,period,moduleTimerHandler,NULL,NULL);
+
+    return key;
+}
+
+/* Stop a timer, returns REDISMODULE_OK if the timer was found, belonged to the
+ * calling module, and was stopped, otherwise REDISMODULE_ERR is returned.
+ * If not NULL, the data pointer is set to the value of the data argument when
+ * the timer was created. */
+int RM_StopTimer(RedisModuleCtx *ctx, RedisModuleTimerID id, void **data) {
+    RedisModuleTimer *timer = raxFind(Timers,(unsigned char*)&id,sizeof(id));
+    if (timer == raxNotFound || timer->module != ctx->module)
+        return REDISMODULE_ERR;
+    if (data) *data = timer->data;
+    raxRemove(Timers,(unsigned char*)&id,sizeof(id),NULL);
+    zfree(timer);
+    return REDISMODULE_OK;
+}
+
+/* Obtain information about a timer: its remaining time before firing
+ * (in milliseconds), and the private data pointer associated with the timer.
+ * If the timer specified does not exist or belongs to a different module
+ * no information is returned and the function returns REDISMODULE_ERR, otherwise
+ * REDISMODULE_OK is returned. The arguments remaining or data can be NULL if
+ * the caller does not need certain information. */
+int RM_GetTimerInfo(RedisModuleCtx *ctx, RedisModuleTimerID id, uint64_t *remaining, void **data) {
+    RedisModuleTimer *timer = raxFind(Timers,(unsigned char*)&id,sizeof(id));
+    if (timer == raxNotFound || timer->module != ctx->module)
+        return REDISMODULE_ERR;
+    if (remaining) {
+        int64_t rem = ntohu64(id)-ustime();
+        if (rem < 0) rem = 0;
+        *remaining = rem/1000; /* Scale to milliseconds. */
+    }
+    if (data) *data = timer->data;
+    return REDISMODULE_OK;
+}
+
+/* Query timers to see if any timer belongs to the module.
+ * Return 1 if any timer was found, otherwise 0 would be returned. */
+int moduleHoldsTimer(struct RedisModule *module) {
+    raxIterator iter;
+    int found = 0;
+    raxStart(&iter,Timers);
+    raxSeek(&iter,"^",NULL,0);
+    while (raxNext(&iter)) {
+        RedisModuleTimer *timer = iter.data;
+        if (timer->module == module) {
+            found = 1;
+            break;
+        }
+    }
+    raxStop(&iter);
+    return found;
+}
+
+/* --------------------------------------------------------------------------
+ * ## Modules EventLoop API
+ * --------------------------------------------------------------------------*/
+
+typedef struct EventLoopData {
+    RedisModuleEventLoopFunc rFunc;
+    RedisModuleEventLoopFunc wFunc;
+    void *user_data;
+} EventLoopData;
+
+typedef struct EventLoopOneShot {
+    RedisModuleEventLoopOneShotFunc func;
+    void *user_data;
+} EventLoopOneShot;
+
+list *moduleEventLoopOneShots;
+static pthread_mutex_t moduleEventLoopMutex = PTHREAD_MUTEX_INITIALIZER;
+
+static int eventLoopToAeMask(int mask) {
+    int aeMask = 0;
+    if (mask & REDISMODULE_EVENTLOOP_READABLE)
+        aeMask |= AE_READABLE;
+    if (mask & REDISMODULE_EVENTLOOP_WRITABLE)
+        aeMask |= AE_WRITABLE;
+    return aeMask;
+}
+
+static int eventLoopFromAeMask(int ae_mask) {
+    int mask = 0;
+    if (ae_mask & AE_READABLE)
+        mask |= REDISMODULE_EVENTLOOP_READABLE;
+    if (ae_mask & AE_WRITABLE)
+        mask |= REDISMODULE_EVENTLOOP_WRITABLE;
+    return mask;
+}
+
+static void eventLoopCbReadable(struct aeEventLoop *ae, int fd, void *user_data, int ae_mask) {
+    UNUSED(ae);
+    EventLoopData *data = user_data;
+    data->rFunc(fd, data->user_data, eventLoopFromAeMask(ae_mask));
+}
+
+static void eventLoopCbWritable(struct aeEventLoop *ae, int fd, void *user_data, int ae_mask) {
+    UNUSED(ae);
+    EventLoopData *data = user_data;
+    data->wFunc(fd, data->user_data, eventLoopFromAeMask(ae_mask));
+}
+
+/* Add a pipe / socket event to the event loop.
+ *
+ * * `mask` must be one of the following values:
+ *
+ *     * `REDISMODULE_EVENTLOOP_READABLE`
+ *     * `REDISMODULE_EVENTLOOP_WRITABLE`
+ *     * `REDISMODULE_EVENTLOOP_READABLE | REDISMODULE_EVENTLOOP_WRITABLE`
+ *
+ * On success REDISMODULE_OK is returned, otherwise
+ * REDISMODULE_ERR is returned and errno is set to the following values:
+ *
+ * * ERANGE: `fd` is negative or higher than `maxclients` Redis config.
+ * * EINVAL: `callback` is NULL or `mask` value is invalid.
+ *
+ * `errno` might take other values in case of an internal error.
+ *
+ * Example:
+ *
+ *     void onReadable(int fd, void *user_data, int mask) {
+ *         char buf[32];
+ *         int bytes = read(fd,buf,sizeof(buf));
+ *         printf("Read %d bytes \n", bytes);
+ *     }
+ *     RM_EventLoopAdd(fd, REDISMODULE_EVENTLOOP_READABLE, onReadable, NULL);
+ */
+int RM_EventLoopAdd(int fd, int mask, RedisModuleEventLoopFunc func, void *user_data) {
+    if (fd < 0 || fd >= aeGetSetSize(server.el)) {
+        errno = ERANGE;
+        return REDISMODULE_ERR;
+    }
+
+    if (!func || mask & ~(REDISMODULE_EVENTLOOP_READABLE |
+                          REDISMODULE_EVENTLOOP_WRITABLE)) {
+        errno = EINVAL;
+        return REDISMODULE_ERR;
+    }
+
+    /* We are going to register stub callbacks to 'ae' for two reasons:
+     *
+     * - "ae" callback signature is different from RedisModuleEventLoopCallback,
+     *   that will be handled it in our stub callbacks.
+     * - We need to remap 'mask' value to provide binary compatibility.
+     *
+     * For the stub callbacks, saving user 'callback' and 'user_data' in an
+     * EventLoopData object and passing it to ae, later, we'll extract
+     * 'callback' and 'user_data' from that.
+     */
+    EventLoopData *data = aeGetFileClientData(server.el, fd);
+    if (!data)
+        data = zcalloc(sizeof(*data));
+
+    aeFileProc *aeProc;
+    if (mask & REDISMODULE_EVENTLOOP_READABLE)
+        aeProc = eventLoopCbReadable;
+    else
+        aeProc = eventLoopCbWritable;
+
+    int aeMask = eventLoopToAeMask(mask);
+
+    if (aeCreateFileEvent(server.el, fd, aeMask, aeProc, data) != AE_OK) {
+        if (aeGetFileEvents(server.el, fd) == AE_NONE)
+            zfree(data);
+        return REDISMODULE_ERR;
+    }
+
+    data->user_data = user_data;
+    if (mask & REDISMODULE_EVENTLOOP_READABLE)
+        data->rFunc = func;
+    if (mask & REDISMODULE_EVENTLOOP_WRITABLE)
+        data->wFunc = func;
+
+    errno = 0;
+    return REDISMODULE_OK;
+}
+
+/* Delete a pipe / socket event from the event loop.
+ *
+ * * `mask` must be one of the following values:
+ *
+ *     * `REDISMODULE_EVENTLOOP_READABLE`
+ *     * `REDISMODULE_EVENTLOOP_WRITABLE`
+ *     * `REDISMODULE_EVENTLOOP_READABLE | REDISMODULE_EVENTLOOP_WRITABLE`
+ *
+ * On success REDISMODULE_OK is returned, otherwise
+ * REDISMODULE_ERR is returned and errno is set to the following values:
+ *
+ * * ERANGE: `fd` is negative or higher than `maxclients` Redis config.
+ * * EINVAL: `mask` value is invalid.
+ */
+int RM_EventLoopDel(int fd, int mask) {
+    if (fd < 0 || fd >= aeGetSetSize(server.el)) {
+        errno = ERANGE;
+        return REDISMODULE_ERR;
+    }
+
+    if (mask & ~(REDISMODULE_EVENTLOOP_READABLE |
+                 REDISMODULE_EVENTLOOP_WRITABLE)) {
+        errno = EINVAL;
+        return REDISMODULE_ERR;
+    }
+
+    /* After deleting the event, if fd does not have any registered event
+     * anymore, we can free the EventLoopData object. */
+    EventLoopData *data = aeGetFileClientData(server.el, fd);
+    aeDeleteFileEvent(server.el, fd, eventLoopToAeMask(mask));
+    if (aeGetFileEvents(server.el, fd) == AE_NONE)
+        zfree(data);
+
+    errno = 0;
+    return REDISMODULE_OK;
+}
+
+/* This function can be called from other threads to trigger callback on Redis
+ * main thread. On success REDISMODULE_OK is returned. If `func` is NULL
+ * REDISMODULE_ERR is returned and errno is set to EINVAL.
+ */
+int RM_EventLoopAddOneShot(RedisModuleEventLoopOneShotFunc func, void *user_data) {
+    if (!func) {
+        errno = EINVAL;
+        return REDISMODULE_ERR;
+    }
+
+    EventLoopOneShot *oneshot = zmalloc(sizeof(*oneshot));
+    oneshot->func = func;
+    oneshot->user_data = user_data;
+
+    pthread_mutex_lock(&moduleEventLoopMutex);
+    if (!moduleEventLoopOneShots) moduleEventLoopOneShots = listCreate();
+    listAddNodeTail(moduleEventLoopOneShots, oneshot);
+    pthread_mutex_unlock(&moduleEventLoopMutex);
+
+    if (write(server.module_pipe[1],"A",1) != 1) {
+        /* Pipe is non-blocking, write() may fail if it's full. */
+    }
+
+    errno = 0;
+    return REDISMODULE_OK;
+}
+
+/* This function will check the moduleEventLoopOneShots queue in order to
+ * call the callback for the registered oneshot events. */
+static void eventLoopHandleOneShotEvents(void) {
+    pthread_mutex_lock(&moduleEventLoopMutex);
+    if (moduleEventLoopOneShots) {
+        while (listLength(moduleEventLoopOneShots)) {
+            listNode *ln = listFirst(moduleEventLoopOneShots);
+            EventLoopOneShot *oneshot = ln->value;
+            listDelNode(moduleEventLoopOneShots, ln);
+            /* Unlock mutex before the callback. Another oneshot event can be
+             * added in the callback, it will need to lock the mutex. */
+            pthread_mutex_unlock(&moduleEventLoopMutex);
+            oneshot->func(oneshot->user_data);
+            zfree(oneshot);
+            /* Lock again for the next iteration */
+            pthread_mutex_lock(&moduleEventLoopMutex);
+        }
+    }
+    pthread_mutex_unlock(&moduleEventLoopMutex);
+}
+
+/* --------------------------------------------------------------------------
+ * ## Modules ACL API
+ *
+ * Implements a hook into the authentication and authorization within Redis.
+ * --------------------------------------------------------------------------*/
+
+/* This function is called when a client's user has changed and invokes the
+ * client's user changed callback if it was set. This callback should
+ * cleanup any state the module was tracking about this client.
+ *
+ * A client's user can be changed through the AUTH command, module
+ * authentication, and when a client is freed. */
+void moduleNotifyUserChanged(client *c) {
+    if (c->auth_callback) {
+        c->auth_callback(c->id, c->auth_callback_privdata);
+
+        /* The callback will fire exactly once, even if the user remains
+         * the same. It is expected to completely clean up the state
+         * so all references are cleared here. */
+        c->auth_callback = NULL;
+        c->auth_callback_privdata = NULL;
+        c->auth_module = NULL;
+    }
+}
+
+void revokeClientAuthentication(client *c) {
+    /* Freeing the client would result in moduleNotifyUserChanged() to be
+     * called later, however since we use revokeClientAuthentication() also
+     * in moduleFreeAuthenticatedClients() to implement module unloading, we
+     * do this action ASAP: this way if the module is unloaded, when the client
+     * is eventually freed we don't rely on the module to still exist. */
+    moduleNotifyUserChanged(c);
+
+    c->user = DefaultUser;
+    c->authenticated = 0;
+    /* We will write replies to this client later, so we can't close it
+     * directly even if async. */
+    if (c == server.current_client) {
+        c->flags |= CLIENT_CLOSE_AFTER_COMMAND;
+    } else {
+        freeClientAsync(c);
+    }
+}
+
+/* Cleanup all clients that have been authenticated with this module. This
+ * is called from onUnload() to give the module a chance to cleanup any
+ * resources associated with clients it has authenticated. */
+static void moduleFreeAuthenticatedClients(RedisModule *module) {
+    listIter li;
+    listNode *ln;
+    listRewind(server.clients,&li);
+    while ((ln = listNext(&li)) != NULL) {
+        client *c = listNodeValue(ln);
+        if (!c->auth_module) continue;
+
+        RedisModule *auth_module = (RedisModule *) c->auth_module;
+        if (auth_module == module) {
+            revokeClientAuthentication(c);
+        }
+    }
+}
+
+/* Creates a Redis ACL user that the module can use to authenticate a client.
+ * After obtaining the user, the module should set what such user can do
+ * using the RM_SetUserACL() function. Once configured, the user
+ * can be used in order to authenticate a connection, with the specified
+ * ACL rules, using the RedisModule_AuthClientWithUser() function.
+ *
+ * Note that:
+ *
+ * * Users created here are not listed by the ACL command.
+ * * Users created here are not checked for duplicated name, so it's up to
+ *   the module calling this function to take care of not creating users
+ *   with the same name.
+ * * The created user can be used to authenticate multiple Redis connections.
+ *
+ * The caller can later free the user using the function
+ * RM_FreeModuleUser(). When this function is called, if there are
+ * still clients authenticated with this user, they are disconnected.
+ * The function to free the user should only be used when the caller really
+ * wants to invalidate the user to define a new one with different
+ * capabilities. */
+RedisModuleUser *RM_CreateModuleUser(const char *name) {
+    RedisModuleUser *new_user = zmalloc(sizeof(RedisModuleUser));
+    new_user->user = ACLCreateUnlinkedUser();
+    new_user->free_user = 1;
+
+    /* Free the previous temporarily assigned name to assign the new one */
+    sdsfree(new_user->user->name);
+    new_user->user->name = sdsnew(name);
+    return new_user;
+}
+
+/* Frees a given user and disconnects all of the clients that have been
+ * authenticated with it. See RM_CreateModuleUser for detailed usage.*/
+int RM_FreeModuleUser(RedisModuleUser *user) {
+    if (user->free_user)
+        ACLFreeUserAndKillClients(user->user);
+    zfree(user);
+    return REDISMODULE_OK;
+}
+
+/* Sets the permissions of a user created through the redis module
+ * interface. The syntax is the same as ACL SETUSER, so refer to the
+ * documentation in acl.c for more information. See RM_CreateModuleUser
+ * for detailed usage.
+ *
+ * Returns REDISMODULE_OK on success and REDISMODULE_ERR on failure
+ * and will set an errno describing why the operation failed. */
+int RM_SetModuleUserACL(RedisModuleUser *user, const char* acl) {
+    return ACLSetUser(user->user, acl, -1);
+}
+
+/* Sets the permission of a user with a complete ACL string, such as one
+ * would use on the redis ACL SETUSER command line API. This differs from
+ * RM_SetModuleUserACL, which only takes single ACL operations at a time.
+ *
+ * Returns REDISMODULE_OK on success and REDISMODULE_ERR on failure
+ * if a RedisModuleString is provided in error, a string describing the error
+ * will be returned */
+int RM_SetModuleUserACLString(RedisModuleCtx *ctx, RedisModuleUser *user, const char *acl, RedisModuleString **error) {
+    serverAssert(user != NULL);
+
+    int argc;
+    sds *argv = sdssplitargs(acl, &argc);
+
+    sds err = ACLStringSetUser(user->user, NULL, argv, argc);
+
+    sdsfreesplitres(argv, argc);
+
+    if (err) {
+        if (error) {
+            *error = createObject(OBJ_STRING, err);
+            if (ctx != NULL) autoMemoryAdd(ctx, REDISMODULE_AM_STRING, *error);
+        } else {
+            sdsfree(err);
+        }
+
+        return REDISMODULE_ERR;
+    }
+
+    return REDISMODULE_OK;
+}
+
+/* Get the ACL string for a given user
+ * Returns a RedisModuleString
+ */
+RedisModuleString *RM_GetModuleUserACLString(RedisModuleUser *user) {
+    serverAssert(user != NULL);
+
+    return ACLDescribeUser(user->user);
+}
+
+/* Retrieve the user name of the client connection behind the current context.
+ * The user name can be used later, in order to get a RedisModuleUser.
+ * See more information in RM_GetModuleUserFromUserName.
+ *
+ * The returned string must be released with RedisModule_FreeString() or by
+ * enabling automatic memory management. */
+RedisModuleString *RM_GetCurrentUserName(RedisModuleCtx *ctx) {
+    return RM_CreateString(ctx,ctx->client->user->name,sdslen(ctx->client->user->name));
+}
+
+/* A RedisModuleUser can be used to check if command, key or channel can be executed or
+ * accessed according to the ACLs rules associated with that user.
+ * When a Module wants to do ACL checks on a general ACL user (not created by RM_CreateModuleUser),
+ * it can get the RedisModuleUser from this API, based on the user name retrieved by RM_GetCurrentUserName.
+ *
+ * Since a general ACL user can be deleted at any time, this RedisModuleUser should be used only in the context
+ * where this function was called. In order to do ACL checks out of that context, the Module can store the user name,
+ * and call this API at any other context.
+ *
+ * Returns NULL if the user is disabled or the user does not exist.
+ * The caller should later free the user using the function RM_FreeModuleUser().*/
+RedisModuleUser *RM_GetModuleUserFromUserName(RedisModuleString *name) {
+    /* First, verify that the user exist */
+    user *acl_user = ACLGetUserByName(name->ptr, sdslen(name->ptr));
+    if (acl_user == NULL) {
+        return NULL;
+    }
+
+    RedisModuleUser *new_user = zmalloc(sizeof(RedisModuleUser));
+    new_user->user = acl_user;
+    new_user->free_user = 0;
+    return new_user;
+}
+
+/* Checks if the command can be executed by the user, according to the ACLs associated with it.
+ *
+ * On success a REDISMODULE_OK is returned, otherwise
+ * REDISMODULE_ERR is returned and errno is set to the following values:
+ *
+ * * ENOENT: Specified command does not exist.
+ * * EACCES: Command cannot be executed, according to ACL rules
+ */
+int RM_ACLCheckCommandPermissions(RedisModuleUser *user, RedisModuleString **argv, int argc) {
+    int keyidxptr;
+    struct redisCommand *cmd;
+
+    /* Find command */
+    if ((cmd = lookupCommand(argv, argc)) == NULL) {
+        errno = ENOENT;
+        return REDISMODULE_ERR;
+    }
+
+    if (ACLCheckAllUserCommandPerm(user->user, cmd, argv, argc, &keyidxptr) != ACL_OK) {
+        errno = EACCES;
+        return REDISMODULE_ERR;
+    }
+
+    return REDISMODULE_OK;
+}
+
+/* Check if the key can be accessed by the user according to the ACLs attached to the user
+ * and the flags representing the key access. The flags are the same that are used in the
+ * keyspec for logical operations. These flags are documented in RedisModule_SetCommandInfo as
+ * the REDISMODULE_CMD_KEY_ACCESS, REDISMODULE_CMD_KEY_UPDATE, REDISMODULE_CMD_KEY_INSERT,
+ * and REDISMODULE_CMD_KEY_DELETE flags.
+ * 
+ * If no flags are supplied, the user is still required to have some access to the key for
+ * this command to return successfully.
+ *
+ * If the user is able to access the key then REDISMODULE_OK is returned, otherwise
+ * REDISMODULE_ERR is returned and errno is set to one of the following values:
+ * 
+ * * EINVAL: The provided flags are invalid.
+ * * EACCESS: The user does not have permission to access the key.
+ */
+int RM_ACLCheckKeyPermissions(RedisModuleUser *user, RedisModuleString *key, int flags) {
+    const int allow_mask = (REDISMODULE_CMD_KEY_ACCESS
+        | REDISMODULE_CMD_KEY_INSERT
+        | REDISMODULE_CMD_KEY_DELETE
+        | REDISMODULE_CMD_KEY_UPDATE);
+
+    if ((flags & allow_mask) != flags) {
+        errno = EINVAL;
+        return REDISMODULE_ERR;
+    }
+
+    int keyspec_flags = moduleConvertKeySpecsFlags(flags, 0);
+    if (ACLUserCheckKeyPerm(user->user, key->ptr, sdslen(key->ptr), keyspec_flags) != ACL_OK) {
+        errno = EACCES;
+        return REDISMODULE_ERR;
+    }
+
+    return REDISMODULE_OK;
+}
+
+/* Check if the pubsub channel can be accessed by the user based off of the given
+ * access flags. See RM_ChannelAtPosWithFlags for more information about the
+ * possible flags that can be passed in.
+ *
+ * If the user is able to access the pubsub channel then REDISMODULE_OK is returned, otherwise
+ * REDISMODULE_ERR is returned and errno is set to one of the following values:
+ * 
+ * * EINVAL: The provided flags are invalid.
+ * * EACCESS: The user does not have permission to access the pubsub channel. 
+ */
+int RM_ACLCheckChannelPermissions(RedisModuleUser *user, RedisModuleString *ch, int flags) {
+    const int allow_mask = (REDISMODULE_CMD_CHANNEL_PUBLISH
+        | REDISMODULE_CMD_CHANNEL_SUBSCRIBE
+        | REDISMODULE_CMD_CHANNEL_UNSUBSCRIBE
+        | REDISMODULE_CMD_CHANNEL_PATTERN);
+
+    if ((flags & allow_mask) != flags) {
+        errno = EINVAL;
+        return REDISMODULE_ERR;
+    }
+
+    /* Unsubscribe permissions are currently always allowed. */
+    if (flags & REDISMODULE_CMD_CHANNEL_UNSUBSCRIBE){
+        return REDISMODULE_OK;
+    }
+
+    int is_pattern = flags & REDISMODULE_CMD_CHANNEL_PATTERN;
+    if (ACLUserCheckChannelPerm(user->user, ch->ptr, is_pattern) != ACL_OK)
+        return REDISMODULE_ERR;
+
+    return REDISMODULE_OK;
+}
+
+/* Helper function to map a RedisModuleACLLogEntryReason to ACL Log entry reason. */
+int moduleGetACLLogEntryReason(RedisModuleACLLogEntryReason reason) {
+    int acl_reason = 0;
+    switch (reason) {
+        case REDISMODULE_ACL_LOG_AUTH: acl_reason = ACL_DENIED_AUTH; break;
+        case REDISMODULE_ACL_LOG_KEY: acl_reason = ACL_DENIED_KEY; break;
+        case REDISMODULE_ACL_LOG_CHANNEL: acl_reason = ACL_DENIED_CHANNEL; break;
+        case REDISMODULE_ACL_LOG_CMD: acl_reason = ACL_DENIED_CMD; break;
+        default: break;
+    }
+    return acl_reason;
+}
+
+/* Adds a new entry in the ACL log.
+ * Returns REDISMODULE_OK on success and REDISMODULE_ERR on error.
+ *
+ * For more information about ACL log, please refer to https://redis.io/commands/acl-log */
+int RM_ACLAddLogEntry(RedisModuleCtx *ctx, RedisModuleUser *user, RedisModuleString *object, RedisModuleACLLogEntryReason reason) {
+    int acl_reason = moduleGetACLLogEntryReason(reason);
+    if (!acl_reason) return REDISMODULE_ERR;
+    addACLLogEntry(ctx->client, acl_reason, ACL_LOG_CTX_MODULE, -1, user->user->name, sdsdup(object->ptr));
+    return REDISMODULE_OK;
+}
+
+/* Adds a new entry in the ACL log with the `username` RedisModuleString provided.
+ * Returns REDISMODULE_OK on success and REDISMODULE_ERR on error.
+ *
+ * For more information about ACL log, please refer to https://redis.io/commands/acl-log */
+int RM_ACLAddLogEntryByUserName(RedisModuleCtx *ctx, RedisModuleString *username, RedisModuleString *object, RedisModuleACLLogEntryReason reason) {
+    int acl_reason = moduleGetACLLogEntryReason(reason);
+    if (!acl_reason) return REDISMODULE_ERR;
+    addACLLogEntry(ctx->client, acl_reason, ACL_LOG_CTX_MODULE, -1, username->ptr, sdsdup(object->ptr));
+    return REDISMODULE_OK;
+}
+
+/* Authenticate the client associated with the context with
+ * the provided user. Returns REDISMODULE_OK on success and
+ * REDISMODULE_ERR on error.
+ *
+ * This authentication can be tracked with the optional callback and private
+ * data fields. The callback will be called whenever the user of the client
+ * changes. This callback should be used to cleanup any state that is being
+ * kept in the module related to the client authentication. It will only be
+ * called once, even when the user hasn't changed, in order to allow for a
+ * new callback to be specified. If this authentication does not need to be
+ * tracked, pass in NULL for the callback and privdata.
+ *
+ * If client_id is not NULL, it will be filled with the id of the client
+ * that was authenticated. This can be used with the
+ * RM_DeauthenticateAndCloseClient() API in order to deauthenticate a
+ * previously authenticated client if the authentication is no longer valid.
+ *
+ * For expensive authentication operations, it is recommended to block the
+ * client and do the authentication in the background and then attach the user
+ * to the client in a threadsafe context. */
+static int authenticateClientWithUser(RedisModuleCtx *ctx, user *user, RedisModuleUserChangedFunc callback, void *privdata, uint64_t *client_id) {
+    if (user->flags & USER_FLAG_DISABLED) {
+        return REDISMODULE_ERR;
+    }
+
+    /* Avoid settings which are meaningless and will be lost */
+    if (!ctx->client || (ctx->client->flags & CLIENT_MODULE)) {
+        return REDISMODULE_ERR;
+    }
+
+    moduleNotifyUserChanged(ctx->client);
+
+    ctx->client->user = user;
+    ctx->client->authenticated = 1;
+
+    if (clientHasModuleAuthInProgress(ctx->client)) {
+        ctx->client->flags |= CLIENT_MODULE_AUTH_HAS_RESULT;
+    }
+
+    if (callback) {
+        ctx->client->auth_callback = callback;
+        ctx->client->auth_callback_privdata = privdata;
+        ctx->client->auth_module = ctx->module;
+    }
+
+    if (client_id) {
+        *client_id = ctx->client->id;
+    }
+
+    return REDISMODULE_OK;
+}
+
+
+/* Authenticate the current context's user with the provided redis acl user.
+ * Returns REDISMODULE_ERR if the user is disabled.
+ *
+ * See authenticateClientWithUser for information about callback, client_id,
+ * and general usage for authentication. */
+int RM_AuthenticateClientWithUser(RedisModuleCtx *ctx, RedisModuleUser *module_user, RedisModuleUserChangedFunc callback, void *privdata, uint64_t *client_id) {
+    return authenticateClientWithUser(ctx, module_user->user, callback, privdata, client_id);
+}
+
+/* Authenticate the current context's user with the provided redis acl user.
+ * Returns REDISMODULE_ERR if the user is disabled or the user does not exist.
+ *
+ * See authenticateClientWithUser for information about callback, client_id,
+ * and general usage for authentication. */
+int RM_AuthenticateClientWithACLUser(RedisModuleCtx *ctx, const char *name, size_t len, RedisModuleUserChangedFunc callback, void *privdata, uint64_t *client_id) {
+    user *acl_user = ACLGetUserByName(name, len);
+
+    if (!acl_user) {
+        return REDISMODULE_ERR;
+    }
+    return authenticateClientWithUser(ctx, acl_user, callback, privdata, client_id);
+}
+
+/* Deauthenticate and close the client. The client resources will not be
+ * immediately freed, but will be cleaned up in a background job. This is
+ * the recommended way to deauthenticate a client since most clients can't
+ * handle users becoming deauthenticated. Returns REDISMODULE_ERR when the
+ * client doesn't exist and REDISMODULE_OK when the operation was successful.
+ *
+ * The client ID is returned from the RM_AuthenticateClientWithUser and
+ * RM_AuthenticateClientWithACLUser APIs, but can be obtained through
+ * the CLIENT api or through server events.
+ *
+ * This function is not thread safe, and must be executed within the context
+ * of a command or thread safe context. */
+int RM_DeauthenticateAndCloseClient(RedisModuleCtx *ctx, uint64_t client_id) {
+    UNUSED(ctx);
+    client *c = lookupClientByID(client_id);
+    if (c == NULL) return REDISMODULE_ERR;
+
+    /* Revoke also marks client to be closed ASAP */
+    revokeClientAuthentication(c);
+    return REDISMODULE_OK;
+}
+
+/* Redact the client command argument specified at the given position. Redacted arguments 
+ * are obfuscated in user facing commands such as SLOWLOG or MONITOR, as well as
+ * never being written to server logs. This command may be called multiple times on the
+ * same position.
+ * 
+ * Note that the command name, position 0, can not be redacted. 
+ * 
+ * Returns REDISMODULE_OK if the argument was redacted and REDISMODULE_ERR if there 
+ * was an invalid parameter passed in or the position is outside the client 
+ * argument range. */
+int RM_RedactClientCommandArgument(RedisModuleCtx *ctx, int pos) {
+    if (!ctx || !ctx->client || pos <= 0 || ctx->client->argc <= pos) {
+        return REDISMODULE_ERR;
+    }
+    redactClientCommandArgument(ctx->client, pos);
+    return REDISMODULE_OK;
+}
+
+/* Return the X.509 client-side certificate used by the client to authenticate
+ * this connection.
+ *
+ * The return value is an allocated RedisModuleString that is a X.509 certificate
+ * encoded in PEM (Base64) format. It should be freed (or auto-freed) by the caller.
+ *
+ * A NULL value is returned in the following conditions:
+ *
+ * - Connection ID does not exist
+ * - Connection is not a TLS connection
+ * - Connection is a TLS connection but no client certificate was used
+ */
+RedisModuleString *RM_GetClientCertificate(RedisModuleCtx *ctx, uint64_t client_id) {
+    client *c = lookupClientByID(client_id);
+    if (c == NULL) return NULL;
+
+    sds cert = connGetPeerCert(c->conn);
+    if (!cert) return NULL;
+
+    RedisModuleString *s = createObject(OBJ_STRING, cert);
+    if (ctx != NULL) autoMemoryAdd(ctx, REDISMODULE_AM_STRING, s);
+
+    return s;
+}
+
+/* --------------------------------------------------------------------------
+ * ## Modules Dictionary API
+ *
+ * Implements a sorted dictionary (actually backed by a radix tree) with
+ * the usual get / set / del / num-items API, together with an iterator
+ * capable of going back and forth.
+ * -------------------------------------------------------------------------- */
+
+/* Create a new dictionary. The 'ctx' pointer can be the current module context
+ * or NULL, depending on what you want. Please follow the following rules:
+ *
+ * 1. Use a NULL context if you plan to retain a reference to this dictionary
+ *    that will survive the time of the module callback where you created it.
+ * 2. Use a NULL context if no context is available at the time you are creating
+ *    the dictionary (of course...).
+ * 3. However use the current callback context as 'ctx' argument if the
+ *    dictionary time to live is just limited to the callback scope. In this
+ *    case, if enabled, you can enjoy the automatic memory management that will
+ *    reclaim the dictionary memory, as well as the strings returned by the
+ *    Next / Prev dictionary iterator calls.
+ */
+RedisModuleDict *RM_CreateDict(RedisModuleCtx *ctx) {
+    struct RedisModuleDict *d = zmalloc(sizeof(*d));
+    d->rax = raxNew();
+    if (ctx != NULL) autoMemoryAdd(ctx,REDISMODULE_AM_DICT,d);
+    return d;
+}
+
+/* Free a dictionary created with RM_CreateDict(). You need to pass the
+ * context pointer 'ctx' only if the dictionary was created using the
+ * context instead of passing NULL. */
+void RM_FreeDict(RedisModuleCtx *ctx, RedisModuleDict *d) {
+    if (ctx != NULL) autoMemoryFreed(ctx,REDISMODULE_AM_DICT,d);
+    raxFree(d->rax);
+    zfree(d);
+}
+
+/* Return the size of the dictionary (number of keys). */
+uint64_t RM_DictSize(RedisModuleDict *d) {
+    return raxSize(d->rax);
+}
+
+/* Store the specified key into the dictionary, setting its value to the
+ * pointer 'ptr'. If the key was added with success, since it did not
+ * already exist, REDISMODULE_OK is returned. Otherwise if the key already
+ * exists the function returns REDISMODULE_ERR. */
+int RM_DictSetC(RedisModuleDict *d, void *key, size_t keylen, void *ptr) {
+    int retval = raxTryInsert(d->rax,key,keylen,ptr,NULL);
+    return (retval == 1) ? REDISMODULE_OK : REDISMODULE_ERR;
+}
+
+/* Like RedisModule_DictSetC() but will replace the key with the new
+ * value if the key already exists. */
+int RM_DictReplaceC(RedisModuleDict *d, void *key, size_t keylen, void *ptr) {
+    int retval = raxInsert(d->rax,key,keylen,ptr,NULL);
+    return (retval == 1) ? REDISMODULE_OK : REDISMODULE_ERR;
+}
+
+/* Like RedisModule_DictSetC() but takes the key as a RedisModuleString. */
+int RM_DictSet(RedisModuleDict *d, RedisModuleString *key, void *ptr) {
+    return RM_DictSetC(d,key->ptr,sdslen(key->ptr),ptr);
+}
+
+/* Like RedisModule_DictReplaceC() but takes the key as a RedisModuleString. */
+int RM_DictReplace(RedisModuleDict *d, RedisModuleString *key, void *ptr) {
+    return RM_DictReplaceC(d,key->ptr,sdslen(key->ptr),ptr);
+}
+
+/* Return the value stored at the specified key. The function returns NULL
+ * both in the case the key does not exist, or if you actually stored
+ * NULL at key. So, optionally, if the 'nokey' pointer is not NULL, it will
+ * be set by reference to 1 if the key does not exist, or to 0 if the key
+ * exists. */
+void *RM_DictGetC(RedisModuleDict *d, void *key, size_t keylen, int *nokey) {
+    void *res = raxFind(d->rax,key,keylen);
+    if (nokey) *nokey = (res == raxNotFound);
+    return (res == raxNotFound) ? NULL : res;
+}
+
+/* Like RedisModule_DictGetC() but takes the key as a RedisModuleString. */
+void *RM_DictGet(RedisModuleDict *d, RedisModuleString *key, int *nokey) {
+    return RM_DictGetC(d,key->ptr,sdslen(key->ptr),nokey);
+}
+
+/* Remove the specified key from the dictionary, returning REDISMODULE_OK if
+ * the key was found and deleted, or REDISMODULE_ERR if instead there was
+ * no such key in the dictionary. When the operation is successful, if
+ * 'oldval' is not NULL, then '*oldval' is set to the value stored at the
+ * key before it was deleted. Using this feature it is possible to get
+ * a pointer to the value (for instance in order to release it), without
+ * having to call RedisModule_DictGet() before deleting the key. */
+int RM_DictDelC(RedisModuleDict *d, void *key, size_t keylen, void *oldval) {
+    int retval = raxRemove(d->rax,key,keylen,oldval);
+    return retval ? REDISMODULE_OK : REDISMODULE_ERR;
+}
+
+/* Like RedisModule_DictDelC() but gets the key as a RedisModuleString. */
+int RM_DictDel(RedisModuleDict *d, RedisModuleString *key, void *oldval) {
+    return RM_DictDelC(d,key->ptr,sdslen(key->ptr),oldval);
+}
+
+/* Return an iterator, setup in order to start iterating from the specified
+ * key by applying the operator 'op', which is just a string specifying the
+ * comparison operator to use in order to seek the first element. The
+ * operators available are:
+ *
+ * * `^`   -- Seek the first (lexicographically smaller) key.
+ * * `$`   -- Seek the last  (lexicographically bigger) key.
+ * * `>`   -- Seek the first element greater than the specified key.
+ * * `>=`  -- Seek the first element greater or equal than the specified key.
+ * * `<`   -- Seek the first element smaller than the specified key.
+ * * `<=`  -- Seek the first element smaller or equal than the specified key.
+ * * `==`  -- Seek the first element matching exactly the specified key.
+ *
+ * Note that for `^` and `$` the passed key is not used, and the user may
+ * just pass NULL with a length of 0.
+ *
+ * If the element to start the iteration cannot be seeked based on the
+ * key and operator passed, RedisModule_DictNext() / Prev() will just return
+ * REDISMODULE_ERR at the first call, otherwise they'll produce elements.
+ */
+RedisModuleDictIter *RM_DictIteratorStartC(RedisModuleDict *d, const char *op, void *key, size_t keylen) {
+    RedisModuleDictIter *di = zmalloc(sizeof(*di));
+    di->dict = d;
+    raxStart(&di->ri,d->rax);
+    raxSeek(&di->ri,op,key,keylen);
+    return di;
+}
+
+/* Exactly like RedisModule_DictIteratorStartC, but the key is passed as a
+ * RedisModuleString. */
+RedisModuleDictIter *RM_DictIteratorStart(RedisModuleDict *d, const char *op, RedisModuleString *key) {
+    return RM_DictIteratorStartC(d,op,key->ptr,sdslen(key->ptr));
+}
+
+/* Release the iterator created with RedisModule_DictIteratorStart(). This call
+ * is mandatory otherwise a memory leak is introduced in the module. */
+void RM_DictIteratorStop(RedisModuleDictIter *di) {
+    raxStop(&di->ri);
+    zfree(di);
+}
+
+/* After its creation with RedisModule_DictIteratorStart(), it is possible to
+ * change the currently selected element of the iterator by using this
+ * API call. The result based on the operator and key is exactly like
+ * the function RedisModule_DictIteratorStart(), however in this case the
+ * return value is just REDISMODULE_OK in case the seeked element was found,
+ * or REDISMODULE_ERR in case it was not possible to seek the specified
+ * element. It is possible to reseek an iterator as many times as you want. */
+int RM_DictIteratorReseekC(RedisModuleDictIter *di, const char *op, void *key, size_t keylen) {
+    return raxSeek(&di->ri,op,key,keylen);
+}
+
+/* Like RedisModule_DictIteratorReseekC() but takes the key as a
+ * RedisModuleString. */
+int RM_DictIteratorReseek(RedisModuleDictIter *di, const char *op, RedisModuleString *key) {
+    return RM_DictIteratorReseekC(di,op,key->ptr,sdslen(key->ptr));
+}
+
+/* Return the current item of the dictionary iterator `di` and steps to the
+ * next element. If the iterator already yield the last element and there
+ * are no other elements to return, NULL is returned, otherwise a pointer
+ * to a string representing the key is provided, and the `*keylen` length
+ * is set by reference (if keylen is not NULL). The `*dataptr`, if not NULL
+ * is set to the value of the pointer stored at the returned key as auxiliary
+ * data (as set by the RedisModule_DictSet API).
+ *
+ * Usage example:
+ *
+ *      ... create the iterator here ...
+ *      char *key;
+ *      void *data;
+ *      while((key = RedisModule_DictNextC(iter,&keylen,&data)) != NULL) {
+ *          printf("%.*s %p\n", (int)keylen, key, data);
+ *      }
+ *
+ * The returned pointer is of type void because sometimes it makes sense
+ * to cast it to a `char*` sometimes to an unsigned `char*` depending on the
+ * fact it contains or not binary data, so this API ends being more
+ * comfortable to use.
+ *
+ * The validity of the returned pointer is until the next call to the
+ * next/prev iterator step. Also the pointer is no longer valid once the
+ * iterator is released. */
+void *RM_DictNextC(RedisModuleDictIter *di, size_t *keylen, void **dataptr) {
+    if (!raxNext(&di->ri)) return NULL;
+    if (keylen) *keylen = di->ri.key_len;
+    if (dataptr) *dataptr = di->ri.data;
+    return di->ri.key;
+}
+
+/* This function is exactly like RedisModule_DictNext() but after returning
+ * the currently selected element in the iterator, it selects the previous
+ * element (lexicographically smaller) instead of the next one. */
+void *RM_DictPrevC(RedisModuleDictIter *di, size_t *keylen, void **dataptr) {
+    if (!raxPrev(&di->ri)) return NULL;
+    if (keylen) *keylen = di->ri.key_len;
+    if (dataptr) *dataptr = di->ri.data;
+    return di->ri.key;
+}
+
+/* Like RedisModuleNextC(), but instead of returning an internally allocated
+ * buffer and key length, it returns directly a module string object allocated
+ * in the specified context 'ctx' (that may be NULL exactly like for the main
+ * API RedisModule_CreateString).
+ *
+ * The returned string object should be deallocated after use, either manually
+ * or by using a context that has automatic memory management active. */
+RedisModuleString *RM_DictNext(RedisModuleCtx *ctx, RedisModuleDictIter *di, void **dataptr) {
+    size_t keylen;
+    void *key = RM_DictNextC(di,&keylen,dataptr);
+    if (key == NULL) return NULL;
+    return RM_CreateString(ctx,key,keylen);
+}
+
+/* Like RedisModule_DictNext() but after returning the currently selected
+ * element in the iterator, it selects the previous element (lexicographically
+ * smaller) instead of the next one. */
+RedisModuleString *RM_DictPrev(RedisModuleCtx *ctx, RedisModuleDictIter *di, void **dataptr) {
+    size_t keylen;
+    void *key = RM_DictPrevC(di,&keylen,dataptr);
+    if (key == NULL) return NULL;
+    return RM_CreateString(ctx,key,keylen);
+}
+
+/* Compare the element currently pointed by the iterator to the specified
+ * element given by key/keylen, according to the operator 'op' (the set of
+ * valid operators are the same valid for RedisModule_DictIteratorStart).
+ * If the comparison is successful the command returns REDISMODULE_OK
+ * otherwise REDISMODULE_ERR is returned.
+ *
+ * This is useful when we want to just emit a lexicographical range, so
+ * in the loop, as we iterate elements, we can also check if we are still
+ * on range.
+ *
+ * The function return REDISMODULE_ERR if the iterator reached the
+ * end of elements condition as well. */
+int RM_DictCompareC(RedisModuleDictIter *di, const char *op, void *key, size_t keylen) {
+    if (raxEOF(&di->ri)) return REDISMODULE_ERR;
+    int res = raxCompare(&di->ri,op,key,keylen);
+    return res ? REDISMODULE_OK : REDISMODULE_ERR;
+}
+
+/* Like RedisModule_DictCompareC but gets the key to compare with the current
+ * iterator key as a RedisModuleString. */
+int RM_DictCompare(RedisModuleDictIter *di, const char *op, RedisModuleString *key) {
+    if (raxEOF(&di->ri)) return REDISMODULE_ERR;
+    int res = raxCompare(&di->ri,op,key->ptr,sdslen(key->ptr));
+    return res ? REDISMODULE_OK : REDISMODULE_ERR;
+}
+
+
+
+
+/* --------------------------------------------------------------------------
+ * ## Modules Info fields
+ * -------------------------------------------------------------------------- */
+
+int RM_InfoEndDictField(RedisModuleInfoCtx *ctx);
+
+/* Used to start a new section, before adding any fields. the section name will
+ * be prefixed by `<modulename>_` and must only include A-Z,a-z,0-9.
+ * NULL or empty string indicates the default section (only `<modulename>`) is used.
+ * When return value is REDISMODULE_ERR, the section should and will be skipped. */
+int RM_InfoAddSection(RedisModuleInfoCtx *ctx, const char *name) {
+    sds full_name = sdsdup(ctx->module->name);
+    if (name != NULL && strlen(name) > 0)
+        full_name = sdscatfmt(full_name, "_%s", name);
+
+    /* Implicitly end dicts, instead of returning an error which is likely un checked. */
+    if (ctx->in_dict_field)
+        RM_InfoEndDictField(ctx);
+
+    /* proceed only if:
+     * 1) no section was requested (emit all)
+     * 2) the module name was requested (emit all)
+     * 3) this specific section was requested. */
+    if (ctx->requested_sections) {
+        if ((!full_name || !dictFind(ctx->requested_sections, full_name)) &&
+            (!dictFind(ctx->requested_sections, ctx->module->name)))
+        {
+            sdsfree(full_name);
+            ctx->in_section = 0;
+            return REDISMODULE_ERR;
+        }
+    }
+    if (ctx->sections++) ctx->info = sdscat(ctx->info,"\r\n");
+    ctx->info = sdscatfmt(ctx->info, "# %S\r\n", full_name);
+    ctx->in_section = 1;
+    sdsfree(full_name);
+    return REDISMODULE_OK;
+}
+
+/* Starts a dict field, similar to the ones in INFO KEYSPACE. Use normal
+ * RedisModule_InfoAddField* functions to add the items to this field, and
+ * terminate with RedisModule_InfoEndDictField. */
+int RM_InfoBeginDictField(RedisModuleInfoCtx *ctx, const char *name) {
+    if (!ctx->in_section)
+        return REDISMODULE_ERR;
+    /* Implicitly end dicts, instead of returning an error which is likely un checked. */
+    if (ctx->in_dict_field)
+        RM_InfoEndDictField(ctx);
+    char *tmpmodname, *tmpname;
+    ctx->info = sdscatfmt(ctx->info,
+        "%s_%s:",
+        getSafeInfoString(ctx->module->name, strlen(ctx->module->name), &tmpmodname),
+        getSafeInfoString(name, strlen(name), &tmpname));
+    if (tmpmodname != NULL) zfree(tmpmodname);
+    if (tmpname != NULL) zfree(tmpname);
+    ctx->in_dict_field = 1;
+    return REDISMODULE_OK;
+}
+
+/* Ends a dict field, see RedisModule_InfoBeginDictField */
+int RM_InfoEndDictField(RedisModuleInfoCtx *ctx) {
+    if (!ctx->in_dict_field)
+        return REDISMODULE_ERR;
+    /* trim the last ',' if found. */
+    if (ctx->info[sdslen(ctx->info)-1]==',')
+        sdsIncrLen(ctx->info, -1);
+    ctx->info = sdscat(ctx->info, "\r\n");
+    ctx->in_dict_field = 0;
+    return REDISMODULE_OK;
+}
+
+/* Used by RedisModuleInfoFunc to add info fields.
+ * Each field will be automatically prefixed by `<modulename>_`.
+ * Field names or values must not include `\r\n` or `:`. */
+int RM_InfoAddFieldString(RedisModuleInfoCtx *ctx, const char *field, RedisModuleString *value) {
+    if (!ctx->in_section)
+        return REDISMODULE_ERR;
+    if (ctx->in_dict_field) {
+        ctx->info = sdscatfmt(ctx->info,
+            "%s=%S,",
+            field,
+            (sds)value->ptr);
+        return REDISMODULE_OK;
+    }
+    ctx->info = sdscatfmt(ctx->info,
+        "%s_%s:%S\r\n",
+        ctx->module->name,
+        field,
+        (sds)value->ptr);
+    return REDISMODULE_OK;
+}
+
+/* See RedisModule_InfoAddFieldString(). */
+int RM_InfoAddFieldCString(RedisModuleInfoCtx *ctx, const char *field, const char *value) {
+    if (!ctx->in_section)
+        return REDISMODULE_ERR;
+    if (ctx->in_dict_field) {
+        ctx->info = sdscatfmt(ctx->info,
+            "%s=%s,",
+            field,
+            value);
+        return REDISMODULE_OK;
+    }
+    ctx->info = sdscatfmt(ctx->info,
+        "%s_%s:%s\r\n",
+        ctx->module->name,
+        field,
+        value);
+    return REDISMODULE_OK;
+}
+
+/* See RedisModule_InfoAddFieldString(). */
+int RM_InfoAddFieldDouble(RedisModuleInfoCtx *ctx, const char *field, double value) {
+    if (!ctx->in_section)
+        return REDISMODULE_ERR;
+    if (ctx->in_dict_field) {
+        ctx->info = sdscatprintf(ctx->info,
+            "%s=%.17g,",
+            field,
+            value);
+        return REDISMODULE_OK;
+    }
+    ctx->info = sdscatprintf(ctx->info,
+        "%s_%s:%.17g\r\n",
+        ctx->module->name,
+        field,
+        value);
+    return REDISMODULE_OK;
+}
+
+/* See RedisModule_InfoAddFieldString(). */
+int RM_InfoAddFieldLongLong(RedisModuleInfoCtx *ctx, const char *field, long long value) {
+    if (!ctx->in_section)
+        return REDISMODULE_ERR;
+    if (ctx->in_dict_field) {
+        ctx->info = sdscatfmt(ctx->info,
+            "%s=%I,",
+            field,
+            value);
+        return REDISMODULE_OK;
+    }
+    ctx->info = sdscatfmt(ctx->info,
+        "%s_%s:%I\r\n",
+        ctx->module->name,
+        field,
+        value);
+    return REDISMODULE_OK;
+}
+
+/* See RedisModule_InfoAddFieldString(). */
+int RM_InfoAddFieldULongLong(RedisModuleInfoCtx *ctx, const char *field, unsigned long long value) {
+    if (!ctx->in_section)
+        return REDISMODULE_ERR;
+    if (ctx->in_dict_field) {
+        ctx->info = sdscatfmt(ctx->info,
+            "%s=%U,",
+            field,
+            value);
+        return REDISMODULE_OK;
+    }
+    ctx->info = sdscatfmt(ctx->info,
+        "%s_%s:%U\r\n",
+        ctx->module->name,
+        field,
+        value);
+    return REDISMODULE_OK;
+}
+
+/* Registers callback for the INFO command. The callback should add INFO fields
+ * by calling the `RedisModule_InfoAddField*()` functions. */
+int RM_RegisterInfoFunc(RedisModuleCtx *ctx, RedisModuleInfoFunc cb) {
+    ctx->module->info_cb = cb;
+    return REDISMODULE_OK;
+}
+
+sds modulesCollectInfo(sds info, dict *sections_dict, int for_crash_report, int sections) {
+    dictIterator *di = dictGetIterator(modules);
+    dictEntry *de;
+
+    while ((de = dictNext(di)) != NULL) {
+        struct RedisModule *module = dictGetVal(de);
+        if (!module->info_cb)
+            continue;
+        RedisModuleInfoCtx info_ctx = {module, sections_dict, info, sections, 0, 0};
+        module->info_cb(&info_ctx, for_crash_report);
+        /* Implicitly end dicts (no way to handle errors, and we must add the newline). */
+        if (info_ctx.in_dict_field)
+            RM_InfoEndDictField(&info_ctx);
+        info = info_ctx.info;
+        sections = info_ctx.sections;
+    }
+    dictReleaseIterator(di);
+    return info;
+}
+
+/* Get information about the server similar to the one that returns from the
+ * INFO command. This function takes an optional 'section' argument that may
+ * be NULL. The return value holds the output and can be used with
+ * RedisModule_ServerInfoGetField and alike to get the individual fields.
+ * When done, it needs to be freed with RedisModule_FreeServerInfo or with the
+ * automatic memory management mechanism if enabled. */
+RedisModuleServerInfoData *RM_GetServerInfo(RedisModuleCtx *ctx, const char *section) {
+    struct RedisModuleServerInfoData *d = zmalloc(sizeof(*d));
+    d->rax = raxNew();
+    if (ctx != NULL) autoMemoryAdd(ctx,REDISMODULE_AM_INFO,d);
+    int all = 0, everything = 0;
+    robj *argv[1];
+    argv[0] = section ? createStringObject(section, strlen(section)) : NULL;
+    dict *section_dict = genInfoSectionDict(argv, section ? 1 : 0, NULL, &all, &everything);
+    sds info = genRedisInfoString(section_dict, all, everything);
+    int totlines, i;
+    sds *lines = sdssplitlen(info, sdslen(info), "\r\n", 2, &totlines);
+    for(i=0; i<totlines; i++) {
+        sds line = lines[i];
+        if (line[0]=='#') continue;
+        char *sep = strchr(line, ':');
+        if (!sep) continue;
+        unsigned char *key = (unsigned char*)line;
+        size_t keylen = (intptr_t)sep-(intptr_t)line;
+        sds val = sdsnewlen(sep+1,sdslen(line)-((intptr_t)sep-(intptr_t)line)-1);
+        if (!raxTryInsert(d->rax,key,keylen,val,NULL))
+            sdsfree(val);
+    }
+    sdsfree(info);
+    sdsfreesplitres(lines,totlines);
+    releaseInfoSectionDict(section_dict);
+    if(argv[0]) decrRefCount(argv[0]);
+    return d;
+}
+
+/* Free data created with RM_GetServerInfo(). You need to pass the
+ * context pointer 'ctx' only if the dictionary was created using the
+ * context instead of passing NULL. */
+void RM_FreeServerInfo(RedisModuleCtx *ctx, RedisModuleServerInfoData *data) {
+    if (ctx != NULL) autoMemoryFreed(ctx,REDISMODULE_AM_INFO,data);
+    raxFreeWithCallback(data->rax, (void(*)(void*))sdsfree);
+    zfree(data);
+}
+
+/* Get the value of a field from data collected with RM_GetServerInfo(). You
+ * need to pass the context pointer 'ctx' only if you want to use auto memory
+ * mechanism to release the returned string. Return value will be NULL if the
+ * field was not found. */
+RedisModuleString *RM_ServerInfoGetField(RedisModuleCtx *ctx, RedisModuleServerInfoData *data, const char* field) {
+    sds val = raxFind(data->rax, (unsigned char *)field, strlen(field));
+    if (val == raxNotFound) return NULL;
+    RedisModuleString *o = createStringObject(val,sdslen(val));
+    if (ctx != NULL) autoMemoryAdd(ctx,REDISMODULE_AM_STRING,o);
+    return o;
+}
+
+/* Similar to RM_ServerInfoGetField, but returns a char* which should not be freed but the caller. */
+const char *RM_ServerInfoGetFieldC(RedisModuleServerInfoData *data, const char* field) {
+    sds val = raxFind(data->rax, (unsigned char *)field, strlen(field));
+    if (val == raxNotFound) return NULL;
+    return val;
+}
+
+/* Get the value of a field from data collected with RM_GetServerInfo(). If the
+ * field is not found, or is not numerical or out of range, return value will be
+ * 0, and the optional out_err argument will be set to REDISMODULE_ERR. */
+long long RM_ServerInfoGetFieldSigned(RedisModuleServerInfoData *data, const char* field, int *out_err) {
+    long long ll;
+    sds val = raxFind(data->rax, (unsigned char *)field, strlen(field));
+    if (val == raxNotFound) {
+        if (out_err) *out_err = REDISMODULE_ERR;
+        return 0;
+    }
+    if (!string2ll(val,sdslen(val),&ll)) {
+        if (out_err) *out_err = REDISMODULE_ERR;
+        return 0;
+    }
+    if (out_err) *out_err = REDISMODULE_OK;
+    return ll;
+}
+
+/* Get the value of a field from data collected with RM_GetServerInfo(). If the
+ * field is not found, or is not numerical or out of range, return value will be
+ * 0, and the optional out_err argument will be set to REDISMODULE_ERR. */
+unsigned long long RM_ServerInfoGetFieldUnsigned(RedisModuleServerInfoData *data, const char* field, int *out_err) {
+    unsigned long long ll;
+    sds val = raxFind(data->rax, (unsigned char *)field, strlen(field));
+    if (val == raxNotFound) {
+        if (out_err) *out_err = REDISMODULE_ERR;
+        return 0;
+    }
+    if (!string2ull(val,&ll)) {
+        if (out_err) *out_err = REDISMODULE_ERR;
+        return 0;
+    }
+    if (out_err) *out_err = REDISMODULE_OK;
+    return ll;
+}
+
+/* Get the value of a field from data collected with RM_GetServerInfo(). If the
+ * field is not found, or is not a double, return value will be 0, and the
+ * optional out_err argument will be set to REDISMODULE_ERR. */
+double RM_ServerInfoGetFieldDouble(RedisModuleServerInfoData *data, const char* field, int *out_err) {
+    double dbl;
+    sds val = raxFind(data->rax, (unsigned char *)field, strlen(field));
+    if (val == raxNotFound) {
+        if (out_err) *out_err = REDISMODULE_ERR;
+        return 0;
+    }
+    if (!string2d(val,sdslen(val),&dbl)) {
+        if (out_err) *out_err = REDISMODULE_ERR;
+        return 0;
+    }
+    if (out_err) *out_err = REDISMODULE_OK;
+    return dbl;
+}
+
+/* --------------------------------------------------------------------------
+ * ## Modules utility APIs
+ * -------------------------------------------------------------------------- */
+
+/* Return random bytes using SHA1 in counter mode with a /dev/urandom
+ * initialized seed. This function is fast so can be used to generate
+ * many bytes without any effect on the operating system entropy pool.
+ * Currently this function is not thread safe. */
+void RM_GetRandomBytes(unsigned char *dst, size_t len) {
+    getRandomBytes(dst,len);
+}
+
+/* Like RedisModule_GetRandomBytes() but instead of setting the string to
+ * random bytes the string is set to random characters in the in the
+ * hex charset [0-9a-f]. */
+void RM_GetRandomHexChars(char *dst, size_t len) {
+    getRandomHexChars(dst,len);
+}
+
+/* --------------------------------------------------------------------------
+ * ## Modules API exporting / importing
+ * -------------------------------------------------------------------------- */
+
+/* This function is called by a module in order to export some API with a
+ * given name. Other modules will be able to use this API by calling the
+ * symmetrical function RM_GetSharedAPI() and casting the return value to
+ * the right function pointer.
+ *
+ * The function will return REDISMODULE_OK if the name is not already taken,
+ * otherwise REDISMODULE_ERR will be returned and no operation will be
+ * performed.
+ *
+ * IMPORTANT: the apiname argument should be a string literal with static
+ * lifetime. The API relies on the fact that it will always be valid in
+ * the future. */
+int RM_ExportSharedAPI(RedisModuleCtx *ctx, const char *apiname, void *func) {
+    RedisModuleSharedAPI *sapi = zmalloc(sizeof(*sapi));
+    sapi->module = ctx->module;
+    sapi->func = func;
+    if (dictAdd(server.sharedapi, (char*)apiname, sapi) != DICT_OK) {
+        zfree(sapi);
+        return REDISMODULE_ERR;
+    }
+    return REDISMODULE_OK;
+}
+
+/* Request an exported API pointer. The return value is just a void pointer
+ * that the caller of this function will be required to cast to the right
+ * function pointer, so this is a private contract between modules.
+ *
+ * If the requested API is not available then NULL is returned. Because
+ * modules can be loaded at different times with different order, this
+ * function calls should be put inside some module generic API registering
+ * step, that is called every time a module attempts to execute a
+ * command that requires external APIs: if some API cannot be resolved, the
+ * command should return an error.
+ *
+ * Here is an example:
+ *
+ *     int ... myCommandImplementation(void) {
+ *        if (getExternalAPIs() == 0) {
+ *             reply with an error here if we cannot have the APIs
+ *        }
+ *        // Use the API:
+ *        myFunctionPointer(foo);
+ *     }
+ *
+ * And the function registerAPI() is:
+ *
+ *     int getExternalAPIs(void) {
+ *         static int api_loaded = 0;
+ *         if (api_loaded != 0) return 1; // APIs already resolved.
+ *
+ *         myFunctionPointer = RedisModule_GetSharedAPI("...");
+ *         if (myFunctionPointer == NULL) return 0;
+ *
+ *         return 1;
+ *     }
+ */
+void *RM_GetSharedAPI(RedisModuleCtx *ctx, const char *apiname) {
+    dictEntry *de = dictFind(server.sharedapi, apiname);
+    if (de == NULL) return NULL;
+    RedisModuleSharedAPI *sapi = dictGetVal(de);
+    if (listSearchKey(sapi->module->usedby,ctx->module) == NULL) {
+        listAddNodeTail(sapi->module->usedby,ctx->module);
+        listAddNodeTail(ctx->module->using,sapi->module);
+    }
+    return sapi->func;
+}
+
+/* Remove all the APIs registered by the specified module. Usually you
+ * want this when the module is going to be unloaded. This function
+ * assumes that's caller responsibility to make sure the APIs are not
+ * used by other modules.
+ *
+ * The number of unregistered APIs is returned. */
+int moduleUnregisterSharedAPI(RedisModule *module) {
+    int count = 0;
+    dictIterator *di = dictGetSafeIterator(server.sharedapi);
+    dictEntry *de;
+    while ((de = dictNext(di)) != NULL) {
+        const char *apiname = dictGetKey(de);
+        RedisModuleSharedAPI *sapi = dictGetVal(de);
+        if (sapi->module == module) {
+            dictDelete(server.sharedapi,apiname);
+            zfree(sapi);
+            count++;
+        }
+    }
+    dictReleaseIterator(di);
+    return count;
+}
+
+/* Remove the specified module as an user of APIs of ever other module.
+ * This is usually called when a module is unloaded.
+ *
+ * Returns the number of modules this module was using APIs from. */
+int moduleUnregisterUsedAPI(RedisModule *module) {
+    listIter li;
+    listNode *ln;
+    int count = 0;
+
+    listRewind(module->using,&li);
+    while((ln = listNext(&li))) {
+        RedisModule *used = ln->value;
+        listNode *ln = listSearchKey(used->usedby,module);
+        if (ln) {
+            listDelNode(used->usedby,ln);
+            count++;
+        }
+    }
+    return count;
+}
+
+/* Unregister all filters registered by a module.
+ * This is called when a module is being unloaded.
+ *
+ * Returns the number of filters unregistered. */
+int moduleUnregisterFilters(RedisModule *module) {
+    listIter li;
+    listNode *ln;
+    int count = 0;
+
+    listRewind(module->filters,&li);
+    while((ln = listNext(&li))) {
+        RedisModuleCommandFilter *filter = ln->value;
+        listNode *ln = listSearchKey(moduleCommandFilters,filter);
+        if (ln) {
+            listDelNode(moduleCommandFilters,ln);
+            count++;
+        }
+        zfree(filter);
+    }
+    return count;
+}
+
+/* --------------------------------------------------------------------------
+ * ## Module Command Filter API
+ * -------------------------------------------------------------------------- */
+
+/* Register a new command filter function.
+ *
+ * Command filtering makes it possible for modules to extend Redis by plugging
+ * into the execution flow of all commands.
+ *
+ * A registered filter gets called before Redis executes *any* command.  This
+ * includes both core Redis commands and commands registered by any module.  The
+ * filter applies in all execution paths including:
+ *
+ * 1. Invocation by a client.
+ * 2. Invocation through `RedisModule_Call()` by any module.
+ * 3. Invocation through Lua `redis.call()`.
+ * 4. Replication of a command from a master.
+ *
+ * The filter executes in a special filter context, which is different and more
+ * limited than a RedisModuleCtx.  Because the filter affects any command, it
+ * must be implemented in a very efficient way to reduce the performance impact
+ * on Redis.  All Redis Module API calls that require a valid context (such as
+ * `RedisModule_Call()`, `RedisModule_OpenKey()`, etc.) are not supported in a
+ * filter context.
+ *
+ * The `RedisModuleCommandFilterCtx` can be used to inspect or modify the
+ * executed command and its arguments.  As the filter executes before Redis
+ * begins processing the command, any change will affect the way the command is
+ * processed.  For example, a module can override Redis commands this way:
+ *
+ * 1. Register a `MODULE.SET` command which implements an extended version of
+ *    the Redis `SET` command.
+ * 2. Register a command filter which detects invocation of `SET` on a specific
+ *    pattern of keys.  Once detected, the filter will replace the first
+ *    argument from `SET` to `MODULE.SET`.
+ * 3. When filter execution is complete, Redis considers the new command name
+ *    and therefore executes the module's own command.
+ *
+ * Note that in the above use case, if `MODULE.SET` itself uses
+ * `RedisModule_Call()` the filter will be applied on that call as well.  If
+ * that is not desired, the `REDISMODULE_CMDFILTER_NOSELF` flag can be set when
+ * registering the filter.
+ *
+ * The `REDISMODULE_CMDFILTER_NOSELF` flag prevents execution flows that
+ * originate from the module's own `RM_Call()` from reaching the filter.  This
+ * flag is effective for all execution flows, including nested ones, as long as
+ * the execution begins from the module's command context or a thread-safe
+ * context that is associated with a blocking command.
+ *
+ * Detached thread-safe contexts are *not* associated with the module and cannot
+ * be protected by this flag.
+ *
+ * If multiple filters are registered (by the same or different modules), they
+ * are executed in the order of registration.
+ */
+RedisModuleCommandFilter *RM_RegisterCommandFilter(RedisModuleCtx *ctx, RedisModuleCommandFilterFunc callback, int flags) {
+    RedisModuleCommandFilter *filter = zmalloc(sizeof(*filter));
+    filter->module = ctx->module;
+    filter->callback = callback;
+    filter->flags = flags;
+
+    listAddNodeTail(moduleCommandFilters, filter);
+    listAddNodeTail(ctx->module->filters, filter);
+    return filter;
+}
+
+/* Unregister a command filter.
+ */
+int RM_UnregisterCommandFilter(RedisModuleCtx *ctx, RedisModuleCommandFilter *filter) {
+    listNode *ln;
+
+    /* A module can only remove its own filters */
+    if (filter->module != ctx->module) return REDISMODULE_ERR;
+
+    ln = listSearchKey(moduleCommandFilters,filter);
+    if (!ln) return REDISMODULE_ERR;
+    listDelNode(moduleCommandFilters,ln);
+
+    ln = listSearchKey(ctx->module->filters,filter);
+    if (!ln) return REDISMODULE_ERR;    /* Shouldn't happen */
+    listDelNode(ctx->module->filters,ln);
+
+    zfree(filter);
+
+    return REDISMODULE_OK;
+}
+
+void moduleCallCommandFilters(client *c) {
+    if (listLength(moduleCommandFilters) == 0) return;
+
+    listIter li;
+    listNode *ln;
+    listRewind(moduleCommandFilters,&li);
+
+    RedisModuleCommandFilterCtx filter = {
+        .argv = c->argv,
+        .argv_len = c->argv_len,
+        .argc = c->argc,
+        .c = c
+    };
+
+    while((ln = listNext(&li))) {
+        RedisModuleCommandFilter *f = ln->value;
+
+        /* Skip filter if REDISMODULE_CMDFILTER_NOSELF is set and module is
+         * currently processing a command.
+         */
+        if ((f->flags & REDISMODULE_CMDFILTER_NOSELF) && f->module->in_call) continue;
+
+        /* Call filter */
+        f->callback(&filter);
+    }
+
+    c->argv = filter.argv;
+    c->argv_len = filter.argv_len;
+    c->argc = filter.argc;
+}
+
+/* Return the number of arguments a filtered command has.  The number of
+ * arguments include the command itself.
+ */
+int RM_CommandFilterArgsCount(RedisModuleCommandFilterCtx *fctx)
+{
+    return fctx->argc;
+}
+
+/* Return the specified command argument.  The first argument (position 0) is
+ * the command itself, and the rest are user-provided args.
+ */
+RedisModuleString *RM_CommandFilterArgGet(RedisModuleCommandFilterCtx *fctx, int pos)
+{
+    if (pos < 0 || pos >= fctx->argc) return NULL;
+    return fctx->argv[pos];
+}
+
+/* Modify the filtered command by inserting a new argument at the specified
+ * position.  The specified RedisModuleString argument may be used by Redis
+ * after the filter context is destroyed, so it must not be auto-memory
+ * allocated, freed or used elsewhere.
+ */
+int RM_CommandFilterArgInsert(RedisModuleCommandFilterCtx *fctx, int pos, RedisModuleString *arg)
+{
+    int i;
+
+    if (pos < 0 || pos > fctx->argc) return REDISMODULE_ERR;
+
+    if (fctx->argv_len < fctx->argc+1) {
+        fctx->argv_len = fctx->argc+1;
+        fctx->argv = zrealloc(fctx->argv, fctx->argv_len*sizeof(RedisModuleString *));
+    }
+    for (i = fctx->argc; i > pos; i--) {
+        fctx->argv[i] = fctx->argv[i-1];
+    }
+    fctx->argv[pos] = arg;
+    fctx->argc++;
+
+    return REDISMODULE_OK;
+}
+
+/* Modify the filtered command by replacing an existing argument with a new one.
+ * The specified RedisModuleString argument may be used by Redis after the
+ * filter context is destroyed, so it must not be auto-memory allocated, freed
+ * or used elsewhere.
+ */
+int RM_CommandFilterArgReplace(RedisModuleCommandFilterCtx *fctx, int pos, RedisModuleString *arg)
+{
+    if (pos < 0 || pos >= fctx->argc) return REDISMODULE_ERR;
+
+    decrRefCount(fctx->argv[pos]);
+    fctx->argv[pos] = arg;
+
+    return REDISMODULE_OK;
+}
+
+/* Modify the filtered command by deleting an argument at the specified
+ * position.
+ */
+int RM_CommandFilterArgDelete(RedisModuleCommandFilterCtx *fctx, int pos)
+{
+    int i;
+    if (pos < 0 || pos >= fctx->argc) return REDISMODULE_ERR;
+
+    decrRefCount(fctx->argv[pos]);
+    for (i = pos; i < fctx->argc-1; i++) {
+        fctx->argv[i] = fctx->argv[i+1];
+    }
+    fctx->argc--;
+
+    return REDISMODULE_OK;
+}
+
+/* Get Client ID for client that issued the command we are filtering */
+unsigned long long RM_CommandFilterGetClientId(RedisModuleCommandFilterCtx *fctx) {
+    return fctx->c->id;
+}
+
+/* For a given pointer allocated via RedisModule_Alloc() or
+ * RedisModule_Realloc(), return the amount of memory allocated for it.
+ * Note that this may be different (larger) than the memory we allocated
+ * with the allocation calls, since sometimes the underlying allocator
+ * will allocate more memory.
+ */
+size_t RM_MallocSize(void* ptr) {
+    return zmalloc_size(ptr);
+}
+
+/* Similar to RM_MallocSize, the difference is that RM_MallocUsableSize
+ * returns the usable size of memory by the module. */
+size_t RM_MallocUsableSize(void *ptr) {
+    /* It is safe to use 'zmalloc_usable_size()' to manipulate additional
+     * memory space, as we guarantee that the compiler can recognize this
+     * after 'RM_Alloc', 'RM_TryAlloc', 'RM_Realloc', or 'RM_Calloc'. */
+    return zmalloc_usable_size(ptr);
+}
+
+/* Same as RM_MallocSize, except it works on RedisModuleString pointers.
+ */
+size_t RM_MallocSizeString(RedisModuleString* str) {
+    serverAssert(str->type == OBJ_STRING);
+    return sizeof(*str) + getStringObjectSdsUsedMemory(str);
+}
+
+/* Same as RM_MallocSize, except it works on RedisModuleDict pointers.
+ * Note that the returned value is only the overhead of the underlying structures,
+ * it does not include the allocation size of the keys and values.
+ */
+size_t RM_MallocSizeDict(RedisModuleDict* dict) {
+    size_t size = sizeof(RedisModuleDict) + sizeof(rax);
+    size += dict->rax->numnodes * sizeof(raxNode);
+    /* For more info about this weird line, see streamRadixTreeMemoryUsage */
+    size += dict->rax->numnodes * sizeof(long)*30;
+    return size;
+}
+
+/* Return the a number between 0 to 1 indicating the amount of memory
+ * currently used, relative to the Redis "maxmemory" configuration.
+ *
+ * * 0 - No memory limit configured.
+ * * Between 0 and 1 - The percentage of the memory used normalized in 0-1 range.
+ * * Exactly 1 - Memory limit reached.
+ * * Greater 1 - More memory used than the configured limit.
+ */
+float RM_GetUsedMemoryRatio(void){
+    float level;
+    getMaxmemoryState(NULL, NULL, NULL, &level);
+    return level;
+}
+
+/* --------------------------------------------------------------------------
+ * ## Scanning keyspace and hashes
+ * -------------------------------------------------------------------------- */
+
+typedef void (*RedisModuleScanCB)(RedisModuleCtx *ctx, RedisModuleString *keyname, RedisModuleKey *key, void *privdata);
+typedef struct {
+    RedisModuleCtx *ctx;
+    void* user_data;
+    RedisModuleScanCB fn;
+} ScanCBData;
+
+typedef struct RedisModuleScanCursor{
+    unsigned long cursor;
+    int done;
+}RedisModuleScanCursor;
+
+static void moduleScanCallback(void *privdata, const dictEntry *de) {
+    ScanCBData *data = privdata;
+    sds key = dictGetKey(de);
+    robj* val = dictGetVal(de);
+    RedisModuleString *keyname = createObject(OBJ_STRING,sdsdup(key));
+
+    /* Setup the key handle. */
+    RedisModuleKey kp = {0};
+    moduleInitKey(&kp, data->ctx, keyname, val, REDISMODULE_READ);
+
+    data->fn(data->ctx, keyname, &kp, data->user_data);
+
+    moduleCloseKey(&kp);
+    decrRefCount(keyname);
+}
+
+/* Create a new cursor to be used with RedisModule_Scan */
+RedisModuleScanCursor *RM_ScanCursorCreate(void) {
+    RedisModuleScanCursor* cursor = zmalloc(sizeof(*cursor));
+    cursor->cursor = 0;
+    cursor->done = 0;
+    return cursor;
+}
+
+/* Restart an existing cursor. The keys will be rescanned. */
+void RM_ScanCursorRestart(RedisModuleScanCursor *cursor) {
+    cursor->cursor = 0;
+    cursor->done = 0;
+}
+
+/* Destroy the cursor struct. */
+void RM_ScanCursorDestroy(RedisModuleScanCursor *cursor) {
+    zfree(cursor);
+}
+
+/* Scan API that allows a module to scan all the keys and value in
+ * the selected db.
+ *
+ * Callback for scan implementation.
+ *
+ *     void scan_callback(RedisModuleCtx *ctx, RedisModuleString *keyname,
+ *                        RedisModuleKey *key, void *privdata);
+ *
+ * - `ctx`: the redis module context provided to for the scan.
+ * - `keyname`: owned by the caller and need to be retained if used after this
+ *   function.
+ * - `key`: holds info on the key and value, it is provided as best effort, in
+ *   some cases it might be NULL, in which case the user should (can) use
+ *   RedisModule_OpenKey() (and CloseKey too).
+ *   when it is provided, it is owned by the caller and will be free when the
+ *   callback returns.
+ * - `privdata`: the user data provided to RedisModule_Scan().
+ *
+ * The way it should be used:
+ *
+ *      RedisModuleScanCursor *c = RedisModule_ScanCursorCreate();
+ *      while(RedisModule_Scan(ctx, c, callback, privateData));
+ *      RedisModule_ScanCursorDestroy(c);
+ *
+ * It is also possible to use this API from another thread while the lock
+ * is acquired during the actual call to RM_Scan:
+ *
+ *      RedisModuleScanCursor *c = RedisModule_ScanCursorCreate();
+ *      RedisModule_ThreadSafeContextLock(ctx);
+ *      while(RedisModule_Scan(ctx, c, callback, privateData)){
+ *          RedisModule_ThreadSafeContextUnlock(ctx);
+ *          // do some background job
+ *          RedisModule_ThreadSafeContextLock(ctx);
+ *      }
+ *      RedisModule_ScanCursorDestroy(c);
+ *
+ * The function will return 1 if there are more elements to scan and
+ * 0 otherwise, possibly setting errno if the call failed.
+ *
+ * It is also possible to restart an existing cursor using RM_ScanCursorRestart.
+ *
+ * IMPORTANT: This API is very similar to the Redis SCAN command from the
+ * point of view of the guarantees it provides. This means that the API
+ * may report duplicated keys, but guarantees to report at least one time
+ * every key that was there from the start to the end of the scanning process.
+ *
+ * NOTE: If you do database changes within the callback, you should be aware
+ * that the internal state of the database may change. For instance it is safe
+ * to delete or modify the current key, but may not be safe to delete any
+ * other key.
+ * Moreover playing with the Redis keyspace while iterating may have the
+ * effect of returning more duplicates. A safe pattern is to store the keys
+ * names you want to modify elsewhere, and perform the actions on the keys
+ * later when the iteration is complete. However this can cost a lot of
+ * memory, so it may make sense to just operate on the current key when
+ * possible during the iteration, given that this is safe. */
+int RM_Scan(RedisModuleCtx *ctx, RedisModuleScanCursor *cursor, RedisModuleScanCB fn, void *privdata) {
+    if (cursor->done) {
+        errno = ENOENT;
+        return 0;
+    }
+    int ret = 1;
+    ScanCBData data = { ctx, privdata, fn };
+    cursor->cursor = dictScan(ctx->client->db->dict, cursor->cursor, moduleScanCallback, &data);
+    if (cursor->cursor == 0) {
+        cursor->done = 1;
+        ret = 0;
+    }
+    errno = 0;
+    return ret;
+}
+
+typedef void (*RedisModuleScanKeyCB)(RedisModuleKey *key, RedisModuleString *field, RedisModuleString *value, void *privdata);
+typedef struct {
+    RedisModuleKey *key;
+    void* user_data;
+    RedisModuleScanKeyCB fn;
+} ScanKeyCBData;
+
+static void moduleScanKeyCallback(void *privdata, const dictEntry *de) {
+    ScanKeyCBData *data = privdata;
+    sds key = dictGetKey(de);
+    robj *o = data->key->value;
+    robj *field = createStringObject(key, sdslen(key));
+    robj *value = NULL;
+    if (o->type == OBJ_SET) {
+        value = NULL;
+    } else if (o->type == OBJ_HASH) {
+        sds val = dictGetVal(de);
+        value = createStringObject(val, sdslen(val));
+    } else if (o->type == OBJ_ZSET) {
+        double *val = (double*)dictGetVal(de);
+        value = createStringObjectFromLongDouble(*val, 0);
+    }
+
+    data->fn(data->key, field, value, data->user_data);
+    decrRefCount(field);
+    if (value) decrRefCount(value);
+}
+
+/* Scan api that allows a module to scan the elements in a hash, set or sorted set key
+ *
+ * Callback for scan implementation.
+ *
+ *     void scan_callback(RedisModuleKey *key, RedisModuleString* field, RedisModuleString* value, void *privdata);
+ *
+ * - key - the redis key context provided to for the scan.
+ * - field - field name, owned by the caller and need to be retained if used
+ *   after this function.
+ * - value - value string or NULL for set type, owned by the caller and need to
+ *   be retained if used after this function.
+ * - privdata - the user data provided to RedisModule_ScanKey.
+ *
+ * The way it should be used:
+ *
+ *      RedisModuleScanCursor *c = RedisModule_ScanCursorCreate();
+ *      RedisModuleKey *key = RedisModule_OpenKey(...)
+ *      while(RedisModule_ScanKey(key, c, callback, privateData));
+ *      RedisModule_CloseKey(key);
+ *      RedisModule_ScanCursorDestroy(c);
+ *
+ * It is also possible to use this API from another thread while the lock is acquired during
+ * the actual call to RM_ScanKey, and re-opening the key each time:
+ *
+ *      RedisModuleScanCursor *c = RedisModule_ScanCursorCreate();
+ *      RedisModule_ThreadSafeContextLock(ctx);
+ *      RedisModuleKey *key = RedisModule_OpenKey(...)
+ *      while(RedisModule_ScanKey(ctx, c, callback, privateData)){
+ *          RedisModule_CloseKey(key);
+ *          RedisModule_ThreadSafeContextUnlock(ctx);
+ *          // do some background job
+ *          RedisModule_ThreadSafeContextLock(ctx);
+ *          RedisModuleKey *key = RedisModule_OpenKey(...)
+ *      }
+ *      RedisModule_CloseKey(key);
+ *      RedisModule_ScanCursorDestroy(c);
+ *
+ * The function will return 1 if there are more elements to scan and 0 otherwise,
+ * possibly setting errno if the call failed.
+ * It is also possible to restart an existing cursor using RM_ScanCursorRestart.
+ *
+ * NOTE: Certain operations are unsafe while iterating the object. For instance
+ * while the API guarantees to return at least one time all the elements that
+ * are present in the data structure consistently from the start to the end
+ * of the iteration (see HSCAN and similar commands documentation), the more
+ * you play with the elements, the more duplicates you may get. In general
+ * deleting the current element of the data structure is safe, while removing
+ * the key you are iterating is not safe. */
+int RM_ScanKey(RedisModuleKey *key, RedisModuleScanCursor *cursor, RedisModuleScanKeyCB fn, void *privdata) {
+    if (key == NULL || key->value == NULL) {
+        errno = EINVAL;
+        return 0;
+    }
+    dict *ht = NULL;
+    robj *o = key->value;
+    if (o->type == OBJ_SET) {
+        if (o->encoding == OBJ_ENCODING_HT)
+            ht = o->ptr;
+    } else if (o->type == OBJ_HASH) {
+        if (o->encoding == OBJ_ENCODING_HT)
+            ht = o->ptr;
+    } else if (o->type == OBJ_ZSET) {
+        if (o->encoding == OBJ_ENCODING_SKIPLIST)
+            ht = ((zset *)o->ptr)->dict;
+    } else {
+        errno = EINVAL;
+        return 0;
+    }
+    if (cursor->done) {
+        errno = ENOENT;
+        return 0;
+    }
+    int ret = 1;
+    if (ht) {
+        ScanKeyCBData data = { key, privdata, fn };
+        cursor->cursor = dictScan(ht, cursor->cursor, moduleScanKeyCallback, &data);
+        if (cursor->cursor == 0) {
+            cursor->done = 1;
+            ret = 0;
+        }
+    } else if (o->type == OBJ_SET) {
+        setTypeIterator *si = setTypeInitIterator(o);
+        sds sdsele;
+        while ((sdsele = setTypeNextObject(si)) != NULL) {
+            robj *field = createObject(OBJ_STRING, sdsele);
+            fn(key, field, NULL, privdata);
+            decrRefCount(field);
+        }
+        setTypeReleaseIterator(si);
+        cursor->cursor = 1;
+        cursor->done = 1;
+        ret = 0;
+    } else if (o->type == OBJ_ZSET || o->type == OBJ_HASH) {
+        unsigned char *p = lpSeek(o->ptr,0);
+        unsigned char *vstr;
+        unsigned int vlen;
+        long long vll;
+        while(p) {
+            vstr = lpGetValue(p,&vlen,&vll);
+            robj *field = (vstr != NULL) ?
+                createStringObject((char*)vstr,vlen) :
+                createStringObjectFromLongLongWithSds(vll);
+            p = lpNext(o->ptr,p);
+            vstr = lpGetValue(p,&vlen,&vll);
+            robj *value = (vstr != NULL) ?
+                createStringObject((char*)vstr,vlen) :
+                createStringObjectFromLongLongWithSds(vll);
+            fn(key, field, value, privdata);
+            p = lpNext(o->ptr,p);
+            decrRefCount(field);
+            decrRefCount(value);
+        }
+        cursor->cursor = 1;
+        cursor->done = 1;
+        ret = 0;
+    }
+    errno = 0;
+    return ret;
+}
+
+
+/* --------------------------------------------------------------------------
+ * ## Module fork API
+ * -------------------------------------------------------------------------- */
+
+/* Create a background child process with the current frozen snapshot of the
+ * main process where you can do some processing in the background without
+ * affecting / freezing the traffic and no need for threads and GIL locking.
+ * Note that Redis allows for only one concurrent fork.
+ * When the child wants to exit, it should call RedisModule_ExitFromChild.
+ * If the parent wants to kill the child it should call RedisModule_KillForkChild
+ * The done handler callback will be executed on the parent process when the
+ * child existed (but not when killed)
+ * Return: -1 on failure, on success the parent process will get a positive PID
+ * of the child, and the child process will get 0.
+ */
+int RM_Fork(RedisModuleForkDoneHandler cb, void *user_data) {
+    pid_t childpid;
+
+    if ((childpid = redisFork(CHILD_TYPE_MODULE)) == 0) {
+        /* Child */
+        redisSetProcTitle("redis-module-fork");
+    } else if (childpid == -1) {
+        serverLog(LL_WARNING,"Can't fork for module: %s", strerror(errno));
+    } else {
+        /* Parent */
+        moduleForkInfo.done_handler = cb;
+        moduleForkInfo.done_handler_user_data = user_data;
+        serverLog(LL_VERBOSE, "Module fork started pid: %ld ", (long) childpid);
+    }
+    return childpid;
+}
+
+/* The module is advised to call this function from the fork child once in a while,
+ * so that it can report progress and COW memory to the parent which will be
+ * reported in INFO.
+ * The `progress` argument should between 0 and 1, or -1 when not available. */
+void RM_SendChildHeartbeat(double progress) {
+    sendChildInfoGeneric(CHILD_INFO_TYPE_CURRENT_INFO, 0, progress, "Module fork");
+}
+
+/* Call from the child process when you want to terminate it.
+ * retcode will be provided to the done handler executed on the parent process.
+ */
+int RM_ExitFromChild(int retcode) {
+    sendChildCowInfo(CHILD_INFO_TYPE_MODULE_COW_SIZE, "Module fork");
+    exitFromChild(retcode);
+    return REDISMODULE_OK;
+}
+
+/* Kill the active module forked child, if there is one active and the
+ * pid matches, and returns C_OK. Otherwise if there is no active module
+ * child or the pid does not match, return C_ERR without doing anything. */
+int TerminateModuleForkChild(int child_pid, int wait) {
+    /* Module child should be active and pid should match. */
+    if (server.child_type != CHILD_TYPE_MODULE ||
+        server.child_pid != child_pid) return C_ERR;
+
+    int statloc;
+    serverLog(LL_VERBOSE,"Killing running module fork child: %ld",
+        (long) server.child_pid);
+    if (kill(server.child_pid,SIGUSR1) != -1 && wait) {
+        while(waitpid(server.child_pid, &statloc, 0) !=
+              server.child_pid);
+    }
+    /* Reset the buffer accumulating changes while the child saves. */
+    resetChildState();
+    moduleForkInfo.done_handler = NULL;
+    moduleForkInfo.done_handler_user_data = NULL;
+    return C_OK;
+}
+
+/* Can be used to kill the forked child process from the parent process.
+ * child_pid would be the return value of RedisModule_Fork. */
+int RM_KillForkChild(int child_pid) {
+    /* Kill module child, wait for child exit. */
+    if (TerminateModuleForkChild(child_pid,1) == C_OK)
+        return REDISMODULE_OK;
+    else
+        return REDISMODULE_ERR;
+}
+
+void ModuleForkDoneHandler(int exitcode, int bysignal) {
+    serverLog(LL_NOTICE,
+        "Module fork exited pid: %ld, retcode: %d, bysignal: %d",
+        (long) server.child_pid, exitcode, bysignal);
+    if (moduleForkInfo.done_handler) {
+        moduleForkInfo.done_handler(exitcode, bysignal,
+            moduleForkInfo.done_handler_user_data);
+    }
+
+    moduleForkInfo.done_handler = NULL;
+    moduleForkInfo.done_handler_user_data = NULL;
+}
+
+/* --------------------------------------------------------------------------
+ * ## Server hooks implementation
+ * -------------------------------------------------------------------------- */
+
+/* This must be synced with REDISMODULE_EVENT_*
+ * We use -1 (MAX_UINT64) to denote that this event doesn't have
+ * a data structure associated with it. We use MAX_UINT64 on purpose,
+ * in order to pass the check in RedisModule_SubscribeToServerEvent. */
+static uint64_t moduleEventVersions[] = {
+    REDISMODULE_REPLICATIONINFO_VERSION, /* REDISMODULE_EVENT_REPLICATION_ROLE_CHANGED */
+    -1, /* REDISMODULE_EVENT_PERSISTENCE */
+    REDISMODULE_FLUSHINFO_VERSION, /* REDISMODULE_EVENT_FLUSHDB */
+    -1, /* REDISMODULE_EVENT_LOADING */
+    REDISMODULE_CLIENTINFO_VERSION, /* REDISMODULE_EVENT_CLIENT_CHANGE */
+    -1, /* REDISMODULE_EVENT_SHUTDOWN */
+    -1, /* REDISMODULE_EVENT_REPLICA_CHANGE */
+    -1, /* REDISMODULE_EVENT_MASTER_LINK_CHANGE */
+    REDISMODULE_CRON_LOOP_VERSION, /* REDISMODULE_EVENT_CRON_LOOP */
+    REDISMODULE_MODULE_CHANGE_VERSION, /* REDISMODULE_EVENT_MODULE_CHANGE */
+    REDISMODULE_LOADING_PROGRESS_VERSION, /* REDISMODULE_EVENT_LOADING_PROGRESS */
+    REDISMODULE_SWAPDBINFO_VERSION, /* REDISMODULE_EVENT_SWAPDB */
+    -1, /* REDISMODULE_EVENT_REPL_BACKUP */
+    -1, /* REDISMODULE_EVENT_FORK_CHILD */
+    -1, /* REDISMODULE_EVENT_REPL_ASYNC_LOAD */
+    -1, /* REDISMODULE_EVENT_EVENTLOOP */
+    -1, /* REDISMODULE_EVENT_CONFIG */
+    REDISMODULE_KEYINFO_VERSION, /* REDISMODULE_EVENT_KEY */
+};
+
+/* Register to be notified, via a callback, when the specified server event
+ * happens. The callback is called with the event as argument, and an additional
+ * argument which is a void pointer and should be cased to a specific type
+ * that is event-specific (but many events will just use NULL since they do not
+ * have additional information to pass to the callback).
+ *
+ * If the callback is NULL and there was a previous subscription, the module
+ * will be unsubscribed. If there was a previous subscription and the callback
+ * is not null, the old callback will be replaced with the new one.
+ *
+ * The callback must be of this type:
+ *
+ *     int (*RedisModuleEventCallback)(RedisModuleCtx *ctx,
+ *                                     RedisModuleEvent eid,
+ *                                     uint64_t subevent,
+ *                                     void *data);
+ *
+ * The 'ctx' is a normal Redis module context that the callback can use in
+ * order to call other modules APIs. The 'eid' is the event itself, this
+ * is only useful in the case the module subscribed to multiple events: using
+ * the 'id' field of this structure it is possible to check if the event
+ * is one of the events we registered with this callback. The 'subevent' field
+ * depends on the event that fired.
+ *
+ * Finally the 'data' pointer may be populated, only for certain events, with
+ * more relevant data.
+ *
+ * Here is a list of events you can use as 'eid' and related sub events:
+ *
+ * * RedisModuleEvent_ReplicationRoleChanged:
+ *
+ *     This event is called when the instance switches from master
+ *     to replica or the other way around, however the event is
+ *     also called when the replica remains a replica but starts to
+ *     replicate with a different master.
+ *
+ *     The following sub events are available:
+ *
+ *     * `REDISMODULE_SUBEVENT_REPLROLECHANGED_NOW_MASTER`
+ *     * `REDISMODULE_SUBEVENT_REPLROLECHANGED_NOW_REPLICA`
+ *
+ *     The 'data' field can be casted by the callback to a
+ *     `RedisModuleReplicationInfo` structure with the following fields:
+ *
+ *         int master; // true if master, false if replica
+ *         char *masterhost; // master instance hostname for NOW_REPLICA
+ *         int masterport; // master instance port for NOW_REPLICA
+ *         char *replid1; // Main replication ID
+ *         char *replid2; // Secondary replication ID
+ *         uint64_t repl1_offset; // Main replication offset
+ *         uint64_t repl2_offset; // Offset of replid2 validity
+ *
+ * * RedisModuleEvent_Persistence
+ *
+ *     This event is called when RDB saving or AOF rewriting starts
+ *     and ends. The following sub events are available:
+ *
+ *     * `REDISMODULE_SUBEVENT_PERSISTENCE_RDB_START`
+ *     * `REDISMODULE_SUBEVENT_PERSISTENCE_AOF_START`
+ *     * `REDISMODULE_SUBEVENT_PERSISTENCE_SYNC_RDB_START`
+ *     * `REDISMODULE_SUBEVENT_PERSISTENCE_SYNC_AOF_START`
+ *     * `REDISMODULE_SUBEVENT_PERSISTENCE_ENDED`
+ *     * `REDISMODULE_SUBEVENT_PERSISTENCE_FAILED`
+ *
+ *     The above events are triggered not just when the user calls the
+ *     relevant commands like BGSAVE, but also when a saving operation
+ *     or AOF rewriting occurs because of internal server triggers.
+ *     The SYNC_RDB_START sub events are happening in the foreground due to
+ *     SAVE command, FLUSHALL, or server shutdown, and the other RDB and
+ *     AOF sub events are executed in a background fork child, so any
+ *     action the module takes can only affect the generated AOF or RDB,
+ *     but will not be reflected in the parent process and affect connected
+ *     clients and commands. Also note that the AOF_START sub event may end
+ *     up saving RDB content in case of an AOF with rdb-preamble.
+ *
+ * * RedisModuleEvent_FlushDB
+ *
+ *     The FLUSHALL, FLUSHDB or an internal flush (for instance
+ *     because of replication, after the replica synchronization)
+ *     happened. The following sub events are available:
+ *
+ *     * `REDISMODULE_SUBEVENT_FLUSHDB_START`
+ *     * `REDISMODULE_SUBEVENT_FLUSHDB_END`
+ *
+ *     The data pointer can be casted to a RedisModuleFlushInfo
+ *     structure with the following fields:
+ *
+ *         int32_t async;  // True if the flush is done in a thread.
+ *                         // See for instance FLUSHALL ASYNC.
+ *                         // In this case the END callback is invoked
+ *                         // immediately after the database is put
+ *                         // in the free list of the thread.
+ *         int32_t dbnum;  // Flushed database number, -1 for all the DBs
+ *                         // in the case of the FLUSHALL operation.
+ *
+ *     The start event is called *before* the operation is initiated, thus
+ *     allowing the callback to call DBSIZE or other operation on the
+ *     yet-to-free keyspace.
+ *
+ * * RedisModuleEvent_Loading
+ *
+ *     Called on loading operations: at startup when the server is
+ *     started, but also after a first synchronization when the
+ *     replica is loading the RDB file from the master.
+ *     The following sub events are available:
+ *
+ *     * `REDISMODULE_SUBEVENT_LOADING_RDB_START`
+ *     * `REDISMODULE_SUBEVENT_LOADING_AOF_START`
+ *     * `REDISMODULE_SUBEVENT_LOADING_REPL_START`
+ *     * `REDISMODULE_SUBEVENT_LOADING_ENDED`
+ *     * `REDISMODULE_SUBEVENT_LOADING_FAILED`
+ *
+ *     Note that AOF loading may start with an RDB data in case of
+ *     rdb-preamble, in which case you'll only receive an AOF_START event.
+ *
+ * * RedisModuleEvent_ClientChange
+ *
+ *     Called when a client connects or disconnects.
+ *     The data pointer can be casted to a RedisModuleClientInfo
+ *     structure, documented in RedisModule_GetClientInfoById().
+ *     The following sub events are available:
+ *
+ *     * `REDISMODULE_SUBEVENT_CLIENT_CHANGE_CONNECTED`
+ *     * `REDISMODULE_SUBEVENT_CLIENT_CHANGE_DISCONNECTED`
+ *
+ * * RedisModuleEvent_Shutdown
+ *
+ *     The server is shutting down. No subevents are available.
+ *
+ * * RedisModuleEvent_ReplicaChange
+ *
+ *     This event is called when the instance (that can be both a
+ *     master or a replica) get a new online replica, or lose a
+ *     replica since it gets disconnected.
+ *     The following sub events are available:
+ *
+ *     * `REDISMODULE_SUBEVENT_REPLICA_CHANGE_ONLINE`
+ *     * `REDISMODULE_SUBEVENT_REPLICA_CHANGE_OFFLINE`
+ *
+ *     No additional information is available so far: future versions
+ *     of Redis will have an API in order to enumerate the replicas
+ *     connected and their state.
+ *
+ * * RedisModuleEvent_CronLoop
+ *
+ *     This event is called every time Redis calls the serverCron()
+ *     function in order to do certain bookkeeping. Modules that are
+ *     required to do operations from time to time may use this callback.
+ *     Normally Redis calls this function 10 times per second, but
+ *     this changes depending on the "hz" configuration.
+ *     No sub events are available.
+ *
+ *     The data pointer can be casted to a RedisModuleCronLoop
+ *     structure with the following fields:
+ *
+ *         int32_t hz;  // Approximate number of events per second.
+ *
+ * * RedisModuleEvent_MasterLinkChange
+ *
+ *     This is called for replicas in order to notify when the
+ *     replication link becomes functional (up) with our master,
+ *     or when it goes down. Note that the link is not considered
+ *     up when we just connected to the master, but only if the
+ *     replication is happening correctly.
+ *     The following sub events are available:
+ *
+ *     * `REDISMODULE_SUBEVENT_MASTER_LINK_UP`
+ *     * `REDISMODULE_SUBEVENT_MASTER_LINK_DOWN`
+ *
+ * * RedisModuleEvent_ModuleChange
+ *
+ *     This event is called when a new module is loaded or one is unloaded.
+ *     The following sub events are available:
+ *
+ *     * `REDISMODULE_SUBEVENT_MODULE_LOADED`
+ *     * `REDISMODULE_SUBEVENT_MODULE_UNLOADED`
+ *
+ *     The data pointer can be casted to a RedisModuleModuleChange
+ *     structure with the following fields:
+ *
+ *         const char* module_name;  // Name of module loaded or unloaded.
+ *         int32_t module_version;  // Module version.
+ *
+ * * RedisModuleEvent_LoadingProgress
+ *
+ *     This event is called repeatedly called while an RDB or AOF file
+ *     is being loaded.
+ *     The following sub events are available:
+ *
+ *     * `REDISMODULE_SUBEVENT_LOADING_PROGRESS_RDB`
+ *     * `REDISMODULE_SUBEVENT_LOADING_PROGRESS_AOF`
+ *
+ *     The data pointer can be casted to a RedisModuleLoadingProgress
+ *     structure with the following fields:
+ *
+ *         int32_t hz;  // Approximate number of events per second.
+ *         int32_t progress;  // Approximate progress between 0 and 1024,
+ *                            // or -1 if unknown.
+ *
+ * * RedisModuleEvent_SwapDB
+ *
+ *     This event is called when a SWAPDB command has been successfully
+ *     Executed.
+ *     For this event call currently there is no subevents available.
+ *
+ *     The data pointer can be casted to a RedisModuleSwapDbInfo
+ *     structure with the following fields:
+ *
+ *         int32_t dbnum_first;    // Swap Db first dbnum
+ *         int32_t dbnum_second;   // Swap Db second dbnum
+ *
+ * * RedisModuleEvent_ReplBackup
+ * 
+ *     WARNING: Replication Backup events are deprecated since Redis 7.0 and are never fired.
+ *     See RedisModuleEvent_ReplAsyncLoad for understanding how Async Replication Loading events
+ *     are now triggered when repl-diskless-load is set to swapdb.
+ *
+ *     Called when repl-diskless-load config is set to swapdb,
+ *     And redis needs to backup the current database for the
+ *     possibility to be restored later. A module with global data and
+ *     maybe with aux_load and aux_save callbacks may need to use this
+ *     notification to backup / restore / discard its globals.
+ *     The following sub events are available:
+ *
+ *     * `REDISMODULE_SUBEVENT_REPL_BACKUP_CREATE`
+ *     * `REDISMODULE_SUBEVENT_REPL_BACKUP_RESTORE`
+ *     * `REDISMODULE_SUBEVENT_REPL_BACKUP_DISCARD`
+ * 
+ * * RedisModuleEvent_ReplAsyncLoad
+ *
+ *     Called when repl-diskless-load config is set to swapdb and a replication with a master of same
+ *     data set history (matching replication ID) occurs.
+ *     In which case redis serves current data set while loading new database in memory from socket.
+ *     Modules must have declared they support this mechanism in order to activate it, through
+ *     REDISMODULE_OPTIONS_HANDLE_REPL_ASYNC_LOAD flag.
+ *     The following sub events are available:
+ *
+ *     * `REDISMODULE_SUBEVENT_REPL_ASYNC_LOAD_STARTED`
+ *     * `REDISMODULE_SUBEVENT_REPL_ASYNC_LOAD_ABORTED`
+ *     * `REDISMODULE_SUBEVENT_REPL_ASYNC_LOAD_COMPLETED`
+ *
+ * * RedisModuleEvent_ForkChild
+ *
+ *     Called when a fork child (AOFRW, RDBSAVE, module fork...) is born/dies
+ *     The following sub events are available:
+ *
+ *     * `REDISMODULE_SUBEVENT_FORK_CHILD_BORN`
+ *     * `REDISMODULE_SUBEVENT_FORK_CHILD_DIED`
+ *
+ * * RedisModuleEvent_EventLoop
+ *
+ *     Called on each event loop iteration, once just before the event loop goes
+ *     to sleep or just after it wakes up.
+ *     The following sub events are available:
+ *
+ *     * `REDISMODULE_SUBEVENT_EVENTLOOP_BEFORE_SLEEP`
+ *     * `REDISMODULE_SUBEVENT_EVENTLOOP_AFTER_SLEEP`
+ *
+ * * RedisModule_Event_Config
+ *
+ *     Called when a configuration event happens
+ *     The following sub events are available:
+ *
+ *     * `REDISMODULE_SUBEVENT_CONFIG_CHANGE`
+ *
+ *     The data pointer can be casted to a RedisModuleConfigChange
+ *     structure with the following fields:
+ *
+ *         const char **config_names; // An array of C string pointers containing the
+ *                                    // name of each modified configuration item 
+ *         uint32_t num_changes;      // The number of elements in the config_names array
+ *
+ * * RedisModule_Event_Key
+ *
+ *     Called when a key is removed from the keyspace. We can't modify any key in
+ *     the event.
+ *     The following sub events are available:
+ *
+ *     * `REDISMODULE_SUBEVENT_KEY_DELETED`
+ *     * `REDISMODULE_SUBEVENT_KEY_EXPIRED`
+ *     * `REDISMODULE_SUBEVENT_KEY_EVICTED`
+ *     * `REDISMODULE_SUBEVENT_KEY_OVERWRITTEN`
+ *
+ *     The data pointer can be casted to a RedisModuleKeyInfo
+ *     structure with the following fields:
+ *
+ *         RedisModuleKey *key;    // Key name
+ *
+ * The function returns REDISMODULE_OK if the module was successfully subscribed
+ * for the specified event. If the API is called from a wrong context or unsupported event
+ * is given then REDISMODULE_ERR is returned. */
+int RM_SubscribeToServerEvent(RedisModuleCtx *ctx, RedisModuleEvent event, RedisModuleEventCallback callback) {
+    RedisModuleEventListener *el;
+
+    /* Protect in case of calls from contexts without a module reference. */
+    if (ctx->module == NULL) return REDISMODULE_ERR;
+    if (event.id >= _REDISMODULE_EVENT_NEXT) return REDISMODULE_ERR;
+    if (event.dataver > moduleEventVersions[event.id]) return REDISMODULE_ERR; /* Module compiled with a newer redismodule.h than we support */
+
+    /* Search an event matching this module and event ID. */
+    listIter li;
+    listNode *ln;
+    listRewind(RedisModule_EventListeners,&li);
+    while((ln = listNext(&li))) {
+        el = ln->value;
+        if (el->module == ctx->module && el->event.id == event.id)
+            break; /* Matching event found. */
+    }
+
+    /* Modify or remove the event listener if we already had one. */
+    if (ln) {
+        if (callback == NULL) {
+            listDelNode(RedisModule_EventListeners,ln);
+            zfree(el);
+        } else {
+            el->callback = callback; /* Update the callback with the new one. */
+        }
+        return REDISMODULE_OK;
+    }
+
+    /* No event found, we need to add a new one. */
+    el = zmalloc(sizeof(*el));
+    el->module = ctx->module;
+    el->event = event;
+    el->callback = callback;
+    listAddNodeTail(RedisModule_EventListeners,el);
+    return REDISMODULE_OK;
+}
+
+/**
+ * For a given server event and subevent, return zero if the
+ * subevent is not supported and non-zero otherwise.
+ */
+int RM_IsSubEventSupported(RedisModuleEvent event, int64_t subevent) {
+    switch (event.id) {
+    case REDISMODULE_EVENT_REPLICATION_ROLE_CHANGED:
+        return subevent < _REDISMODULE_EVENT_REPLROLECHANGED_NEXT;
+    case REDISMODULE_EVENT_PERSISTENCE:
+        return subevent < _REDISMODULE_SUBEVENT_PERSISTENCE_NEXT;
+    case REDISMODULE_EVENT_FLUSHDB:
+        return subevent < _REDISMODULE_SUBEVENT_FLUSHDB_NEXT;
+    case REDISMODULE_EVENT_LOADING:
+        return subevent < _REDISMODULE_SUBEVENT_LOADING_NEXT;
+    case REDISMODULE_EVENT_CLIENT_CHANGE:
+        return subevent < _REDISMODULE_SUBEVENT_CLIENT_CHANGE_NEXT;
+    case REDISMODULE_EVENT_SHUTDOWN:
+        return subevent < _REDISMODULE_SUBEVENT_SHUTDOWN_NEXT;
+    case REDISMODULE_EVENT_REPLICA_CHANGE:
+        return subevent < _REDISMODULE_EVENT_REPLROLECHANGED_NEXT;
+    case REDISMODULE_EVENT_MASTER_LINK_CHANGE:
+        return subevent < _REDISMODULE_SUBEVENT_MASTER_NEXT;
+    case REDISMODULE_EVENT_CRON_LOOP:
+        return subevent < _REDISMODULE_SUBEVENT_CRON_LOOP_NEXT;
+    case REDISMODULE_EVENT_MODULE_CHANGE:
+        return subevent < _REDISMODULE_SUBEVENT_MODULE_NEXT;
+    case REDISMODULE_EVENT_LOADING_PROGRESS:
+        return subevent < _REDISMODULE_SUBEVENT_LOADING_PROGRESS_NEXT;
+    case REDISMODULE_EVENT_SWAPDB:
+        return subevent < _REDISMODULE_SUBEVENT_SWAPDB_NEXT;
+    case REDISMODULE_EVENT_REPL_ASYNC_LOAD:
+        return subevent < _REDISMODULE_SUBEVENT_REPL_ASYNC_LOAD_NEXT;
+    case REDISMODULE_EVENT_FORK_CHILD:
+        return subevent < _REDISMODULE_SUBEVENT_FORK_CHILD_NEXT;
+    case REDISMODULE_EVENT_EVENTLOOP:
+        return subevent < _REDISMODULE_SUBEVENT_EVENTLOOP_NEXT;
+    case REDISMODULE_EVENT_CONFIG:
+        return subevent < _REDISMODULE_SUBEVENT_CONFIG_NEXT; 
+    case REDISMODULE_EVENT_KEY:
+        return subevent < _REDISMODULE_SUBEVENT_KEY_NEXT;
+    default:
+        break;
+    }
+    return 0;
+}
+
+typedef struct KeyInfo {
+    int32_t dbnum;
+    RedisModuleString *key;
+    robj *value;
+    int mode;
+} KeyInfo;
+
+/* This is called by the Redis internals every time we want to fire an
+ * event that can be intercepted by some module. The pointer 'data' is useful
+ * in order to populate the event-specific structure when needed, in order
+ * to return the structure with more information to the callback.
+ *
+ * 'eid' and 'subid' are just the main event ID and the sub event associated
+ * with the event, depending on what exactly happened. */
+void moduleFireServerEvent(uint64_t eid, int subid, void *data) {
+    /* Fast path to return ASAP if there is nothing to do, avoiding to
+     * setup the iterator and so forth: we want this call to be extremely
+     * cheap if there are no registered modules. */
+    if (listLength(RedisModule_EventListeners) == 0) return;
+
+    listIter li;
+    listNode *ln;
+    listRewind(RedisModule_EventListeners,&li);
+    while((ln = listNext(&li))) {
+        RedisModuleEventListener *el = ln->value;
+        if (el->event.id == eid) {
+            RedisModuleCtx ctx;
+            if (eid == REDISMODULE_EVENT_CLIENT_CHANGE) {
+                /* In the case of client changes, we're pushing the real client
+                 * so the event handler can mutate it if needed. For example,
+                 * to change its authentication state in a way that does not
+                 * depend on specific commands executed later.
+                 */
+                moduleCreateContext(&ctx,el->module,REDISMODULE_CTX_NONE);
+                ctx.client = (client *) data;
+            } else {
+                moduleCreateContext(&ctx,el->module,REDISMODULE_CTX_TEMP_CLIENT);
+            }
+
+            void *moduledata = NULL;
+            RedisModuleClientInfoV1 civ1;
+            RedisModuleReplicationInfoV1 riv1;
+            RedisModuleModuleChangeV1 mcv1;
+            RedisModuleKey key;
+            RedisModuleKeyInfoV1 ki = {REDISMODULE_KEYINFO_VERSION, &key};
+
+            /* Event specific context and data pointer setup. */
+            if (eid == REDISMODULE_EVENT_CLIENT_CHANGE) {
+                serverAssert(modulePopulateClientInfoStructure(&civ1,data, el->event.dataver) == REDISMODULE_OK);
+                moduledata = &civ1;
+            } else if (eid == REDISMODULE_EVENT_REPLICATION_ROLE_CHANGED) {
+                serverAssert(modulePopulateReplicationInfoStructure(&riv1,el->event.dataver) == REDISMODULE_OK);
+                moduledata = &riv1;
+            } else if (eid == REDISMODULE_EVENT_FLUSHDB) {
+                moduledata = data;
+                RedisModuleFlushInfoV1 *fi = data;
+                if (fi->dbnum != -1)
+                    selectDb(ctx.client, fi->dbnum);
+            } else if (eid == REDISMODULE_EVENT_MODULE_CHANGE) {
+                RedisModule *m = data;
+                if (m == el->module) {
+                    moduleFreeContext(&ctx);
+                    continue;
+                }
+                mcv1.version = REDISMODULE_MODULE_CHANGE_VERSION;
+                mcv1.module_name = m->name;
+                mcv1.module_version = m->ver;
+                moduledata = &mcv1;
+            } else if (eid == REDISMODULE_EVENT_LOADING_PROGRESS) {
+                moduledata = data;
+            } else if (eid == REDISMODULE_EVENT_CRON_LOOP) {
+                moduledata = data;
+            } else if (eid == REDISMODULE_EVENT_SWAPDB) {
+                moduledata = data;
+            } else if (eid == REDISMODULE_EVENT_CONFIG) {
+                moduledata = data;
+            } else if (eid == REDISMODULE_EVENT_KEY) {
+                KeyInfo *info = data;
+                selectDb(ctx.client, info->dbnum);
+                moduleInitKey(&key, &ctx, info->key, info->value, info->mode);
+                moduledata = &ki;
+            }
+
+            el->module->in_hook++;
+            el->callback(&ctx,el->event,subid,moduledata);
+            el->module->in_hook--;
+
+            if (eid == REDISMODULE_EVENT_KEY) {
+                moduleCloseKey(&key);
+            }
+
+            moduleFreeContext(&ctx);
+        }
+    }
+}
+
+/* Remove all the listeners for this module: this is used before unloading
+ * a module. */
+void moduleUnsubscribeAllServerEvents(RedisModule *module) {
+    RedisModuleEventListener *el;
+    listIter li;
+    listNode *ln;
+    listRewind(RedisModule_EventListeners,&li);
+
+    while((ln = listNext(&li))) {
+        el = ln->value;
+        if (el->module == module) {
+            listDelNode(RedisModule_EventListeners,ln);
+            zfree(el);
+        }
+    }
+}
+
+void processModuleLoadingProgressEvent(int is_aof) {
+    long long now = server.ustime;
+    static long long next_event = 0;
+    if (now >= next_event) {
+        /* Fire the loading progress modules end event. */
+        int progress = -1;
+        if (server.loading_total_bytes)
+            progress = (server.loading_loaded_bytes<<10) / server.loading_total_bytes;
+        RedisModuleLoadingProgressV1 fi = {REDISMODULE_LOADING_PROGRESS_VERSION,
+                                     server.hz,
+                                     progress};
+        moduleFireServerEvent(REDISMODULE_EVENT_LOADING_PROGRESS,
+                              is_aof?
+                                REDISMODULE_SUBEVENT_LOADING_PROGRESS_AOF:
+                                REDISMODULE_SUBEVENT_LOADING_PROGRESS_RDB,
+                              &fi);
+        /* decide when the next event should fire. */
+        next_event = now + 1000000 / server.hz;
+    }
+}
+
+/* When a key is deleted (in dbAsyncDelete/dbSyncDelete/setKey), it
+*  will be called to tell the module which key is about to be released. */
+void moduleNotifyKeyUnlink(robj *key, robj *val, int dbid, int flags) {
+    server.lazy_expire_disabled++;
+    int subevent = REDISMODULE_SUBEVENT_KEY_DELETED;
+    if (flags & DB_FLAG_KEY_EXPIRED) {
+        subevent = REDISMODULE_SUBEVENT_KEY_EXPIRED;
+    } else if (flags & DB_FLAG_KEY_EVICTED) {
+        subevent = REDISMODULE_SUBEVENT_KEY_EVICTED;
+    } else if (flags & DB_FLAG_KEY_OVERWRITE) {
+        subevent = REDISMODULE_SUBEVENT_KEY_OVERWRITTEN;
+    }
+    KeyInfo info = {dbid, key, val, REDISMODULE_READ};
+    moduleFireServerEvent(REDISMODULE_EVENT_KEY, subevent, &info);
+
+    if (val->type == OBJ_MODULE) {
+        moduleValue *mv = val->ptr;
+        moduleType *mt = mv->type;
+        /* We prefer to use the enhanced version. */
+        if (mt->unlink2 != NULL) {
+            RedisModuleKeyOptCtx ctx = {key, NULL, dbid, -1};
+            mt->unlink2(&ctx,mv->value);
+        } else if (mt->unlink != NULL) {
+            mt->unlink(key,mv->value);
+        }
+    }
+    server.lazy_expire_disabled--;
+}
+
+/* Return the free_effort of the module, it will automatically choose to call 
+ * `free_effort` or `free_effort2`, and the default return value is 1.
+ * value of 0 means very high effort (always asynchronous freeing). */
+size_t moduleGetFreeEffort(robj *key, robj *val, int dbid) {
+    moduleValue *mv = val->ptr;
+    moduleType *mt = mv->type;
+    size_t effort = 1;
+    /* We prefer to use the enhanced version. */
+    if (mt->free_effort2 != NULL) {
+        RedisModuleKeyOptCtx ctx = {key, NULL, dbid, -1};
+        effort = mt->free_effort2(&ctx,mv->value);
+    } else if (mt->free_effort != NULL) {
+        effort = mt->free_effort(key,mv->value);
+    }  
+
+    return effort;
+}
+
+/* Return the memory usage of the module, it will automatically choose to call 
+ * `mem_usage` or `mem_usage2`, and the default return value is 0. */
+size_t moduleGetMemUsage(robj *key, robj *val, size_t sample_size, int dbid) {
+    moduleValue *mv = val->ptr;
+    moduleType *mt = mv->type;
+    size_t size = 0;
+    /* We prefer to use the enhanced version. */
+    if (mt->mem_usage2 != NULL) {
+        RedisModuleKeyOptCtx ctx = {key, NULL, dbid, -1};
+        size = mt->mem_usage2(&ctx, mv->value, sample_size);
+    } else if (mt->mem_usage != NULL) {
+        size = mt->mem_usage(mv->value);
+    } 
+
+    return size;
+}
+
+/* --------------------------------------------------------------------------
+ * Modules API internals
+ * -------------------------------------------------------------------------- */
+
+/* server.moduleapi dictionary type. Only uses plain C strings since
+ * this gets queries from modules. */
+
+uint64_t dictCStringKeyHash(const void *key) {
+    return dictGenHashFunction((unsigned char*)key, strlen((char*)key));
+}
+
+int dictCStringKeyCompare(dict *d, const void *key1, const void *key2) {
+    UNUSED(d);
+    return strcmp(key1,key2) == 0;
+}
+
+dictType moduleAPIDictType = {
+    dictCStringKeyHash,        /* hash function */
+    NULL,                      /* key dup */
+    NULL,                      /* val dup */
+    dictCStringKeyCompare,     /* key compare */
+    NULL,                      /* key destructor */
+    NULL,                      /* val destructor */
+    NULL                       /* allow to expand */
+};
+
+int moduleRegisterApi(const char *funcname, void *funcptr) {
+    return dictAdd(server.moduleapi, (char*)funcname, funcptr);
+}
+
+#define REGISTER_API(name) \
+    moduleRegisterApi("RedisModule_" #name, (void *)(unsigned long)RM_ ## name)
+
+/* Global initialization at Redis startup. */
+void moduleRegisterCoreAPI(void);
+
+/* Currently, this function is just a placeholder for the module system
+ * initialization steps that need to be run after server initialization.
+ * A previous issue, selectDb() in createClient() requires that server.db has
+ * been initialized, see #7323. */
+void moduleInitModulesSystemLast(void) {
+}
+
+
+dictType sdsKeyValueHashDictType = {
+    dictSdsCaseHash,            /* hash function */
+    NULL,                       /* key dup */
+    NULL,                       /* val dup */
+    dictSdsKeyCaseCompare,      /* key compare */
+    dictSdsDestructor,          /* key destructor */
+    dictSdsDestructor,          /* val destructor */
+    NULL                        /* allow to expand */
+};
+
+void moduleInitModulesSystem(void) {
+    moduleUnblockedClients = listCreate();
+    server.loadmodule_queue = listCreate();
+    server.module_configs_queue = dictCreate(&sdsKeyValueHashDictType);
+    modules = dictCreate(&modulesDictType);
+    moduleAuthCallbacks = listCreate();
+
+    /* Set up the keyspace notification subscriber list and static client */
+    moduleKeyspaceSubscribers = listCreate();
+
+    modulePostExecUnitJobs = listCreate();
+
+    /* Set up filter list */
+    moduleCommandFilters = listCreate();
+
+    moduleRegisterCoreAPI();
+
+    /* Create a pipe for module threads to be able to wake up the redis main thread.
+     * Make the pipe non blocking. This is just a best effort aware mechanism
+     * and we do not want to block not in the read nor in the write half.
+     * Enable close-on-exec flag on pipes in case of the fork-exec system calls in
+     * sentinels or redis servers. */
+    if (anetPipe(server.module_pipe, O_CLOEXEC|O_NONBLOCK, O_CLOEXEC|O_NONBLOCK) == -1) {
+        serverLog(LL_WARNING,
+            "Can't create the pipe for module threads: %s", strerror(errno));
+        exit(1);
+    }
+
+    /* Create the timers radix tree. */
+    Timers = raxNew();
+
+    /* Setup the event listeners data structures. */
+    RedisModule_EventListeners = listCreate();
+
+    /* Making sure moduleEventVersions is synced with the number of events. */
+    serverAssert(sizeof(moduleEventVersions)/sizeof(moduleEventVersions[0]) == _REDISMODULE_EVENT_NEXT);
+
+    /* Our thread-safe contexts GIL must start with already locked:
+     * it is just unlocked when it's safe. */
+    pthread_mutex_lock(&moduleGIL);
+}
+
+void modulesCron(void) {
+    /* Check number of temporary clients in the pool and free the unused ones
+     * since the last cron. moduleTempClientMinCount tracks minimum count of
+     * clients in the pool since the last cron. This is the number of clients
+     * that we didn't use for the last cron period. */
+
+    /* Limit the max client count to be freed at once to avoid latency spikes.*/
+    int iteration = 50;
+    /* We are freeing clients if we have more than 8 unused clients. Keeping
+     * small amount of clients to avoid client allocation costs if temporary
+     * clients are required after some idle period. */
+    const unsigned int min_client = 8;
+    while (iteration > 0 && moduleTempClientCount > 0 && moduleTempClientMinCount > min_client) {
+        client *c = moduleTempClients[--moduleTempClientCount];
+        freeClient(c);
+        iteration--;
+        moduleTempClientMinCount--;
+    }
+    moduleTempClientMinCount = moduleTempClientCount;
+
+    /* Shrink moduleTempClients array itself if it is wasting some space */
+    if (moduleTempClientCap > 32 && moduleTempClientCap > moduleTempClientCount * 4) {
+        moduleTempClientCap /= 4;
+        moduleTempClients = zrealloc(moduleTempClients,sizeof(client*)*moduleTempClientCap);
+    }
+}
+
+void moduleLoadQueueEntryFree(struct moduleLoadQueueEntry *loadmod) {
+    if (!loadmod) return;
+    sdsfree(loadmod->path);
+    for (int i = 0; i < loadmod->argc; i++) {
+        decrRefCount(loadmod->argv[i]);
+    }
+    zfree(loadmod->argv);
+    zfree(loadmod);
+}
+
+/* Remove Module Configs from standardConfig array in config.c */
+void moduleRemoveConfigs(RedisModule *module) {
+    listIter li;
+    listNode *ln;
+    listRewind(module->module_configs, &li);
+    while ((ln = listNext(&li))) {
+        ModuleConfig *config = listNodeValue(ln);
+        sds module_name = sdsnew(module->name);
+        sds full_name = sdscat(sdscat(module_name, "."), config->name); /* ModuleName.ModuleConfig */
+        removeConfig(full_name);
+        sdsfree(full_name);
+    }
+}
+
+/* Load all the modules in the server.loadmodule_queue list, which is
+ * populated by `loadmodule` directives in the configuration file.
+ * We can't load modules directly when processing the configuration file
+ * because the server must be fully initialized before loading modules.
+ *
+ * The function aborts the server on errors, since to start with missing
+ * modules is not considered sane: clients may rely on the existence of
+ * given commands, loading AOF also may need some modules to exist, and
+ * if this instance is a slave, it must understand commands from master. */
+void moduleLoadFromQueue(void) {
+    listIter li;
+    listNode *ln;
+
+    listRewind(server.loadmodule_queue,&li);
+    while((ln = listNext(&li))) {
+        struct moduleLoadQueueEntry *loadmod = ln->value;
+        if (moduleLoad(loadmod->path,(void **)loadmod->argv,loadmod->argc, 0)
+            == C_ERR)
+        {
+            serverLog(LL_WARNING,
+                "Can't load module from %s: server aborting",
+                loadmod->path);
+            exit(1);
+        }
+        moduleLoadQueueEntryFree(loadmod);
+        listDelNode(server.loadmodule_queue, ln);
+    }
+    if (dictSize(server.module_configs_queue)) {
+        serverLog(LL_WARNING, "Module Configuration detected without loadmodule directive or no ApplyConfig call: aborting");
+        exit(1);
+    }
+}
+
+void moduleFreeModuleStructure(struct RedisModule *module) {
+    listRelease(module->types);
+    listRelease(module->filters);
+    listRelease(module->usedby);
+    listRelease(module->using);
+    listRelease(module->module_configs);
+    sdsfree(module->name);
+    moduleLoadQueueEntryFree(module->loadmod);
+    zfree(module);
+}
+
+void moduleFreeArgs(struct redisCommandArg *args, int num_args) {
+    for (int j = 0; j < num_args; j++) {
+        zfree((char *)args[j].name);
+        zfree((char *)args[j].token);
+        zfree((char *)args[j].summary);
+        zfree((char *)args[j].since);
+        zfree((char *)args[j].deprecated_since);
+        zfree((char *)args[j].display_text);
+
+        if (args[j].subargs) {
+            moduleFreeArgs(args[j].subargs, args[j].num_args);
+        }
+    }
+    zfree(args);
+}
+
+/* Free the command registered with the specified module.
+ * On success C_OK is returned, otherwise C_ERR is returned.
+ *
+ * Note that caller needs to handle the deletion of the command table dict,
+ * and after that needs to free the command->fullname and the command itself.
+ */
+int moduleFreeCommand(struct RedisModule *module, struct redisCommand *cmd) {
+    if (cmd->proc != RedisModuleCommandDispatcher)
+        return C_ERR;
+
+    RedisModuleCommand *cp = cmd->module_cmd;
+    if (cp->module != module)
+        return C_ERR;
+
+    /* Free everything except cmd->fullname and cmd itself. */
+    for (int j = 0; j < cmd->key_specs_num; j++) {
+        if (cmd->key_specs[j].notes)
+            zfree((char *)cmd->key_specs[j].notes);
+        if (cmd->key_specs[j].begin_search_type == KSPEC_BS_KEYWORD)
+            zfree((char *)cmd->key_specs[j].bs.keyword.keyword);
+    }
+    zfree(cmd->key_specs);
+    for (int j = 0; cmd->tips && cmd->tips[j]; j++)
+        zfree((char *)cmd->tips[j]);
+    zfree(cmd->tips);
+    for (int j = 0; cmd->history && cmd->history[j].since; j++) {
+        zfree((char *)cmd->history[j].since);
+        zfree((char *)cmd->history[j].changes);
+    }
+    zfree(cmd->history);
+    zfree((char *)cmd->summary);
+    zfree((char *)cmd->since);
+    zfree((char *)cmd->deprecated_since);
+    zfree((char *)cmd->complexity);
+    if (cmd->latency_histogram) {
+        hdr_close(cmd->latency_histogram);
+        cmd->latency_histogram = NULL;
+    }
+    moduleFreeArgs(cmd->args, cmd->num_args);
+    zfree(cp);
+
+    if (cmd->subcommands_dict) {
+        dictEntry *de;
+        dictIterator *di = dictGetSafeIterator(cmd->subcommands_dict);
+        while ((de = dictNext(di)) != NULL) {
+            struct redisCommand *sub = dictGetVal(de);
+            if (moduleFreeCommand(module, sub) != C_OK) continue;
+
+            serverAssert(dictDelete(cmd->subcommands_dict, sub->declared_name) == DICT_OK);
+            sdsfree((sds)sub->declared_name);
+            sdsfree(sub->fullname);
+            zfree(sub);
+        }
+        dictReleaseIterator(di);
+        dictRelease(cmd->subcommands_dict);
+    }
+
+    return C_OK;
+}
+
+void moduleUnregisterCommands(struct RedisModule *module) {
+    /* Unregister all the commands registered by this module. */
+    dictIterator *di = dictGetSafeIterator(server.commands);
+    dictEntry *de;
+    while ((de = dictNext(di)) != NULL) {
+        struct redisCommand *cmd = dictGetVal(de);
+        if (moduleFreeCommand(module, cmd) != C_OK) continue;
+
+        serverAssert(dictDelete(server.commands, cmd->fullname) == DICT_OK);
+        serverAssert(dictDelete(server.orig_commands, cmd->fullname) == DICT_OK);
+        sdsfree((sds)cmd->declared_name);
+        sdsfree(cmd->fullname);
+        zfree(cmd);
+    }
+    dictReleaseIterator(di);
+}
+
+/* We parse argv to add sds "NAME VALUE" pairs to the server.module_configs_queue list of configs.
+ * We also increment the module_argv pointer to just after ARGS if there are args, otherwise
+ * we set it to NULL */
+int parseLoadexArguments(RedisModuleString ***module_argv, int *module_argc) {
+    int args_specified = 0;
+    RedisModuleString **argv = *module_argv;
+    int argc = *module_argc;
+    for (int i = 0; i < argc; i++) {
+        char *arg_val = argv[i]->ptr;
+        if (!strcasecmp(arg_val, "CONFIG")) {
+            if (i + 2 >= argc) {
+                serverLog(LL_NOTICE, "CONFIG specified without name value pair");
+                return REDISMODULE_ERR;
+            }
+            sds name = sdsdup(argv[i + 1]->ptr);
+            sds value = sdsdup(argv[i + 2]->ptr);
+            if (!dictReplace(server.module_configs_queue, name, value)) sdsfree(name);
+            i += 2;
+        } else if (!strcasecmp(arg_val, "ARGS")) {
+            args_specified = 1;
+            i++;
+            if (i >= argc) {
+                *module_argv = NULL;
+                *module_argc = 0;
+            } else {
+                *module_argv = argv + i;
+                *module_argc = argc - i;
+            }
+            break;
+        } else {
+            serverLog(LL_NOTICE, "Syntax Error from arguments to loadex around %s.", arg_val);
+            return REDISMODULE_ERR;
+        }
+    }
+    if (!args_specified) {
+        *module_argv = NULL;
+        *module_argc = 0;
+    }
+    return REDISMODULE_OK;
+}
+
+/* Unregister module-related things, called when moduleLoad fails or moduleUnload. */
+void moduleUnregisterCleanup(RedisModule *module) {
+    moduleFreeAuthenticatedClients(module);
+    moduleUnregisterCommands(module);
+    moduleUnsubscribeNotifications(module);
+    moduleUnregisterSharedAPI(module);
+    moduleUnregisterUsedAPI(module);
+    moduleUnregisterFilters(module);
+    moduleUnsubscribeAllServerEvents(module);
+    moduleRemoveConfigs(module);
+    moduleUnregisterAuthCBs(module);
+}
+
+/* Load a module and initialize it. On success C_OK is returned, otherwise
+ * C_ERR is returned. */
+int moduleLoad(const char *path, void **module_argv, int module_argc, int is_loadex) {
+    int (*onload)(void *, void **, int);
+    void *handle;
+
+    struct stat st;
+    if (stat(path, &st) == 0) {
+        /* This check is best effort */
+        if (!(st.st_mode & (S_IXUSR  | S_IXGRP | S_IXOTH))) {
+            serverLog(LL_WARNING, "Module %s failed to load: It does not have execute permissions.", path);
+            return C_ERR;
+        }
+    }
+
+    handle = dlopen(path,RTLD_NOW|RTLD_LOCAL);
+    if (handle == NULL) {
+        serverLog(LL_WARNING, "Module %s failed to load: %s", path, dlerror());
+        return C_ERR;
+    }
+    onload = (int (*)(void *, void **, int))(unsigned long) dlsym(handle,"RedisModule_OnLoad");
+    if (onload == NULL) {
+        dlclose(handle);
+        serverLog(LL_WARNING,
+            "Module %s does not export RedisModule_OnLoad() "
+            "symbol. Module not loaded.",path);
+        return C_ERR;
+    }
+    RedisModuleCtx ctx;
+    moduleCreateContext(&ctx, NULL, REDISMODULE_CTX_TEMP_CLIENT); /* We pass NULL since we don't have a module yet. */
+    if (onload((void*)&ctx,module_argv,module_argc) == REDISMODULE_ERR) {
+        serverLog(LL_WARNING,
+            "Module %s initialization failed. Module not loaded",path);
+        if (ctx.module) {
+            moduleUnregisterCleanup(ctx.module);
+            moduleFreeModuleStructure(ctx.module);
+        }
+        moduleFreeContext(&ctx);
+        dlclose(handle);
+        return C_ERR;
+    }
+
+    /* Redis module loaded! Register it. */
+    dictAdd(modules,ctx.module->name,ctx.module);
+    ctx.module->blocked_clients = 0;
+    ctx.module->handle = handle;
+    ctx.module->loadmod = zmalloc(sizeof(struct moduleLoadQueueEntry));
+    ctx.module->loadmod->path = sdsnew(path);
+    ctx.module->loadmod->argv = module_argc ? zmalloc(sizeof(robj*)*module_argc) : NULL;
+    ctx.module->loadmod->argc = module_argc;
+    for (int i = 0; i < module_argc; i++) {
+        ctx.module->loadmod->argv[i] = module_argv[i];
+        incrRefCount(ctx.module->loadmod->argv[i]);
+    }
+
+    /* If module commands have ACL categories, recompute command bits 
+     * for all existing users once the modules has been registered. */
+    if (ctx.module->num_commands_with_acl_categories) {
+        ACLRecomputeCommandBitsFromCommandRulesAllUsers();
+    }
+    serverLog(LL_NOTICE,"Module '%s' loaded from %s",ctx.module->name,path);
+    ctx.module->onload = 0;
+
+    int post_load_err = 0;
+    if (listLength(ctx.module->module_configs) && !ctx.module->configs_initialized) {
+        serverLogRaw(LL_WARNING, "Module Configurations were not set, likely a missing LoadConfigs call. Unloading the module.");
+        post_load_err = 1;
+    }
+
+    if (is_loadex && dictSize(server.module_configs_queue)) {
+        serverLogRaw(LL_WARNING, "Loadex configurations were not applied, likely due to invalid arguments. Unloading the module.");
+        post_load_err = 1;
+    }
+
+    if (post_load_err) {
+        moduleUnload(ctx.module->name, NULL);
+        moduleFreeContext(&ctx);
+        return C_ERR;
+    }
+
+    /* Fire the loaded modules event. */
+    moduleFireServerEvent(REDISMODULE_EVENT_MODULE_CHANGE,
+                          REDISMODULE_SUBEVENT_MODULE_LOADED,
+                          ctx.module);
+
+    moduleFreeContext(&ctx);
+    return C_OK;
+}
+
+/* Unload the module registered with the specified name. On success
+ * C_OK is returned, otherwise C_ERR is returned and errmsg is set
+ * with an appropriate message. */
+int moduleUnload(sds name, const char **errmsg) {
+    struct RedisModule *module = dictFetchValue(modules,name);
+
+    if (module == NULL) {
+        *errmsg = "no such module with that name";
+        return C_ERR;
+    } else if (listLength(module->types)) {
+        *errmsg = "the module exports one or more module-side data "
+                  "types, can't unload";
+        return C_ERR;
+    } else if (listLength(module->usedby)) {
+        *errmsg = "the module exports APIs used by other modules. "
+                  "Please unload them first and try again";
+        return C_ERR;
+    } else if (module->blocked_clients) {
+        *errmsg = "the module has blocked clients. "
+                  "Please wait for them to be unblocked and try again";
+        return C_ERR;
+    } else if (moduleHoldsTimer(module)) {
+        *errmsg = "the module holds timer that is not fired. "
+                  "Please stop the timer or wait until it fires.";
+        return C_ERR;
+    }
+
+    /* Give module a chance to clean up. */
+    int (*onunload)(void *);
+    onunload = (int (*)(void *))(unsigned long) dlsym(module->handle, "RedisModule_OnUnload");
+    if (onunload) {
+        RedisModuleCtx ctx;
+        moduleCreateContext(&ctx, module, REDISMODULE_CTX_TEMP_CLIENT);
+        int unload_status = onunload((void*)&ctx);
+        moduleFreeContext(&ctx);
+
+        if (unload_status == REDISMODULE_ERR) {
+            serverLog(LL_WARNING, "Module %s OnUnload failed.  Unload canceled.", name);
+            errno = ECANCELED;
+            return C_ERR;
+        }
+    }
+
+    moduleUnregisterCleanup(module);
+
+    /* Unload the dynamic library. */
+    if (dlclose(module->handle) == -1) {
+        char *error = dlerror();
+        if (error == NULL) error = "Unknown error";
+        serverLog(LL_WARNING,"Error when trying to close the %s module: %s",
+            module->name, error);
+    }
+
+    /* Fire the unloaded modules event. */
+    moduleFireServerEvent(REDISMODULE_EVENT_MODULE_CHANGE,
+                          REDISMODULE_SUBEVENT_MODULE_UNLOADED,
+                          module);
+
+    /* Remove from list of modules. */
+    serverLog(LL_NOTICE,"Module %s unloaded",module->name);
+    dictDelete(modules,module->name);
+    module->name = NULL; /* The name was already freed by dictDelete(). */
+    moduleFreeModuleStructure(module);
+
+    /* Recompute command bits for all users once the modules has been completely unloaded. */
+    ACLRecomputeCommandBitsFromCommandRulesAllUsers();
+    return C_OK;
+}
+
+void modulePipeReadable(aeEventLoop *el, int fd, void *privdata, int mask) {
+    UNUSED(el);
+    UNUSED(fd);
+    UNUSED(mask);
+    UNUSED(privdata);
+
+    char buf[128];
+    while (read(fd, buf, sizeof(buf)) == sizeof(buf));
+
+    /* Handle event loop events if pipe was written from event loop API */
+    eventLoopHandleOneShotEvents();
+}
+
+/* Helper function for the MODULE and HELLO command: send the list of the
+ * loaded modules to the client. */
+void addReplyLoadedModules(client *c) {
+    dictIterator *di = dictGetIterator(modules);
+    dictEntry *de;
+
+    addReplyArrayLen(c,dictSize(modules));
+    while ((de = dictNext(di)) != NULL) {
+        sds name = dictGetKey(de);
+        struct RedisModule *module = dictGetVal(de);
+        sds path = module->loadmod->path;
+        addReplyMapLen(c,4);
+        addReplyBulkCString(c,"name");
+        addReplyBulkCBuffer(c,name,sdslen(name));
+        addReplyBulkCString(c,"ver");
+        addReplyLongLong(c,module->ver);
+        addReplyBulkCString(c,"path");
+        addReplyBulkCBuffer(c,path,sdslen(path));
+        addReplyBulkCString(c,"args");
+        addReplyArrayLen(c,module->loadmod->argc);
+        for (int i = 0; i < module->loadmod->argc; i++) {
+            addReplyBulk(c,module->loadmod->argv[i]);
+        }
+    }
+    dictReleaseIterator(di);
+}
+
+/* Helper for genModulesInfoString(): given a list of modules, return
+ * an SDS string in the form "[modulename|modulename2|...]" */
+sds genModulesInfoStringRenderModulesList(list *l) {
+    listIter li;
+    listNode *ln;
+    listRewind(l,&li);
+    sds output = sdsnew("[");
+    while((ln = listNext(&li))) {
+        RedisModule *module = ln->value;
+        output = sdscat(output,module->name);
+        if (ln != listLast(l))
+            output = sdscat(output,"|");
+    }
+    output = sdscat(output,"]");
+    return output;
+}
+
+/* Helper for genModulesInfoString(): render module options as an SDS string. */
+sds genModulesInfoStringRenderModuleOptions(struct RedisModule *module) {
+    sds output = sdsnew("[");
+    if (module->options & REDISMODULE_OPTIONS_HANDLE_IO_ERRORS)
+        output = sdscat(output,"handle-io-errors|");
+    if (module->options & REDISMODULE_OPTIONS_HANDLE_REPL_ASYNC_LOAD)
+        output = sdscat(output,"handle-repl-async-load|");
+    if (module->options & REDISMODULE_OPTION_NO_IMPLICIT_SIGNAL_MODIFIED)
+        output = sdscat(output,"no-implicit-signal-modified|");
+    output = sdstrim(output,"|");
+    output = sdscat(output,"]");
+    return output;
+}
+
+
+/* Helper function for the INFO command: adds loaded modules as to info's
+ * output.
+ *
+ * After the call, the passed sds info string is no longer valid and all the
+ * references must be substituted with the new pointer returned by the call. */
+sds genModulesInfoString(sds info) {
+    dictIterator *di = dictGetIterator(modules);
+    dictEntry *de;
+
+    while ((de = dictNext(di)) != NULL) {
+        sds name = dictGetKey(de);
+        struct RedisModule *module = dictGetVal(de);
+
+        sds usedby = genModulesInfoStringRenderModulesList(module->usedby);
+        sds using = genModulesInfoStringRenderModulesList(module->using);
+        sds options = genModulesInfoStringRenderModuleOptions(module);
+        info = sdscatfmt(info,
+            "module:name=%S,ver=%i,api=%i,filters=%i,"
+            "usedby=%S,using=%S,options=%S\r\n",
+                name, module->ver, module->apiver,
+                (int)listLength(module->filters), usedby, using, options);
+        sdsfree(usedby);
+        sdsfree(using);
+        sdsfree(options);
+    }
+    dictReleaseIterator(di);
+    return info;
+}
+
+/* --------------------------------------------------------------------------
+ * Module Configurations API internals
+ * -------------------------------------------------------------------------- */
+	 
+/* Check if the configuration name is already registered */
+int isModuleConfigNameRegistered(RedisModule *module, sds name) {
+    listNode *match = listSearchKey(module->module_configs, (void *) name);
+    return match != NULL;
+}
+
+/* Assert that the flags passed into the RM_RegisterConfig Suite are valid */
+int moduleVerifyConfigFlags(unsigned int flags, configType type) {
+    if ((flags & ~(REDISMODULE_CONFIG_DEFAULT
+                    | REDISMODULE_CONFIG_IMMUTABLE
+                    | REDISMODULE_CONFIG_SENSITIVE
+                    | REDISMODULE_CONFIG_HIDDEN
+                    | REDISMODULE_CONFIG_PROTECTED
+                    | REDISMODULE_CONFIG_DENY_LOADING
+                    | REDISMODULE_CONFIG_BITFLAGS
+                    | REDISMODULE_CONFIG_MEMORY))) {
+        serverLogRaw(LL_WARNING, "Invalid flag(s) for configuration");
+        return REDISMODULE_ERR;
+    }
+    if (type != NUMERIC_CONFIG && flags & REDISMODULE_CONFIG_MEMORY) {
+        serverLogRaw(LL_WARNING, "Numeric flag provided for non-numeric configuration.");
+        return REDISMODULE_ERR;
+    }
+    if (type != ENUM_CONFIG && flags & REDISMODULE_CONFIG_BITFLAGS) {
+        serverLogRaw(LL_WARNING, "Enum flag provided for non-enum configuration.");
+        return REDISMODULE_ERR;
+    }
+    return REDISMODULE_OK;
+}
+
+int moduleVerifyConfigName(sds name) {
+    if (sdslen(name) == 0) {
+        serverLogRaw(LL_WARNING, "Module config names cannot be an empty string.");
+        return REDISMODULE_ERR;
+    }
+    for (size_t i = 0 ; i < sdslen(name) ; ++i) {
+        char curr_char = name[i];
+        if ((curr_char >= 'a' && curr_char <= 'z') ||
+            (curr_char >= 'A' && curr_char <= 'Z') ||
+            (curr_char >= '0' && curr_char <= '9') ||
+            (curr_char == '_') || (curr_char == '-'))
+        {
+            continue;
+        }
+        serverLog(LL_WARNING, "Invalid character %c in Module Config name %s.", curr_char, name);
+        return REDISMODULE_ERR;
+    }
+    return REDISMODULE_OK;
+}
+
+/* This is a series of set functions for each type that act as dispatchers for 
+ * config.c to call module set callbacks. */
+#define CONFIG_ERR_SIZE 256
+static char configerr[CONFIG_ERR_SIZE];
+static void propagateErrorString(RedisModuleString *err_in, const char **err) {
+    if (err_in) {
+        redis_strlcpy(configerr, err_in->ptr, CONFIG_ERR_SIZE);
+        decrRefCount(err_in);
+        *err = configerr;
+    }
+}
+
+int setModuleBoolConfig(ModuleConfig *config, int val, const char **err) {
+    RedisModuleString *error = NULL;
+    int return_code = config->set_fn.set_bool(config->name, val, config->privdata, &error);
+    propagateErrorString(error, err);
+    return return_code == REDISMODULE_OK ? 1 : 0;
+}
+
+int setModuleStringConfig(ModuleConfig *config, sds strval, const char **err) {
+    RedisModuleString *error = NULL;
+    RedisModuleString *new = createStringObject(strval, sdslen(strval));
+    int return_code = config->set_fn.set_string(config->name, new, config->privdata, &error);
+    propagateErrorString(error, err);
+    decrRefCount(new);
+    return return_code == REDISMODULE_OK ? 1 : 0;
+}
+
+int setModuleEnumConfig(ModuleConfig *config, int val, const char **err) {
+    RedisModuleString *error = NULL;
+    int return_code = config->set_fn.set_enum(config->name, val, config->privdata, &error);
+    propagateErrorString(error, err);
+    return return_code == REDISMODULE_OK ? 1 : 0;
+}
+
+int setModuleNumericConfig(ModuleConfig *config, long long val, const char **err) {
+    RedisModuleString *error = NULL;
+    int return_code = config->set_fn.set_numeric(config->name, val, config->privdata, &error);
+    propagateErrorString(error, err);
+    return return_code == REDISMODULE_OK ? 1 : 0;
+}
+
+/* This is a series of get functions for each type that act as dispatchers for 
+ * config.c to call module set callbacks. */
+int getModuleBoolConfig(ModuleConfig *module_config) {
+    return module_config->get_fn.get_bool(module_config->name, module_config->privdata);
+}
+
+sds getModuleStringConfig(ModuleConfig *module_config) {
+    RedisModuleString *val = module_config->get_fn.get_string(module_config->name, module_config->privdata);
+    return val ? sdsdup(val->ptr) : NULL;
+}
+
+int getModuleEnumConfig(ModuleConfig *module_config) {
+    return module_config->get_fn.get_enum(module_config->name, module_config->privdata);
+}
+
+long long getModuleNumericConfig(ModuleConfig *module_config) {
+    return module_config->get_fn.get_numeric(module_config->name, module_config->privdata);
+}
+
+/* This function takes a module and a list of configs stored as sds NAME VALUE pairs.
+ * It attempts to call set on each of these configs. */
+int loadModuleConfigs(RedisModule *module) {
+    listIter li;
+    listNode *ln;
+    const char *err = NULL;
+    listRewind(module->module_configs, &li);
+    while ((ln = listNext(&li))) {
+        ModuleConfig *module_config = listNodeValue(ln);
+        sds config_name = sdscatfmt(sdsempty(), "%s.%s", module->name, module_config->name);
+        dictEntry *config_argument = dictFind(server.module_configs_queue, config_name);
+        if (config_argument) {
+            if (!performModuleConfigSetFromName(dictGetKey(config_argument), dictGetVal(config_argument), &err)) {
+                serverLog(LL_WARNING, "Issue during loading of configuration %s : %s", (sds) dictGetKey(config_argument), err);
+                sdsfree(config_name);
+                dictEmpty(server.module_configs_queue, NULL);
+                return REDISMODULE_ERR;
+            }
+        } else {
+            if (!performModuleConfigSetDefaultFromName(config_name, &err)) {
+                serverLog(LL_WARNING, "Issue attempting to set default value of configuration %s : %s", module_config->name, err);
+                sdsfree(config_name);
+                dictEmpty(server.module_configs_queue, NULL);
+                return REDISMODULE_ERR;
+            }
+        }
+        dictDelete(server.module_configs_queue, config_name);
+        sdsfree(config_name);
+    }
+    module->configs_initialized = 1;
+    return REDISMODULE_OK;
+}
+
+/* Add module_config to the list if the apply and privdata do not match one already in it. */
+void addModuleConfigApply(list *module_configs, ModuleConfig *module_config) {
+    if (!module_config->apply_fn) return;
+    listIter li;
+    listNode *ln;
+    ModuleConfig *pending_apply;
+    listRewind(module_configs, &li);
+    while ((ln = listNext(&li))) {
+        pending_apply = listNodeValue(ln);
+        if (pending_apply->apply_fn == module_config->apply_fn && pending_apply->privdata == module_config->privdata) {
+            return;
+        }
+    }
+    listAddNodeTail(module_configs, module_config);
+}
+
+/* Call apply on all module configs specified in set, if an apply function was specified at registration time. */
+int moduleConfigApplyConfig(list *module_configs, const char **err, const char **err_arg_name) {
+    if (!listLength(module_configs)) return 1;
+    listIter li;
+    listNode *ln;
+    ModuleConfig *module_config;
+    RedisModuleString *error = NULL;
+    RedisModuleCtx ctx;
+
+    listRewind(module_configs, &li);
+    while ((ln = listNext(&li))) {
+        module_config = listNodeValue(ln);
+        moduleCreateContext(&ctx, module_config->module, REDISMODULE_CTX_NONE);
+        if (module_config->apply_fn(&ctx, module_config->privdata, &error)) {
+            if (err_arg_name) *err_arg_name = module_config->name;
+            propagateErrorString(error, err);
+            moduleFreeContext(&ctx);
+            return 0;
+        }
+        moduleFreeContext(&ctx);
+    }
+    return 1;
+}
+
+/* --------------------------------------------------------------------------
+ * ## Module Configurations API
+ * -------------------------------------------------------------------------- */
+
+/* Create a module config object. */
+ModuleConfig *createModuleConfig(sds name, RedisModuleConfigApplyFunc apply_fn, void *privdata, RedisModule *module) {
+    ModuleConfig *new_config = zmalloc(sizeof(ModuleConfig));
+    new_config->name = sdsdup(name);
+    new_config->apply_fn = apply_fn;
+    new_config->privdata = privdata;
+    new_config->module = module;
+    return new_config;
+}
+
+int moduleConfigValidityCheck(RedisModule *module, sds name, unsigned int flags, configType type) {
+    if (!module->onload) {
+        errno = EBUSY;
+        return REDISMODULE_ERR;
+    }
+    if (moduleVerifyConfigFlags(flags, type) || moduleVerifyConfigName(name)) {
+        errno = EINVAL;
+        return REDISMODULE_ERR;
+    }
+    if (isModuleConfigNameRegistered(module, name)) {
+        serverLog(LL_WARNING, "Configuration by the name: %s already registered", name);
+        errno = EALREADY;
+        return REDISMODULE_ERR;
+    }
+    return REDISMODULE_OK;
+}
+
+unsigned int maskModuleConfigFlags(unsigned int flags) {
+    unsigned int new_flags = 0;
+    if (flags & REDISMODULE_CONFIG_DEFAULT) new_flags |= MODIFIABLE_CONFIG;
+    if (flags & REDISMODULE_CONFIG_IMMUTABLE) new_flags |= IMMUTABLE_CONFIG;
+    if (flags & REDISMODULE_CONFIG_HIDDEN) new_flags |= HIDDEN_CONFIG;
+    if (flags & REDISMODULE_CONFIG_PROTECTED) new_flags |= PROTECTED_CONFIG;
+    if (flags & REDISMODULE_CONFIG_DENY_LOADING) new_flags |= DENY_LOADING_CONFIG;
+    return new_flags;
+}
+
+unsigned int maskModuleNumericConfigFlags(unsigned int flags) {
+    unsigned int new_flags = 0;
+    if (flags & REDISMODULE_CONFIG_MEMORY) new_flags |= MEMORY_CONFIG;
+    return new_flags;
+}
+
+unsigned int maskModuleEnumConfigFlags(unsigned int flags) {
+    unsigned int new_flags = 0;
+    if (flags & REDISMODULE_CONFIG_BITFLAGS) new_flags |= MULTI_ARG_CONFIG;
+    return new_flags;
+}
+
+/* Create a string config that Redis users can interact with via the Redis config file,
+ * `CONFIG SET`, `CONFIG GET`, and `CONFIG REWRITE` commands.
+ *
+ * The actual config value is owned by the module, and the `getfn`, `setfn` and optional
+ * `applyfn` callbacks that are provided to Redis in order to access or manipulate the
+ * value. The `getfn` callback retrieves the value from the module, while the `setfn`
+ * callback provides a value to be stored into the module config.
+ * The optional `applyfn` callback is called after a `CONFIG SET` command modified one or
+ * more configs using the `setfn` callback and can be used to atomically apply a config
+ * after several configs were changed together.
+ * If there are multiple configs with `applyfn` callbacks set by a single `CONFIG SET`
+ * command, they will be deduplicated if their `applyfn` function and `privdata` pointers
+ * are identical, and the callback will only be run once.
+ * Both the `setfn` and `applyfn` can return an error if the provided value is invalid or
+ * cannot be used.
+ * The config also declares a type for the value that is validated by Redis and
+ * provided to the module. The config system provides the following types:
+ *
+ * * Redis String: Binary safe string data.
+ * * Enum: One of a finite number of string tokens, provided during registration.
+ * * Numeric: 64 bit signed integer, which also supports min and max values.
+ * * Bool: Yes or no value.
+ *
+ * The `setfn` callback is expected to return REDISMODULE_OK when the value is successfully
+ * applied. It can also return REDISMODULE_ERR if the value can't be applied, and the
+ * *err pointer can be set with a RedisModuleString error message to provide to the client.
+ * This RedisModuleString will be freed by redis after returning from the set callback.
+ *
+ * All configs are registered with a name, a type, a default value, private data that is made
+ * available in the callbacks, as well as several flags that modify the behavior of the config.
+ * The name must only contain alphanumeric characters or dashes. The supported flags are:
+ *
+ * * REDISMODULE_CONFIG_DEFAULT: The default flags for a config. This creates a config that can be modified after startup.
+ * * REDISMODULE_CONFIG_IMMUTABLE: This config can only be provided loading time.
+ * * REDISMODULE_CONFIG_SENSITIVE: The value stored in this config is redacted from all logging.
+ * * REDISMODULE_CONFIG_HIDDEN: The name is hidden from `CONFIG GET` with pattern matching.
+ * * REDISMODULE_CONFIG_PROTECTED: This config will be only be modifiable based off the value of enable-protected-configs.
+ * * REDISMODULE_CONFIG_DENY_LOADING: This config is not modifiable while the server is loading data.
+ * * REDISMODULE_CONFIG_MEMORY: For numeric configs, this config will convert data unit notations into their byte equivalent.
+ * * REDISMODULE_CONFIG_BITFLAGS: For enum configs, this config will allow multiple entries to be combined as bit flags.
+ *
+ * Default values are used on startup to set the value if it is not provided via the config file
+ * or command line. Default values are also used to compare to on a config rewrite.
+ *
+ * Notes:
+ *
+ *  1. On string config sets that the string passed to the set callback will be freed after execution and the module must retain it.
+ *  2. On string config gets the string will not be consumed and will be valid after execution.
+ *
+ * Example implementation:
+ *
+ *     RedisModuleString *strval;
+ *     int adjustable = 1;
+ *     RedisModuleString *getStringConfigCommand(const char *name, void *privdata) {
+ *         return strval;
+ *     }
+ *
+ *     int setStringConfigCommand(const char *name, RedisModuleString *new, void *privdata, RedisModuleString **err) {
+ *        if (adjustable) {
+ *            RedisModule_Free(strval);
+ *            RedisModule_RetainString(NULL, new);
+ *            strval = new;
+ *            return REDISMODULE_OK;
+ *        }
+ *        *err = RedisModule_CreateString(NULL, "Not adjustable.", 15);
+ *        return REDISMODULE_ERR;
+ *     }
+ *     ...
+ *     RedisModule_RegisterStringConfig(ctx, "string", NULL, REDISMODULE_CONFIG_DEFAULT, getStringConfigCommand, setStringConfigCommand, NULL, NULL);
+ *
+ * If the registration fails, REDISMODULE_ERR is returned and one of the following
+ * errno is set:
+ * * EBUSY: Registering the Config outside of RedisModule_OnLoad.
+ * * EINVAL: The provided flags are invalid for the registration or the name of the config contains invalid characters.
+ * * EALREADY: The provided configuration name is already used. */
+int RM_RegisterStringConfig(RedisModuleCtx *ctx, const char *name, const char *default_val, unsigned int flags, RedisModuleConfigGetStringFunc getfn, RedisModuleConfigSetStringFunc setfn, RedisModuleConfigApplyFunc applyfn, void *privdata) {
+    RedisModule *module = ctx->module;
+    sds config_name = sdsnew(name);
+    if (moduleConfigValidityCheck(module, config_name, flags, NUMERIC_CONFIG)) {
+        sdsfree(config_name);
+        return REDISMODULE_ERR;
+    }
+    ModuleConfig *new_config = createModuleConfig(config_name, applyfn, privdata, module);
+    sdsfree(config_name);
+    new_config->get_fn.get_string = getfn;
+    new_config->set_fn.set_string = setfn;
+    listAddNodeTail(module->module_configs, new_config);
+    flags = maskModuleConfigFlags(flags);
+    addModuleStringConfig(module->name, name, flags, new_config, default_val ? sdsnew(default_val) : NULL);
+    return REDISMODULE_OK;
+}
+
+/* Create a bool config that server clients can interact with via the 
+ * `CONFIG SET`, `CONFIG GET`, and `CONFIG REWRITE` commands. See 
+ * RedisModule_RegisterStringConfig for detailed information about configs. */
+int RM_RegisterBoolConfig(RedisModuleCtx *ctx, const char *name, int default_val, unsigned int flags, RedisModuleConfigGetBoolFunc getfn, RedisModuleConfigSetBoolFunc setfn, RedisModuleConfigApplyFunc applyfn, void *privdata) {
+    RedisModule *module = ctx->module;
+    sds config_name = sdsnew(name);
+    if (moduleConfigValidityCheck(module, config_name, flags, BOOL_CONFIG)) {
+        sdsfree(config_name);
+        return REDISMODULE_ERR;
+    }
+    ModuleConfig *new_config = createModuleConfig(config_name, applyfn, privdata, module);
+    sdsfree(config_name);
+    new_config->get_fn.get_bool = getfn;
+    new_config->set_fn.set_bool = setfn;
+    listAddNodeTail(module->module_configs, new_config);
+    flags = maskModuleConfigFlags(flags);
+    addModuleBoolConfig(module->name, name, flags, new_config, default_val);
+    return REDISMODULE_OK;
+}
+
+/* 
+ * Create an enum config that server clients can interact with via the 
+ * `CONFIG SET`, `CONFIG GET`, and `CONFIG REWRITE` commands. 
+ * Enum configs are a set of string tokens to corresponding integer values, where 
+ * the string value is exposed to Redis clients but the value passed Redis and the
+ * module is the integer value. These values are defined in enum_values, an array
+ * of null-terminated c strings, and int_vals, an array of enum values who has an
+ * index partner in enum_values.
+ * Example Implementation:
+ *      const char *enum_vals[3] = {"first", "second", "third"};
+ *      const int int_vals[3] = {0, 2, 4};
+ *      int enum_val = 0;
+ *
+ *      int getEnumConfigCommand(const char *name, void *privdata) {
+ *          return enum_val;
+ *      }
+ *       
+ *      int setEnumConfigCommand(const char *name, int val, void *privdata, const char **err) {
+ *          enum_val = val;
+ *          return REDISMODULE_OK;
+ *      }
+ *      ...
+ *      RedisModule_RegisterEnumConfig(ctx, "enum", 0, REDISMODULE_CONFIG_DEFAULT, enum_vals, int_vals, 3, getEnumConfigCommand, setEnumConfigCommand, NULL, NULL);
+ *
+ * Note that you can use REDISMODULE_CONFIG_BITFLAGS so that multiple enum string
+ * can be combined into one integer as bit flags, in which case you may want to
+ * sort your enums so that the preferred combinations are present first.
+ *
+ * See RedisModule_RegisterStringConfig for detailed general information about configs. */
+int RM_RegisterEnumConfig(RedisModuleCtx *ctx, const char *name, int default_val, unsigned int flags, const char **enum_values, const int *int_values, int num_enum_vals, RedisModuleConfigGetEnumFunc getfn, RedisModuleConfigSetEnumFunc setfn, RedisModuleConfigApplyFunc applyfn, void *privdata) {
+    RedisModule *module = ctx->module;
+    sds config_name = sdsnew(name);
+    if (moduleConfigValidityCheck(module, config_name, flags, ENUM_CONFIG)) {
+        sdsfree(config_name);
+        return REDISMODULE_ERR;
+    }
+    ModuleConfig *new_config = createModuleConfig(config_name, applyfn, privdata, module);
+    sdsfree(config_name);
+    new_config->get_fn.get_enum = getfn;
+    new_config->set_fn.set_enum = setfn;
+    configEnum *enum_vals = zmalloc((num_enum_vals + 1) * sizeof(configEnum));
+    for (int i = 0; i < num_enum_vals; i++) {
+        enum_vals[i].name = zstrdup(enum_values[i]);
+        enum_vals[i].val = int_values[i];
+    }
+    enum_vals[num_enum_vals].name = NULL;
+    enum_vals[num_enum_vals].val = 0;
+    listAddNodeTail(module->module_configs, new_config);
+    flags = maskModuleConfigFlags(flags) | maskModuleEnumConfigFlags(flags);
+    addModuleEnumConfig(module->name, name, flags, new_config, default_val, enum_vals);
+    return REDISMODULE_OK;
+}
+
+/*
+ * Create an integer config that server clients can interact with via the 
+ * `CONFIG SET`, `CONFIG GET`, and `CONFIG REWRITE` commands. See 
+ * RedisModule_RegisterStringConfig for detailed information about configs. */
+int RM_RegisterNumericConfig(RedisModuleCtx *ctx, const char *name, long long default_val, unsigned int flags, long long min, long long max, RedisModuleConfigGetNumericFunc getfn, RedisModuleConfigSetNumericFunc setfn, RedisModuleConfigApplyFunc applyfn, void *privdata) {
+    RedisModule *module = ctx->module;
+    sds config_name = sdsnew(name);
+    if (moduleConfigValidityCheck(module, config_name, flags, NUMERIC_CONFIG)) {
+        sdsfree(config_name);
+        return REDISMODULE_ERR;
+    }
+    ModuleConfig *new_config = createModuleConfig(config_name, applyfn, privdata, module);
+    sdsfree(config_name);
+    new_config->get_fn.get_numeric = getfn;
+    new_config->set_fn.set_numeric = setfn;
+    listAddNodeTail(module->module_configs, new_config);
+    unsigned int numeric_flags = maskModuleNumericConfigFlags(flags);
+    flags = maskModuleConfigFlags(flags);
+    addModuleNumericConfig(module->name, name, flags, new_config, default_val, numeric_flags, min, max);
+    return REDISMODULE_OK;
+}
+
+/* Applies all pending configurations on the module load. This should be called
+ * after all of the configurations have been registered for the module inside of RedisModule_OnLoad.
+ * This will return REDISMODULE_ERR if it is called outside RedisModule_OnLoad.
+ * This API needs to be called when configurations are provided in either `MODULE LOADEX`
+ * or provided as startup arguments. */
+int RM_LoadConfigs(RedisModuleCtx *ctx) {
+    if (!ctx || !ctx->module || !ctx->module->onload) {
+        return REDISMODULE_ERR;
+    }
+    RedisModule *module = ctx->module;
+    /* Load configs from conf file or arguments from loadex */
+    if (loadModuleConfigs(module)) return REDISMODULE_ERR;
+    return REDISMODULE_OK;
+}
+
+/* --------------------------------------------------------------------------
+ * ## RDB load/save API
+ * -------------------------------------------------------------------------- */
+
+#define REDISMODULE_RDB_STREAM_FILE 1
+
+typedef struct RedisModuleRdbStream {
+    int type;
+
+    union {
+        char *filename;
+    } data;
+} RedisModuleRdbStream;
+
+/* Create a stream object to save/load RDB to/from a file.
+ *
+ * This function returns a pointer to RedisModuleRdbStream which is owned
+ * by the caller. It requires a call to RM_RdbStreamFree() to free
+ * the object. */
+RedisModuleRdbStream *RM_RdbStreamCreateFromFile(const char *filename) {
+    RedisModuleRdbStream *stream = zmalloc(sizeof(*stream));
+    stream->type = REDISMODULE_RDB_STREAM_FILE;
+    stream->data.filename = zstrdup(filename);
+    return stream;
+}
+
+/* Release an RDB stream object. */
+void RM_RdbStreamFree(RedisModuleRdbStream *stream) {
+    switch (stream->type) {
+    case REDISMODULE_RDB_STREAM_FILE:
+        zfree(stream->data.filename);
+        break;
+    default:
+        serverAssert(0);
+        break;
+    }
+    zfree(stream);
+}
+
+/* Load RDB file from the `stream`. Dataset will be cleared first and then RDB
+ * file will be loaded.
+ *
+ * `flags` must be zero. This parameter is for future use.
+ *
+ * On success REDISMODULE_OK is returned, otherwise REDISMODULE_ERR is returned
+ * and errno is set accordingly.
+ *
+ * Example:
+ *
+ *     RedisModuleRdbStream *s = RedisModule_RdbStreamCreateFromFile("exp.rdb");
+ *     RedisModule_RdbLoad(ctx, s, 0);
+ *     RedisModule_RdbStreamFree(s);
+ */
+int RM_RdbLoad(RedisModuleCtx *ctx, RedisModuleRdbStream *stream, int flags) {
+    UNUSED(ctx);
+
+    if (!stream || flags != 0) {
+        errno = EINVAL;
+        return REDISMODULE_ERR;
+    }
+
+    /* Not allowed on replicas. */
+    if (server.masterhost != NULL) {
+        errno = ENOTSUP;
+        return REDISMODULE_ERR;
+    }
+
+    /* Drop replicas if exist. */
+    disconnectSlaves();
+    freeReplicationBacklog();
+
+    if (server.aof_state != AOF_OFF) stopAppendOnly();
+
+    /* Kill existing RDB fork as it is saving outdated data. Also killing it
+     * will prevent COW memory issue. */
+    if (server.child_type == CHILD_TYPE_RDB) killRDBChild();
+
+    emptyData(-1,EMPTYDB_NO_FLAGS,NULL);
+
+    /* rdbLoad() can go back to the networking and process network events. If
+     * RM_RdbLoad() is called inside a command callback, we don't want to
+     * process the current client. Otherwise, we may free the client or try to
+     * process next message while we are already in the command callback. */
+    if (server.current_client) protectClient(server.current_client);
+
+    serverAssert(stream->type == REDISMODULE_RDB_STREAM_FILE);
+    int ret = rdbLoad(stream->data.filename,NULL,RDBFLAGS_NONE);
+
+    if (server.current_client) unprotectClient(server.current_client);
+    if (server.aof_state != AOF_OFF) startAppendOnly();
+
+    if (ret != RDB_OK) {
+        errno = (ret == RDB_NOT_EXIST) ? ENOENT : EIO;
+        return REDISMODULE_ERR;
+    }
+
+    errno = 0;
+    return REDISMODULE_OK;
+}
+
+/* Save dataset to the RDB stream.
+ *
+ * `flags` must be zero. This parameter is for future use.
+ *
+ * On success REDISMODULE_OK is returned, otherwise REDISMODULE_ERR is returned
+ * and errno is set accordingly.
+ *
+ * Example:
+ *
+ *     RedisModuleRdbStream *s = RedisModule_RdbStreamCreateFromFile("exp.rdb");
+ *     RedisModule_RdbSave(ctx, s, 0);
+ *     RedisModule_RdbStreamFree(s);
+ */
+int RM_RdbSave(RedisModuleCtx *ctx, RedisModuleRdbStream *stream, int flags) {
+    UNUSED(ctx);
+
+    if (!stream || flags != 0) {
+        errno = EINVAL;
+        return REDISMODULE_ERR;
+    }
+
+    serverAssert(stream->type == REDISMODULE_RDB_STREAM_FILE);
+
+    if (rdbSaveToFile(stream->data.filename) != C_OK) {
+        return REDISMODULE_ERR;
+    }
+
+    errno = 0;
+    return REDISMODULE_OK;
+}
+
+/* Redis MODULE command.
+ *
+ * MODULE LIST
+ * MODULE LOAD <path> [args...]
+ * MODULE LOADEX <path> [[CONFIG NAME VALUE] [CONFIG NAME VALUE]] [ARGS ...]
+ * MODULE UNLOAD <name>
+ */
+void moduleCommand(client *c) {
+    char *subcmd = c->argv[1]->ptr;
+
+    if (c->argc == 2 && !strcasecmp(subcmd,"help")) {
+        const char *help[] = {
+"LIST",
+"    Return a list of loaded modules.",
+"LOAD <path> [<arg> ...]",
+"    Load a module library from <path>, passing to it any optional arguments.",
+"LOADEX <path> [[CONFIG NAME VALUE] [CONFIG NAME VALUE]] [ARGS ...]",
+"    Load a module library from <path>, while passing it module configurations and optional arguments.",
+"UNLOAD <name>",
+"    Unload a module.",
+NULL
+        };
+        addReplyHelp(c, help);
+    } else if (!strcasecmp(subcmd,"load") && c->argc >= 3) {
+        robj **argv = NULL;
+        int argc = 0;
+
+        if (c->argc > 3) {
+            argc = c->argc - 3;
+            argv = &c->argv[3];
+        }
+
+        if (moduleLoad(c->argv[2]->ptr,(void **)argv,argc, 0) == C_OK)
+            addReply(c,shared.ok);
+        else
+            addReplyError(c,
+                "Error loading the extension. Please check the server logs.");
+    } else if (!strcasecmp(subcmd,"loadex") && c->argc >= 3) {
+        robj **argv = NULL;
+        int argc = 0;
+
+        if (c->argc > 3) {
+            argc = c->argc - 3;
+            argv = &c->argv[3];
+        }
+        /* If this is a loadex command we want to populate server.module_configs_queue with 
+         * sds NAME VALUE pairs. We also want to increment argv to just after ARGS, if supplied. */
+        if (parseLoadexArguments((RedisModuleString ***) &argv, &argc) == REDISMODULE_OK &&
+            moduleLoad(c->argv[2]->ptr, (void **)argv, argc, 1) == C_OK)
+            addReply(c,shared.ok);
+        else {
+            dictEmpty(server.module_configs_queue, NULL);
+            addReplyError(c,
+                "Error loading the extension. Please check the server logs.");
+        }
+
+    } else if (!strcasecmp(subcmd,"unload") && c->argc == 3) {
+        const char *errmsg = NULL;
+        if (moduleUnload(c->argv[2]->ptr, &errmsg) == C_OK)
+            addReply(c,shared.ok);
+        else {
+            if (errmsg == NULL) errmsg = "operation not possible.";
+            addReplyErrorFormat(c, "Error unloading module: %s", errmsg);
+            serverLog(LL_WARNING, "Error unloading module %s: %s", (sds) c->argv[2]->ptr, errmsg);
+        }
+    } else if (!strcasecmp(subcmd,"list") && c->argc == 2) {
+        addReplyLoadedModules(c);
+    } else {
+        addReplySubcommandSyntaxError(c);
+        return;
+    }
+}
+
+/* Return the number of registered modules. */
+size_t moduleCount(void) {
+    return dictSize(modules);
+}
+
+/* --------------------------------------------------------------------------
+ * ## Key eviction API
+ * -------------------------------------------------------------------------- */
+
+/* Set the key last access time for LRU based eviction. not relevant if the
+ * servers's maxmemory policy is LFU based. Value is idle time in milliseconds.
+ * returns REDISMODULE_OK if the LRU was updated, REDISMODULE_ERR otherwise. */
+int RM_SetLRU(RedisModuleKey *key, mstime_t lru_idle) {
+    if (!key->value)
+        return REDISMODULE_ERR;
+    if (objectSetLRUOrLFU(key->value, -1, lru_idle, lru_idle>=0 ? LRU_CLOCK() : 0, 1))
+        return REDISMODULE_OK;
+    return REDISMODULE_ERR;
+}
+
+/* Gets the key last access time.
+ * Value is idletime in milliseconds or -1 if the server's eviction policy is
+ * LFU based.
+ * returns REDISMODULE_OK if when key is valid. */
+int RM_GetLRU(RedisModuleKey *key, mstime_t *lru_idle) {
+    *lru_idle = -1;
+    if (!key->value)
+        return REDISMODULE_ERR;
+    if (server.maxmemory_policy & MAXMEMORY_FLAG_LFU)
+        return REDISMODULE_OK;
+    *lru_idle = estimateObjectIdleTime(key->value);
+    return REDISMODULE_OK;
+}
+
+/* Set the key access frequency. only relevant if the server's maxmemory policy
+ * is LFU based.
+ * The frequency is a logarithmic counter that provides an indication of
+ * the access frequencyonly (must be <= 255).
+ * returns REDISMODULE_OK if the LFU was updated, REDISMODULE_ERR otherwise. */
+int RM_SetLFU(RedisModuleKey *key, long long lfu_freq) {
+    if (!key->value)
+        return REDISMODULE_ERR;
+    if (objectSetLRUOrLFU(key->value, lfu_freq, -1, 0, 1))
+        return REDISMODULE_OK;
+    return REDISMODULE_ERR;
+}
+
+/* Gets the key access frequency or -1 if the server's eviction policy is not
+ * LFU based.
+ * returns REDISMODULE_OK if when key is valid. */
+int RM_GetLFU(RedisModuleKey *key, long long *lfu_freq) {
+    *lfu_freq = -1;
+    if (!key->value)
+        return REDISMODULE_ERR;
+    if (server.maxmemory_policy & MAXMEMORY_FLAG_LFU)
+        *lfu_freq = LFUDecrAndReturn(key->value);
+    return REDISMODULE_OK;
+}
+
+/* --------------------------------------------------------------------------
+ * ## Miscellaneous APIs
+ * -------------------------------------------------------------------------- */
+
+/**
+ * Returns the full module options flags mask, using the return value
+ * the module can check if a certain set of module options are supported
+ * by the redis server version in use.
+ * Example:
+ *
+ *        int supportedFlags = RM_GetModuleOptionsAll();
+ *        if (supportedFlags & REDISMODULE_OPTIONS_ALLOW_NESTED_KEYSPACE_NOTIFICATIONS) {
+ *              // REDISMODULE_OPTIONS_ALLOW_NESTED_KEYSPACE_NOTIFICATIONS is supported
+ *        } else{
+ *              // REDISMODULE_OPTIONS_ALLOW_NESTED_KEYSPACE_NOTIFICATIONS is not supported
+ *        }
+ */
+int RM_GetModuleOptionsAll(void) {
+    return _REDISMODULE_OPTIONS_FLAGS_NEXT - 1;
+}
+
+/**
+ * Returns the full ContextFlags mask, using the return value
+ * the module can check if a certain set of flags are supported
+ * by the redis server version in use.
+ * Example:
+ *
+ *        int supportedFlags = RM_GetContextFlagsAll();
+ *        if (supportedFlags & REDISMODULE_CTX_FLAGS_MULTI) {
+ *              // REDISMODULE_CTX_FLAGS_MULTI is supported
+ *        } else{
+ *              // REDISMODULE_CTX_FLAGS_MULTI is not supported
+ *        }
+ */
+int RM_GetContextFlagsAll(void) {
+    return _REDISMODULE_CTX_FLAGS_NEXT - 1;
+}
+
+/**
+ * Returns the full KeyspaceNotification mask, using the return value
+ * the module can check if a certain set of flags are supported
+ * by the redis server version in use.
+ * Example:
+ *
+ *        int supportedFlags = RM_GetKeyspaceNotificationFlagsAll();
+ *        if (supportedFlags & REDISMODULE_NOTIFY_LOADED) {
+ *              // REDISMODULE_NOTIFY_LOADED is supported
+ *        } else{
+ *              // REDISMODULE_NOTIFY_LOADED is not supported
+ *        }
+ */
+int RM_GetKeyspaceNotificationFlagsAll(void) {
+    return _REDISMODULE_NOTIFY_NEXT - 1;
+}
+
+/**
+ * Return the redis version in format of 0x00MMmmpp.
+ * Example for 6.0.7 the return value will be 0x00060007.
+ */
+int RM_GetServerVersion(void) {
+    return REDIS_VERSION_NUM;
+}
+
+/**
+ * Return the current redis-server runtime value of REDISMODULE_TYPE_METHOD_VERSION.
+ * You can use that when calling RM_CreateDataType to know which fields of
+ * RedisModuleTypeMethods are gonna be supported and which will be ignored.
+ */
+int RM_GetTypeMethodVersion(void) {
+    return REDISMODULE_TYPE_METHOD_VERSION;
+}
+
+/* Replace the value assigned to a module type.
+ *
+ * The key must be open for writing, have an existing value, and have a moduleType
+ * that matches the one specified by the caller.
+ *
+ * Unlike RM_ModuleTypeSetValue() which will free the old value, this function
+ * simply swaps the old value with the new value.
+ *
+ * The function returns REDISMODULE_OK on success, REDISMODULE_ERR on errors
+ * such as:
+ *
+ * 1. Key is not opened for writing.
+ * 2. Key is not a module data type key.
+ * 3. Key is a module datatype other than 'mt'.
+ *
+ * If old_value is non-NULL, the old value is returned by reference.
+ */
+int RM_ModuleTypeReplaceValue(RedisModuleKey *key, moduleType *mt, void *new_value, void **old_value) {
+    if (!(key->mode & REDISMODULE_WRITE) || key->iter)
+        return REDISMODULE_ERR;
+    if (!key->value || key->value->type != OBJ_MODULE)
+        return REDISMODULE_ERR;
+
+    moduleValue *mv = key->value->ptr;
+    if (mv->type != mt)
+        return REDISMODULE_ERR;
+
+    if (old_value)
+        *old_value = mv->value;
+    mv->value = new_value;
+
+    return REDISMODULE_OK;
+}
+
+/* For a specified command, parse its arguments and return an array that
+ * contains the indexes of all key name arguments. This function is
+ * essentially a more efficient way to do `COMMAND GETKEYS`.
+ *
+ * The out_flags argument is optional, and can be set to NULL.
+ * When provided it is filled with REDISMODULE_CMD_KEY_ flags in matching
+ * indexes with the key indexes of the returned array.
+ *
+ * A NULL return value indicates the specified command has no keys, or
+ * an error condition. Error conditions are indicated by setting errno
+ * as follows:
+ *
+ * * ENOENT: Specified command does not exist.
+ * * EINVAL: Invalid command arity specified.
+ *
+ * NOTE: The returned array is not a Redis Module object so it does not
+ * get automatically freed even when auto-memory is used. The caller
+ * must explicitly call RM_Free() to free it, same as the out_flags pointer if
+ * used.
+ */
+int *RM_GetCommandKeysWithFlags(RedisModuleCtx *ctx, RedisModuleString **argv, int argc, int *num_keys, int **out_flags) {
+    UNUSED(ctx);
+    struct redisCommand *cmd;
+    int *res = NULL;
+
+    /* Find command */
+    if ((cmd = lookupCommand(argv,argc)) == NULL) {
+        errno = ENOENT;
+        return NULL;
+    }
+
+    /* Bail out if command has no keys */
+    if (!doesCommandHaveKeys(cmd)) {
+        errno = 0;
+        return NULL;
+    }
+
+    if ((cmd->arity > 0 && cmd->arity != argc) || (argc < -cmd->arity)) {
+        errno = EINVAL;
+        return NULL;
+    }
+
+    getKeysResult result = GETKEYS_RESULT_INIT;
+    getKeysFromCommand(cmd, argv, argc, &result);
+
+    *num_keys = result.numkeys;
+    if (!result.numkeys) {
+        errno = 0;
+        getKeysFreeResult(&result);
+        return NULL;
+    }
+
+    /* The return value here expects an array of key positions */
+    unsigned long int size = sizeof(int) * result.numkeys;
+    res = zmalloc(size);
+    if (out_flags)
+        *out_flags = zmalloc(size);
+    for (int i = 0; i < result.numkeys; i++) {
+        res[i] = result.keys[i].pos;
+        if (out_flags)
+            (*out_flags)[i] = moduleConvertKeySpecsFlags(result.keys[i].flags, 0);
+    }
+
+    return res;
+}
+
+/* Identical to RM_GetCommandKeysWithFlags when flags are not needed. */
+int *RM_GetCommandKeys(RedisModuleCtx *ctx, RedisModuleString **argv, int argc, int *num_keys) {
+    return RM_GetCommandKeysWithFlags(ctx, argv, argc, num_keys, NULL);
+}
+
+/* Return the name of the command currently running */
+const char *RM_GetCurrentCommandName(RedisModuleCtx *ctx) {
+    if (!ctx || !ctx->client || !ctx->client->cmd)
+        return NULL;
+
+    return (const char*)ctx->client->cmd->fullname;
+}
+
+/* --------------------------------------------------------------------------
+ * ## Defrag API
+ * -------------------------------------------------------------------------- */
+
+/* The defrag context, used to manage state during calls to the data type
+ * defrag callback.
+ */
+struct RedisModuleDefragCtx {
+    long long int endtime;
+    unsigned long *cursor;
+    struct redisObject *key; /* Optional name of key processed, NULL when unknown. */
+    int dbid;                /* The dbid of the key being processed, -1 when unknown. */
+};
+
+/* Register a defrag callback for global data, i.e. anything that the module
+ * may allocate that is not tied to a specific data type.
+ */
+int RM_RegisterDefragFunc(RedisModuleCtx *ctx, RedisModuleDefragFunc cb) {
+    ctx->module->defrag_cb = cb;
+    return REDISMODULE_OK;
+}
+
+/* When the data type defrag callback iterates complex structures, this
+ * function should be called periodically. A zero (false) return
+ * indicates the callback may continue its work. A non-zero value (true)
+ * indicates it should stop.
+ *
+ * When stopped, the callback may use RM_DefragCursorSet() to store its
+ * position so it can later use RM_DefragCursorGet() to resume defragging.
+ *
+ * When stopped and more work is left to be done, the callback should
+ * return 1. Otherwise, it should return 0.
+ *
+ * NOTE: Modules should consider the frequency in which this function is called,
+ * so it generally makes sense to do small batches of work in between calls.
+ */
+int RM_DefragShouldStop(RedisModuleDefragCtx *ctx) {
+    return (ctx->endtime != 0 && ctx->endtime < ustime());
+}
+
+/* Store an arbitrary cursor value for future re-use.
+ *
+ * This should only be called if RM_DefragShouldStop() has returned a non-zero
+ * value and the defrag callback is about to exit without fully iterating its
+ * data type.
+ *
+ * This behavior is reserved to cases where late defrag is performed. Late
+ * defrag is selected for keys that implement the `free_effort` callback and
+ * return a `free_effort` value that is larger than the defrag
+ * 'active-defrag-max-scan-fields' configuration directive.
+ *
+ * Smaller keys, keys that do not implement `free_effort` or the global
+ * defrag callback are not called in late-defrag mode. In those cases, a
+ * call to this function will return REDISMODULE_ERR.
+ *
+ * The cursor may be used by the module to represent some progress into the
+ * module's data type. Modules may also store additional cursor-related
+ * information locally and use the cursor as a flag that indicates when
+ * traversal of a new key begins. This is possible because the API makes
+ * a guarantee that concurrent defragmentation of multiple keys will
+ * not be performed.
+ */
+int RM_DefragCursorSet(RedisModuleDefragCtx *ctx, unsigned long cursor) {
+    if (!ctx->cursor)
+        return REDISMODULE_ERR;
+
+    *ctx->cursor = cursor;
+    return REDISMODULE_OK;
+}
+
+/* Fetch a cursor value that has been previously stored using RM_DefragCursorSet().
+ *
+ * If not called for a late defrag operation, REDISMODULE_ERR will be returned and
+ * the cursor should be ignored. See RM_DefragCursorSet() for more details on
+ * defrag cursors.
+ */
+int RM_DefragCursorGet(RedisModuleDefragCtx *ctx, unsigned long *cursor) {
+    if (!ctx->cursor)
+        return REDISMODULE_ERR;
+
+    *cursor = *ctx->cursor;
+    return REDISMODULE_OK;
+}
+
+/* Defrag a memory allocation previously allocated by RM_Alloc, RM_Calloc, etc.
+ * The defragmentation process involves allocating a new memory block and copying
+ * the contents to it, like realloc().
+ *
+ * If defragmentation was not necessary, NULL is returned and the operation has
+ * no other effect.
+ *
+ * If a non-NULL value is returned, the caller should use the new pointer instead
+ * of the old one and update any reference to the old pointer, which must not
+ * be used again.
+ */
+void *RM_DefragAlloc(RedisModuleDefragCtx *ctx, void *ptr) {
+    UNUSED(ctx);
+    return activeDefragAlloc(ptr);
+}
+
+/* Defrag a RedisModuleString previously allocated by RM_Alloc, RM_Calloc, etc.
+ * See RM_DefragAlloc() for more information on how the defragmentation process
+ * works.
+ *
+ * NOTE: It is only possible to defrag strings that have a single reference.
+ * Typically this means strings retained with RM_RetainString or RM_HoldString
+ * may not be defragmentable. One exception is command argvs which, if retained
+ * by the module, will end up with a single reference (because the reference
+ * on the Redis side is dropped as soon as the command callback returns).
+ */
+RedisModuleString *RM_DefragRedisModuleString(RedisModuleDefragCtx *ctx, RedisModuleString *str) {
+    UNUSED(ctx);
+    return activeDefragStringOb(str);
+}
+
+
+/* Perform a late defrag of a module datatype key.
+ *
+ * Returns a zero value (and initializes the cursor) if no more needs to be done,
+ * or a non-zero value otherwise.
+ */
+int moduleLateDefrag(robj *key, robj *value, unsigned long *cursor, long long endtime, int dbid) {
+    moduleValue *mv = value->ptr;
+    moduleType *mt = mv->type;
+
+    RedisModuleDefragCtx defrag_ctx = { endtime, cursor, key, dbid};
+
+    /* Invoke callback. Note that the callback may be missing if the key has been
+     * replaced with a different type since our last visit.
+     */
+    int ret = 0;
+    if (mt->defrag)
+        ret = mt->defrag(&defrag_ctx, key, &mv->value);
+
+    if (!ret) {
+        *cursor = 0;    /* No more work to do */
+        return 0;
+    }
+
+    return 1;
+}
+
+/* Attempt to defrag a module data type value. Depending on complexity,
+ * the operation may happen immediately or be scheduled for later.
+ *
+ * Returns 1 if the operation has been completed or 0 if it needs to
+ * be scheduled for late defrag.
+ */
+int moduleDefragValue(robj *key, robj *value, int dbid) {
+    moduleValue *mv = value->ptr;
+    moduleType *mt = mv->type;
+
+    /* Try to defrag moduleValue itself regardless of whether or not
+     * defrag callbacks are provided.
+     */
+    moduleValue *newmv = activeDefragAlloc(mv);
+    if (newmv) {
+        value->ptr = mv = newmv;
+    }
+
+    if (!mt->defrag)
+        return 1;
+
+    /* Use free_effort to determine complexity of module value, and if
+     * necessary schedule it for defragLater instead of quick immediate
+     * defrag.
+     */
+    size_t effort = moduleGetFreeEffort(key, value, dbid);
+    if (!effort)
+        effort = SIZE_MAX;
+    if (effort > server.active_defrag_max_scan_fields) {
+        return 0;  /* Defrag later */
+    }
+
+    RedisModuleDefragCtx defrag_ctx = { 0, NULL, key, dbid };
+    mt->defrag(&defrag_ctx, key, &mv->value);
+    return 1;
+}
+
+/* Call registered module API defrag functions */
+void moduleDefragGlobals(void) {
+    dictIterator *di = dictGetIterator(modules);
+    dictEntry *de;
+
+    while ((de = dictNext(di)) != NULL) {
+        struct RedisModule *module = dictGetVal(de);
+        if (!module->defrag_cb)
+            continue;
+        RedisModuleDefragCtx defrag_ctx = { 0, NULL, NULL, -1};
+        module->defrag_cb(&defrag_ctx);
+    }
+    dictReleaseIterator(di);
+}
+
+/* Returns the name of the key currently being processed.
+ * There is no guarantee that the key name is always available, so this may return NULL.
+ */
+const RedisModuleString *RM_GetKeyNameFromDefragCtx(RedisModuleDefragCtx *ctx) {
+    return ctx->key;
+}
+
+/* Returns the database id of the key currently being processed.
+ * There is no guarantee that this info is always available, so this may return -1.
+ */
+int RM_GetDbIdFromDefragCtx(RedisModuleDefragCtx *ctx) {
+    return ctx->dbid;
+}
+
+/* Register all the APIs we export. Keep this function at the end of the
+ * file so that's easy to seek it to add new entries. */
+void moduleRegisterCoreAPI(void) {
+    server.moduleapi = dictCreate(&moduleAPIDictType);
+    server.sharedapi = dictCreate(&moduleAPIDictType);
+    REGISTER_API(Alloc);
+    REGISTER_API(TryAlloc);
+    REGISTER_API(Calloc);
+    REGISTER_API(Realloc);
+    REGISTER_API(Free);
+    REGISTER_API(Strdup);
+    REGISTER_API(CreateCommand);
+    REGISTER_API(GetCommand);
+    REGISTER_API(CreateSubcommand);
+    REGISTER_API(SetCommandInfo);
+    REGISTER_API(SetCommandACLCategories);
+    REGISTER_API(SetModuleAttribs);
+    REGISTER_API(IsModuleNameBusy);
+    REGISTER_API(WrongArity);
+    REGISTER_API(ReplyWithLongLong);
+    REGISTER_API(ReplyWithError);
+    REGISTER_API(ReplyWithErrorFormat);
+    REGISTER_API(ReplyWithSimpleString);
+    REGISTER_API(ReplyWithArray);
+    REGISTER_API(ReplyWithMap);
+    REGISTER_API(ReplyWithSet);
+    REGISTER_API(ReplyWithAttribute);
+    REGISTER_API(ReplyWithNullArray);
+    REGISTER_API(ReplyWithEmptyArray);
+    REGISTER_API(ReplySetArrayLength);
+    REGISTER_API(ReplySetMapLength);
+    REGISTER_API(ReplySetSetLength);
+    REGISTER_API(ReplySetAttributeLength);
+    REGISTER_API(ReplyWithString);
+    REGISTER_API(ReplyWithEmptyString);
+    REGISTER_API(ReplyWithVerbatimString);
+    REGISTER_API(ReplyWithVerbatimStringType);
+    REGISTER_API(ReplyWithStringBuffer);
+    REGISTER_API(ReplyWithCString);
+    REGISTER_API(ReplyWithNull);
+    REGISTER_API(ReplyWithBool);
+    REGISTER_API(ReplyWithCallReply);
+    REGISTER_API(ReplyWithDouble);
+    REGISTER_API(ReplyWithBigNumber);
+    REGISTER_API(ReplyWithLongDouble);
+    REGISTER_API(GetSelectedDb);
+    REGISTER_API(SelectDb);
+    REGISTER_API(KeyExists);
+    REGISTER_API(OpenKey);
+    REGISTER_API(GetOpenKeyModesAll);
+    REGISTER_API(CloseKey);
+    REGISTER_API(KeyType);
+    REGISTER_API(ValueLength);
+    REGISTER_API(ListPush);
+    REGISTER_API(ListPop);
+    REGISTER_API(ListGet);
+    REGISTER_API(ListSet);
+    REGISTER_API(ListInsert);
+    REGISTER_API(ListDelete);
+    REGISTER_API(StringToLongLong);
+    REGISTER_API(StringToULongLong);
+    REGISTER_API(StringToDouble);
+    REGISTER_API(StringToLongDouble);
+    REGISTER_API(StringToStreamID);
+    REGISTER_API(Call);
+    REGISTER_API(CallReplyProto);
+    REGISTER_API(FreeCallReply);
+    REGISTER_API(CallReplyInteger);
+    REGISTER_API(CallReplyDouble);
+    REGISTER_API(CallReplyBigNumber);
+    REGISTER_API(CallReplyVerbatim);
+    REGISTER_API(CallReplyBool);
+    REGISTER_API(CallReplySetElement);
+    REGISTER_API(CallReplyMapElement);
+    REGISTER_API(CallReplyAttributeElement);
+    REGISTER_API(CallReplyPromiseSetUnblockHandler);
+    REGISTER_API(CallReplyPromiseAbort);
+    REGISTER_API(CallReplyAttribute);
+    REGISTER_API(CallReplyType);
+    REGISTER_API(CallReplyLength);
+    REGISTER_API(CallReplyArrayElement);
+    REGISTER_API(CallReplyStringPtr);
+    REGISTER_API(CreateStringFromCallReply);
+    REGISTER_API(CreateString);
+    REGISTER_API(CreateStringFromLongLong);
+    REGISTER_API(CreateStringFromULongLong);
+    REGISTER_API(CreateStringFromDouble);
+    REGISTER_API(CreateStringFromLongDouble);
+    REGISTER_API(CreateStringFromString);
+    REGISTER_API(CreateStringFromStreamID);
+    REGISTER_API(CreateStringPrintf);
+    REGISTER_API(FreeString);
+    REGISTER_API(StringPtrLen);
+    REGISTER_API(AutoMemory);
+    REGISTER_API(Replicate);
+    REGISTER_API(ReplicateVerbatim);
+    REGISTER_API(DeleteKey);
+    REGISTER_API(UnlinkKey);
+    REGISTER_API(StringSet);
+    REGISTER_API(StringDMA);
+    REGISTER_API(StringTruncate);
+    REGISTER_API(SetExpire);
+    REGISTER_API(GetExpire);
+    REGISTER_API(SetAbsExpire);
+    REGISTER_API(GetAbsExpire);
+    REGISTER_API(ResetDataset);
+    REGISTER_API(DbSize);
+    REGISTER_API(RandomKey);
+    REGISTER_API(ZsetAdd);
+    REGISTER_API(ZsetIncrby);
+    REGISTER_API(ZsetScore);
+    REGISTER_API(ZsetRem);
+    REGISTER_API(ZsetRangeStop);
+    REGISTER_API(ZsetFirstInScoreRange);
+    REGISTER_API(ZsetLastInScoreRange);
+    REGISTER_API(ZsetFirstInLexRange);
+    REGISTER_API(ZsetLastInLexRange);
+    REGISTER_API(ZsetRangeCurrentElement);
+    REGISTER_API(ZsetRangeNext);
+    REGISTER_API(ZsetRangePrev);
+    REGISTER_API(ZsetRangeEndReached);
+    REGISTER_API(HashSet);
+    REGISTER_API(HashGet);
+    REGISTER_API(StreamAdd);
+    REGISTER_API(StreamDelete);
+    REGISTER_API(StreamIteratorStart);
+    REGISTER_API(StreamIteratorStop);
+    REGISTER_API(StreamIteratorNextID);
+    REGISTER_API(StreamIteratorNextField);
+    REGISTER_API(StreamIteratorDelete);
+    REGISTER_API(StreamTrimByLength);
+    REGISTER_API(StreamTrimByID);
+    REGISTER_API(IsKeysPositionRequest);
+    REGISTER_API(KeyAtPos);
+    REGISTER_API(KeyAtPosWithFlags);
+    REGISTER_API(IsChannelsPositionRequest);
+    REGISTER_API(ChannelAtPosWithFlags);
+    REGISTER_API(GetClientId);
+    REGISTER_API(GetClientUserNameById);
+    REGISTER_API(GetContextFlags);
+    REGISTER_API(AvoidReplicaTraffic);
+    REGISTER_API(PoolAlloc);
+    REGISTER_API(CreateDataType);
+    REGISTER_API(ModuleTypeSetValue);
+    REGISTER_API(ModuleTypeReplaceValue);
+    REGISTER_API(ModuleTypeGetType);
+    REGISTER_API(ModuleTypeGetValue);
+    REGISTER_API(IsIOError);
+    REGISTER_API(SetModuleOptions);
+    REGISTER_API(SignalModifiedKey);
+    REGISTER_API(SaveUnsigned);
+    REGISTER_API(LoadUnsigned);
+    REGISTER_API(SaveSigned);
+    REGISTER_API(LoadSigned);
+    REGISTER_API(SaveString);
+    REGISTER_API(SaveStringBuffer);
+    REGISTER_API(LoadString);
+    REGISTER_API(LoadStringBuffer);
+    REGISTER_API(SaveDouble);
+    REGISTER_API(LoadDouble);
+    REGISTER_API(SaveFloat);
+    REGISTER_API(LoadFloat);
+    REGISTER_API(SaveLongDouble);
+    REGISTER_API(LoadLongDouble);
+    REGISTER_API(SaveDataTypeToString);
+    REGISTER_API(LoadDataTypeFromString);
+    REGISTER_API(LoadDataTypeFromStringEncver);
+    REGISTER_API(EmitAOF);
+    REGISTER_API(Log);
+    REGISTER_API(LogIOError);
+    REGISTER_API(_Assert);
+    REGISTER_API(LatencyAddSample);
+    REGISTER_API(StringAppendBuffer);
+    REGISTER_API(TrimStringAllocation);
+    REGISTER_API(RetainString);
+    REGISTER_API(HoldString);
+    REGISTER_API(StringCompare);
+    REGISTER_API(GetContextFromIO);
+    REGISTER_API(GetKeyNameFromIO);
+    REGISTER_API(GetKeyNameFromModuleKey);
+    REGISTER_API(GetDbIdFromModuleKey);
+    REGISTER_API(GetDbIdFromIO);
+    REGISTER_API(GetKeyNameFromOptCtx);
+    REGISTER_API(GetToKeyNameFromOptCtx);
+    REGISTER_API(GetDbIdFromOptCtx);
+    REGISTER_API(GetToDbIdFromOptCtx);
+    REGISTER_API(GetKeyNameFromDefragCtx);
+    REGISTER_API(GetDbIdFromDefragCtx);
+    REGISTER_API(GetKeyNameFromDigest);
+    REGISTER_API(GetDbIdFromDigest);
+    REGISTER_API(BlockClient);
+    REGISTER_API(BlockClientGetPrivateData);
+    REGISTER_API(BlockClientSetPrivateData);
+    REGISTER_API(BlockClientOnAuth);
+    REGISTER_API(UnblockClient);
+    REGISTER_API(IsBlockedReplyRequest);
+    REGISTER_API(IsBlockedTimeoutRequest);
+    REGISTER_API(GetBlockedClientPrivateData);
+    REGISTER_API(AbortBlock);
+    REGISTER_API(Milliseconds);
+    REGISTER_API(MonotonicMicroseconds);
+    REGISTER_API(Microseconds);
+    REGISTER_API(CachedMicroseconds);
+    REGISTER_API(BlockedClientMeasureTimeStart);
+    REGISTER_API(BlockedClientMeasureTimeEnd);
+    REGISTER_API(GetThreadSafeContext);
+    REGISTER_API(GetDetachedThreadSafeContext);
+    REGISTER_API(FreeThreadSafeContext);
+    REGISTER_API(ThreadSafeContextLock);
+    REGISTER_API(ThreadSafeContextTryLock);
+    REGISTER_API(ThreadSafeContextUnlock);
+    REGISTER_API(DigestAddStringBuffer);
+    REGISTER_API(DigestAddLongLong);
+    REGISTER_API(DigestEndSequence);
+    REGISTER_API(NotifyKeyspaceEvent);
+    REGISTER_API(GetNotifyKeyspaceEvents);
+    REGISTER_API(SubscribeToKeyspaceEvents);
+    REGISTER_API(AddPostNotificationJob);
+    REGISTER_API(RegisterClusterMessageReceiver);
+    REGISTER_API(SendClusterMessage);
+    REGISTER_API(GetClusterNodeInfo);
+    REGISTER_API(GetClusterNodesList);
+    REGISTER_API(FreeClusterNodesList);
+    REGISTER_API(CreateTimer);
+    REGISTER_API(StopTimer);
+    REGISTER_API(GetTimerInfo);
+    REGISTER_API(GetMyClusterID);
+    REGISTER_API(GetClusterSize);
+    REGISTER_API(GetRandomBytes);
+    REGISTER_API(GetRandomHexChars);
+    REGISTER_API(BlockedClientDisconnected);
+    REGISTER_API(SetDisconnectCallback);
+    REGISTER_API(GetBlockedClientHandle);
+    REGISTER_API(SetClusterFlags);
+    REGISTER_API(CreateDict);
+    REGISTER_API(FreeDict);
+    REGISTER_API(DictSize);
+    REGISTER_API(DictSetC);
+    REGISTER_API(DictReplaceC);
+    REGISTER_API(DictSet);
+    REGISTER_API(DictReplace);
+    REGISTER_API(DictGetC);
+    REGISTER_API(DictGet);
+    REGISTER_API(DictDelC);
+    REGISTER_API(DictDel);
+    REGISTER_API(DictIteratorStartC);
+    REGISTER_API(DictIteratorStart);
+    REGISTER_API(DictIteratorStop);
+    REGISTER_API(DictIteratorReseekC);
+    REGISTER_API(DictIteratorReseek);
+    REGISTER_API(DictNextC);
+    REGISTER_API(DictPrevC);
+    REGISTER_API(DictNext);
+    REGISTER_API(DictPrev);
+    REGISTER_API(DictCompareC);
+    REGISTER_API(DictCompare);
+    REGISTER_API(ExportSharedAPI);
+    REGISTER_API(GetSharedAPI);
+    REGISTER_API(RegisterCommandFilter);
+    REGISTER_API(UnregisterCommandFilter);
+    REGISTER_API(CommandFilterArgsCount);
+    REGISTER_API(CommandFilterArgGet);
+    REGISTER_API(CommandFilterArgInsert);
+    REGISTER_API(CommandFilterArgReplace);
+    REGISTER_API(CommandFilterArgDelete);
+    REGISTER_API(CommandFilterGetClientId);
+    REGISTER_API(Fork);
+    REGISTER_API(SendChildHeartbeat);
+    REGISTER_API(ExitFromChild);
+    REGISTER_API(KillForkChild);
+    REGISTER_API(RegisterInfoFunc);
+    REGISTER_API(InfoAddSection);
+    REGISTER_API(InfoBeginDictField);
+    REGISTER_API(InfoEndDictField);
+    REGISTER_API(InfoAddFieldString);
+    REGISTER_API(InfoAddFieldCString);
+    REGISTER_API(InfoAddFieldDouble);
+    REGISTER_API(InfoAddFieldLongLong);
+    REGISTER_API(InfoAddFieldULongLong);
+    REGISTER_API(GetServerInfo);
+    REGISTER_API(FreeServerInfo);
+    REGISTER_API(ServerInfoGetField);
+    REGISTER_API(ServerInfoGetFieldC);
+    REGISTER_API(ServerInfoGetFieldSigned);
+    REGISTER_API(ServerInfoGetFieldUnsigned);
+    REGISTER_API(ServerInfoGetFieldDouble);
+    REGISTER_API(GetClientInfoById);
+    REGISTER_API(GetClientNameById);
+    REGISTER_API(SetClientNameById);
+    REGISTER_API(PublishMessage);
+    REGISTER_API(PublishMessageShard);
+    REGISTER_API(SubscribeToServerEvent);
+    REGISTER_API(SetLRU);
+    REGISTER_API(GetLRU);
+    REGISTER_API(SetLFU);
+    REGISTER_API(GetLFU);
+    REGISTER_API(BlockClientOnKeys);
+    REGISTER_API(BlockClientOnKeysWithFlags);
+    REGISTER_API(SignalKeyAsReady);
+    REGISTER_API(GetBlockedClientReadyKey);
+    REGISTER_API(GetUsedMemoryRatio);
+    REGISTER_API(MallocSize);
+    REGISTER_API(MallocUsableSize);
+    REGISTER_API(MallocSizeString);
+    REGISTER_API(MallocSizeDict);
+    REGISTER_API(ScanCursorCreate);
+    REGISTER_API(ScanCursorDestroy);
+    REGISTER_API(ScanCursorRestart);
+    REGISTER_API(Scan);
+    REGISTER_API(ScanKey);
+    REGISTER_API(CreateModuleUser);
+    REGISTER_API(SetContextUser);
+    REGISTER_API(SetModuleUserACL);
+    REGISTER_API(SetModuleUserACLString);
+    REGISTER_API(GetModuleUserACLString);
+    REGISTER_API(GetCurrentUserName);
+    REGISTER_API(GetModuleUserFromUserName);
+    REGISTER_API(ACLCheckCommandPermissions);
+    REGISTER_API(ACLCheckKeyPermissions);
+    REGISTER_API(ACLCheckChannelPermissions);
+    REGISTER_API(ACLAddLogEntry);
+    REGISTER_API(ACLAddLogEntryByUserName);
+    REGISTER_API(FreeModuleUser);
+    REGISTER_API(DeauthenticateAndCloseClient);
+    REGISTER_API(AuthenticateClientWithACLUser);
+    REGISTER_API(AuthenticateClientWithUser);
+    REGISTER_API(GetContextFlagsAll);
+    REGISTER_API(GetModuleOptionsAll);
+    REGISTER_API(GetKeyspaceNotificationFlagsAll);
+    REGISTER_API(IsSubEventSupported);
+    REGISTER_API(GetServerVersion);
+    REGISTER_API(GetClientCertificate);
+    REGISTER_API(RedactClientCommandArgument);
+    REGISTER_API(GetCommandKeys);
+    REGISTER_API(GetCommandKeysWithFlags);
+    REGISTER_API(GetCurrentCommandName);
+    REGISTER_API(GetTypeMethodVersion);
+    REGISTER_API(RegisterDefragFunc);
+    REGISTER_API(DefragAlloc);
+    REGISTER_API(DefragRedisModuleString);
+    REGISTER_API(DefragShouldStop);
+    REGISTER_API(DefragCursorSet);
+    REGISTER_API(DefragCursorGet);
+    REGISTER_API(EventLoopAdd);
+    REGISTER_API(EventLoopDel);
+    REGISTER_API(EventLoopAddOneShot);
+    REGISTER_API(Yield);
+    REGISTER_API(RegisterBoolConfig);
+    REGISTER_API(RegisterNumericConfig);
+    REGISTER_API(RegisterStringConfig);
+    REGISTER_API(RegisterEnumConfig);
+    REGISTER_API(LoadConfigs);
+    REGISTER_API(RegisterAuthCallback);
+    REGISTER_API(RdbStreamCreateFromFile);
+    REGISTER_API(RdbStreamFree);
+    REGISTER_API(RdbLoad);
+    REGISTER_API(RdbSave);
+}