diff options
Diffstat (limited to 'modules/cache/mod_cache.c')
| -rw-r--r-- | modules/cache/mod_cache.c | 2720 |
1 files changed, 2720 insertions, 0 deletions
diff --git a/modules/cache/mod_cache.c b/modules/cache/mod_cache.c new file mode 100644 index 0000000..56a09f5 --- /dev/null +++ b/modules/cache/mod_cache.c @@ -0,0 +1,2720 @@ +/* Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#include "mod_cache.h" + +#include "cache_storage.h" +#include "cache_util.h" + +module AP_MODULE_DECLARE_DATA cache_module; +APR_OPTIONAL_FN_TYPE(ap_cache_generate_key) *cache_generate_key; + +/* -------------------------------------------------------------- */ + + +/* Handles for cache filters, resolved at startup to eliminate + * a name-to-function mapping on each request + */ +static ap_filter_rec_t *cache_filter_handle; +static ap_filter_rec_t *cache_save_filter_handle; +static ap_filter_rec_t *cache_save_subreq_filter_handle; +static ap_filter_rec_t *cache_out_filter_handle; +static ap_filter_rec_t *cache_out_subreq_filter_handle; +static ap_filter_rec_t *cache_remove_url_filter_handle; +static ap_filter_rec_t *cache_invalidate_filter_handle; + +/** + * Entity headers' names + */ +static const char *MOD_CACHE_ENTITY_HEADERS[] = { + "Allow", + "Content-Encoding", + "Content-Language", + "Content-Length", + "Content-Location", + "Content-MD5", + "Content-Range", + "Content-Type", + "Last-Modified", + NULL +}; + +/* + * CACHE handler + * ------------- + * + * Can we deliver this request from the cache? + * If yes: + * deliver the content by installing the CACHE_OUT filter. + * If no: + * check whether we're allowed to try cache it + * If yes: + * add CACHE_SAVE filter + * If No: + * oh well. + * + * By default, the cache handler runs in the quick handler, bypassing + * virtually all server processing and offering the cache its optimal + * performance. In this mode, the cache bolts onto the front of the + * server, and behaves as a discrete RFC2616 caching proxy + * implementation. + * + * Under certain circumstances, an admin might want to run the cache as + * a normal handler instead of a quick handler, allowing the cache to + * run after the authorisation hooks, or by allowing fine control over + * the placement of the cache in the filter chain. This option comes at + * a performance penalty, and should only be used to achieve specific + * caching goals where the admin understands what they are doing. + */ + +static int cache_quick_handler(request_rec *r, int lookup) +{ + apr_status_t rv; + const char *auth; + cache_provider_list *providers; + cache_request_rec *cache; + apr_bucket_brigade *out; + apr_bucket *e; + ap_filter_t *next; + ap_filter_rec_t *cache_out_handle; + cache_server_conf *conf; + + conf = (cache_server_conf *) ap_get_module_config(r->server->module_config, + &cache_module); + + /* only run if the quick handler is enabled */ + if (!conf->quick) { + return DECLINED; + } + + /* + * Which cache module (if any) should handle this request? + */ + if (!(providers = cache_get_providers(r, conf))) { + return DECLINED; + } + + /* make space for the per request config */ + cache = apr_pcalloc(r->pool, sizeof(cache_request_rec)); + cache->size = -1; + cache->out = apr_brigade_create(r->pool, r->connection->bucket_alloc); + + /* save away the possible providers */ + cache->providers = providers; + + /* + * Are we allowed to serve cached info at all? + */ + if (!ap_cache_check_no_store(cache, r)) { + return DECLINED; + } + + /* find certain cache controlling headers */ + auth = apr_table_get(r->headers_in, "Authorization"); + + /* First things first - does the request allow us to return + * cached information at all? If not, just decline the request. + */ + if (auth) { + return DECLINED; + } + + /* Are we PUT/POST/DELETE? If so, prepare to invalidate the cached entities. + */ + switch (r->method_number) { + case M_PUT: + case M_POST: + case M_DELETE: + { + + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(02461) + "PUT/POST/DELETE: Adding CACHE_INVALIDATE filter for %s", + r->uri); + + /* Add cache_invalidate filter to this request to force a + * cache entry to be invalidated if the response is + * ultimately successful (2xx). + */ + ap_add_output_filter_handle( + cache_invalidate_filter_handle, cache, r, + r->connection); + + return DECLINED; + } + case M_GET: { + break; + } + default : { + + ap_log_rerror( + APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(02462) "cache: Method '%s' not cacheable by mod_cache, ignoring: %s", r->method, r->uri); + + return DECLINED; + } + } + + /* + * Try to serve this request from the cache. + * + * If no existing cache file (DECLINED) + * add cache_save filter + * If cached file (OK) + * clear filter stack + * add cache_out filter + * return OK + */ + rv = cache_select(cache, r); + if (rv != OK) { + if (rv == DECLINED) { + if (!lookup) { + + /* try to obtain a cache lock at this point. if we succeed, + * we are the first to try and cache this url. if we fail, + * it means someone else is already trying to cache this + * url, and we should just let the request through to the + * backend without any attempt to cache. this stops + * duplicated simultaneous attempts to cache an entity. + */ + rv = cache_try_lock(conf, cache, r); + if (APR_SUCCESS == rv) { + + /* + * Add cache_save filter to cache this request. Choose + * the correct filter by checking if we are a subrequest + * or not. + */ + if (r->main) { + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, + r, APLOGNO(00749) "Adding CACHE_SAVE_SUBREQ filter for %s", + r->uri); + cache->save_filter = ap_add_output_filter_handle( + cache_save_subreq_filter_handle, cache, r, + r->connection); + } + else { + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, + r, APLOGNO(00750) "Adding CACHE_SAVE filter for %s", + r->uri); + cache->save_filter = ap_add_output_filter_handle( + cache_save_filter_handle, cache, r, + r->connection); + } + + apr_pool_userdata_setn(cache, CACHE_CTX_KEY, NULL, r->pool); + + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(00751) + "Adding CACHE_REMOVE_URL filter for %s", + r->uri); + + /* Add cache_remove_url filter to this request to remove a + * stale cache entry if needed. Also put the current cache + * request rec in the filter context, as the request that + * is available later during running the filter may be + * different due to an internal redirect. + */ + cache->remove_url_filter = ap_add_output_filter_handle( + cache_remove_url_filter_handle, cache, r, + r->connection); + + } + else { + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, + r, APLOGNO(00752) "Cache locked for url, not caching " + "response: %s", r->uri); + /* cache_select() may have added conditional headers */ + if (cache->stale_headers) { + r->headers_in = cache->stale_headers; + } + + } + } + else { + if (cache->stale_headers) { + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, + r, APLOGNO(00753) "Restoring request headers for %s", + r->uri); + + r->headers_in = cache->stale_headers; + } + } + } + else { + /* error */ + return rv; + } + return DECLINED; + } + + /* we've got a cache hit! tell everyone who cares */ + cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_HIT, + "cache hit"); + + /* if we are a lookup, we are exiting soon one way or another; Restore + * the headers. */ + if (lookup) { + if (cache->stale_headers) { + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(00754) + "Restoring request headers."); + r->headers_in = cache->stale_headers; + } + } + + rv = ap_meets_conditions(r); + if (rv != OK) { + /* If we are a lookup, we have to return DECLINED as we have no + * way of knowing if we will be able to serve the content. + */ + if (lookup) { + return DECLINED; + } + + /* Return cached status. */ + return rv; + } + + /* If we're a lookup, we can exit now instead of serving the content. */ + if (lookup) { + return OK; + } + + /* Serve up the content */ + + /* We are in the quick handler hook, which means that no output + * filters have been set. So lets run the insert_filter hook. + */ + ap_run_insert_filter(r); + + /* + * Add cache_out filter to serve this request. Choose + * the correct filter by checking if we are a subrequest + * or not. + */ + if (r->main) { + cache_out_handle = cache_out_subreq_filter_handle; + } + else { + cache_out_handle = cache_out_filter_handle; + } + ap_add_output_filter_handle(cache_out_handle, cache, r, r->connection); + + /* + * Remove all filters that are before the cache_out filter. This ensures + * that we kick off the filter stack with our cache_out filter being the + * first in the chain. This make sense because we want to restore things + * in the same manner as we saved them. + * There may be filters before our cache_out filter, because + * + * 1. We call ap_set_content_type during cache_select. This causes + * Content-Type specific filters to be added. + * 2. We call the insert_filter hook. This causes filters e.g. like + * the ones set with SetOutputFilter to be added. + */ + next = r->output_filters; + while (next && (next->frec != cache_out_handle)) { + ap_remove_output_filter(next); + next = next->next; + } + + /* kick off the filter stack */ + out = apr_brigade_create(r->pool, r->connection->bucket_alloc); + e = apr_bucket_eos_create(out->bucket_alloc); + APR_BRIGADE_INSERT_TAIL(out, e); + + return ap_pass_brigade_fchk(r, out, + "cache_quick_handler(%s): ap_pass_brigade returned", + cache->provider_name); +} + +/** + * If the two filter handles are present within the filter chain, replace + * the last instance of the first filter with the last instance of the + * second filter, and return true. If the second filter is not present at + * all, the first filter is removed, and false is returned. If neither + * filter is present, false is returned and this function does nothing. + * If a stop filter is specified, processing will stop once this filter is + * reached. + */ +static int cache_replace_filter(ap_filter_t *next, ap_filter_rec_t *from, + ap_filter_rec_t *to, ap_filter_rec_t *stop) { + ap_filter_t *ffrom = NULL, *fto = NULL; + while (next && next->frec != stop) { + if (next->frec == from) { + ffrom = next; + } + if (next->frec == to) { + fto = next; + } + next = next->next; + } + if (ffrom && fto) { + ffrom->frec = fto->frec; + ffrom->ctx = fto->ctx; + ap_remove_output_filter(fto); + return 1; + } + if (ffrom) { + ap_remove_output_filter(ffrom); + } + return 0; +} + +/** + * Find the given filter, and return it if found, or NULL otherwise. + */ +static ap_filter_t *cache_get_filter(ap_filter_t *next, ap_filter_rec_t *rec) { + while (next) { + if (next->frec == rec && next->ctx) { + break; + } + next = next->next; + } + return next; +} + +/** + * The cache handler is functionally similar to the cache_quick_hander, + * however a number of steps that are required by the quick handler are + * not required here, as the normal httpd processing has already handled + * these steps. + */ +static int cache_handler(request_rec *r) +{ + apr_status_t rv; + cache_provider_list *providers; + cache_request_rec *cache; + apr_bucket_brigade *out; + apr_bucket *e; + ap_filter_t *next; + ap_filter_rec_t *cache_out_handle; + ap_filter_rec_t *cache_save_handle; + cache_server_conf *conf; + + conf = (cache_server_conf *) ap_get_module_config(r->server->module_config, + &cache_module); + + /* only run if the quick handler is disabled */ + if (conf->quick) { + return DECLINED; + } + + /* + * Which cache module (if any) should handle this request? + */ + if (!(providers = cache_get_providers(r, conf))) { + return DECLINED; + } + + /* make space for the per request config */ + cache = apr_pcalloc(r->pool, sizeof(cache_request_rec)); + cache->size = -1; + cache->out = apr_brigade_create(r->pool, r->connection->bucket_alloc); + + /* save away the possible providers */ + cache->providers = providers; + + /* + * Are we allowed to serve cached info at all? + */ + if (!ap_cache_check_no_store(cache, r)) { + return DECLINED; + } + + /* Are we PUT/POST/DELETE? If so, prepare to invalidate the cached entities. + */ + switch (r->method_number) { + case M_PUT: + case M_POST: + case M_DELETE: + { + + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(02463) + "PUT/POST/DELETE: Adding CACHE_INVALIDATE filter for %s", + r->uri); + + /* Add cache_invalidate filter to this request to force a + * cache entry to be invalidated if the response is + * ultimately successful (2xx). + */ + ap_add_output_filter_handle( + cache_invalidate_filter_handle, cache, r, + r->connection); + + return DECLINED; + } + case M_GET: { + break; + } + default : { + + ap_log_rerror( + APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(02464) "cache: Method '%s' not cacheable by mod_cache, ignoring: %s", r->method, r->uri); + + return DECLINED; + } + } + + /* + * Try to serve this request from the cache. + * + * If no existing cache file (DECLINED) + * add cache_save filter + * If cached file (OK) + * clear filter stack + * add cache_out filter + * return OK + */ + rv = cache_select(cache, r); + if (rv != OK) { + if (rv == DECLINED) { + + /* try to obtain a cache lock at this point. if we succeed, + * we are the first to try and cache this url. if we fail, + * it means someone else is already trying to cache this + * url, and we should just let the request through to the + * backend without any attempt to cache. this stops + * duplicated simultaneous attempts to cache an entity. + */ + rv = cache_try_lock(conf, cache, r); + if (APR_SUCCESS == rv) { + + /* + * Add cache_save filter to cache this request. Choose + * the correct filter by checking if we are a subrequest + * or not. + */ + if (r->main) { + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, + r, APLOGNO(00756) "Adding CACHE_SAVE_SUBREQ filter for %s", + r->uri); + cache_save_handle = cache_save_subreq_filter_handle; + } + else { + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, + r, APLOGNO(00757) "Adding CACHE_SAVE filter for %s", + r->uri); + cache_save_handle = cache_save_filter_handle; + } + ap_add_output_filter_handle(cache_save_handle, cache, r, + r->connection); + + /* + * Did the user indicate the precise location of the + * CACHE_SAVE filter by inserting the CACHE filter as a + * marker? + * + * If so, we get cunning and replace CACHE with the + * CACHE_SAVE filter. This has the effect of inserting + * the CACHE_SAVE filter at the precise location where + * the admin wants to cache the content. All filters that + * lie before and after the original location of the CACHE + * filter will remain in place. + */ + if (cache_replace_filter(r->output_filters, + cache_filter_handle, cache_save_handle, + ap_get_input_filter_handle("SUBREQ_CORE"))) { + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, + r, APLOGNO(00758) "Replacing CACHE with CACHE_SAVE " + "filter for %s", r->uri); + } + + /* save away the save filter stack */ + cache->save_filter = cache_get_filter(r->output_filters, + cache_save_filter_handle); + + apr_pool_userdata_setn(cache, CACHE_CTX_KEY, NULL, r->pool); + + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(00759) + "Adding CACHE_REMOVE_URL filter for %s", + r->uri); + + /* Add cache_remove_url filter to this request to remove a + * stale cache entry if needed. Also put the current cache + * request rec in the filter context, as the request that + * is available later during running the filter may be + * different due to an internal redirect. + */ + cache->remove_url_filter + = ap_add_output_filter_handle( + cache_remove_url_filter_handle, cache, r, + r->connection); + + } + else { + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, + r, APLOGNO(00760) "Cache locked for url, not caching " + "response: %s", r->uri); + } + } + else { + /* error */ + return rv; + } + return DECLINED; + } + + /* we've got a cache hit! tell everyone who cares */ + cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_HIT, + "cache hit"); + + rv = ap_meets_conditions(r); + if (rv != OK) { + return rv; + } + + /* Serve up the content */ + + /* + * Add cache_out filter to serve this request. Choose + * the correct filter by checking if we are a subrequest + * or not. + */ + if (r->main) { + cache_out_handle = cache_out_subreq_filter_handle; + } + else { + cache_out_handle = cache_out_filter_handle; + } + ap_add_output_filter_handle(cache_out_handle, cache, r, r->connection); + + /* + * Did the user indicate the precise location of the CACHE_OUT filter by + * inserting the CACHE filter as a marker? + * + * If so, we get cunning and replace CACHE with the CACHE_OUT filters. + * This has the effect of inserting the CACHE_OUT filter at the precise + * location where the admin wants to cache the content. All filters that + * lie *after* the original location of the CACHE filter will remain in + * place. + */ + if (cache_replace_filter(r->output_filters, cache_filter_handle, + cache_out_handle, ap_get_input_filter_handle("SUBREQ_CORE"))) { + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, + r, APLOGNO(00761) "Replacing CACHE with CACHE_OUT filter for %s", + r->uri); + } + + /* + * Remove all filters that are before the cache_out filter. This ensures + * that we kick off the filter stack with our cache_out filter being the + * first in the chain. This make sense because we want to restore things + * in the same manner as we saved them. + * There may be filters before our cache_out filter, because + * + * 1. We call ap_set_content_type during cache_select. This causes + * Content-Type specific filters to be added. + * 2. We call the insert_filter hook. This causes filters e.g. like + * the ones set with SetOutputFilter to be added. + */ + next = r->output_filters; + while (next && (next->frec != cache_out_handle)) { + ap_remove_output_filter(next); + next = next->next; + } + + /* kick off the filter stack */ + out = apr_brigade_create(r->pool, r->connection->bucket_alloc); + e = apr_bucket_eos_create(out->bucket_alloc); + APR_BRIGADE_INSERT_TAIL(out, e); + return ap_pass_brigade_fchk(r, out, "cache(%s): ap_pass_brigade returned", + cache->provider_name); +} + +/* + * CACHE_OUT filter + * ---------------- + * + * Deliver cached content (headers and body) up the stack. + */ +static apr_status_t cache_out_filter(ap_filter_t *f, apr_bucket_brigade *in) +{ + request_rec *r = f->r; + cache_request_rec *cache = (cache_request_rec *)f->ctx; + + if (!cache) { + /* user likely configured CACHE_OUT manually; they should use mod_cache + * configuration to do that */ + ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(00762) + "CACHE/CACHE_OUT filter enabled while caching is disabled, ignoring"); + ap_remove_output_filter(f); + return ap_pass_brigade(f->next, in); + } + + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(00763) + "cache: running CACHE_OUT filter"); + + /* clean out any previous response up to EOS, if any */ + while (!APR_BRIGADE_EMPTY(in)) { + apr_bucket *e = APR_BRIGADE_FIRST(in); + if (APR_BUCKET_IS_EOS(e)) { + apr_bucket_brigade *bb = apr_brigade_create(r->pool, + r->connection->bucket_alloc); + + /* restore content type of cached response if available */ + /* Needed especially when stale content gets served. */ + const char *ct = apr_table_get(cache->handle->resp_hdrs, "Content-Type"); + if (ct) { + ap_set_content_type(r, ct); + } + + /* restore status of cached response */ + r->status = cache->handle->cache_obj->info.status; + + /* recall_headers() was called in cache_select() */ + cache->provider->recall_body(cache->handle, r->pool, bb); + APR_BRIGADE_PREPEND(in, bb); + + /* This filter is done once it has served up its content */ + ap_remove_output_filter(f); + + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(00764) + "cache: serving %s", r->uri); + return ap_pass_brigade(f->next, in); + + } + apr_bucket_delete(e); + } + + return APR_SUCCESS; +} + +/* + * Having jumped through all the hoops and decided to cache the + * response, call store_body() for each brigade, handling the + * case where the provider can't swallow the full brigade. In this + * case, we write the brigade we were passed out downstream, and + * loop around to try and cache some more until the in brigade is + * completely empty. As soon as the out brigade contains eos, call + * commit_entity() to finalise the cached element. + */ +static int cache_save_store(ap_filter_t *f, apr_bucket_brigade *in, + cache_server_conf *conf, cache_request_rec *cache) +{ + int rv = APR_SUCCESS; + apr_bucket *e; + + /* pass the brigade in into the cache provider, which is then + * expected to move cached buckets to the out brigade, for us + * to pass up the filter stack. repeat until in is empty, or + * we fail. + */ + while (APR_SUCCESS == rv && !APR_BRIGADE_EMPTY(in)) { + + rv = cache->provider->store_body(cache->handle, f->r, in, cache->out); + if (rv != APR_SUCCESS) { + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, f->r, APLOGNO(00765) + "cache: Cache provider's store_body failed for URI %s", f->r->uri); + ap_remove_output_filter(f); + + /* give someone else the chance to cache the file */ + cache_remove_lock(conf, cache, f->r, NULL); + + /* give up trying to cache, just step out the way */ + APR_BRIGADE_PREPEND(in, cache->out); + return ap_pass_brigade(f->next, in); + + } + + /* does the out brigade contain eos? if so, we're done, commit! */ + for (e = APR_BRIGADE_FIRST(cache->out); + e != APR_BRIGADE_SENTINEL(cache->out); + e = APR_BUCKET_NEXT(e)) + { + if (APR_BUCKET_IS_EOS(e)) { + rv = cache->provider->commit_entity(cache->handle, f->r); + break; + } + } + + /* conditionally remove the lock as soon as we see the eos bucket */ + cache_remove_lock(conf, cache, f->r, cache->out); + + if (APR_BRIGADE_EMPTY(cache->out)) { + if (APR_BRIGADE_EMPTY(in)) { + /* cache provider wants more data before passing the brigade + * upstream, oblige the provider by leaving to fetch more. + */ + break; + } + else { + /* oops, no data out, but not all data read in either, be + * safe and stand down to prevent a spin. + */ + ap_log_rerror(APLOG_MARK, APLOG_WARNING, rv, f->r, APLOGNO(00766) + "cache: Cache provider's store_body returned an " + "empty brigade, but didn't consume all of the " + "input brigade, standing down to prevent a spin"); + ap_remove_output_filter(f); + + /* give someone else the chance to cache the file */ + cache_remove_lock(conf, cache, f->r, NULL); + + return ap_pass_brigade(f->next, in); + } + } + + rv = ap_pass_brigade(f->next, cache->out); + } + + return rv; +} + +/** + * Sanity check for 304 Not Modified responses, as per RFC2616 Section 10.3.5. + */ +static int cache_header_cmp(apr_pool_t *pool, apr_table_t *left, + apr_table_t *right, const char *key) +{ + const char *h1, *h2; + + if ((h1 = cache_table_getm(pool, left, key)) + && (h2 = cache_table_getm(pool, right, key)) && (strcmp(h1, h2))) { + return 1; + } + return 0; +} + +/* + * CACHE_SAVE filter + * --------------- + * + * Decide whether or not this content should be cached. + * If we decide no it should not: + * remove the filter from the chain + * If we decide yes it should: + * Have we already started saving the response? + * If we have started, pass the data to the storage manager via store_body + * Otherwise: + * Check to see if we *can* save this particular response. + * If we can, call cache_create_entity() and save the headers and body + * Finally, pass the data to the next filter (the network or whatever) + * + * After the various failure cases, the cache lock is proactively removed, so + * that another request is given the opportunity to attempt to cache without + * waiting for a potentially slow client to acknowledge the failure. + */ + +static apr_status_t cache_save_filter(ap_filter_t *f, apr_bucket_brigade *in) +{ + int rv = !OK; + request_rec *r = f->r; + cache_request_rec *cache = (cache_request_rec *)f->ctx; + cache_server_conf *conf; + cache_dir_conf *dconf; + cache_control_t control; + const char *cc_out, *cl, *pragma; + const char *exps, *lastmods, *dates, *etag; + apr_time_t exp, date, lastmod, now; + apr_off_t size = -1; + cache_info *info = NULL; + const char *reason, **eh; + apr_pool_t *p; + apr_bucket *e; + apr_table_t *headers; + const char *query; + + conf = (cache_server_conf *) ap_get_module_config(r->server->module_config, + &cache_module); + + /* Setup cache_request_rec */ + if (!cache) { + /* user likely configured CACHE_SAVE manually; they should really use + * mod_cache configuration to do that + */ + ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(00767) + "CACHE/CACHE_SAVE filter enabled while caching is disabled, ignoring"); + ap_remove_output_filter(f); + return ap_pass_brigade(f->next, in); + } + + reason = NULL; + p = r->pool; + /* + * Pass Data to Cache + * ------------------ + * This section passes the brigades into the cache modules, but only + * if the setup section (see below) is complete. + */ + if (cache->block_response) { + /* We've already sent down the response and EOS. So, ignore + * whatever comes now. + */ + return APR_SUCCESS; + } + + /* have we already run the cacheability check and set up the + * cached file handle? + */ + if (cache->in_checked) { + return cache_save_store(f, in, conf, cache); + } + + /* + * Setup Data in Cache + * ------------------- + * This section opens the cache entity and sets various caching + * parameters, and decides whether this URL should be cached at + * all. This section is* run before the above section. + */ + + dconf = ap_get_module_config(r->per_dir_config, &cache_module); + + /* RFC2616 13.8 Errors or Incomplete Response Cache Behavior: + * If a cache receives a 5xx response while attempting to revalidate an + * entry, it MAY either forward this response to the requesting client, + * or act as if the server failed to respond. In the latter case, it MAY + * return a previously received response unless the cached entry + * includes the "must-revalidate" cache-control directive (see section + * 14.9). + * + * This covers the case where an error was generated behind us, for example + * by a backend server via mod_proxy. + */ + if (dconf->stale_on_error && r->status >= HTTP_INTERNAL_SERVER_ERROR) { + + ap_remove_output_filter(cache->remove_url_filter); + + if (cache->stale_handle + && !cache->stale_handle->cache_obj->info.control.must_revalidate + && !cache->stale_handle->cache_obj->info.control.proxy_revalidate) { + const char *warn_head; + + /* morph the current save filter into the out filter, and serve from + * cache. + */ + cache->handle = cache->stale_handle; + if (r->main) { + f->frec = cache_out_subreq_filter_handle; + } + else { + f->frec = cache_out_filter_handle; + } + + r->headers_out = cache->stale_handle->resp_hdrs; + + ap_set_content_type(r, apr_table_get( + cache->stale_handle->resp_hdrs, "Content-Type")); + + /* add a revalidation warning */ + warn_head = apr_table_get(r->err_headers_out, "Warning"); + if ((warn_head == NULL) || ((warn_head != NULL) + && (ap_strstr_c(warn_head, "111") == NULL))) { + apr_table_mergen(r->err_headers_out, "Warning", + "111 Revalidation failed"); + } + + cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_HIT, + apr_psprintf(r->pool, + "cache hit: %d status; stale content returned", + r->status)); + + /* give someone else the chance to cache the file */ + cache_remove_lock(conf, cache, f->r, NULL); + + /* pass brigade to our morphed out filter */ + return ap_pass_brigade(f, in); + } + } + + query = cache_use_early_url(r) ? r->parsed_uri.query : r->args; + + /* read expiry date; if a bad date, then leave it so the client can + * read it + */ + exps = apr_table_get(r->err_headers_out, "Expires"); + if (exps == NULL) { + exps = apr_table_get(r->headers_out, "Expires"); + } + if (exps != NULL) { + exp = apr_date_parse_http(exps); + } + else { + exp = APR_DATE_BAD; + } + + /* read the last-modified date; if the date is bad, then delete it */ + lastmods = apr_table_get(r->err_headers_out, "Last-Modified"); + if (lastmods == NULL) { + lastmods = apr_table_get(r->headers_out, "Last-Modified"); + } + if (lastmods != NULL) { + lastmod = apr_date_parse_http(lastmods); + if (lastmod == APR_DATE_BAD) { + lastmods = NULL; + } + } + else { + lastmod = APR_DATE_BAD; + } + + /* read the etag and cache-control from the entity */ + etag = apr_table_get(r->err_headers_out, "Etag"); + if (etag == NULL) { + etag = apr_table_get(r->headers_out, "Etag"); + } + cc_out = cache_table_getm(r->pool, r->err_headers_out, "Cache-Control"); + pragma = cache_table_getm(r->pool, r->err_headers_out, "Pragma"); + headers = r->err_headers_out; + if (!cc_out && !pragma) { + cc_out = cache_table_getm(r->pool, r->headers_out, "Cache-Control"); + pragma = cache_table_getm(r->pool, r->headers_out, "Pragma"); + headers = r->headers_out; + } + + /* Have we received a 304 response without any headers at all? Fall back to + * the original headers in the original cached request. + */ + if (r->status == HTTP_NOT_MODIFIED && cache->stale_handle) { + if (!cc_out && !pragma) { + cc_out = cache_table_getm(r->pool, cache->stale_handle->resp_hdrs, + "Cache-Control"); + pragma = cache_table_getm(r->pool, cache->stale_handle->resp_hdrs, + "Pragma"); + } + + /* 304 does not contain Content-Type and mod_mime regenerates the + * Content-Type based on the r->filename. This would lead to original + * Content-Type to be lost (overwriten by whatever mod_mime generates). + * We preserves the original Content-Type here. */ + ap_set_content_type(r, apr_table_get( + cache->stale_handle->resp_hdrs, "Content-Type")); + } + + /* Parse the cache control header */ + memset(&control, 0, sizeof(cache_control_t)); + ap_cache_control(r, &control, cc_out, pragma, headers); + + /* + * what responses should we not cache? + * + * At this point we decide based on the response headers whether it + * is appropriate _NOT_ to cache the data from the server. There are + * a whole lot of conditions that prevent us from caching this data. + * They are tested here one by one to be clear and unambiguous. + */ + if (r->status != HTTP_OK && r->status != HTTP_NON_AUTHORITATIVE + && r->status != HTTP_PARTIAL_CONTENT + && r->status != HTTP_MULTIPLE_CHOICES + && r->status != HTTP_MOVED_PERMANENTLY + && r->status != HTTP_NOT_MODIFIED) { + /* RFC2616 13.4 we are allowed to cache 200, 203, 206, 300, 301 or 410 + * We allow the caching of 206, but a cache implementation might choose + * to decline to cache a 206 if it doesn't know how to. + * We include 304 Not Modified here too as this is the origin server + * telling us to serve the cached copy. + */ + if (exps != NULL || cc_out != NULL) { + /* We are also allowed to cache any response given that it has a + * valid Expires or Cache Control header. If we find a either of + * those here, we pass request through the rest of the tests. From + * the RFC: + * + * A response received with any other status code (e.g. status + * codes 302 and 307) MUST NOT be returned in a reply to a + * subsequent request unless there are cache-control directives or + * another header(s) that explicitly allow it. For example, these + * include the following: an Expires header (section 14.21); a + * "max-age", "s-maxage", "must-revalidate", "proxy-revalidate", + * "public" or "private" cache-control directive (section 14.9). + * + * FIXME: Wrong if cc_out has just an extension we don't know about + */ + } + else { + reason = apr_psprintf(p, "Response status %d", r->status); + } + } + + if (reason) { + /* noop */ + } + else if (!control.s_maxage && !control.max_age && !dconf->store_expired + && exps != NULL && exp == APR_DATE_BAD) { + /* if a broken Expires header is present, don't cache it + * Unless CC: s-maxage or max-age is present + */ + reason = apr_pstrcat(p, "Broken expires header: ", exps, NULL); + } + else if (!control.s_maxage && !control.max_age + && !dconf->store_expired && exp != APR_DATE_BAD + && exp < r->request_time) { + /* if a Expires header is in the past, don't cache it + * Unless CC: s-maxage or max-age is present + */ + reason = "Expires header already expired; not cacheable"; + } + else if (!dconf->store_expired && (control.must_revalidate + || control.proxy_revalidate) && (!control.s_maxage_value + || (!control.s_maxage && !control.max_age_value)) && lastmods + == NULL && etag == NULL) { + /* if we're already stale, but can never revalidate, don't cache it */ + reason + = "s-maxage or max-age zero and no Last-Modified or Etag; not cacheable"; + } + else if (!conf->ignorequerystring && query && exps == NULL + && !control.max_age && !control.s_maxage) { + /* if a query string is present but no explicit expiration time, + * don't cache it (RFC 2616/13.9 & 13.2.1) + */ + reason = "Query string present but no explicit expiration time"; + } + else if (r->status == HTTP_NOT_MODIFIED && + !cache->handle && !cache->stale_handle) { + /* if the server said 304 Not Modified but we have no cache + * file - pass this untouched to the user agent, it's not for us. + */ + reason = "HTTP Status 304 Not Modified"; + } + else if (r->status == HTTP_OK && lastmods == NULL && etag == NULL && (exps + == NULL) && (dconf->no_last_mod_ignore == 0) && !control.max_age + && !control.s_maxage) { + /* 200 OK response from HTTP/1.0 and up without Last-Modified, + * Etag, Expires, Cache-Control:max-age, or Cache-Control:s-maxage + * headers. + */ + /* Note: mod-include clears last_modified/expires/etags - this + * is why we have an optional function for a key-gen ;-) + */ + reason = "No Last-Modified; Etag; Expires; Cache-Control:max-age or Cache-Control:s-maxage headers"; + } + else if (!dconf->store_nostore && control.no_store) { + /* RFC2616 14.9.2 Cache-Control: no-store response + * indicating do not cache, or stop now if you are + * trying to cache it. + */ + reason = "Cache-Control: no-store present"; + } + else if (!dconf->store_private && control.private) { + /* RFC2616 14.9.1 Cache-Control: private response + * this object is marked for this user's eyes only. Behave + * as a tunnel. + */ + reason = "Cache-Control: private present"; + } + else if (apr_table_get(r->headers_in, "Authorization") + && !(control.s_maxage || control.must_revalidate + || control.proxy_revalidate || control.public)) { + /* RFC2616 14.8 Authorisation: + * if authorisation is included in the request, we don't cache, + * but we can cache if the following exceptions are true: + * 1) If Cache-Control: s-maxage is included + * 2) If Cache-Control: must-revalidate is included + * 3) If Cache-Control: public is included + */ + reason = "Authorization required"; + } + else if (ap_find_token(NULL, apr_table_get(r->headers_out, "Vary"), "*")) { + reason = "Vary header contains '*'"; + } + else if (apr_table_get(r->subprocess_env, "no-cache") != NULL) { + reason = "environment variable 'no-cache' is set"; + } + else if (r->no_cache) { + /* or we've been asked not to cache it above */ + reason = "r->no_cache present"; + } + else if (cache->stale_handle + && APR_DATE_BAD + != (date = apr_date_parse_http( + apr_table_get(r->headers_out, "Date"))) + && date < cache->stale_handle->cache_obj->info.date) { + + /** + * 13.12 Cache Replacement: + * + * Note: a new response that has an older Date header value than + * existing cached responses is not cacheable. + */ + reason = "updated entity is older than cached entity"; + + /* while this response is not cacheable, the previous response still is */ + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(02474) + "cache: Removing CACHE_REMOVE_URL filter."); + ap_remove_output_filter(cache->remove_url_filter); + } + else if (r->status == HTTP_NOT_MODIFIED && cache->stale_handle) { + apr_table_t *left = cache->stale_handle->resp_hdrs; + apr_table_t *right = r->headers_out; + const char *ehs = NULL; + + /* and lastly, contradiction checks for revalidated responses + * as per RFC2616 Section 10.3.5 + */ + if (cache_header_cmp(r->pool, left, right, "ETag")) { + ehs = "ETag"; + } + for (eh = MOD_CACHE_ENTITY_HEADERS; *eh; ++eh) { + if (cache_header_cmp(r->pool, left, right, *eh)) { + ehs = (ehs) ? apr_pstrcat(r->pool, ehs, ", ", *eh, NULL) : *eh; + } + } + if (ehs) { + reason = apr_pstrcat(r->pool, "contradiction: 304 Not Modified; " + "but ", ehs, " modified", NULL); + } + } + + /** + * Enforce RFC2616 Section 10.3.5, just in case. We caught any + * inconsistencies above. + * + * If the conditional GET used a strong cache validator (see section + * 13.3.3), the response SHOULD NOT include other entity-headers. + * Otherwise (i.e., the conditional GET used a weak validator), the + * response MUST NOT include other entity-headers; this prevents + * inconsistencies between cached entity-bodies and updated headers. + */ + if (r->status == HTTP_NOT_MODIFIED) { + for (eh = MOD_CACHE_ENTITY_HEADERS; *eh; ++eh) { + apr_table_unset(r->headers_out, *eh); + } + } + + /* Hold the phone. Some servers might allow us to cache a 2xx, but + * then make their 304 responses non cacheable. RFC2616 says this: + * + * If a 304 response indicates an entity not currently cached, then + * the cache MUST disregard the response and repeat the request + * without the conditional. + * + * A 304 response with contradictory headers is technically a + * different entity, to be safe, we remove the entity from the cache. + */ + if (reason && r->status == HTTP_NOT_MODIFIED && cache->stale_handle) { + + ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, r, APLOGNO(02473) + "cache: %s responded with an uncacheable 304, " + "retrying the request %s. Reason: %s", + cache->key, r->unparsed_uri, reason); + + /* we've got a cache conditional miss! tell anyone who cares */ + cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS, + apr_psprintf(r->pool, + "conditional cache miss: 304 was uncacheable, entity removed: %s", + reason)); + + /* remove the cached entity immediately, we might cache it again */ + ap_remove_output_filter(cache->remove_url_filter); + cache_remove_url(cache, r); + + /* let someone else attempt to cache */ + cache_remove_lock(conf, cache, r, NULL); + + /* remove this filter from the chain */ + ap_remove_output_filter(f); + + /* retry without the conditionals */ + apr_table_unset(r->headers_in, "If-Match"); + apr_table_unset(r->headers_in, "If-Modified-Since"); + apr_table_unset(r->headers_in, "If-None-Match"); + apr_table_unset(r->headers_in, "If-Range"); + apr_table_unset(r->headers_in, "If-Unmodified-Since"); + + /* Currently HTTP_NOT_MODIFIED, and after the redirect, handlers won't think to set status to HTTP_OK */ + r->status = HTTP_OK; + ap_internal_redirect(r->unparsed_uri, r); + + return APR_SUCCESS; + } + + if (reason) { + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00768) + "cache: %s not cached for request %s. Reason: %s", + cache->key, r->unparsed_uri, reason); + + /* we've got a cache miss! tell anyone who cares */ + cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS, + reason); + + /* remove this filter from the chain */ + ap_remove_output_filter(f); + + /* remove the lock file unconditionally */ + cache_remove_lock(conf, cache, r, NULL); + + /* ship the data up the stack */ + return ap_pass_brigade(f->next, in); + } + + /* Make it so that we don't execute this path again. */ + cache->in_checked = 1; + + /* Set the content length if known. + */ + cl = apr_table_get(r->err_headers_out, "Content-Length"); + if (cl == NULL) { + cl = apr_table_get(r->headers_out, "Content-Length"); + } + if (cl) { + char *errp; + if (apr_strtoff(&size, cl, &errp, 10) || *errp || size < 0) { + cl = NULL; /* parse error, see next 'if' block */ + } + } + + if (!cl) { + /* if we don't get the content-length, see if we have all the + * buckets and use their length to calculate the size + */ + int all_buckets_here=0; + size=0; + for (e = APR_BRIGADE_FIRST(in); + e != APR_BRIGADE_SENTINEL(in); + e = APR_BUCKET_NEXT(e)) + { + if (APR_BUCKET_IS_EOS(e)) { + all_buckets_here=1; + break; + } + if (APR_BUCKET_IS_FLUSH(e)) { + continue; + } + if (e->length == (apr_size_t)-1) { + break; + } + size += e->length; + } + if (!all_buckets_here) { + size = -1; + } + } + + /* remember content length to check response size against later */ + cache->size = size; + + /* It's safe to cache the response. + * + * There are two possibilities at this point: + * - cache->handle == NULL. In this case there is no previously + * cached entity anywhere on the system. We must create a brand + * new entity and store the response in it. + * - cache->stale_handle != NULL. In this case there is a stale + * entity in the system which needs to be replaced by new + * content (unless the result was 304 Not Modified, which means + * the cached entity is actually fresh, and we should update + * the headers). + */ + + /* Did we have a stale cache entry that really is stale? + */ + if (cache->stale_handle) { + if (r->status == HTTP_NOT_MODIFIED) { + /* Oh, hey. It isn't that stale! Yay! */ + cache->handle = cache->stale_handle; + info = &cache->handle->cache_obj->info; + rv = OK; + } + else { + /* Oh, well. Toss it. */ + cache->provider->remove_entity(cache->stale_handle); + /* Treat the request as if it wasn't conditional. */ + cache->stale_handle = NULL; + /* + * Restore the original request headers as they may be needed + * by further output filters like the byterange filter to make + * the correct decisions. + */ + r->headers_in = cache->stale_headers; + } + } + + /* no cache handle, create a new entity */ + if (!cache->handle) { + rv = cache_create_entity(cache, r, size, in); + info = apr_pcalloc(r->pool, sizeof(cache_info)); + /* We only set info->status upon the initial creation. */ + info->status = r->status; + } + + if (rv != OK) { + /* we've got a cache miss! tell anyone who cares */ + cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS, + "cache miss: cache unwilling to store response"); + + /* Caching layer declined the opportunity to cache the response */ + ap_remove_output_filter(f); + cache_remove_lock(conf, cache, r, NULL); + return ap_pass_brigade(f->next, in); + } + + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00769) + "cache: Caching url %s for request %s", + cache->key, r->unparsed_uri); + + /* We are actually caching this response. So it does not + * make sense to remove this entity any more. + */ + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00770) + "cache: Removing CACHE_REMOVE_URL filter."); + ap_remove_output_filter(cache->remove_url_filter); + + /* + * We now want to update the cache file header information with + * the new date, last modified, expire and content length and write + * it away to our cache file. First, we determine these values from + * the response, using heuristics if appropriate. + * + * In addition, we make HTTP/1.1 age calculations and write them away + * too. + */ + + /* store away the previously parsed cache control headers */ + memcpy(&info->control, &control, sizeof(cache_control_t)); + + /* Read the date. Generate one if one is not supplied */ + dates = apr_table_get(r->err_headers_out, "Date"); + if (dates == NULL) { + dates = apr_table_get(r->headers_out, "Date"); + } + if (dates != NULL) { + info->date = apr_date_parse_http(dates); + } + else { + info->date = APR_DATE_BAD; + } + + now = apr_time_now(); + if (info->date == APR_DATE_BAD) { /* No, or bad date */ + /* no date header (or bad header)! */ + info->date = now; + } + date = info->date; + + /* set response_time for HTTP/1.1 age calculations */ + info->response_time = now; + + /* get the request time */ + info->request_time = r->request_time; + + /* check last-modified date */ + if (lastmod != APR_DATE_BAD && lastmod > date) { + /* if it's in the future, then replace by date */ + lastmod = date; + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, + r, APLOGNO(00771) "cache: Last modified is in the future, " + "replacing with now"); + } + + + /* CC has priority over Expires. */ + if (control.s_maxage || control.max_age) { + apr_int64_t x; + + x = control.s_maxage ? control.s_maxage_value : control.max_age_value; + x = x * MSEC_ONE_SEC; + + if (x < dconf->minex) { + x = dconf->minex; + } + if (x > dconf->maxex) { + x = dconf->maxex; + } + exp = date + x; + } + + /* if no expiry date then + * if Cache-Control: s-maxage + * expiry date = date + smaxage + * if Cache-Control: max-age + * expiry date = date + max-age + * else if lastmod + * expiry date = date + min((date - lastmod) * factor, maxexpire) + * else + * expire date = date + defaultexpire + */ + + if (exp == APR_DATE_BAD) { + if ((lastmod != APR_DATE_BAD) && (lastmod < date)) { + /* if lastmod == date then you get 0*conf->factor which results in + * an expiration time of now. This causes some problems with + * freshness calculations, so we choose the else path... + */ + apr_time_t x = (apr_time_t) ((date - lastmod) * dconf->factor); + + if (x < dconf->minex) { + x = dconf->minex; + } + if (x > dconf->maxex) { + x = dconf->maxex; + } + exp = date + x; + } + else { + exp = date + dconf->defex; + } + } + info->expire = exp; + + /* We found a stale entry which wasn't really stale. */ + if (cache->stale_handle) { + + /* RFC 2616 10.3.5 states that entity headers are not supposed + * to be in the 304 response. Therefore, we need to combine the + * response headers with the cached headers *before* we update + * the cached headers. + * + * However, before doing that, we need to first merge in + * err_headers_out (note that store_headers() below already selects + * the cacheable only headers using ap_cache_cacheable_headers_out(), + * here we want to keep the original headers in r->headers_out and + * forward all of them to the client, including non-cacheable ones). + */ + r->headers_out = cache_merge_headers_out(r); + apr_table_clear(r->err_headers_out); + + /* Merge in our cached headers. However, keep any updated values. */ + /* take output, overlay on top of cached */ + cache_accept_headers(cache->handle, r, r->headers_out, + cache->handle->resp_hdrs, 1); + } + + /* Write away header information to cache. It is possible that we are + * trying to update headers for an entity which has already been cached. + * + * This may fail, due to an unwritable cache area. E.g. filesystem full, + * permissions problems or a read-only (re)mount. This must be handled + * later. + */ + rv = cache->provider->store_headers(cache->handle, r, info); + + /* Did we just update the cached headers on a revalidated response? + * + * If so, we can now decide what to serve to the client. This is done in + * the same way as with a regular response, but conditions are now checked + * against the cached or merged response headers. + */ + if (cache->stale_handle) { + apr_bucket_brigade *bb; + apr_bucket *bkt; + int status; + + /* Load in the saved status and clear the status line. */ + r->status = info->status; + r->status_line = NULL; + + /* We're just saving response headers, so we are done. Commit + * the response at this point, unless there was a previous error. + */ + if (rv == APR_SUCCESS) { + rv = cache->provider->commit_entity(cache->handle, r); + } + + bb = apr_brigade_create(r->pool, r->connection->bucket_alloc); + + /* Restore the original request headers and see if we need to + * return anything else than the cached response (ie. the original + * request was conditional). + */ + r->headers_in = cache->stale_headers; + status = ap_meets_conditions(r); + if (status != OK) { + r->status = status; + + /* Strip the entity headers merged from the cached headers before + * updating the entry (see cache_accept_headers() above). + */ + for (eh = MOD_CACHE_ENTITY_HEADERS; *eh; ++eh) { + apr_table_unset(r->headers_out, *eh); + } + + bkt = apr_bucket_flush_create(bb->bucket_alloc); + APR_BRIGADE_INSERT_TAIL(bb, bkt); + } + else { + cache->provider->recall_body(cache->handle, r->pool, bb); + + bkt = apr_bucket_eos_create(bb->bucket_alloc); + APR_BRIGADE_INSERT_TAIL(bb, bkt); + } + + cache->block_response = 1; + + /* Before returning we need to handle the possible case of an + * unwritable cache. Rather than leaving the entity in the cache + * and having it constantly re-validated, now that we have recalled + * the body it is safe to try and remove the url from the cache. + */ + if (rv != APR_SUCCESS) { + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r, APLOGNO(00772) + "cache: updating headers with store_headers failed. " + "Removing cached url."); + + rv = cache->provider->remove_url(cache->stale_handle, r); + if (rv != OK) { + /* Probably a mod_cache_disk cache area has been (re)mounted + * read-only, or that there is a permissions problem. + */ + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r, APLOGNO(00773) + "cache: attempt to remove url from cache unsuccessful."); + } + + /* we've got a cache conditional hit! tell anyone who cares */ + cache_run_cache_status(cache->handle, r, r->headers_out, + AP_CACHE_REVALIDATE, + "conditional cache hit: entity refresh failed"); + + } + else { + + /* we've got a cache conditional hit! tell anyone who cares */ + cache_run_cache_status(cache->handle, r, r->headers_out, + AP_CACHE_REVALIDATE, + "conditional cache hit: entity refreshed"); + + } + + /* let someone else attempt to cache */ + cache_remove_lock(conf, cache, r, NULL); + + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(02971) + "cache: serving %s (revalidated)", r->uri); + + return ap_pass_brigade(f->next, bb); + } + + if (rv != APR_SUCCESS) { + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r, APLOGNO(00774) + "cache: store_headers failed"); + + /* we've got a cache miss! tell anyone who cares */ + cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS, + "cache miss: store_headers failed"); + + ap_remove_output_filter(f); + cache_remove_lock(conf, cache, r, NULL); + return ap_pass_brigade(f->next, in); + } + + /* we've got a cache miss! tell anyone who cares */ + cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS, + "cache miss: attempting entity save"); + + return cache_save_store(f, in, conf, cache); +} + +/* + * CACHE_REMOVE_URL filter + * ----------------------- + * + * This filter gets added in the quick handler every time the CACHE_SAVE filter + * gets inserted. Its purpose is to remove a confirmed stale cache entry from + * the cache. + * + * CACHE_REMOVE_URL has to be a protocol filter to ensure that is run even if + * the response is a canned error message, which removes the content filters + * and thus the CACHE_SAVE filter from the chain. + * + * CACHE_REMOVE_URL expects cache request rec within its context because the + * request this filter runs on can be different from the one whose cache entry + * should be removed, due to internal redirects. + * + * Note that CACHE_SAVE_URL (as a content-set filter, hence run before the + * protocol filters) will remove this filter if it decides to cache the file. + * Therefore, if this filter is left in, it must mean we need to toss any + * existing files. + */ +static apr_status_t cache_remove_url_filter(ap_filter_t *f, + apr_bucket_brigade *in) +{ + request_rec *r = f->r; + cache_request_rec *cache; + + /* Setup cache_request_rec */ + cache = (cache_request_rec *) f->ctx; + + if (!cache) { + /* user likely configured CACHE_REMOVE_URL manually; they should really + * use mod_cache configuration to do that. So: + * 1. Remove ourselves + * 2. Do nothing and bail out + */ + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00775) + "cache: CACHE_REMOVE_URL enabled unexpectedly"); + ap_remove_output_filter(f); + return ap_pass_brigade(f->next, in); + } + + /* Now remove this cache entry from the cache */ + cache_remove_url(cache, r); + + /* remove ourselves */ + ap_remove_output_filter(f); + return ap_pass_brigade(f->next, in); +} + +/* + * CACHE_INVALIDATE filter + * ----------------------- + * + * This filter gets added in the quick handler should a PUT, POST or DELETE + * method be detected. If the response is successful, we must invalidate any + * cached entity as per RFC2616 section 13.10. + * + * CACHE_INVALIDATE has to be a protocol filter to ensure that is run even if + * the response is a canned error message, which removes the content filters + * from the chain. + * + * CACHE_INVALIDATE expects cache request rec within its context because the + * request this filter runs on can be different from the one whose cache entry + * should be removed, due to internal redirects. + */ +static apr_status_t cache_invalidate_filter(ap_filter_t *f, + apr_bucket_brigade *in) +{ + request_rec *r = f->r; + cache_request_rec *cache; + + /* Setup cache_request_rec */ + cache = (cache_request_rec *) f->ctx; + + if (!cache) { + /* user likely configured CACHE_INVALIDATE manually; they should really + * use mod_cache configuration to do that. So: + * 1. Remove ourselves + * 2. Do nothing and bail out + */ + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(02465) + "cache: CACHE_INVALIDATE enabled unexpectedly: %s", r->uri); + } + else { + + if (r->status > 299) { + + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(02466) + "cache: response status to '%s' method is %d (>299), not invalidating cached entity: %s", r->method, r->status, r->uri); + + } + else { + + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(02467) + "cache: Invalidating all cached entities in response to '%s' request for %s", + r->method, r->uri); + + cache_invalidate(cache, r); + + /* we've got a cache invalidate! tell everyone who cares */ + cache_run_cache_status(cache->handle, r, r->headers_out, + AP_CACHE_INVALIDATE, apr_psprintf(r->pool, + "cache invalidated by %s", r->method)); + + } + + } + + /* remove ourselves */ + ap_remove_output_filter(f); + return ap_pass_brigade(f->next, in); +} + +/* + * CACHE filter + * ------------ + * + * This filter can be optionally inserted into the filter chain by the admin as + * a marker representing the precise location within the filter chain where + * caching is to be performed. + * + * When the filter chain is set up in the non-quick version of the URL handler, + * the CACHE filter is replaced by the CACHE_OUT or CACHE_SAVE filter, + * effectively inserting the caching filters at the point indicated by the + * admin. The CACHE filter is then removed. + * + * This allows caching to be performed before the content is passed to the + * INCLUDES filter, or to a filter that might perform transformations unique + * to the specific request and that would otherwise be non-cacheable. + */ +static apr_status_t cache_filter(ap_filter_t *f, apr_bucket_brigade *in) +{ + + cache_server_conf + *conf = + (cache_server_conf *) ap_get_module_config(f->r->server->module_config, + &cache_module); + + /* was the quick handler enabled */ + if (conf->quick) { + ap_log_rerror(APLOG_MARK, APLOG_WARNING, 0, f->r, APLOGNO(00776) + "cache: CACHE filter was added in quick handler mode and " + "will be ignored: %s", f->r->unparsed_uri); + } + /* otherwise we may have been bypassed, nothing to see here */ + else { + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, f->r, APLOGNO(00777) + "cache: CACHE filter was added twice, or was added where " + "the cache has been bypassed and will be ignored: %s", + f->r->unparsed_uri); + } + + /* we are just a marker, so let's just remove ourselves */ + ap_remove_output_filter(f); + return ap_pass_brigade(f->next, in); +} + +/** + * If configured, add the status of the caching attempt to the subprocess + * environment, and if configured, to headers in the response. + * + * The status is saved below the broad category of the status (hit, miss, + * revalidate), as well as a single cache-status key. This can be used for + * conditional logging. + * + * The status is optionally saved to an X-Cache header, and the detail of + * why a particular cache entry was cached (or not cached) is optionally + * saved to an X-Cache-Detail header. This extra detail is useful for + * service developers who may need to know whether their Cache-Control headers + * are working correctly. + */ +static int cache_status(cache_handle_t *h, request_rec *r, + apr_table_t *headers, ap_cache_status_e status, const char *reason) +{ + cache_server_conf + *conf = + (cache_server_conf *) ap_get_module_config(r->server->module_config, + &cache_module); + + cache_dir_conf *dconf = ap_get_module_config(r->per_dir_config, &cache_module); + int x_cache = 0, x_cache_detail = 0; + + switch (status) { + case AP_CACHE_HIT: { + apr_table_setn(r->subprocess_env, AP_CACHE_HIT_ENV, reason); + break; + } + case AP_CACHE_REVALIDATE: { + apr_table_setn(r->subprocess_env, AP_CACHE_REVALIDATE_ENV, reason); + break; + } + case AP_CACHE_MISS: { + apr_table_setn(r->subprocess_env, AP_CACHE_MISS_ENV, reason); + break; + } + case AP_CACHE_INVALIDATE: { + apr_table_setn(r->subprocess_env, AP_CACHE_INVALIDATE_ENV, reason); + break; + } + } + + apr_table_setn(r->subprocess_env, AP_CACHE_STATUS_ENV, reason); + + if (dconf && dconf->x_cache_set) { + x_cache = dconf->x_cache; + } + else { + x_cache = conf->x_cache; + } + if (x_cache) { + apr_table_setn(headers, "X-Cache", apr_psprintf(r->pool, "%s from %s", + status == AP_CACHE_HIT ? "HIT" + : status == AP_CACHE_REVALIDATE ? "REVALIDATE" : status + == AP_CACHE_INVALIDATE ? "INVALIDATE" : "MISS", + r->server->server_hostname)); + } + + if (dconf && dconf->x_cache_detail_set) { + x_cache_detail = dconf->x_cache_detail; + } + else { + x_cache_detail = conf->x_cache_detail; + } + if (x_cache_detail) { + apr_table_setn(headers, "X-Cache-Detail", apr_psprintf(r->pool, + "\"%s\" from %s", reason, r->server->server_hostname)); + } + + return OK; +} + +/** + * If an error has occurred, but we have a stale cached entry, restore the + * filter stack from the save filter onwards. The canned error message will + * be discarded in the process, and replaced with the cached response. + */ +static void cache_insert_error_filter(request_rec *r) +{ + void *dummy; + cache_dir_conf *dconf; + + /* ignore everything except for 5xx errors */ + if (r->status < HTTP_INTERNAL_SERVER_ERROR) { + return; + } + + dconf = ap_get_module_config(r->per_dir_config, &cache_module); + + if (!dconf->stale_on_error) { + return; + } + + /* RFC2616 13.8 Errors or Incomplete Response Cache Behavior: + * If a cache receives a 5xx response while attempting to revalidate an + * entry, it MAY either forward this response to the requesting client, + * or act as if the server failed to respond. In the latter case, it MAY + * return a previously received response unless the cached entry + * includes the "must-revalidate" cache-control directive (see section + * 14.9). + * + * This covers the case where the error was generated by our server via + * ap_die(). + */ + apr_pool_userdata_get(&dummy, CACHE_CTX_KEY, r->pool); + if (dummy) { + cache_request_rec *cache = (cache_request_rec *) dummy; + + ap_remove_output_filter(cache->remove_url_filter); + + if (cache->stale_handle && cache->save_filter + && !cache->stale_handle->cache_obj->info.control.must_revalidate + && !cache->stale_handle->cache_obj->info.control.proxy_revalidate + && !cache->stale_handle->cache_obj->info.control.s_maxage) { + const char *warn_head; + cache_server_conf + *conf = + (cache_server_conf *) ap_get_module_config(r->server->module_config, + &cache_module); + + /* morph the current save filter into the out filter, and serve from + * cache. + */ + cache->handle = cache->stale_handle; + if (r->main) { + cache->save_filter->frec = cache_out_subreq_filter_handle; + } + else { + cache->save_filter->frec = cache_out_filter_handle; + } + + r->output_filters = cache->save_filter; + + r->err_headers_out = cache->stale_handle->resp_hdrs; + + /* add a revalidation warning */ + warn_head = apr_table_get(r->err_headers_out, "Warning"); + if ((warn_head == NULL) || ((warn_head != NULL) + && (ap_strstr_c(warn_head, "111") == NULL))) { + apr_table_mergen(r->err_headers_out, "Warning", + "111 Revalidation failed"); + } + + cache_run_cache_status( + cache->handle, + r, + r->err_headers_out, + AP_CACHE_HIT, + apr_psprintf( + r->pool, + "cache hit: %d status; stale content returned", + r->status)); + + /* give someone else the chance to cache the file */ + cache_remove_lock(conf, cache, r, NULL); + + } + } + + return; +} + +/* -------------------------------------------------------------- */ +/* Setup configurable data */ + +static void *create_dir_config(apr_pool_t *p, char *dummy) +{ + cache_dir_conf *dconf = apr_pcalloc(p, sizeof(cache_dir_conf)); + + dconf->no_last_mod_ignore = 0; + dconf->store_expired = 0; + dconf->store_private = 0; + dconf->store_nostore = 0; + + /* maximum time to cache a document */ + dconf->maxex = DEFAULT_CACHE_MAXEXPIRE; + dconf->minex = DEFAULT_CACHE_MINEXPIRE; + /* default time to cache a document */ + dconf->defex = DEFAULT_CACHE_EXPIRE; + + /* factor used to estimate Expires date from LastModified date */ + dconf->factor = DEFAULT_CACHE_LMFACTOR; + + dconf->x_cache = DEFAULT_X_CACHE; + dconf->x_cache_detail = DEFAULT_X_CACHE_DETAIL; + + dconf->stale_on_error = DEFAULT_CACHE_STALE_ON_ERROR; + + /* array of providers for this URL space */ + dconf->cacheenable = apr_array_make(p, 10, sizeof(struct cache_enable)); + + return dconf; +} + +static void *merge_dir_config(apr_pool_t *p, void *basev, void *addv) { + cache_dir_conf *new = (cache_dir_conf *) apr_pcalloc(p, sizeof(cache_dir_conf)); + cache_dir_conf *add = (cache_dir_conf *) addv; + cache_dir_conf *base = (cache_dir_conf *) basev; + + new->no_last_mod_ignore = (add->no_last_mod_ignore_set == 0) ? base->no_last_mod_ignore : add->no_last_mod_ignore; + new->no_last_mod_ignore_set = add->no_last_mod_ignore_set || base->no_last_mod_ignore_set; + + new->store_expired = (add->store_expired_set == 0) ? base->store_expired : add->store_expired; + new->store_expired_set = add->store_expired_set || base->store_expired_set; + new->store_private = (add->store_private_set == 0) ? base->store_private : add->store_private; + new->store_private_set = add->store_private_set || base->store_private_set; + new->store_nostore = (add->store_nostore_set == 0) ? base->store_nostore : add->store_nostore; + new->store_nostore_set = add->store_nostore_set || base->store_nostore_set; + + /* maximum time to cache a document */ + new->maxex = (add->maxex_set == 0) ? base->maxex : add->maxex; + new->maxex_set = add->maxex_set || base->maxex_set; + new->minex = (add->minex_set == 0) ? base->minex : add->minex; + new->minex_set = add->minex_set || base->minex_set; + + /* default time to cache a document */ + new->defex = (add->defex_set == 0) ? base->defex : add->defex; + new->defex_set = add->defex_set || base->defex_set; + + /* factor used to estimate Expires date from LastModified date */ + new->factor = (add->factor_set == 0) ? base->factor : add->factor; + new->factor_set = add->factor_set || base->factor_set; + + new->x_cache = (add->x_cache_set == 0) ? base->x_cache : add->x_cache; + new->x_cache_set = add->x_cache_set || base->x_cache_set; + new->x_cache_detail = (add->x_cache_detail_set == 0) ? base->x_cache_detail + : add->x_cache_detail; + new->x_cache_detail_set = add->x_cache_detail_set + || base->x_cache_detail_set; + + new->stale_on_error = (add->stale_on_error_set == 0) ? base->stale_on_error + : add->stale_on_error; + new->stale_on_error_set = add->stale_on_error_set + || base->stale_on_error_set; + + new->cacheenable = add->enable_set ? apr_array_append(p, base->cacheenable, + add->cacheenable) : base->cacheenable; + new->enable_set = add->enable_set || base->enable_set; + new->disable = (add->disable_set == 0) ? base->disable : add->disable; + new->disable_set = add->disable_set || base->disable_set; + + return new; +} + +static void * create_cache_config(apr_pool_t *p, server_rec *s) +{ + const char *tmppath = NULL; + cache_server_conf *ps = apr_pcalloc(p, sizeof(cache_server_conf)); + + /* array of URL prefixes for which caching is enabled */ + ps->cacheenable = apr_array_make(p, 10, sizeof(struct cache_enable)); + /* array of URL prefixes for which caching is disabled */ + ps->cachedisable = apr_array_make(p, 10, sizeof(struct cache_disable)); + ps->ignorecachecontrol = 0; + ps->ignorecachecontrol_set = 0; + /* array of headers that should not be stored in cache */ + ps->ignore_headers = apr_array_make(p, 10, sizeof(char *)); + ps->ignore_headers_set = CACHE_IGNORE_HEADERS_UNSET; + /* flag indicating that query-string should be ignored when caching */ + ps->ignorequerystring = 0; + ps->ignorequerystring_set = 0; + /* by default, run in the quick handler */ + ps->quick = 1; + ps->quick_set = 0; + /* array of identifiers that should not be used for key calculation */ + ps->ignore_session_id = apr_array_make(p, 10, sizeof(char *)); + ps->ignore_session_id_set = CACHE_IGNORE_SESSION_ID_UNSET; + ps->lock = 0; /* thundering herd lock defaults to off */ + ps->lock_set = 0; + apr_temp_dir_get(&tmppath, p); + if (tmppath) { + ps->lockpath = apr_pstrcat(p, tmppath, DEFAULT_CACHE_LOCKPATH, NULL); + } + ps->lockmaxage = apr_time_from_sec(DEFAULT_CACHE_MAXAGE); + ps->x_cache = DEFAULT_X_CACHE; + ps->x_cache_detail = DEFAULT_X_CACHE_DETAIL; + return ps; +} + +static void * merge_cache_config(apr_pool_t *p, void *basev, void *overridesv) +{ + cache_server_conf *ps = apr_pcalloc(p, sizeof(cache_server_conf)); + cache_server_conf *base = (cache_server_conf *) basev; + cache_server_conf *overrides = (cache_server_conf *) overridesv; + + /* array of URL prefixes for which caching is disabled */ + ps->cachedisable = apr_array_append(p, + base->cachedisable, + overrides->cachedisable); + /* array of URL prefixes for which caching is enabled */ + ps->cacheenable = apr_array_append(p, + base->cacheenable, + overrides->cacheenable); + + ps->ignorecachecontrol = + (overrides->ignorecachecontrol_set == 0) + ? base->ignorecachecontrol + : overrides->ignorecachecontrol; + ps->ignore_headers = + (overrides->ignore_headers_set == CACHE_IGNORE_HEADERS_UNSET) + ? base->ignore_headers + : overrides->ignore_headers; + ps->ignorequerystring = + (overrides->ignorequerystring_set == 0) + ? base->ignorequerystring + : overrides->ignorequerystring; + ps->ignore_session_id = + (overrides->ignore_session_id_set == CACHE_IGNORE_SESSION_ID_UNSET) + ? base->ignore_session_id + : overrides->ignore_session_id; + ps->lock = + (overrides->lock_set == 0) + ? base->lock + : overrides->lock; + ps->lockpath = + (overrides->lockpath_set == 0) + ? base->lockpath + : overrides->lockpath; + ps->lockmaxage = + (overrides->lockmaxage_set == 0) + ? base->lockmaxage + : overrides->lockmaxage; + ps->quick = + (overrides->quick_set == 0) + ? base->quick + : overrides->quick; + ps->x_cache = + (overrides->x_cache_set == 0) + ? base->x_cache + : overrides->x_cache; + ps->x_cache_detail = + (overrides->x_cache_detail_set == 0) + ? base->x_cache_detail + : overrides->x_cache_detail; + ps->base_uri = + (overrides->base_uri_set == 0) + ? base->base_uri + : overrides->base_uri; + return ps; +} + +static const char *set_cache_quick_handler(cmd_parms *parms, void *dummy, + int flag) +{ + cache_server_conf *conf; + + conf = + (cache_server_conf *)ap_get_module_config(parms->server->module_config, + &cache_module); + conf->quick = flag; + conf->quick_set = 1; + return NULL; + +} + +static const char *set_cache_ignore_no_last_mod(cmd_parms *parms, void *dummy, + int flag) +{ + cache_dir_conf *dconf = (cache_dir_conf *)dummy; + + dconf->no_last_mod_ignore = flag; + dconf->no_last_mod_ignore_set = 1; + return NULL; + +} + +static const char *set_cache_ignore_cachecontrol(cmd_parms *parms, + void *dummy, int flag) +{ + cache_server_conf *conf; + + conf = + (cache_server_conf *)ap_get_module_config(parms->server->module_config, + &cache_module); + conf->ignorecachecontrol = flag; + conf->ignorecachecontrol_set = 1; + return NULL; +} + +static const char *set_cache_store_expired(cmd_parms *parms, void *dummy, + int flag) +{ + cache_dir_conf *dconf = (cache_dir_conf *)dummy; + + dconf->store_expired = flag; + dconf->store_expired_set = 1; + return NULL; +} + +static const char *set_cache_store_private(cmd_parms *parms, void *dummy, + int flag) +{ + cache_dir_conf *dconf = (cache_dir_conf *)dummy; + + dconf->store_private = flag; + dconf->store_private_set = 1; + return NULL; +} + +static const char *set_cache_store_nostore(cmd_parms *parms, void *dummy, + int flag) +{ + cache_dir_conf *dconf = (cache_dir_conf *)dummy; + + dconf->store_nostore = flag; + dconf->store_nostore_set = 1; + return NULL; +} + +static const char *add_ignore_header(cmd_parms *parms, void *dummy, + const char *header) +{ + cache_server_conf *conf; + char **new; + + conf = + (cache_server_conf *)ap_get_module_config(parms->server->module_config, + &cache_module); + if (!strcasecmp(header, "None")) { + /* if header None is listed clear array */ + conf->ignore_headers->nelts = 0; + } + else { + if ((conf->ignore_headers_set == CACHE_IGNORE_HEADERS_UNSET) || + (conf->ignore_headers->nelts)) { + /* Only add header if no "None" has been found in header list + * so far. + * (When 'None' is passed, IGNORE_HEADERS_SET && nelts == 0.) + */ + new = (char **)apr_array_push(conf->ignore_headers); + (*new) = (char *)header; + } + } + conf->ignore_headers_set = CACHE_IGNORE_HEADERS_SET; + return NULL; +} + +static const char *add_ignore_session_id(cmd_parms *parms, void *dummy, + const char *identifier) +{ + cache_server_conf *conf; + char **new; + + conf = + (cache_server_conf *)ap_get_module_config(parms->server->module_config, + &cache_module); + if (!strcasecmp(identifier, "None")) { + /* if identifier None is listed clear array */ + conf->ignore_session_id->nelts = 0; + } + else { + if ((conf->ignore_session_id_set == CACHE_IGNORE_SESSION_ID_UNSET) || + (conf->ignore_session_id->nelts)) { + /* + * Only add identifier if no "None" has been found in identifier + * list so far. + */ + new = (char **)apr_array_push(conf->ignore_session_id); + (*new) = (char *)identifier; + } + } + conf->ignore_session_id_set = CACHE_IGNORE_SESSION_ID_SET; + return NULL; +} + +static const char *add_cache_enable(cmd_parms *parms, void *dummy, + const char *type, + const char *url) +{ + cache_dir_conf *dconf = (cache_dir_conf *)dummy; + cache_server_conf *conf; + struct cache_enable *new; + + const char *err = ap_check_cmd_context(parms, + NOT_IN_DIRECTORY|NOT_IN_LIMIT|NOT_IN_FILES); + if (err != NULL) { + return err; + } + + if (*type == '/') { + return apr_psprintf(parms->pool, + "provider (%s) starts with a '/'. Are url and provider switched?", + type); + } + + if (!url) { + url = parms->path; + } + if (!url) { + return apr_psprintf(parms->pool, + "CacheEnable provider (%s) is missing an URL.", type); + } + if (parms->path && strncmp(parms->path, url, strlen(parms->path))) { + return "When in a Location, CacheEnable must specify a path or an URL below " + "that location."; + } + + conf = + (cache_server_conf *)ap_get_module_config(parms->server->module_config, + &cache_module); + + if (parms->path) { + new = apr_array_push(dconf->cacheenable); + dconf->enable_set = 1; + } + else { + new = apr_array_push(conf->cacheenable); + } + + new->type = type; + if (apr_uri_parse(parms->pool, url, &(new->url))) { + return NULL; + } + if (new->url.path) { + new->pathlen = strlen(new->url.path); + } else { + new->pathlen = 1; + new->url.path = "/"; + } + return NULL; +} + +static const char *add_cache_disable(cmd_parms *parms, void *dummy, + const char *url) +{ + cache_dir_conf *dconf = (cache_dir_conf *)dummy; + cache_server_conf *conf; + struct cache_disable *new; + + const char *err = ap_check_cmd_context(parms, + NOT_IN_DIRECTORY|NOT_IN_LIMIT|NOT_IN_FILES); + if (err != NULL) { + return err; + } + + conf = + (cache_server_conf *)ap_get_module_config(parms->server->module_config, + &cache_module); + + if (parms->path) { + if (!strcasecmp(url, "on")) { + dconf->disable = 1; + dconf->disable_set = 1; + return NULL; + } + else { + return "CacheDisable must be followed by the word 'on' when in a Location."; + } + } + + if (!url || (url[0] != '/' && !ap_strchr_c(url, ':'))) { + return "CacheDisable must specify a path or an URL."; + } + + new = apr_array_push(conf->cachedisable); + if (apr_uri_parse(parms->pool, url, &(new->url))) { + return NULL; + } + if (new->url.path) { + new->pathlen = strlen(new->url.path); + } else { + new->pathlen = 1; + new->url.path = "/"; + } + return NULL; +} + +static const char *set_cache_maxex(cmd_parms *parms, void *dummy, + const char *arg) +{ + cache_dir_conf *dconf = (cache_dir_conf *)dummy; + + dconf->maxex = (apr_time_t) (atol(arg) * MSEC_ONE_SEC); + dconf->maxex_set = 1; + return NULL; +} + +static const char *set_cache_minex(cmd_parms *parms, void *dummy, + const char *arg) +{ + cache_dir_conf *dconf = (cache_dir_conf *)dummy; + + dconf->minex = (apr_time_t) (atol(arg) * MSEC_ONE_SEC); + dconf->minex_set = 1; + return NULL; +} + +static const char *set_cache_defex(cmd_parms *parms, void *dummy, + const char *arg) +{ + cache_dir_conf *dconf = (cache_dir_conf *)dummy; + + dconf->defex = (apr_time_t) (atol(arg) * MSEC_ONE_SEC); + dconf->defex_set = 1; + return NULL; +} + +static const char *set_cache_factor(cmd_parms *parms, void *dummy, + const char *arg) +{ + cache_dir_conf *dconf = (cache_dir_conf *)dummy; + double val; + + if (sscanf(arg, "%lg", &val) != 1) { + return "CacheLastModifiedFactor value must be a float"; + } + dconf->factor = val; + dconf->factor_set = 1; + return NULL; +} + +static const char *set_cache_ignore_querystring(cmd_parms *parms, void *dummy, + int flag) +{ + cache_server_conf *conf; + + conf = + (cache_server_conf *)ap_get_module_config(parms->server->module_config, + &cache_module); + conf->ignorequerystring = flag; + conf->ignorequerystring_set = 1; + return NULL; +} + +static const char *set_cache_lock(cmd_parms *parms, void *dummy, + int flag) +{ + cache_server_conf *conf; + + conf = + (cache_server_conf *)ap_get_module_config(parms->server->module_config, + &cache_module); + conf->lock = flag; + conf->lock_set = 1; + return NULL; +} + +static const char *set_cache_lock_path(cmd_parms *parms, void *dummy, + const char *arg) +{ + cache_server_conf *conf; + + conf = + (cache_server_conf *)ap_get_module_config(parms->server->module_config, + &cache_module); + + conf->lockpath = ap_server_root_relative(parms->pool, arg); + if (!conf->lockpath) { + return apr_pstrcat(parms->pool, "Invalid CacheLockPath path ", + arg, NULL); + } + conf->lockpath_set = 1; + return NULL; +} + +static const char *set_cache_lock_maxage(cmd_parms *parms, void *dummy, + const char *arg) +{ + cache_server_conf *conf; + apr_int64_t seconds; + + conf = + (cache_server_conf *)ap_get_module_config(parms->server->module_config, + &cache_module); + seconds = apr_atoi64(arg); + if (seconds <= 0) { + return "CacheLockMaxAge value must be a non-zero positive integer"; + } + conf->lockmaxage = apr_time_from_sec(seconds); + conf->lockmaxage_set = 1; + return NULL; +} + +static const char *set_cache_x_cache(cmd_parms *parms, void *dummy, int flag) +{ + + if (parms->path) { + cache_dir_conf *dconf = (cache_dir_conf *)dummy; + + dconf->x_cache = flag; + dconf->x_cache_set = 1; + + } + else { + cache_server_conf *conf = + (cache_server_conf *)ap_get_module_config(parms->server->module_config, + &cache_module); + + conf->x_cache = flag; + conf->x_cache_set = 1; + + } + + return NULL; +} + +static const char *set_cache_x_cache_detail(cmd_parms *parms, void *dummy, int flag) +{ + + if (parms->path) { + cache_dir_conf *dconf = (cache_dir_conf *)dummy; + + dconf->x_cache_detail = flag; + dconf->x_cache_detail_set = 1; + + } + else { + cache_server_conf *conf = + (cache_server_conf *)ap_get_module_config(parms->server->module_config, + &cache_module); + + conf->x_cache_detail = flag; + conf->x_cache_detail_set = 1; + + } + + return NULL; +} + +static const char *set_cache_key_base_url(cmd_parms *parms, void *dummy, + const char *arg) +{ + cache_server_conf *conf; + apr_status_t rv; + + conf = + (cache_server_conf *)ap_get_module_config(parms->server->module_config, + &cache_module); + conf->base_uri = apr_pcalloc(parms->pool, sizeof(apr_uri_t)); + rv = apr_uri_parse(parms->pool, arg, conf->base_uri); + if (rv != APR_SUCCESS) { + return apr_psprintf(parms->pool, "Could not parse '%s' as an URL.", arg); + } + else if (!conf->base_uri->scheme && !conf->base_uri->hostname && + !conf->base_uri->port_str) { + return apr_psprintf(parms->pool, "URL '%s' must contain at least one of a scheme, a hostname or a port.", arg); + } + conf->base_uri_set = 1; + return NULL; +} + +static const char *set_cache_stale_on_error(cmd_parms *parms, void *dummy, + int flag) +{ + cache_dir_conf *dconf = (cache_dir_conf *)dummy; + + dconf->stale_on_error = flag; + dconf->stale_on_error_set = 1; + return NULL; +} + +static int cache_post_config(apr_pool_t *p, apr_pool_t *plog, + apr_pool_t *ptemp, server_rec *s) +{ + /* This is the means by which unusual (non-unix) os's may find alternate + * means to run a given command (e.g. shebang/registry parsing on Win32) + */ + cache_generate_key = APR_RETRIEVE_OPTIONAL_FN(ap_cache_generate_key); + if (!cache_generate_key) { + cache_generate_key = cache_generate_key_default; + } + return OK; +} + + +static const command_rec cache_cmds[] = +{ + /* XXX + * Consider a new config directive that enables loading specific cache + * implememtations (like mod_cache_mem, mod_cache_file, etc.). + * Rather than using a LoadModule directive, admin would use something + * like CacheModule mem_cache_module | file_cache_module, etc, + * which would cause the approprpriate cache module to be loaded. + * This is more intuitive that requiring a LoadModule directive. + */ + + AP_INIT_TAKE12("CacheEnable", add_cache_enable, NULL, RSRC_CONF|ACCESS_CONF, + "A cache type and partial URL prefix below which " + "caching is enabled"), + AP_INIT_TAKE1("CacheDisable", add_cache_disable, NULL, RSRC_CONF|ACCESS_CONF, + "A partial URL prefix below which caching is disabled"), + AP_INIT_TAKE1("CacheMaxExpire", set_cache_maxex, NULL, RSRC_CONF|ACCESS_CONF, + "The maximum time in seconds to cache a document"), + AP_INIT_TAKE1("CacheMinExpire", set_cache_minex, NULL, RSRC_CONF|ACCESS_CONF, + "The minimum time in seconds to cache a document"), + AP_INIT_TAKE1("CacheDefaultExpire", set_cache_defex, NULL, RSRC_CONF|ACCESS_CONF, + "The default time in seconds to cache a document"), + AP_INIT_FLAG("CacheQuickHandler", set_cache_quick_handler, NULL, + RSRC_CONF, + "Run the cache in the quick handler, default on"), + AP_INIT_FLAG("CacheIgnoreNoLastMod", set_cache_ignore_no_last_mod, NULL, + RSRC_CONF|ACCESS_CONF, + "Ignore Responses where there is no Last Modified Header"), + AP_INIT_FLAG("CacheIgnoreCacheControl", set_cache_ignore_cachecontrol, + NULL, RSRC_CONF, + "Ignore requests from the client for uncached content"), + AP_INIT_FLAG("CacheStoreExpired", set_cache_store_expired, + NULL, RSRC_CONF|ACCESS_CONF, + "Ignore expiration dates when populating cache, resulting in " + "an If-Modified-Since request to the backend on retrieval"), + AP_INIT_FLAG("CacheStorePrivate", set_cache_store_private, + NULL, RSRC_CONF|ACCESS_CONF, + "Ignore 'Cache-Control: private' and store private content"), + AP_INIT_FLAG("CacheStoreNoStore", set_cache_store_nostore, + NULL, RSRC_CONF|ACCESS_CONF, + "Ignore 'Cache-Control: no-store' and store sensitive content"), + AP_INIT_ITERATE("CacheIgnoreHeaders", add_ignore_header, NULL, RSRC_CONF, + "A space separated list of headers that should not be " + "stored by the cache"), + AP_INIT_FLAG("CacheIgnoreQueryString", set_cache_ignore_querystring, + NULL, RSRC_CONF, + "Ignore query-string when caching"), + AP_INIT_ITERATE("CacheIgnoreURLSessionIdentifiers", add_ignore_session_id, + NULL, RSRC_CONF, "A space separated list of session " + "identifiers that should be ignored for creating the key " + "of the cached entity."), + AP_INIT_TAKE1("CacheLastModifiedFactor", set_cache_factor, NULL, RSRC_CONF|ACCESS_CONF, + "The factor used to estimate Expires date from " + "LastModified date"), + AP_INIT_FLAG("CacheLock", set_cache_lock, + NULL, RSRC_CONF, + "Enable or disable the thundering herd lock."), + AP_INIT_TAKE1("CacheLockPath", set_cache_lock_path, NULL, RSRC_CONF, + "The thundering herd lock path. Defaults to the '" + DEFAULT_CACHE_LOCKPATH "' directory in the system " + "temp directory."), + AP_INIT_TAKE1("CacheLockMaxAge", set_cache_lock_maxage, NULL, RSRC_CONF, + "Maximum age of any thundering herd lock."), + AP_INIT_FLAG("CacheHeader", set_cache_x_cache, NULL, RSRC_CONF | ACCESS_CONF, + "Add a X-Cache header to responses. Default is off."), + AP_INIT_FLAG("CacheDetailHeader", set_cache_x_cache_detail, NULL, + RSRC_CONF | ACCESS_CONF, + "Add a X-Cache-Detail header to responses. Default is off."), + AP_INIT_TAKE1("CacheKeyBaseURL", set_cache_key_base_url, NULL, RSRC_CONF, + "Override the base URL of reverse proxied cache keys."), + AP_INIT_FLAG("CacheStaleOnError", set_cache_stale_on_error, + NULL, RSRC_CONF|ACCESS_CONF, + "Serve stale content on 5xx errors if present. Defaults to on."), + {NULL} +}; + +static void register_hooks(apr_pool_t *p) +{ + /* cache initializer */ + /* cache quick handler */ + ap_hook_quick_handler(cache_quick_handler, NULL, NULL, APR_HOOK_FIRST); + /* cache handler */ + ap_hook_handler(cache_handler, NULL, NULL, APR_HOOK_REALLY_FIRST); + /* cache status */ + cache_hook_cache_status(cache_status, NULL, NULL, APR_HOOK_MIDDLE); + /* cache error handler */ + ap_hook_insert_error_filter(cache_insert_error_filter, NULL, NULL, APR_HOOK_MIDDLE); + /* cache filters + * XXX The cache filters need to run right after the handlers and before + * any other filters. Consider creating AP_FTYPE_CACHE for this purpose. + * + * Depending on the type of request (subrequest / main request) they + * need to be run before AP_FTYPE_CONTENT_SET / after AP_FTYPE_CONTENT_SET + * filters. Thus create two filter handles for each type: + * cache_save_filter_handle / cache_out_filter_handle to be used by + * main requests and + * cache_save_subreq_filter_handle / cache_out_subreq_filter_handle + * to be run by subrequest + */ + /* + * CACHE is placed into the filter chain at an admin specified location, + * and when the cache_handler is run, the CACHE filter is swapped with + * the CACHE_OUT filter, or CACHE_SAVE filter as appropriate. This has + * the effect of offering optional fine control of where the cache is + * inserted into the filter chain. + */ + cache_filter_handle = + ap_register_output_filter("CACHE", + cache_filter, + NULL, + AP_FTYPE_RESOURCE); + /* + * CACHE_SAVE must go into the filter chain after a possible DEFLATE + * filter to ensure that the compressed content is stored. + * Incrementing filter type by 1 ensures this happens. + */ + cache_save_filter_handle = + ap_register_output_filter("CACHE_SAVE", + cache_save_filter, + NULL, + AP_FTYPE_CONTENT_SET+1); + /* + * CACHE_SAVE_SUBREQ must go into the filter chain before SUBREQ_CORE to + * handle subrequsts. Decrementing filter type by 1 ensures this + * happens. + */ + cache_save_subreq_filter_handle = + ap_register_output_filter("CACHE_SAVE_SUBREQ", + cache_save_filter, + NULL, + AP_FTYPE_CONTENT_SET-1); + /* + * CACHE_OUT must go into the filter chain after a possible DEFLATE + * filter to ensure that already compressed cache objects do not + * get compressed again. Incrementing filter type by 1 ensures + * this happens. + */ + cache_out_filter_handle = + ap_register_output_filter("CACHE_OUT", + cache_out_filter, + NULL, + AP_FTYPE_CONTENT_SET+1); + /* + * CACHE_OUT_SUBREQ must go into the filter chain before SUBREQ_CORE to + * handle subrequsts. Decrementing filter type by 1 ensures this + * happens. + */ + cache_out_subreq_filter_handle = + ap_register_output_filter("CACHE_OUT_SUBREQ", + cache_out_filter, + NULL, + AP_FTYPE_CONTENT_SET-1); + /* CACHE_REMOVE_URL has to be a protocol filter to ensure that is + * run even if the response is a canned error message, which + * removes the content filters. + */ + cache_remove_url_filter_handle = + ap_register_output_filter("CACHE_REMOVE_URL", + cache_remove_url_filter, + NULL, + AP_FTYPE_PROTOCOL); + cache_invalidate_filter_handle = + ap_register_output_filter("CACHE_INVALIDATE", + cache_invalidate_filter, + NULL, + AP_FTYPE_PROTOCOL); + ap_hook_post_config(cache_post_config, NULL, NULL, APR_HOOK_REALLY_FIRST); +} + +AP_DECLARE_MODULE(cache) = +{ + STANDARD20_MODULE_STUFF, + create_dir_config, /* create per-directory config structure */ + merge_dir_config, /* merge per-directory config structures */ + create_cache_config, /* create per-server config structure */ + merge_cache_config, /* merge per-server config structures */ + cache_cmds, /* command apr_table_t */ + register_hooks +}; + +APR_HOOK_STRUCT( + APR_HOOK_LINK(cache_status) +) + +APR_IMPLEMENT_EXTERNAL_HOOK_RUN_ALL(cache, CACHE, int, cache_status, + (cache_handle_t *h, request_rec *r, + apr_table_t *headers, ap_cache_status_e status, + const char *reason), (h, r, headers, status, reason), + OK, DECLINED) |