diff options
Diffstat (limited to 'modules/cache/cache_storage.c')
| -rw-r--r-- | modules/cache/cache_storage.c | 791 |
1 files changed, 791 insertions, 0 deletions
diff --git a/modules/cache/cache_storage.c b/modules/cache/cache_storage.c new file mode 100644 index 0000000..41f638c --- /dev/null +++ b/modules/cache/cache_storage.c @@ -0,0 +1,791 @@ +/* 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" + +APLOG_USE_MODULE(cache); + +extern APR_OPTIONAL_FN_TYPE(ap_cache_generate_key) *cache_generate_key; + +extern module AP_MODULE_DECLARE_DATA cache_module; + +/* -------------------------------------------------------------- */ + +/* + * delete all URL entities from the cache + * + */ +int cache_remove_url(cache_request_rec *cache, request_rec *r) +{ + cache_provider_list *list; + cache_handle_t *h; + + list = cache->providers; + + /* Remove the stale cache entry if present. If not, we're + * being called from outside of a request; remove the + * non-stale handle. + */ + h = cache->stale_handle ? cache->stale_handle : cache->handle; + if (!h) { + return OK; + } + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00691) + "cache: Removing url %s from the cache", h->cache_obj->key); + + /* for each specified cache type, delete the URL */ + while (list) { + list->provider->remove_url(h, r); + list = list->next; + } + return OK; +} + + +/* + * create a new URL entity in the cache + * + * It is possible to store more than once entity per URL. This + * function will always create a new entity, regardless of whether + * other entities already exist for the same URL. + * + * The size of the entity is provided so that a cache module can + * decide whether or not it wants to cache this particular entity. + * If the size is unknown, a size of -1 should be set. + */ +int cache_create_entity(cache_request_rec *cache, request_rec *r, + apr_off_t size, apr_bucket_brigade *in) +{ + cache_provider_list *list; + cache_handle_t *h = apr_pcalloc(r->pool, sizeof(cache_handle_t)); + apr_status_t rv; + + if (!cache) { + /* This should never happen */ + ap_log_rerror(APLOG_MARK, APLOG_ERR, APR_EGENERAL, r, APLOGNO(00692) + "cache: No cache request information available for key" + " generation"); + return APR_EGENERAL; + } + + if (!cache->key) { + rv = cache_generate_key(r, r->pool, &cache->key); + if (rv != APR_SUCCESS) { + return rv; + } + } + + list = cache->providers; + /* for each specified cache type, delete the URL */ + while (list) { + switch (rv = list->provider->create_entity(h, r, cache->key, size, in)) { + case OK: { + cache->handle = h; + cache->provider = list->provider; + cache->provider_name = list->provider_name; + return OK; + } + case DECLINED: { + list = list->next; + continue; + } + default: { + return rv; + } + } + } + return DECLINED; +} + +static int filter_header_do(void *v, const char *key, const char *val) +{ + if ((*key == 'W' || *key == 'w') && !ap_cstr_casecmp(key, "Warning") + && *val == '1') { + /* any stored Warning headers with warn-code 1xx (see section + * 14.46) MUST be deleted from the cache entry and the forwarded + * response. + */ + } + else { + apr_table_addn(v, key, val); + } + return 1; +} +static int remove_header_do(void *v, const char *key, const char *val) +{ + if ((*key == 'W' || *key == 'w') && !ap_cstr_casecmp(key, "Warning")) { + /* any stored Warning headers with warn-code 2xx MUST be retained + * in the cache entry and the forwarded response. + */ + } + else { + apr_table_unset(v, key); + } + return 1; +} +static int add_header_do(void *v, const char *key, const char *val) +{ + apr_table_addn(v, key, val); + return 1; +} + +/** + * Take two sets of headers, sandwich them together, and apply the result to + * r->headers_out. + * + * To complicate this, a header may be duplicated in either table. Should a + * header exist in the top table, all matching headers will be removed from + * the bottom table before the headers are combined. The Warning headers are + * handled specially. Warnings are added rather than being replaced, while + * in the case of revalidation 1xx Warnings are stripped. + * + * The Content-Type and Last-Modified headers are then re-parsed and inserted + * into the request. + */ +void cache_accept_headers(cache_handle_t *h, request_rec *r, apr_table_t *top, + apr_table_t *bottom, int revalidation) +{ + const char *v; + + if (revalidation) { + r->headers_out = apr_table_make(r->pool, 10); + apr_table_do(filter_header_do, r->headers_out, bottom, NULL); + } + else if (r->headers_out != bottom) { + r->headers_out = apr_table_copy(r->pool, bottom); + } + apr_table_do(remove_header_do, r->headers_out, top, NULL); + apr_table_do(add_header_do, r->headers_out, top, NULL); + + v = apr_table_get(r->headers_out, "Content-Type"); + if (v) { + ap_set_content_type(r, v); + /* + * Also unset possible Content-Type headers in r->headers_out and + * r->err_headers_out as they may be different to what we have received + * from the cache. + * Actually they are not needed as r->content_type set by + * ap_set_content_type above will be used in the store_headers functions + * of the storage providers as a fallback and the HTTP_HEADER filter + * does overwrite the Content-Type header with r->content_type anyway. + */ + apr_table_unset(r->headers_out, "Content-Type"); + apr_table_unset(r->err_headers_out, "Content-Type"); + } + + /* If the cache gave us a Last-Modified header, we can't just + * pass it on blindly because of restrictions on future values. + */ + v = apr_table_get(r->headers_out, "Last-Modified"); + if (v) { + ap_update_mtime(r, apr_date_parse_http(v)); + ap_set_last_modified(r); + } + +} + +/* + * select a specific URL entity in the cache + * + * It is possible to store more than one entity per URL. Content + * negotiation is used to select an entity. Once an entity is + * selected, details of it are stored in the per request + * config to save time when serving the request later. + * + * This function returns OK if successful, DECLINED if no + * cached entity fits the bill. + */ +int cache_select(cache_request_rec *cache, request_rec *r) +{ + cache_provider_list *list; + apr_status_t rv; + cache_handle_t *h; + + if (!cache) { + /* This should never happen */ + ap_log_rerror(APLOG_MARK, APLOG_ERR, APR_EGENERAL, r, APLOGNO(00693) + "cache: No cache request information available for key" + " generation"); + return DECLINED; + } + + /* if no-cache, we can't serve from the cache, but we may store to the + * cache. + */ + if (!ap_cache_check_no_cache(cache, r)) { + return DECLINED; + } + + if (!cache->key) { + rv = cache_generate_key(r, r->pool, &cache->key); + if (rv != APR_SUCCESS) { + return DECLINED; + } + } + + /* go through the cache types till we get a match */ + h = apr_palloc(r->pool, sizeof(cache_handle_t)); + + list = cache->providers; + + while (list) { + switch ((rv = list->provider->open_entity(h, r, cache->key))) { + case OK: { + char *vary = NULL; + int mismatch = 0; + char *last = NULL; + + if (list->provider->recall_headers(h, r) != APR_SUCCESS) { + /* try again with next cache type */ + list = list->next; + continue; + } + + /* + * Check Content-Negotiation - Vary + * + * At this point we need to make sure that the object we found in + * the cache is the same object that would be delivered to the + * client, when the effects of content negotiation are taken into + * effect. + * + * In plain english, we want to make sure that a language-negotiated + * document in one language is not given to a client asking for a + * language negotiated document in a different language by mistake. + * + * This code makes the assumption that the storage manager will + * cache the req_hdrs if the response contains a Vary + * header. + * + * RFC2616 13.6 and 14.44 describe the Vary mechanism. + */ + vary = cache_strqtok( + apr_pstrdup(r->pool, + cache_table_getm(r->pool, h->resp_hdrs, "Vary")), + CACHE_SEPARATOR, &last); + while (vary) { + const char *h1, *h2; + + /* + * is this header in the request and the header in the cached + * request identical? If not, we give up and do a straight get + */ + h1 = cache_table_getm(r->pool, r->headers_in, vary); + h2 = cache_table_getm(r->pool, h->req_hdrs, vary); + if (h1 == h2) { + /* both headers NULL, so a match - do nothing */ + } + else if (h1 && h2 && !strcmp(h1, h2)) { + /* both headers exist and are equal - do nothing */ + } + else { + /* headers do not match, so Vary failed */ + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, + r, APLOGNO(00694) "cache_select(): Vary header mismatch."); + mismatch = 1; + break; + } + vary = cache_strqtok(NULL, CACHE_SEPARATOR, &last); + } + + /* no vary match, try next provider */ + if (mismatch) { + /* try again with next cache type */ + list = list->next; + continue; + } + + cache->provider = list->provider; + cache->provider_name = list->provider_name; + + /* + * RFC2616 13.3.4 Rules for When to Use Entity Tags and Last-Modified + * Dates: An HTTP/1.1 caching proxy, upon receiving a conditional request + * that includes both a Last-Modified date and one or more entity tags as + * cache validators, MUST NOT return a locally cached response to the + * client unless that cached response is consistent with all of the + * conditional header fields in the request. + */ + if (ap_condition_if_match(r, h->resp_hdrs) == AP_CONDITION_NOMATCH + || ap_condition_if_unmodified_since(r, h->resp_hdrs) + == AP_CONDITION_NOMATCH + || ap_condition_if_none_match(r, h->resp_hdrs) + == AP_CONDITION_NOMATCH + || ap_condition_if_modified_since(r, h->resp_hdrs) + == AP_CONDITION_NOMATCH + || ap_condition_if_range(r, h->resp_hdrs) == AP_CONDITION_NOMATCH) { + mismatch = 1; + } + + /* Is our cached response fresh enough? */ + if (mismatch || !cache_check_freshness(h, cache, r)) { + const char *etag, *lastmod; + + /* Cache-Control: only-if-cached and revalidation required, try + * the next provider + */ + if (cache->control_in.only_if_cached) { + /* try again with next cache type */ + list = list->next; + continue; + } + + /* set aside the stale entry for accessing later */ + cache->stale_headers = apr_table_copy(r->pool, + r->headers_in); + cache->stale_handle = h; + + /* if no existing conditionals, use conditionals of our own */ + if (!mismatch) { + + ap_log_rerror( + APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(00695) "Cached response for %s isn't fresh. Adding " + "conditional request headers.", r->uri); + + /* Remove existing conditionals that might conflict with ours */ + 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"); + + etag = apr_table_get(h->resp_hdrs, "ETag"); + lastmod = apr_table_get(h->resp_hdrs, "Last-Modified"); + + if (etag || lastmod) { + /* If we have a cached etag and/or Last-Modified add in + * our own conditionals. + */ + + if (etag) { + apr_table_set(r->headers_in, "If-None-Match", etag); + } + + if (lastmod) { + apr_table_set(r->headers_in, "If-Modified-Since", + lastmod); + } + + /* + * Do not do Range requests with our own conditionals: If + * we get 304 the Range does not matter and otherwise the + * entity changed and we want to have the complete entity + */ + apr_table_unset(r->headers_in, "Range"); + + } + + } + + /* ready to revalidate, pretend we were never here */ + return DECLINED; + } + + /* Okay, this response looks okay. Merge in our stuff and go. */ + cache_accept_headers(h, r, h->resp_hdrs, r->headers_out, 0); + + cache->handle = h; + return OK; + } + case DECLINED: { + /* try again with next cache type */ + list = list->next; + continue; + } + default: { + /* oo-er! an error */ + return rv; + } + } + } + + /* if Cache-Control: only-if-cached, and not cached, return 504 */ + if (cache->control_in.only_if_cached) { + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(00696) + "cache: 'only-if-cached' requested and no cached entity, " + "returning 504 Gateway Timeout for: %s", r->uri); + return HTTP_GATEWAY_TIME_OUT; + } + + return DECLINED; +} + +static apr_status_t cache_canonicalise_key(request_rec *r, apr_pool_t* p, + const char *path, const char *query, + apr_uri_t *parsed_uri, + const char **key) +{ + cache_server_conf *conf; + char *port_str, *hn, *lcs; + const char *hostname, *scheme; + int i; + const char *kpath; + const char *kquery; + + if (*key) { + /* + * We have been here before during the processing of this request. + */ + return APR_SUCCESS; + } + + /* + * Get the module configuration. We need this for the CacheIgnoreQueryString + * option below. + */ + conf = (cache_server_conf *) ap_get_module_config(r->server->module_config, + &cache_module); + + /* + * Use the canonical name to improve cache hit rate, but only if this is + * not a proxy request or if this is a reverse proxy request. + * We need to handle both cases in the same manner as for the reverse proxy + * case we have the following situation: + * + * If a cached entry is looked up by mod_cache's quick handler r->proxyreq + * is still unset in the reverse proxy case as it only gets set in the + * translate name hook (either by ProxyPass or mod_rewrite) which is run + * after the quick handler hook. This is different to the forward proxy + * case where it gets set before the quick handler is run (in the + * post_read_request hook). + * If a cache entry is created by the CACHE_SAVE filter we always have + * r->proxyreq set correctly. + * So we must ensure that in the reverse proxy case we use the same code + * path and using the canonical name seems to be the right thing to do + * in the reverse proxy case. + */ + if (!r->proxyreq || (r->proxyreq == PROXYREQ_REVERSE)) { + if (conf->base_uri && conf->base_uri->hostname) { + hostname = conf->base_uri->hostname; + } + else { + /* Use _default_ as the hostname if none present, as in mod_vhost */ + hostname = ap_get_server_name(r); + if (!hostname) { + hostname = "_default_"; + } + } + } + else if (parsed_uri->hostname) { + /* Copy the parsed uri hostname */ + hn = apr_pstrdup(p, parsed_uri->hostname); + ap_str_tolower(hn); + /* const work-around */ + hostname = hn; + } + else { + /* We are a proxied request, with no hostname. Unlikely + * to get very far - but just in case */ + hostname = "_default_"; + } + + /* + * Copy the scheme, ensuring that it is lower case. If the parsed uri + * contains no string or if this is not a proxy request get the http + * scheme for this request. As r->parsed_uri.scheme is not set if this + * is a reverse proxy request, it is ensured that the cases + * "no proxy request" and "reverse proxy request" are handled in the same + * manner (see above why this is needed). + */ + if (r->proxyreq && parsed_uri->scheme) { + /* Copy the scheme and lower-case it */ + lcs = apr_pstrdup(p, parsed_uri->scheme); + ap_str_tolower(lcs); + /* const work-around */ + scheme = lcs; + } + else { + if (conf->base_uri && conf->base_uri->scheme) { + scheme = conf->base_uri->scheme; + } + else { + scheme = ap_http_scheme(r); + } + } + + /* + * If this is a proxy request, but not a reverse proxy request (see comment + * above why these cases must be handled in the same manner), copy the + * URI's port-string (which may be a service name). If the URI contains + * no port-string, use apr-util's notion of the default port for that + * scheme - if available. Otherwise use the port-number of the current + * server. + */ + if (r->proxyreq && (r->proxyreq != PROXYREQ_REVERSE)) { + if (parsed_uri->port_str) { + port_str = apr_pcalloc(p, strlen(parsed_uri->port_str) + 2); + port_str[0] = ':'; + for (i = 0; parsed_uri->port_str[i]; i++) { + port_str[i + 1] = apr_tolower(parsed_uri->port_str[i]); + } + } + else if (apr_uri_port_of_scheme(scheme)) { + port_str = apr_psprintf(p, ":%u", apr_uri_port_of_scheme(scheme)); + } + else { + /* No port string given in the AbsoluteUri, and we have no + * idea what the default port for the scheme is. Leave it + * blank and live with the inefficiency of some extra cached + * entities. + */ + port_str = ""; + } + } + else { + if (conf->base_uri && conf->base_uri->port_str) { + port_str = conf->base_uri->port_str; + } + else if (conf->base_uri && conf->base_uri->hostname) { + port_str = ""; + } + else { + /* Use the server port */ + port_str = apr_psprintf(p, ":%u", ap_get_server_port(r)); + } + } + + /* + * Check if we need to ignore session identifiers in the URL and do so + * if needed. + */ + kpath = path; + kquery = conf->ignorequerystring ? NULL : query; + if (conf->ignore_session_id->nelts) { + int i; + char **identifier; + + identifier = (char **) conf->ignore_session_id->elts; + for (i = 0; i < conf->ignore_session_id->nelts; i++, identifier++) { + int len; + const char *param; + + len = strlen(*identifier); + /* + * Check that we have a parameter separator in the last segment + * of the path and that the parameter matches our identifier + */ + if ((param = ap_strrchr_c(kpath, ';')) + && !strncmp(param + 1, *identifier, len) + && (*(param + len + 1) == '=') + && !ap_strchr_c(param + len + 2, '/')) { + kpath = apr_pstrmemdup(p, kpath, param - kpath); + continue; + } + /* + * Check if the identifier is in the query string and cut it out. + */ + if (kquery && *kquery) { + /* + * First check if the identifier is at the beginning of the + * query string and followed by a '=' + */ + if (!strncmp(kquery, *identifier, len) && kquery[len] == '=') { + param = kquery; + } + else { + char *complete; + + /* + * In order to avoid subkey matching (PR 48401) prepend + * identifier with a '&' and append a '=' + */ + complete = apr_pstrcat(p, "&", *identifier, "=", NULL); + param = ap_strstr_c(kquery, complete); + /* If we found something we are sitting on the '&' */ + if (param) { + param++; + } + } + if (param) { + const char *amp; + char *dup = NULL; + + if (kquery != param) { + dup = apr_pstrmemdup(p, kquery, param - kquery); + kquery = dup; + } + else { + kquery = ""; + } + + if ((amp = ap_strchr_c(param + len + 1, '&'))) { + kquery = apr_pstrcat(p, kquery, amp + 1, NULL); + } + else { + /* + * If query string is not "", then we have the case + * that the identifier parameter we removed was the + * last one in the original query string. Hence we have + * a trailing '&' which needs to be removed. + */ + if (dup) { + dup[strlen(dup) - 1] = '\0'; + } + } + } + } + } + } + + /* Key format is a URI, optionally without the query-string (NULL + * per above if conf->ignorequerystring) + */ + *key = apr_pstrcat(p, scheme, "://", hostname, port_str, + kpath, "?", kquery, NULL); + + /* + * Store the key in the request_config for the cache as r->parsed_uri + * might have changed in the time from our first visit here triggered by the + * quick handler and our possible second visit triggered by the CACHE_SAVE + * filter (e.g. r->parsed_uri got unescaped). In this case we would save the + * resource in the cache under a key where it is never found by the quick + * handler during following requests. + */ + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(00698) + "cache: Key for entity %s?%s is %s", path, query, *key); + + return APR_SUCCESS; +} + +apr_status_t cache_generate_key_default(request_rec *r, apr_pool_t* p, + const char **key) +{ + /* In early processing (quick-handler, forward proxy), we want the initial + * query-string from r->parsed_uri, since any change before CACHE_SAVE + * shouldn't modify the key. Otherwise we want the actual query-string. + */ + const char *path = r->uri; + const char *query = r->args; + if (cache_use_early_url(r)) { + path = r->parsed_uri.path; + query = r->parsed_uri.query; + } + return cache_canonicalise_key(r, p, path, query, &r->parsed_uri, key); +} + +/* + * Invalidate a specific URL entity in all caches + * + * All cached entities for this URL are removed, usually in + * response to a POST/PUT or DELETE. + * + * This function returns OK if at least one entity was found and + * removed, and DECLINED if no cached entities were removed. + */ +int cache_invalidate(cache_request_rec *cache, request_rec *r) +{ + cache_provider_list *list; + apr_status_t rv, status = DECLINED; + cache_handle_t *h; + apr_uri_t location_uri; + apr_uri_t content_location_uri; + + const char *location, *location_key = NULL; + const char *content_location, *content_location_key = NULL; + + if (!cache) { + /* This should never happen */ + ap_log_rerror( + APLOG_MARK, APLOG_ERR, APR_EGENERAL, r, APLOGNO(00697) "cache: No cache request information available for key" + " generation"); + return DECLINED; + } + + if (!cache->key) { + rv = cache_generate_key(r, r->pool, &cache->key); + if (rv != APR_SUCCESS) { + return DECLINED; + } + } + + location = apr_table_get(r->headers_out, "Location"); + if (location) { + if (apr_uri_parse(r->pool, location, &location_uri) + || cache_canonicalise_key(r, r->pool, + location_uri.path, + location_uri.query, + &location_uri, &location_key) + || !(r->parsed_uri.hostname + && location_uri.hostname + && !strcmp(r->parsed_uri.hostname, + location_uri.hostname))) { + location_key = NULL; + } + } + + content_location = apr_table_get(r->headers_out, "Content-Location"); + if (content_location) { + if (apr_uri_parse(r->pool, content_location, + &content_location_uri) + || cache_canonicalise_key(r, r->pool, + content_location_uri.path, + content_location_uri.query, + &content_location_uri, + &content_location_key) + || !(r->parsed_uri.hostname + && content_location_uri.hostname + && !strcmp(r->parsed_uri.hostname, + content_location_uri.hostname))) { + content_location_key = NULL; + } + } + + /* go through the cache types */ + h = apr_palloc(r->pool, sizeof(cache_handle_t)); + + list = cache->providers; + + while (list) { + + /* invalidate the request uri */ + rv = list->provider->open_entity(h, r, cache->key); + if (OK == rv) { + rv = list->provider->invalidate_entity(h, r); + status = OK; + } + ap_log_rerror( + APLOG_MARK, APLOG_DEBUG, rv, r, APLOGNO(02468) "cache: Attempted to invalidate cached entity with key: %s", cache->key); + + /* invalidate the Location */ + if (location_key) { + rv = list->provider->open_entity(h, r, location_key); + if (OK == rv) { + rv = list->provider->invalidate_entity(h, r); + status = OK; + } + ap_log_rerror( + APLOG_MARK, APLOG_DEBUG, rv, r, APLOGNO(02469) "cache: Attempted to invalidate cached entity with key: %s", location_key); + } + + /* invalidate the Content-Location */ + if (content_location_key) { + rv = list->provider->open_entity(h, r, content_location_key); + if (OK == rv) { + rv = list->provider->invalidate_entity(h, r); + status = OK; + } + ap_log_rerror( + APLOG_MARK, APLOG_DEBUG, rv, r, APLOGNO(02470) "cache: Attempted to invalidate cached entity with key: %s", content_location_key); + } + + list = list->next; + } + + return status; +} |