cache_util.h revision 6d14bedccc13d7a5f95fb9328eb6d1a07b58731b
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering/* Licensed to the Apache Software Foundation (ASF) under one or more
12b42c76672a66c2d4ea7212c14f8f1b5a62b78dTom Gundersen * contributor license agreements. See the NOTICE file distributed with
4149f86d816fc0fef41d35de5beb09bfe81e0d6aBrandon Philips * this work for additional information regarding copyright ownership.
4149f86d816fc0fef41d35de5beb09bfe81e0d6aBrandon Philips * The ASF licenses this file to You under the Apache License, Version 2.0
4149f86d816fc0fef41d35de5beb09bfe81e0d6aBrandon Philips * (the "License"); you may not use this file except in compliance with
4149f86d816fc0fef41d35de5beb09bfe81e0d6aBrandon Philips * the License. You may obtain a copy of the License at
4149f86d816fc0fef41d35de5beb09bfe81e0d6aBrandon Philips * http://www.apache.org/licenses/LICENSE-2.0
5430f7f2bc7330f3088b894166bf3524a067e3d8Lennart Poettering * Unless required by applicable law or agreed to in writing, software
4149f86d816fc0fef41d35de5beb09bfe81e0d6aBrandon Philips * distributed under the License is distributed on an "AS IS" BASIS,
4149f86d816fc0fef41d35de5beb09bfe81e0d6aBrandon Philips * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
4149f86d816fc0fef41d35de5beb09bfe81e0d6aBrandon Philips * See the License for the specific language governing permissions and
4149f86d816fc0fef41d35de5beb09bfe81e0d6aBrandon Philips * limitations under the License.
4149f86d816fc0fef41d35de5beb09bfe81e0d6aBrandon Philips * @brief Cache Storage Functions
4149f86d816fc0fef41d35de5beb09bfe81e0d6aBrandon Philips * @defgroup Cache_util Cache Utility Functions
4149f86d816fc0fef41d35de5beb09bfe81e0d6aBrandon Philips * @ingroup MOD_CACHE
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek#define MAX(a,b) ((a) > (b) ? (a) : (b))
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek#define MIN(a,b) ((a) < (b) ? (a) : (b))
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek#define MSEC_ONE_DAY ((apr_time_t)(86400*APR_USEC_PER_SEC)) /* one day, in microseconds */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek#define MSEC_ONE_HR ((apr_time_t)(3600*APR_USEC_PER_SEC)) /* one hour, in microseconds */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek#define MSEC_ONE_MIN ((apr_time_t)(60*APR_USEC_PER_SEC)) /* one minute, in microseconds */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek#define MSEC_ONE_SEC ((apr_time_t)(APR_USEC_PER_SEC)) /* one second, in microseconds */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek#define DEFAULT_CACHE_MAXEXPIRE MSEC_ONE_DAY
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek#define DEFAULT_CACHE_MINEXPIRE 0
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek#define DEFAULT_CACHE_EXPIRE MSEC_ONE_HR
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek#define DEFAULT_CACHE_LMFACTOR (0.1)
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek#define DEFAULT_CACHE_LOCKPATH "/mod_cache-lock"
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek#define CACHE_LOCKNAME_KEY "mod_cache-lockname"
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek#define CACHE_LOCKFILE_KEY "mod_cache-lockfile"
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek/* static information about the local cache */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek apr_array_header_t *cacheenable; /* URLs to cache */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek apr_array_header_t *cachedisable; /* URLs not to cache */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek /* Maximum time to keep cached files in msecs */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek /* default time to keep cached file in msecs */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek /* factor for estimating expires date */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek /** ignore the last-modified header when deciding to cache this request */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek /** ignore client's requests for uncached responses */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek /** ignore expiration date from server */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek /** ignore Cache-Control: private header from server */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek /** ignore Cache-Control: no-store header from client or server */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek /* flag if CacheIgnoreHeader has been set */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek #define CACHE_IGNORE_HEADERS_UNSET 0
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek /** store the headers that should not be stored in the cache */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek apr_array_header_t *ignore_headers;
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek /* Minimum time to keep cached files in msecs */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek /** ignore query-string when caching */
6a9171d2ec4f2cc1d7850fcb7b076cb75fbd3dd3Lennart Poettering /* flag if CacheIgnoreURLSessionIdentifiers has been set */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek #define CACHE_IGNORE_SESSION_ID_SET 1
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek #define CACHE_IGNORE_SESSION_ID_UNSET 0
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek /** store the identifiers that should not be used for key calculation */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek apr_array_header_t *ignore_session_id;
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek /* thundering herd lock */
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek /** run within the quick handler */
b938cb902c3b5bca807a94b277672c64d6767886Jan Engelhardt/* A linked-list of authn providers. */
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poetteringtypedef struct cache_provider_list cache_provider_list;
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering/* per request cache information */
b938cb902c3b5bca807a94b277672c64d6767886Jan Engelhardttypedef struct {
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering cache_provider_list *providers; /* possible cache providers */
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering const cache_provider *provider; /* current cache provider */
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering const char *provider_name; /* current cache provider name */
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering cache_handle_t *handle; /* current cache handle */
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering cache_handle_t *stale_handle; /* stale cache handle */
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering apr_table_t *stale_headers; /* original request headers. */
b938cb902c3b5bca807a94b277672c64d6767886Jan Engelhardt int in_checked; /* CACHE_SAVE must cache the entity */
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering int block_response; /* CACHE_SAVE must block response. */
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering apr_bucket_brigade *saved_brigade; /* copy of partial response */
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering apr_off_t saved_size; /* length of saved_brigade */
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering apr_time_t lastmod; /* last-modified time */
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering cache_info *info; /* current cache info */
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering ap_filter_t *remove_url_filter; /* Enable us to remove the filter */
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering const char *key; /* The cache key created for this
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering apr_off_t size; /* the content length from the headers, or -1 */
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering apr_bucket_brigade *out; /* brigade to reuse for upstream responses */
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * Check the freshness of the cache object per RFC2616 section 13.2 (Expiration Model)
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * @param h cache_handle_t
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * @param r request_rec
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * @return 0 ==> cache object is stale, 1 ==> cache object is fresh
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poetteringint cache_check_freshness(cache_handle_t *h, cache_request_rec *cache,
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * Try obtain a cache wide lock on the given cache key.
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * If we return APR_SUCCESS, we obtained the lock, and we are clear to
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * proceed to the backend. If we return APR_EEXISTS, the the lock is
b938cb902c3b5bca807a94b277672c64d6767886Jan Engelhardt * already locked, someone else has gone to refresh the backend data
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * already, so we must return stale data with a warning in the mean
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * time. If we return anything else, then something has gone pear
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * shaped, and we allow the request through to the backend regardless.
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * This lock is created from the request pool, meaning that should
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * something go wrong and the lock isn't deleted on return of the
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * request headers from the backend for whatever reason, at worst the
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * lock will be cleaned up when the request is dies or finishes.
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * If something goes truly bananas and the lock isn't deleted when the
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * request dies, the lock will be trashed when its max-age is reached,
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * or when a request arrives containing a Cache-Control: no-cache. At
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * no point is it possible for this lock to permanently deny access to
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * the backend.
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poetteringapr_status_t cache_try_lock(cache_server_conf *conf,
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering cache_request_rec *cache, request_rec *r, char *key);
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * Remove the cache lock, if present.
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * First, try to close the file handle, whose delete-on-close should
5fb13eb51bf641a3434828947e137e1a5f2d7eb2Lennart Poettering * kill the file. Otherwise, just delete the file by name.
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek * If no lock name has yet been calculated, do the calculation of the
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek * lock name first before trying to delete the file.
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek * If an optional bucket brigade is passed, the lock will only be
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek * removed if the bucket brigade contains an EOS bucket.
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmekapr_status_t cache_remove_lock(cache_server_conf *conf,
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek cache_request_rec *cache, request_rec *r, char *key,
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmekcache_provider_list *cache_get_providers(request_rec *r,
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek cache_server_conf *conf, apr_uri_t uri);
302fbdf29eb0ad4ca1fe8ee18755edad7db11b37Zbigniew Jędrzejewski-Szmek#endif /* !CACHE_UTIL_H */