1 /* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements. See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License. You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 #include "mod_cache.h"
19 #include "cache_storage.h"
20 #include "cache_util.h"
22 module AP_MODULE_DECLARE_DATA cache_module;
23 APR_OPTIONAL_FN_TYPE(ap_cache_generate_key) *cache_generate_key;
25 /* -------------------------------------------------------------- */
28 /* Handles for cache filters, resolved at startup to eliminate
29 * a name-to-function mapping on each request
31 static ap_filter_rec_t *cache_filter_handle;
32 static ap_filter_rec_t *cache_save_filter_handle;
33 static ap_filter_rec_t *cache_save_subreq_filter_handle;
34 static ap_filter_rec_t *cache_out_filter_handle;
35 static ap_filter_rec_t *cache_out_subreq_filter_handle;
36 static ap_filter_rec_t *cache_remove_url_filter_handle;
42 * Can we deliver this request from the cache?
44 * deliver the content by installing the CACHE_OUT filter.
46 * check whether we're allowed to try cache it
48 * add CACHE_SAVE filter
52 * By default, the cache handler runs in the quick handler, bypassing
53 * virtually all server processing and offering the cache its optimal
54 * performance. In this mode, the cache bolts onto the front of the
55 * server, and behaves as a discrete RFC2616 caching proxy
58 * Under certain circumstances, an admin might want to run the cache as
59 * a normal handler instead of a quick handler, allowing the cache to
60 * run after the authorisation hooks, or by allowing fine control over
61 * the placement of the cache in the filter chain. This option comes at
62 * a performance penalty, and should only be used to achieve specific
63 * caching goals where the admin understands what they are doing.
66 static int cache_quick_handler(request_rec *r, int lookup)
70 cache_provider_list *providers;
71 cache_request_rec *cache;
72 apr_bucket_brigade *out;
75 ap_filter_rec_t *cache_out_handle;
76 cache_server_conf *conf;
78 conf = (cache_server_conf *) ap_get_module_config(r->server->module_config,
81 /* only run if the quick handler is enabled */
87 * Which cache module (if any) should handle this request?
89 if (!(providers = cache_get_providers(r, conf, r->parsed_uri))) {
93 /* make space for the per request config */
94 cache = apr_pcalloc(r->pool, sizeof(cache_request_rec));
96 cache->out = apr_brigade_create(r->pool, r->connection->bucket_alloc);
98 /* save away the possible providers */
99 cache->providers = providers;
102 * Are we allowed to serve cached info at all?
105 /* find certain cache controlling headers */
106 auth = apr_table_get(r->headers_in, "Authorization");
108 /* First things first - does the request allow us to return
109 * cached information at all? If not, just decline the request.
115 /* Are we something other than GET or HEAD? If so, invalidate
116 * the cached entities.
118 if (r->method_number != M_GET) {
120 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r,
121 "Invalidating all cached entities in response to '%s' request for %s",
124 cache_invalidate(cache, r);
126 /* we've got a cache invalidate! tell everyone who cares */
127 cache_run_cache_status(cache->handle, r, r->headers_out,
128 AP_CACHE_INVALIDATE, apr_psprintf(r->pool,
129 "cache invalidated by %s", r->method));
135 * Try to serve this request from the cache.
137 * If no existing cache file (DECLINED)
138 * add cache_save filter
139 * If cached file (OK)
141 * add cache_out filter
144 rv = cache_select(cache, r);
146 if (rv == DECLINED) {
149 /* try to obtain a cache lock at this point. if we succeed,
150 * we are the first to try and cache this url. if we fail,
151 * it means someone else is already trying to cache this
152 * url, and we should just let the request through to the
153 * backend without any attempt to cache. this stops
154 * duplicated simultaneous attempts to cache an entity.
156 rv = cache_try_lock(conf, cache, r);
157 if (APR_SUCCESS == rv) {
160 * Add cache_save filter to cache this request. Choose
161 * the correct filter by checking if we are a subrequest
165 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS,
166 r, "Adding CACHE_SAVE_SUBREQ filter for %s",
168 cache->save_filter = ap_add_output_filter_handle(
169 cache_save_subreq_filter_handle, cache, r,
173 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS,
174 r, "Adding CACHE_SAVE filter for %s",
176 cache->save_filter = ap_add_output_filter_handle(
177 cache_save_filter_handle, cache, r,
181 apr_pool_userdata_setn(cache, CACHE_CTX_KEY, NULL, r->pool);
183 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r,
184 "Adding CACHE_REMOVE_URL filter for %s",
187 /* Add cache_remove_url filter to this request to remove a
188 * stale cache entry if needed. Also put the current cache
189 * request rec in the filter context, as the request that
190 * is available later during running the filter may be
191 * different due to an internal redirect.
193 cache->remove_url_filter = ap_add_output_filter_handle(
194 cache_remove_url_filter_handle, cache, r,
199 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv,
200 r, "Cache locked for url, not caching "
201 "response: %s", r->uri);
205 if (cache->stale_headers) {
206 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS,
207 r, "Restoring request headers for %s",
210 r->headers_in = cache->stale_headers;
221 /* we've got a cache hit! tell everyone who cares */
222 cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_HIT,
225 /* if we are a lookup, we are exiting soon one way or another; Restore
228 if (cache->stale_headers) {
229 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r,
230 "Restoring request headers.");
231 r->headers_in = cache->stale_headers;
235 rv = ap_meets_conditions(r);
237 /* If we are a lookup, we have to return DECLINED as we have no
238 * way of knowing if we will be able to serve the content.
244 /* Return cached status. */
248 /* If we're a lookup, we can exit now instead of serving the content. */
253 /* Serve up the content */
255 /* We are in the quick handler hook, which means that no output
256 * filters have been set. So lets run the insert_filter hook.
258 ap_run_insert_filter(r);
261 * Add cache_out filter to serve this request. Choose
262 * the correct filter by checking if we are a subrequest
266 cache_out_handle = cache_out_subreq_filter_handle;
269 cache_out_handle = cache_out_filter_handle;
271 ap_add_output_filter_handle(cache_out_handle, cache, r, r->connection);
274 * Remove all filters that are before the cache_out filter. This ensures
275 * that we kick off the filter stack with our cache_out filter being the
276 * first in the chain. This make sense because we want to restore things
277 * in the same manner as we saved them.
278 * There may be filters before our cache_out filter, because
280 * 1. We call ap_set_content_type during cache_select. This causes
281 * Content-Type specific filters to be added.
282 * 2. We call the insert_filter hook. This causes filters e.g. like
283 * the ones set with SetOutputFilter to be added.
285 next = r->output_filters;
286 while (next && (next->frec != cache_out_handle)) {
287 ap_remove_output_filter(next);
291 /* kick off the filter stack */
292 out = apr_brigade_create(r->pool, r->connection->bucket_alloc);
293 e = apr_bucket_eos_create(out->bucket_alloc);
294 APR_BRIGADE_INSERT_TAIL(out, e);
295 rv = ap_pass_brigade(r->output_filters, out);
296 if (rv != APR_SUCCESS) {
297 if (rv != AP_FILTER_ERROR) {
298 /* no way to know what type of error occurred */
299 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r,
300 "cache_quick_handler(%s): ap_pass_brigade returned %i",
301 cache->provider_name, rv);
302 return HTTP_INTERNAL_SERVER_ERROR;
311 * If the two filter handles are present within the filter chain, replace
312 * the last instance of the first filter with the last instance of the
313 * second filter, and return true. If the second filter is not present at
314 * all, the first filter is removed, and false is returned. If neither
315 * filter is present, false is returned and this function does nothing.
316 * If a stop filter is specified, processing will stop once this filter is
319 static int cache_replace_filter(ap_filter_t *next, ap_filter_rec_t *from,
320 ap_filter_rec_t *to, ap_filter_rec_t *stop) {
321 ap_filter_t *ffrom = NULL, *fto = NULL;
322 while (next && next->frec != stop) {
323 if (next->frec == from && !next->ctx) {
326 if (next->frec == to && !next->ctx) {
332 ffrom->frec = fto->frec;
333 ffrom->ctx = fto->ctx;
334 ap_remove_output_filter(fto);
338 ap_remove_output_filter(ffrom);
344 * Find the given filter, and return it if found, or NULL otherwise.
346 static ap_filter_t *cache_get_filter(ap_filter_t *next, ap_filter_rec_t *rec) {
348 if (next->frec == rec && next->ctx) {
357 * The cache handler is functionally similar to the cache_quick_hander,
358 * however a number of steps that are required by the quick handler are
359 * not required here, as the normal httpd processing has already handled
362 static int cache_handler(request_rec *r)
365 cache_provider_list *providers;
366 cache_request_rec *cache;
367 apr_bucket_brigade *out;
370 ap_filter_rec_t *cache_out_handle;
371 ap_filter_rec_t *cache_save_handle;
372 cache_server_conf *conf;
374 conf = (cache_server_conf *) ap_get_module_config(r->server->module_config,
377 /* only run if the quick handler is disabled */
383 * Which cache module (if any) should handle this request?
385 if (!(providers = cache_get_providers(r, conf, r->parsed_uri))) {
389 /* make space for the per request config */
390 cache = apr_pcalloc(r->pool, sizeof(cache_request_rec));
392 cache->out = apr_brigade_create(r->pool, r->connection->bucket_alloc);
394 /* save away the possible providers */
395 cache->providers = providers;
397 /* Are we something other than GET or HEAD? If so, invalidate
398 * the cached entities.
400 if (r->method_number != M_GET) {
402 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r,
403 "Invalidating all cached entities in response to '%s' request for %s",
406 cache_invalidate(cache, r);
408 /* we've got a cache invalidate! tell everyone who cares */
409 cache_run_cache_status(cache->handle, r, r->headers_out,
410 AP_CACHE_INVALIDATE, apr_psprintf(r->pool,
411 "cache invalidated by %s", r->method));
418 * Try to serve this request from the cache.
420 * If no existing cache file (DECLINED)
421 * add cache_save filter
422 * If cached file (OK)
424 * add cache_out filter
427 rv = cache_select(cache, r);
429 if (rv == DECLINED) {
431 /* try to obtain a cache lock at this point. if we succeed,
432 * we are the first to try and cache this url. if we fail,
433 * it means someone else is already trying to cache this
434 * url, and we should just let the request through to the
435 * backend without any attempt to cache. this stops
436 * duplicated simultaneous attempts to cache an entity.
438 rv = cache_try_lock(conf, cache, r);
439 if (APR_SUCCESS == rv) {
442 * Add cache_save filter to cache this request. Choose
443 * the correct filter by checking if we are a subrequest
447 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS,
448 r, "Adding CACHE_SAVE_SUBREQ filter for %s",
450 cache_save_handle = cache_save_subreq_filter_handle;
453 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS,
454 r, "Adding CACHE_SAVE filter for %s",
456 cache_save_handle = cache_save_filter_handle;
458 ap_add_output_filter_handle(cache_save_handle, cache, r,
462 * Did the user indicate the precise location of the
463 * CACHE_SAVE filter by inserting the CACHE filter as a
466 * If so, we get cunning and replace CACHE with the
467 * CACHE_SAVE filter. This has the effect of inserting
468 * the CACHE_SAVE filter at the precise location where
469 * the admin wants to cache the content. All filters that
470 * lie before and after the original location of the CACHE
471 * filter will remain in place.
473 if (cache_replace_filter(r->output_filters,
474 cache_filter_handle, cache_save_handle,
475 ap_get_input_filter_handle("SUBREQ_CORE"))) {
476 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS,
477 r, "Replacing CACHE with CACHE_SAVE "
478 "filter for %s", r->uri);
481 /* save away the save filter stack */
482 cache->save_filter = cache_get_filter(r->output_filters,
483 cache_save_filter_handle);
485 apr_pool_userdata_setn(cache, CACHE_CTX_KEY, NULL, r->pool);
487 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r,
488 "Adding CACHE_REMOVE_URL filter for %s",
491 /* Add cache_remove_url filter to this request to remove a
492 * stale cache entry if needed. Also put the current cache
493 * request rec in the filter context, as the request that
494 * is available later during running the filter may be
495 * different due to an internal redirect.
497 cache->remove_url_filter
498 = ap_add_output_filter_handle(
499 cache_remove_url_filter_handle, cache, r,
504 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv,
505 r, "Cache locked for url, not caching "
506 "response: %s", r->uri);
516 /* we've got a cache hit! tell everyone who cares */
517 cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_HIT,
520 rv = ap_meets_conditions(r);
525 /* Serve up the content */
528 * Add cache_out filter to serve this request. Choose
529 * the correct filter by checking if we are a subrequest
533 cache_out_handle = cache_out_subreq_filter_handle;
536 cache_out_handle = cache_out_filter_handle;
538 ap_add_output_filter_handle(cache_out_handle, cache, r, r->connection);
541 * Did the user indicate the precise location of the CACHE_OUT filter by
542 * inserting the CACHE filter as a marker?
544 * If so, we get cunning and replace CACHE with the CACHE_OUT filters.
545 * This has the effect of inserting the CACHE_OUT filter at the precise
546 * location where the admin wants to cache the content. All filters that
547 * lie *after* the original location of the CACHE filter will remain in
550 if (cache_replace_filter(r->output_filters, cache_filter_handle,
551 cache_out_handle, ap_get_input_filter_handle("SUBREQ_CORE"))) {
552 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS,
553 r, "Replacing CACHE with CACHE_OUT filter for %s",
558 * Remove all filters that are before the cache_out filter. This ensures
559 * that we kick off the filter stack with our cache_out filter being the
560 * first in the chain. This make sense because we want to restore things
561 * in the same manner as we saved them.
562 * There may be filters before our cache_out filter, because
564 * 1. We call ap_set_content_type during cache_select. This causes
565 * Content-Type specific filters to be added.
566 * 2. We call the insert_filter hook. This causes filters e.g. like
567 * the ones set with SetOutputFilter to be added.
569 next = r->output_filters;
570 while (next && (next->frec != cache_out_handle)) {
571 ap_remove_output_filter(next);
575 /* kick off the filter stack */
576 out = apr_brigade_create(r->pool, r->connection->bucket_alloc);
577 e = apr_bucket_eos_create(out->bucket_alloc);
578 APR_BRIGADE_INSERT_TAIL(out, e);
579 rv = ap_pass_brigade(r->output_filters, out);
580 if (rv != APR_SUCCESS) {
581 if (rv != AP_FILTER_ERROR) {
582 /* no way to know what type of error occurred */
583 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r,
584 "cache_handler(%s): ap_pass_brigade returned %i",
585 cache->provider_name, rv);
586 return HTTP_INTERNAL_SERVER_ERROR;
598 * Deliver cached content (headers and body) up the stack.
600 static int cache_out_filter(ap_filter_t *f, apr_bucket_brigade *in)
602 request_rec *r = f->r;
604 cache_request_rec *cache = (cache_request_rec *)f->ctx;
607 /* user likely configured CACHE_OUT manually; they should use mod_cache
608 * configuration to do that */
609 ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
610 "CACHE/CACHE_OUT filter enabled while caching is disabled, ignoring");
611 ap_remove_output_filter(f);
612 return ap_pass_brigade(f->next, in);
615 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r,
616 "cache: running CACHE_OUT filter");
618 /* clean out any previous response up to EOS, if any */
619 for (e = APR_BRIGADE_FIRST(in);
620 e != APR_BRIGADE_SENTINEL(in);
621 e = APR_BUCKET_NEXT(e))
623 if (APR_BUCKET_IS_EOS(e)) {
624 apr_bucket_brigade *bb = apr_brigade_create(r->pool,
625 r->connection->bucket_alloc);
627 /* restore status of cached response */
628 r->status = cache->handle->cache_obj->info.status;
630 /* recall_headers() was called in cache_select() */
631 cache->provider->recall_body(cache->handle, r->pool, bb);
632 APR_BRIGADE_PREPEND(in, bb);
634 /* This filter is done once it has served up its content */
635 ap_remove_output_filter(f);
637 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r,
638 "cache: serving %s", r->uri);
639 return ap_pass_brigade(f->next, in);
642 apr_bucket_delete(e);
649 * Having jumped through all the hoops and decided to cache the
650 * response, call store_body() for each brigade, handling the
651 * case where the provider can't swallow the full brigade. In this
652 * case, we write the brigade we were passed out downstream, and
653 * loop around to try and cache some more until the in brigade is
654 * completely empty. As soon as the out brigade contains eos, call
655 * commit_entity() to finalise the cached element.
657 static int cache_save_store(ap_filter_t *f, apr_bucket_brigade *in,
658 cache_server_conf *conf, cache_request_rec *cache)
660 int rv = APR_SUCCESS;
663 /* pass the brigade in into the cache provider, which is then
664 * expected to move cached buckets to the out brigade, for us
665 * to pass up the filter stack. repeat until in is empty, or
668 while (APR_SUCCESS == rv && !APR_BRIGADE_EMPTY(in)) {
670 rv = cache->provider->store_body(cache->handle, f->r, in, cache->out);
671 if (rv != APR_SUCCESS) {
672 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, f->r,
673 "cache: Cache provider's store_body failed!");
674 ap_remove_output_filter(f);
676 /* give someone else the chance to cache the file */
677 cache_remove_lock(conf, cache, f->r, NULL);
679 /* give up trying to cache, just step out the way */
680 APR_BRIGADE_PREPEND(in, cache->out);
681 return ap_pass_brigade(f->next, in);
685 /* does the out brigade contain eos? if so, we're done, commit! */
686 for (e = APR_BRIGADE_FIRST(cache->out);
687 e != APR_BRIGADE_SENTINEL(cache->out);
688 e = APR_BUCKET_NEXT(e))
690 if (APR_BUCKET_IS_EOS(e)) {
691 rv = cache->provider->commit_entity(cache->handle, f->r);
696 /* conditionally remove the lock as soon as we see the eos bucket */
697 cache_remove_lock(conf, cache, f->r, cache->out);
699 if (APR_BRIGADE_EMPTY(cache->out)) {
700 if (APR_BRIGADE_EMPTY(in)) {
701 /* cache provider wants more data before passing the brigade
702 * upstream, oblige the provider by leaving to fetch more.
707 /* oops, no data out, but not all data read in either, be
708 * safe and stand down to prevent a spin.
710 ap_log_rerror(APLOG_MARK, APLOG_WARNING, rv, f->r,
711 "cache: Cache provider's store_body returned an "
712 "empty brigade, but didn't consume all of the"
713 "input brigade, standing down to prevent a spin");
714 ap_remove_output_filter(f);
716 /* give someone else the chance to cache the file */
717 cache_remove_lock(conf, cache, f->r, NULL);
719 return ap_pass_brigade(f->next, in);
723 rv = ap_pass_brigade(f->next, cache->out);
733 * Decide whether or not this content should be cached.
734 * If we decide no it should not:
735 * remove the filter from the chain
736 * If we decide yes it should:
737 * Have we already started saving the response?
738 * If we have started, pass the data to the storage manager via store_body
740 * Check to see if we *can* save this particular response.
741 * If we can, call cache_create_entity() and save the headers and body
742 * Finally, pass the data to the next filter (the network or whatever)
744 * After the various failure cases, the cache lock is proactively removed, so
745 * that another request is given the opportunity to attempt to cache without
746 * waiting for a potentially slow client to acknowledge the failure.
749 static int cache_save_filter(ap_filter_t *f, apr_bucket_brigade *in)
752 request_rec *r = f->r;
753 cache_request_rec *cache = (cache_request_rec *)f->ctx;
754 cache_server_conf *conf;
755 cache_dir_conf *dconf;
756 cache_control_t control;
757 const char *cc_out, *cl, *pragma;
758 const char *exps, *lastmods, *dates, *etag;
759 apr_time_t exp, date, lastmod, now;
761 cache_info *info = NULL;
765 apr_table_t *headers;
767 conf = (cache_server_conf *) ap_get_module_config(r->server->module_config,
770 /* Setup cache_request_rec */
772 /* user likely configured CACHE_SAVE manually; they should really use
773 * mod_cache configuration to do that
775 ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
776 "CACHE/CACHE_SAVE filter enabled while caching is disabled, ignoring");
777 ap_remove_output_filter(f);
778 return ap_pass_brigade(f->next, in);
786 * This section passes the brigades into the cache modules, but only
787 * if the setup section (see below) is complete.
789 if (cache->block_response) {
790 /* We've already sent down the response and EOS. So, ignore
791 * whatever comes now.
796 /* have we already run the cacheability check and set up the
797 * cached file handle?
799 if (cache->in_checked) {
800 return cache_save_store(f, in, conf, cache);
804 * Setup Data in Cache
805 * -------------------
806 * This section opens the cache entity and sets various caching
807 * parameters, and decides whether this URL should be cached at
808 * all. This section is* run before the above section.
811 dconf = ap_get_module_config(r->per_dir_config, &cache_module);
813 /* RFC2616 13.8 Errors or Incomplete Response Cache Behavior:
814 * If a cache receives a 5xx response while attempting to revalidate an
815 * entry, it MAY either forward this response to the requesting client,
816 * or act as if the server failed to respond. In the latter case, it MAY
817 * return a previously received response unless the cached entry
818 * includes the "must-revalidate" cache-control directive (see section
821 * This covers the case where an error was generated behind us, for example
822 * by a backend server via mod_proxy.
824 if (dconf->stale_on_error && r->status >= HTTP_INTERNAL_SERVER_ERROR) {
826 ap_remove_output_filter(cache->remove_url_filter);
828 if (cache->stale_handle
829 && !cache->stale_handle->cache_obj->info.control.must_revalidate
830 && !cache->stale_handle->cache_obj->info.control.proxy_revalidate) {
831 const char *warn_head;
833 /* morph the current save filter into the out filter, and serve from
836 cache->handle = cache->stale_handle;
838 f->frec = cache_out_subreq_filter_handle;
841 f->frec = cache_out_filter_handle;
844 r->headers_out = cache->stale_handle->resp_hdrs;
846 /* add a revalidation warning */
847 warn_head = apr_table_get(r->err_headers_out, "Warning");
848 if ((warn_head == NULL) || ((warn_head != NULL)
849 && (ap_strstr_c(warn_head, "111") == NULL))) {
850 apr_table_mergen(r->err_headers_out, "Warning",
851 "111 Revalidation failed");
854 cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_HIT,
855 apr_psprintf(r->pool,
856 "cache hit: %d status; stale content returned",
859 /* give someone else the chance to cache the file */
860 cache_remove_lock(conf, cache, f->r, NULL);
862 /* pass brigade to our morphed out filter */
863 return ap_pass_brigade(f, in);
867 /* read expiry date; if a bad date, then leave it so the client can
870 exps = apr_table_get(r->err_headers_out, "Expires");
872 exps = apr_table_get(r->headers_out, "Expires");
875 exp = apr_date_parse_http(exps);
881 /* read the last-modified date; if the date is bad, then delete it */
882 lastmods = apr_table_get(r->err_headers_out, "Last-Modified");
883 if (lastmods == NULL) {
884 lastmods = apr_table_get(r->headers_out, "Last-Modified");
886 if (lastmods != NULL) {
887 lastmod = apr_date_parse_http(lastmods);
888 if (lastmod == APR_DATE_BAD) {
893 lastmod = APR_DATE_BAD;
896 /* read the etag and cache-control from the entity */
897 etag = apr_table_get(r->err_headers_out, "Etag");
899 etag = apr_table_get(r->headers_out, "Etag");
901 cc_out = apr_table_get(r->err_headers_out, "Cache-Control");
902 pragma = apr_table_get(r->err_headers_out, "Pragma");
903 headers = r->err_headers_out;
904 if (!cc_out && !pragma) {
905 cc_out = apr_table_get(r->headers_out, "Cache-Control");
906 pragma = apr_table_get(r->headers_out, "Pragma");
907 headers = r->headers_out;
910 /* Have we received a 304 response without any headers at all? Fall back to
911 * the original headers in the original cached request.
913 if (r->status == HTTP_NOT_MODIFIED && cache->stale_handle && !cc_out
915 cc_out = apr_table_get(cache->stale_handle->resp_hdrs, "Cache-Control");
916 pragma = apr_table_get(cache->stale_handle->resp_hdrs, "Pragma");
919 /* Parse the cache control header */
920 memset(&control, 0, sizeof(cache_control_t));
921 ap_cache_control(r, &control, cc_out, pragma, headers);
924 * what responses should we not cache?
926 * At this point we decide based on the response headers whether it
927 * is appropriate _NOT_ to cache the data from the server. There are
928 * a whole lot of conditions that prevent us from caching this data.
929 * They are tested here one by one to be clear and unambiguous.
931 if (r->status != HTTP_OK && r->status != HTTP_NON_AUTHORITATIVE
932 && r->status != HTTP_PARTIAL_CONTENT
933 && r->status != HTTP_MULTIPLE_CHOICES
934 && r->status != HTTP_MOVED_PERMANENTLY
935 && r->status != HTTP_NOT_MODIFIED) {
936 /* RFC2616 13.4 we are allowed to cache 200, 203, 206, 300, 301 or 410
937 * We allow the caching of 206, but a cache implementation might choose
938 * to decline to cache a 206 if it doesn't know how to.
939 * We include 304 Not Modified here too as this is the origin server
940 * telling us to serve the cached copy.
942 if (exps != NULL || cc_out != NULL) {
943 /* We are also allowed to cache any response given that it has a
944 * valid Expires or Cache Control header. If we find a either of
945 * those here, we pass request through the rest of the tests. From
948 * A response received with any other status code (e.g. status
949 * codes 302 and 307) MUST NOT be returned in a reply to a
950 * subsequent request unless there are cache-control directives or
951 * another header(s) that explicitly allow it. For example, these
952 * include the following: an Expires header (section 14.21); a
953 * "max-age", "s-maxage", "must-revalidate", "proxy-revalidate",
954 * "public" or "private" cache-control directive (section 14.9).
958 reason = apr_psprintf(p, "Response status %d", r->status);
965 else if (exps != NULL && exp == APR_DATE_BAD) {
966 /* if a broken Expires header is present, don't cache it */
967 reason = apr_pstrcat(p, "Broken expires header: ", exps, NULL);
969 else if (!dconf->store_expired && exp != APR_DATE_BAD
970 && exp < r->request_time) {
971 /* if a Expires header is in the past, don't cache it */
972 reason = "Expires header already expired; not cacheable";
974 else if (!dconf->store_expired && (control.must_revalidate
975 || control.proxy_revalidate) && (!control.s_maxage_value
976 || (!control.s_maxage && !control.max_age_value)) && lastmods
977 == NULL && etag == NULL) {
978 /* if we're already stale, but can never revalidate, don't cache it */
980 = "s-maxage or max-age zero and no Last-Modified or Etag; not cacheable";
982 else if (!conf->ignorequerystring && r->parsed_uri.query && exps == NULL
983 && !control.max_age && !control.s_maxage) {
984 /* if a query string is present but no explicit expiration time,
985 * don't cache it (RFC 2616/13.9 & 13.2.1)
987 reason = "Query string present but no explicit expiration time";
989 else if (r->status == HTTP_NOT_MODIFIED &&
990 !cache->handle && !cache->stale_handle) {
991 /* if the server said 304 Not Modified but we have no cache
992 * file - pass this untouched to the user agent, it's not for us.
994 reason = "HTTP Status 304 Not Modified";
996 else if (r->status == HTTP_OK && lastmods == NULL && etag == NULL && (exps
997 == NULL) && (dconf->no_last_mod_ignore == 0) && !control.max_age
998 && !control.s_maxage) {
999 /* 200 OK response from HTTP/1.0 and up without Last-Modified,
1000 * Etag, Expires, Cache-Control:max-age, or Cache-Control:s-maxage
1003 /* Note: mod-include clears last_modified/expires/etags - this
1004 * is why we have an optional function for a key-gen ;-)
1006 reason = "No Last-Modified; Etag; Expires; Cache-Control:max-age or Cache-Control:s-maxage headers";
1008 else if (!dconf->store_nostore && control.no_store) {
1009 /* RFC2616 14.9.2 Cache-Control: no-store response
1010 * indicating do not cache, or stop now if you are
1011 * trying to cache it.
1013 reason = "Cache-Control: no-store present";
1015 else if (!dconf->store_private && control.private) {
1016 /* RFC2616 14.9.1 Cache-Control: private response
1017 * this object is marked for this user's eyes only. Behave
1020 reason = "Cache-Control: private present";
1022 else if (apr_table_get(r->headers_in, "Authorization")
1023 && !(control.s_maxage || control.must_revalidate
1024 || control.proxy_revalidate || control.public)) {
1025 /* RFC2616 14.8 Authorisation:
1026 * if authorisation is included in the request, we don't cache,
1027 * but we can cache if the following exceptions are true:
1028 * 1) If Cache-Control: s-maxage is included
1029 * 2) If Cache-Control: must-revalidate is included
1030 * 3) If Cache-Control: public is included
1032 reason = "Authorization required";
1034 else if (ap_cache_liststr(NULL,
1035 apr_table_get(r->headers_out, "Vary"),
1037 reason = "Vary header contains '*'";
1039 else if (apr_table_get(r->subprocess_env, "no-cache") != NULL) {
1040 reason = "environment variable 'no-cache' is set";
1042 else if (r->no_cache) {
1043 /* or we've been asked not to cache it above */
1044 reason = "r->no_cache present";
1047 /* Hold the phone. Some servers might allow us to cache a 2xx, but
1048 * then make their 304 responses non cacheable. This leaves us in a
1049 * sticky position. If the 304 is in answer to our own conditional
1050 * request, we cannot send this 304 back to the client because the
1051 * client isn't expecting it. Instead, our only option is to respect
1052 * the answer to the question we asked (has it changed, answer was
1053 * no) and return the cached item to the client, and then respect
1054 * the uncacheable nature of this 304 by allowing the remove_url
1055 * filter to kick in and remove the cached entity.
1057 if (reason && r->status == HTTP_NOT_MODIFIED &&
1058 cache->stale_handle) {
1059 apr_bucket_brigade *bb;
1063 cache->handle = cache->stale_handle;
1064 info = &cache->handle->cache_obj->info;
1066 /* Load in the saved status and clear the status line. */
1067 r->status = info->status;
1068 r->status_line = NULL;
1070 bb = apr_brigade_create(r->pool, r->connection->bucket_alloc);
1072 r->headers_in = cache->stale_headers;
1073 status = ap_meets_conditions(r);
1077 bkt = apr_bucket_flush_create(bb->bucket_alloc);
1078 APR_BRIGADE_INSERT_TAIL(bb, bkt);
1081 cache->provider->recall_body(cache->handle, r->pool, bb);
1083 bkt = apr_bucket_eos_create(bb->bucket_alloc);
1084 APR_BRIGADE_INSERT_TAIL(bb, bkt);
1087 cache->block_response = 1;
1089 /* we've got a cache conditional hit! tell anyone who cares */
1090 cache_run_cache_status(
1094 AP_CACHE_REVALIDATE,
1097 "conditional cache hit: 304 was uncacheable though (%s); entity removed",
1100 /* let someone else attempt to cache */
1101 cache_remove_lock(conf, cache, r, NULL);
1103 return ap_pass_brigade(f->next, bb);
1107 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
1108 "cache: %s not cached. Reason: %s", r->unparsed_uri,
1111 /* we've got a cache miss! tell anyone who cares */
1112 cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
1115 /* remove this filter from the chain */
1116 ap_remove_output_filter(f);
1118 /* remove the lock file unconditionally */
1119 cache_remove_lock(conf, cache, r, NULL);
1121 /* ship the data up the stack */
1122 return ap_pass_brigade(f->next, in);
1125 /* Make it so that we don't execute this path again. */
1126 cache->in_checked = 1;
1128 /* Set the content length if known.
1130 cl = apr_table_get(r->err_headers_out, "Content-Length");
1132 cl = apr_table_get(r->headers_out, "Content-Length");
1136 if (apr_strtoff(&size, cl, &errp, 10) || *errp || size < 0) {
1137 cl = NULL; /* parse error, see next 'if' block */
1142 /* if we don't get the content-length, see if we have all the
1143 * buckets and use their length to calculate the size
1145 int all_buckets_here=0;
1147 for (e = APR_BRIGADE_FIRST(in);
1148 e != APR_BRIGADE_SENTINEL(in);
1149 e = APR_BUCKET_NEXT(e))
1151 if (APR_BUCKET_IS_EOS(e)) {
1155 if (APR_BUCKET_IS_FLUSH(e)) {
1158 if (e->length == (apr_size_t)-1) {
1163 if (!all_buckets_here) {
1168 /* remember content length to check response size against later */
1171 /* It's safe to cache the response.
1173 * There are two possiblities at this point:
1174 * - cache->handle == NULL. In this case there is no previously
1175 * cached entity anywhere on the system. We must create a brand
1176 * new entity and store the response in it.
1177 * - cache->stale_handle != NULL. In this case there is a stale
1178 * entity in the system which needs to be replaced by new
1179 * content (unless the result was 304 Not Modified, which means
1180 * the cached entity is actually fresh, and we should update
1184 /* Did we have a stale cache entry that really is stale?
1186 if (cache->stale_handle) {
1187 if (r->status == HTTP_NOT_MODIFIED) {
1188 /* Oh, hey. It isn't that stale! Yay! */
1189 cache->handle = cache->stale_handle;
1190 info = &cache->handle->cache_obj->info;
1194 /* Oh, well. Toss it. */
1195 cache->provider->remove_entity(cache->stale_handle);
1196 /* Treat the request as if it wasn't conditional. */
1197 cache->stale_handle = NULL;
1199 * Restore the original request headers as they may be needed
1200 * by further output filters like the byterange filter to make
1201 * the correct decisions.
1203 r->headers_in = cache->stale_headers;
1207 /* no cache handle, create a new entity */
1208 if (!cache->handle) {
1209 rv = cache_create_entity(cache, r, size, in);
1210 info = apr_pcalloc(r->pool, sizeof(cache_info));
1211 /* We only set info->status upon the initial creation. */
1212 info->status = r->status;
1216 /* we've got a cache miss! tell anyone who cares */
1217 cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
1218 "cache miss: create_entity failed");
1220 /* Caching layer declined the opportunity to cache the response */
1221 ap_remove_output_filter(f);
1222 cache_remove_lock(conf, cache, r, NULL);
1223 return ap_pass_brigade(f->next, in);
1226 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
1227 "cache: Caching url: %s", r->unparsed_uri);
1229 /* We are actually caching this response. So it does not
1230 * make sense to remove this entity any more.
1232 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
1233 "cache: Removing CACHE_REMOVE_URL filter.");
1234 ap_remove_output_filter(cache->remove_url_filter);
1237 * We now want to update the cache file header information with
1238 * the new date, last modified, expire and content length and write
1239 * it away to our cache file. First, we determine these values from
1240 * the response, using heuristics if appropriate.
1242 * In addition, we make HTTP/1.1 age calculations and write them away
1246 /* store away the previously parsed cache control headers */
1247 memcpy(&info->control, &control, sizeof(cache_control_t));
1249 /* Read the date. Generate one if one is not supplied */
1250 dates = apr_table_get(r->err_headers_out, "Date");
1251 if (dates == NULL) {
1252 dates = apr_table_get(r->headers_out, "Date");
1254 if (dates != NULL) {
1255 info->date = apr_date_parse_http(dates);
1258 info->date = APR_DATE_BAD;
1261 now = apr_time_now();
1262 if (info->date == APR_DATE_BAD) { /* No, or bad date */
1263 /* no date header (or bad header)! */
1268 /* set response_time for HTTP/1.1 age calculations */
1269 info->response_time = now;
1271 /* get the request time */
1272 info->request_time = r->request_time;
1274 /* check last-modified date */
1275 if (lastmod != APR_DATE_BAD && lastmod > date) {
1276 /* if it's in the future, then replace by date */
1279 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0,
1280 r, "cache: Last modified is in the future, "
1281 "replacing with now");
1284 /* if no expiry date then
1285 * if Cache-Control: max-age
1286 * expiry date = date + max-age
1288 * expiry date = date + min((date - lastmod) * factor, maxexpire)
1290 * expire date = date + defaultexpire
1292 if (exp == APR_DATE_BAD) {
1294 if (control.max_age) {
1298 x = control.max_age_value;
1303 x = x * MSEC_ONE_SEC;
1305 if (x < dconf->minex) {
1308 if (x > dconf->maxex) {
1313 else if ((lastmod != APR_DATE_BAD) && (lastmod < date)) {
1314 /* if lastmod == date then you get 0*conf->factor which results in
1315 * an expiration time of now. This causes some problems with
1316 * freshness calculations, so we choose the else path...
1318 apr_time_t x = (apr_time_t) ((date - lastmod) * dconf->factor);
1320 if (x < dconf->minex) {
1323 if (x > dconf->maxex) {
1329 exp = date + dconf->defex;
1334 /* We found a stale entry which wasn't really stale. */
1335 if (cache->stale_handle) {
1336 /* Load in the saved status and clear the status line. */
1337 r->status = info->status;
1338 r->status_line = NULL;
1340 /* RFC 2616 10.3.5 states that entity headers are not supposed
1341 * to be in the 304 response. Therefore, we need to combine the
1342 * response headers with the cached headers *before* we update
1343 * the cached headers.
1345 * However, before doing that, we need to first merge in
1346 * err_headers_out and we also need to strip any hop-by-hop
1347 * headers that might have snuck in.
1349 r->headers_out = ap_cache_cacheable_headers_out(r);
1351 /* Merge in our cached headers. However, keep any updated values. */
1352 cache_accept_headers(cache->handle, r, 1);
1355 /* Write away header information to cache. It is possible that we are
1356 * trying to update headers for an entity which has already been cached.
1358 * This may fail, due to an unwritable cache area. E.g. filesystem full,
1359 * permissions problems or a read-only (re)mount. This must be handled
1362 rv = cache->provider->store_headers(cache->handle, r, info);
1364 /* Did we just update the cached headers on a revalidated response?
1366 * If so, we can now decide what to serve to the client. This is done in
1367 * the same way as with a regular response, but conditions are now checked
1368 * against the cached or merged response headers.
1370 if (cache->stale_handle) {
1371 apr_bucket_brigade *bb;
1375 /* We're just saving response headers, so we are done. Commit
1376 * the response at this point, unless there was a previous error.
1378 if (rv == APR_SUCCESS) {
1379 rv = cache->provider->commit_entity(cache->handle, r);
1382 bb = apr_brigade_create(r->pool, r->connection->bucket_alloc);
1384 /* Restore the original request headers and see if we need to
1385 * return anything else than the cached response (ie. the original
1386 * request was conditional).
1388 r->headers_in = cache->stale_headers;
1389 status = ap_meets_conditions(r);
1393 bkt = apr_bucket_flush_create(bb->bucket_alloc);
1394 APR_BRIGADE_INSERT_TAIL(bb, bkt);
1397 cache->provider->recall_body(cache->handle, r->pool, bb);
1399 bkt = apr_bucket_eos_create(bb->bucket_alloc);
1400 APR_BRIGADE_INSERT_TAIL(bb, bkt);
1403 cache->block_response = 1;
1405 /* Before returning we need to handle the possible case of an
1406 * unwritable cache. Rather than leaving the entity in the cache
1407 * and having it constantly re-validated, now that we have recalled
1408 * the body it is safe to try and remove the url from the cache.
1410 if (rv != APR_SUCCESS) {
1411 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r,
1412 "cache: updating headers with store_headers failed. "
1413 "Removing cached url.");
1415 rv = cache->provider->remove_url(cache->stale_handle, r);
1417 /* Probably a mod_cache_disk cache area has been (re)mounted
1418 * read-only, or that there is a permissions problem.
1420 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r,
1421 "cache: attempt to remove url from cache unsuccessful.");
1424 /* we've got a cache conditional hit! tell anyone who cares */
1425 cache_run_cache_status(cache->handle, r, r->headers_out,
1426 AP_CACHE_REVALIDATE,
1427 "conditional cache hit: entity refresh failed");
1432 /* we've got a cache conditional hit! tell anyone who cares */
1433 cache_run_cache_status(cache->handle, r, r->headers_out,
1434 AP_CACHE_REVALIDATE,
1435 "conditional cache hit: entity refreshed");
1439 /* let someone else attempt to cache */
1440 cache_remove_lock(conf, cache, r, NULL);
1442 return ap_pass_brigade(f->next, bb);
1445 if (rv != APR_SUCCESS) {
1446 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r,
1447 "cache: store_headers failed");
1449 /* we've got a cache miss! tell anyone who cares */
1450 cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
1451 "cache miss: store_headers failed");
1453 ap_remove_output_filter(f);
1454 cache_remove_lock(conf, cache, r, NULL);
1455 return ap_pass_brigade(f->next, in);
1458 /* we've got a cache miss! tell anyone who cares */
1459 cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
1460 "cache miss: attempting entity save");
1462 return cache_save_store(f, in, conf, cache);
1466 * CACHE_REMOVE_URL filter
1467 * -----------------------
1469 * This filter gets added in the quick handler every time the CACHE_SAVE filter
1470 * gets inserted. Its purpose is to remove a confirmed stale cache entry from
1473 * CACHE_REMOVE_URL has to be a protocol filter to ensure that is run even if
1474 * the response is a canned error message, which removes the content filters
1475 * and thus the CACHE_SAVE filter from the chain.
1477 * CACHE_REMOVE_URL expects cache request rec within its context because the
1478 * request this filter runs on can be different from the one whose cache entry
1479 * should be removed, due to internal redirects.
1481 * Note that CACHE_SAVE_URL (as a content-set filter, hence run before the
1482 * protocol filters) will remove this filter if it decides to cache the file.
1483 * Therefore, if this filter is left in, it must mean we need to toss any
1486 static int cache_remove_url_filter(ap_filter_t *f, apr_bucket_brigade *in)
1488 request_rec *r = f->r;
1489 cache_request_rec *cache;
1491 /* Setup cache_request_rec */
1492 cache = (cache_request_rec *) f->ctx;
1495 /* user likely configured CACHE_REMOVE_URL manually; they should really
1496 * use mod_cache configuration to do that. So:
1497 * 1. Remove ourselves
1498 * 2. Do nothing and bail out
1500 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
1501 "cache: CACHE_REMOVE_URL enabled unexpectedly");
1502 ap_remove_output_filter(f);
1503 return ap_pass_brigade(f->next, in);
1506 /* Now remove this cache entry from the cache */
1507 cache_remove_url(cache, r);
1509 /* remove ourselves */
1510 ap_remove_output_filter(f);
1511 return ap_pass_brigade(f->next, in);
1518 * This filter can be optionally inserted into the filter chain by the admin as
1519 * a marker representing the precise location within the filter chain where
1520 * caching is to be performed.
1522 * When the filter chain is set up in the non-quick version of the URL handler,
1523 * the CACHE filter is replaced by the CACHE_OUT or CACHE_SAVE filter,
1524 * effectively inserting the caching filters at the point indicated by the
1525 * admin. The CACHE filter is then removed.
1527 * This allows caching to be performed before the content is passed to the
1528 * INCLUDES filter, or to a filter that might perform transformations unique
1529 * to the specific request and that would otherwise be non-cacheable.
1531 static int cache_filter(ap_filter_t *f, apr_bucket_brigade *in)
1533 /* we are just a marker, so let's just remove ourselves */
1534 ap_log_rerror(APLOG_MARK, APLOG_WARNING, 0, f->r,
1535 "cache: CACHE filter was added twice, or was added in quick "
1536 "handler mode and will be ignored.");
1537 ap_remove_output_filter(f);
1538 return ap_pass_brigade(f->next, in);
1542 * If configured, add the status of the caching attempt to the subprocess
1543 * environment, and if configured, to headers in the response.
1545 * The status is saved below the broad category of the status (hit, miss,
1546 * revalidate), as well as a single cache-status key. This can be used for
1547 * conditional logging.
1549 * The status is optionally saved to an X-Cache header, and the detail of
1550 * why a particular cache entry was cached (or not cached) is optionally
1551 * saved to an X-Cache-Detail header. This extra detail is useful for
1552 * service developers who may need to know whether their Cache-Control headers
1553 * are working correctly.
1555 static int cache_status(cache_handle_t *h, request_rec *r,
1556 apr_table_t *headers, ap_cache_status_e status, const char *reason)
1560 (cache_server_conf *) ap_get_module_config(r->server->module_config,
1563 cache_dir_conf *dconf = ap_get_module_config(r->per_dir_config, &cache_module);
1564 int x_cache = 0, x_cache_detail = 0;
1567 case AP_CACHE_HIT: {
1568 apr_table_setn(r->subprocess_env, AP_CACHE_HIT_ENV, reason);
1571 case AP_CACHE_REVALIDATE: {
1572 apr_table_setn(r->subprocess_env, AP_CACHE_REVALIDATE_ENV, reason);
1575 case AP_CACHE_MISS: {
1576 apr_table_setn(r->subprocess_env, AP_CACHE_MISS_ENV, reason);
1579 case AP_CACHE_INVALIDATE: {
1580 apr_table_setn(r->subprocess_env, AP_CACHE_INVALIDATE_ENV, reason);
1585 apr_table_setn(r->subprocess_env, AP_CACHE_STATUS_ENV, reason);
1587 if (dconf && dconf->x_cache_set) {
1588 x_cache = dconf->x_cache;
1591 x_cache = conf->x_cache;
1594 apr_table_setn(headers, "X-Cache", apr_psprintf(r->pool, "%s from %s",
1595 status == AP_CACHE_HIT ? "HIT"
1596 : status == AP_CACHE_REVALIDATE ? "REVALIDATE" : status
1597 == AP_CACHE_INVALIDATE ? "INVALIDATE" : "MISS",
1598 r->server->server_hostname));
1601 if (dconf && dconf->x_cache_detail_set) {
1602 x_cache_detail = dconf->x_cache_detail;
1605 x_cache_detail = conf->x_cache_detail;
1607 if (x_cache_detail) {
1608 apr_table_setn(headers, "X-Cache-Detail", apr_psprintf(r->pool,
1609 "\"%s\" from %s", reason, r->server->server_hostname));
1616 * If an error has occurred, but we have a stale cached entry, restore the
1617 * filter stack from the save filter onwards. The canned error message will
1618 * be discarded in the process, and replaced with the cached response.
1620 static void cache_insert_error_filter(request_rec *r)
1623 cache_dir_conf *dconf;
1625 /* ignore everything except for 5xx errors */
1626 if (r->status < HTTP_INTERNAL_SERVER_ERROR) {
1630 dconf = ap_get_module_config(r->per_dir_config, &cache_module);
1632 if (!dconf->stale_on_error) {
1636 /* RFC2616 13.8 Errors or Incomplete Response Cache Behavior:
1637 * If a cache receives a 5xx response while attempting to revalidate an
1638 * entry, it MAY either forward this response to the requesting client,
1639 * or act as if the server failed to respond. In the latter case, it MAY
1640 * return a previously received response unless the cached entry
1641 * includes the "must-revalidate" cache-control directive (see section
1644 * This covers the case where the error was generated by our server via
1647 apr_pool_userdata_get(&dummy, CACHE_CTX_KEY, r->pool);
1649 cache_request_rec *cache = (cache_request_rec *) dummy;
1651 ap_remove_output_filter(cache->remove_url_filter);
1653 if (cache->stale_handle && cache->save_filter
1654 && !cache->stale_handle->cache_obj->info.control.must_revalidate
1655 && !cache->stale_handle->cache_obj->info.control.proxy_revalidate) {
1656 const char *warn_head;
1659 (cache_server_conf *) ap_get_module_config(r->server->module_config,
1662 /* morph the current save filter into the out filter, and serve from
1665 cache->handle = cache->stale_handle;
1667 cache->save_filter->frec = cache_out_subreq_filter_handle;
1670 cache->save_filter->frec = cache_out_filter_handle;
1673 r->output_filters = cache->save_filter;
1675 r->err_headers_out = cache->stale_handle->resp_hdrs;
1677 /* add a revalidation warning */
1678 warn_head = apr_table_get(r->err_headers_out, "Warning");
1679 if ((warn_head == NULL) || ((warn_head != NULL)
1680 && (ap_strstr_c(warn_head, "111") == NULL))) {
1681 apr_table_mergen(r->err_headers_out, "Warning",
1682 "111 Revalidation failed");
1685 cache_run_cache_status(
1692 "cache hit: %d status; stale content returned",
1695 /* give someone else the chance to cache the file */
1696 cache_remove_lock(conf, cache, r, NULL);
1704 /* -------------------------------------------------------------- */
1705 /* Setup configurable data */
1707 static void *create_dir_config(apr_pool_t *p, char *dummy)
1709 cache_dir_conf *dconf = apr_pcalloc(p, sizeof(cache_dir_conf));
1711 dconf->no_last_mod_ignore = 0;
1712 dconf->store_expired = 0;
1713 dconf->store_private = 0;
1714 dconf->store_nostore = 0;
1716 /* maximum time to cache a document */
1717 dconf->maxex = DEFAULT_CACHE_MAXEXPIRE;
1718 dconf->minex = DEFAULT_CACHE_MINEXPIRE;
1719 /* default time to cache a document */
1720 dconf->defex = DEFAULT_CACHE_EXPIRE;
1722 /* factor used to estimate Expires date from LastModified date */
1723 dconf->factor = DEFAULT_CACHE_LMFACTOR;
1725 dconf->x_cache = DEFAULT_X_CACHE;
1726 dconf->x_cache_detail = DEFAULT_X_CACHE_DETAIL;
1728 dconf->stale_on_error = DEFAULT_CACHE_STALE_ON_ERROR;
1730 /* array of providers for this URL space */
1731 dconf->cacheenable = apr_array_make(p, 10, sizeof(struct cache_enable));
1736 static void *merge_dir_config(apr_pool_t *p, void *basev, void *addv) {
1737 cache_dir_conf *new = (cache_dir_conf *) apr_pcalloc(p, sizeof(cache_dir_conf));
1738 cache_dir_conf *add = (cache_dir_conf *) addv;
1739 cache_dir_conf *base = (cache_dir_conf *) basev;
1741 new->no_last_mod_ignore = (add->no_last_mod_ignore_set == 0) ? base->no_last_mod_ignore : add->no_last_mod_ignore;
1742 new->no_last_mod_ignore_set = add->no_last_mod_ignore_set || base->no_last_mod_ignore_set;
1744 new->store_expired = (add->store_expired_set == 0) ? base->store_expired : add->store_expired;
1745 new->store_expired_set = add->store_expired_set || base->store_expired_set;
1746 new->store_private = (add->store_private_set == 0) ? base->store_private : add->store_private;
1747 new->store_private_set = add->store_private_set || base->store_private_set;
1748 new->store_nostore = (add->store_nostore_set == 0) ? base->store_nostore : add->store_nostore;
1749 new->store_nostore_set = add->store_nostore_set || base->store_nostore_set;
1751 /* maximum time to cache a document */
1752 new->maxex = (add->maxex_set == 0) ? base->maxex : add->maxex;
1753 new->maxex_set = add->maxex_set || base->maxex_set;
1754 new->minex = (add->minex_set == 0) ? base->minex : add->minex;
1755 new->minex_set = add->minex_set || base->minex_set;
1757 /* default time to cache a document */
1758 new->defex = (add->defex_set == 0) ? base->defex : add->defex;
1759 new->defex_set = add->defex_set || base->defex_set;
1761 /* factor used to estimate Expires date from LastModified date */
1762 new->factor = (add->factor_set == 0) ? base->factor : add->factor;
1763 new->factor_set = add->factor_set || base->factor_set;
1765 new->x_cache = (add->x_cache_set == 0) ? base->x_cache : add->x_cache;
1766 new->x_cache_set = add->x_cache_set || base->x_cache_set;
1767 new->x_cache_detail = (add->x_cache_detail_set == 0) ? base->x_cache_detail
1768 : add->x_cache_detail;
1769 new->x_cache_detail_set = add->x_cache_detail_set
1770 || base->x_cache_detail_set;
1772 new->stale_on_error = (add->stale_on_error_set == 0) ? base->stale_on_error
1773 : add->stale_on_error;
1774 new->stale_on_error_set = add->stale_on_error_set
1775 || base->stale_on_error_set;
1777 new->cacheenable = add->enable_set ? apr_array_append(p, base->cacheenable,
1778 add->cacheenable) : base->cacheenable;
1779 new->enable_set = add->enable_set || base->enable_set;
1780 new->disable = (add->disable_set == 0) ? base->disable : add->disable;
1781 new->disable_set = add->disable_set || base->disable_set;
1786 static void * create_cache_config(apr_pool_t *p, server_rec *s)
1788 const char *tmppath;
1789 cache_server_conf *ps = apr_pcalloc(p, sizeof(cache_server_conf));
1791 /* array of URL prefixes for which caching is enabled */
1792 ps->cacheenable = apr_array_make(p, 10, sizeof(struct cache_enable));
1793 /* array of URL prefixes for which caching is disabled */
1794 ps->cachedisable = apr_array_make(p, 10, sizeof(struct cache_disable));
1795 ps->ignorecachecontrol = 0;
1796 ps->ignorecachecontrol_set = 0;
1797 /* array of headers that should not be stored in cache */
1798 ps->ignore_headers = apr_array_make(p, 10, sizeof(char *));
1799 ps->ignore_headers_set = CACHE_IGNORE_HEADERS_UNSET;
1800 /* flag indicating that query-string should be ignored when caching */
1801 ps->ignorequerystring = 0;
1802 ps->ignorequerystring_set = 0;
1803 /* by default, run in the quick handler */
1806 /* array of identifiers that should not be used for key calculation */
1807 ps->ignore_session_id = apr_array_make(p, 10, sizeof(char *));
1808 ps->ignore_session_id_set = CACHE_IGNORE_SESSION_ID_UNSET;
1809 ps->lock = 0; /* thundering herd lock defaults to off */
1811 apr_temp_dir_get(&tmppath, p);
1813 ps->lockpath = apr_pstrcat(p, tmppath, DEFAULT_CACHE_LOCKPATH, NULL);
1815 ps->lockmaxage = apr_time_from_sec(DEFAULT_CACHE_MAXAGE);
1816 ps->x_cache = DEFAULT_X_CACHE;
1817 ps->x_cache_detail = DEFAULT_X_CACHE_DETAIL;
1821 static void * merge_cache_config(apr_pool_t *p, void *basev, void *overridesv)
1823 cache_server_conf *ps = apr_pcalloc(p, sizeof(cache_server_conf));
1824 cache_server_conf *base = (cache_server_conf *) basev;
1825 cache_server_conf *overrides = (cache_server_conf *) overridesv;
1827 /* array of URL prefixes for which caching is disabled */
1828 ps->cachedisable = apr_array_append(p,
1830 overrides->cachedisable);
1831 /* array of URL prefixes for which caching is enabled */
1832 ps->cacheenable = apr_array_append(p,
1834 overrides->cacheenable);
1836 ps->ignorecachecontrol =
1837 (overrides->ignorecachecontrol_set == 0)
1838 ? base->ignorecachecontrol
1839 : overrides->ignorecachecontrol;
1840 ps->ignore_headers =
1841 (overrides->ignore_headers_set == CACHE_IGNORE_HEADERS_UNSET)
1842 ? base->ignore_headers
1843 : overrides->ignore_headers;
1844 ps->ignorequerystring =
1845 (overrides->ignorequerystring_set == 0)
1846 ? base->ignorequerystring
1847 : overrides->ignorequerystring;
1848 ps->ignore_session_id =
1849 (overrides->ignore_session_id_set == CACHE_IGNORE_SESSION_ID_UNSET)
1850 ? base->ignore_session_id
1851 : overrides->ignore_session_id;
1853 (overrides->lock_set == 0)
1857 (overrides->lockpath_set == 0)
1859 : overrides->lockpath;
1861 (overrides->lockmaxage_set == 0)
1863 : overrides->lockmaxage;
1865 (overrides->quick_set == 0)
1869 (overrides->x_cache_set == 0)
1871 : overrides->x_cache;
1872 ps->x_cache_detail =
1873 (overrides->x_cache_detail_set == 0)
1874 ? base->x_cache_detail
1875 : overrides->x_cache_detail;
1877 (overrides->base_uri_set == 0)
1879 : overrides->base_uri;
1883 static const char *set_cache_quick_handler(cmd_parms *parms, void *dummy,
1886 cache_server_conf *conf;
1889 (cache_server_conf *)ap_get_module_config(parms->server->module_config
1893 conf->quick_set = 1;
1898 static const char *set_cache_ignore_no_last_mod(cmd_parms *parms, void *dummy,
1901 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
1903 dconf->no_last_mod_ignore = flag;
1904 dconf->no_last_mod_ignore_set = 1;
1909 static const char *set_cache_ignore_cachecontrol(cmd_parms *parms,
1910 void *dummy, int flag)
1912 cache_server_conf *conf;
1915 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
1917 conf->ignorecachecontrol = flag;
1918 conf->ignorecachecontrol_set = 1;
1922 static const char *set_cache_store_expired(cmd_parms *parms, void *dummy,
1925 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
1927 dconf->store_expired = flag;
1928 dconf->store_expired_set = 1;
1932 static const char *set_cache_store_private(cmd_parms *parms, void *dummy,
1935 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
1937 dconf->store_private = flag;
1938 dconf->store_private_set = 1;
1942 static const char *set_cache_store_nostore(cmd_parms *parms, void *dummy,
1945 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
1947 dconf->store_nostore = flag;
1948 dconf->store_nostore_set = 1;
1952 static const char *add_ignore_header(cmd_parms *parms, void *dummy,
1955 cache_server_conf *conf;
1959 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
1961 if (!strcasecmp(header, "None")) {
1962 /* if header None is listed clear array */
1963 conf->ignore_headers->nelts = 0;
1966 if ((conf->ignore_headers_set == CACHE_IGNORE_HEADERS_UNSET) ||
1967 (conf->ignore_headers->nelts)) {
1968 /* Only add header if no "None" has been found in header list
1970 * (When 'None' is passed, IGNORE_HEADERS_SET && nelts == 0.)
1972 new = (char **)apr_array_push(conf->ignore_headers);
1973 (*new) = (char *)header;
1976 conf->ignore_headers_set = CACHE_IGNORE_HEADERS_SET;
1980 static const char *add_ignore_session_id(cmd_parms *parms, void *dummy,
1981 const char *identifier)
1983 cache_server_conf *conf;
1987 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
1989 if (!strcasecmp(identifier, "None")) {
1990 /* if identifier None is listed clear array */
1991 conf->ignore_session_id->nelts = 0;
1994 if ((conf->ignore_session_id_set == CACHE_IGNORE_SESSION_ID_UNSET) ||
1995 (conf->ignore_session_id->nelts)) {
1997 * Only add identifier if no "None" has been found in identifier
2000 new = (char **)apr_array_push(conf->ignore_session_id);
2001 (*new) = (char *)identifier;
2004 conf->ignore_session_id_set = CACHE_IGNORE_SESSION_ID_SET;
2008 static const char *add_cache_enable(cmd_parms *parms, void *dummy,
2012 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2013 cache_server_conf *conf;
2014 struct cache_enable *new;
2016 const char *err = ap_check_cmd_context(parms,
2017 NOT_IN_DIRECTORY|NOT_IN_LIMIT|NOT_IN_FILES);
2023 return apr_psprintf(parms->pool,
2024 "provider (%s) starts with a '/'. Are url and provider switched?",
2032 return apr_psprintf(parms->pool,
2033 "CacheEnable provider (%s) is missing an URL.", type);
2035 if (parms->path && strncmp(parms->path, url, strlen(parms->path))) {
2036 return "When in a Location, CacheEnable must specify a path or an URL below "
2041 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2045 new = apr_array_push(dconf->cacheenable);
2046 dconf->enable_set = 1;
2049 new = apr_array_push(conf->cacheenable);
2053 if (apr_uri_parse(parms->pool, url, &(new->url))) {
2056 if (new->url.path) {
2057 new->pathlen = strlen(new->url.path);
2060 new->url.path = "/";
2065 static const char *add_cache_disable(cmd_parms *parms, void *dummy,
2068 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2069 cache_server_conf *conf;
2070 struct cache_disable *new;
2072 const char *err = ap_check_cmd_context(parms,
2073 NOT_IN_DIRECTORY|NOT_IN_LIMIT|NOT_IN_FILES);
2078 if (parms->path && !strcmp(url, "on")) {
2081 if (url[0] != '/' && !ap_strchr_c(url, ':')) {
2082 return "CacheDisable must specify a path or an URL, or when in a Location, "
2086 if (parms->path && strncmp(parms->path, url, strlen(parms->path))) {
2087 return "When in a Location, CacheDisable must specify a path or an URL below "
2092 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2097 dconf->disable_set = 1;
2101 new = apr_array_push(conf->cachedisable);
2102 if (apr_uri_parse(parms->pool, url, &(new->url))) {
2105 if (new->url.path) {
2106 new->pathlen = strlen(new->url.path);
2109 new->url.path = "/";
2114 static const char *set_cache_maxex(cmd_parms *parms, void *dummy,
2117 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2119 dconf->maxex = (apr_time_t) (atol(arg) * MSEC_ONE_SEC);
2120 dconf->maxex_set = 1;
2124 static const char *set_cache_minex(cmd_parms *parms, void *dummy,
2127 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2129 dconf->minex = (apr_time_t) (atol(arg) * MSEC_ONE_SEC);
2130 dconf->minex_set = 1;
2134 static const char *set_cache_defex(cmd_parms *parms, void *dummy,
2137 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2139 dconf->defex = (apr_time_t) (atol(arg) * MSEC_ONE_SEC);
2140 dconf->defex_set = 1;
2144 static const char *set_cache_factor(cmd_parms *parms, void *dummy,
2147 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2150 if (sscanf(arg, "%lg", &val) != 1) {
2151 return "CacheLastModifiedFactor value must be a float";
2153 dconf->factor = val;
2154 dconf->factor_set = 1;
2158 static const char *set_cache_ignore_querystring(cmd_parms *parms, void *dummy,
2161 cache_server_conf *conf;
2164 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2166 conf->ignorequerystring = flag;
2167 conf->ignorequerystring_set = 1;
2171 static const char *set_cache_lock(cmd_parms *parms, void *dummy,
2174 cache_server_conf *conf;
2177 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2184 static const char *set_cache_lock_path(cmd_parms *parms, void *dummy,
2187 cache_server_conf *conf;
2190 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2193 conf->lockpath = ap_server_root_relative(parms->pool, arg);
2194 if (!conf->lockpath) {
2195 return apr_pstrcat(parms->pool, "Invalid CacheLockPath path ",
2198 conf->lockpath_set = 1;
2202 static const char *set_cache_lock_maxage(cmd_parms *parms, void *dummy,
2205 cache_server_conf *conf;
2206 apr_int64_t seconds;
2209 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2211 seconds = apr_atoi64(arg);
2213 return "CacheLockMaxAge value must be a non-zero positive integer";
2215 conf->lockmaxage = apr_time_from_sec(seconds);
2216 conf->lockmaxage_set = 1;
2220 static const char *set_cache_x_cache(cmd_parms *parms, void *dummy, int flag)
2224 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2226 dconf->x_cache = flag;
2227 dconf->x_cache_set = 1;
2231 cache_server_conf *conf =
2232 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2235 conf->x_cache = flag;
2236 conf->x_cache_set = 1;
2243 static const char *set_cache_x_cache_detail(cmd_parms *parms, void *dummy, int flag)
2247 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2249 dconf->x_cache_detail = flag;
2250 dconf->x_cache_detail_set = 1;
2254 cache_server_conf *conf =
2255 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2258 conf->x_cache_detail = flag;
2259 conf->x_cache_detail_set = 1;
2266 static const char *set_cache_key_base_url(cmd_parms *parms, void *dummy,
2269 cache_server_conf *conf;
2273 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2275 conf->base_uri = apr_pcalloc(parms->pool, sizeof(apr_uri_t));
2276 rv = apr_uri_parse(parms->pool, arg, conf->base_uri);
2277 if (rv != APR_SUCCESS) {
2278 return apr_psprintf(parms->pool, "Could not parse '%s' as an URL.", arg);
2280 else if (!conf->base_uri->scheme && !conf->base_uri->hostname &&
2281 !conf->base_uri->port_str) {
2282 return apr_psprintf(parms->pool, "URL '%s' must contain at least one of a scheme, a hostname or a port.", arg);
2284 conf->base_uri_set = 1;
2288 static const char *set_cache_stale_on_error(cmd_parms *parms, void *dummy,
2291 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2293 dconf->stale_on_error = flag;
2294 dconf->stale_on_error_set = 1;
2298 static int cache_post_config(apr_pool_t *p, apr_pool_t *plog,
2299 apr_pool_t *ptemp, server_rec *s)
2301 /* This is the means by which unusual (non-unix) os's may find alternate
2302 * means to run a given command (e.g. shebang/registry parsing on Win32)
2304 cache_generate_key = APR_RETRIEVE_OPTIONAL_FN(ap_cache_generate_key);
2305 if (!cache_generate_key) {
2306 cache_generate_key = cache_generate_key_default;
2312 static const command_rec cache_cmds[] =
2315 * Consider a new config directive that enables loading specific cache
2316 * implememtations (like mod_cache_mem, mod_cache_file, etc.).
2317 * Rather than using a LoadModule directive, admin would use something
2318 * like CacheModule mem_cache_module | file_cache_module, etc,
2319 * which would cause the approprpriate cache module to be loaded.
2320 * This is more intuitive that requiring a LoadModule directive.
2323 AP_INIT_TAKE12("CacheEnable", add_cache_enable, NULL, RSRC_CONF|ACCESS_CONF,
2324 "A cache type and partial URL prefix below which "
2325 "caching is enabled"),
2326 AP_INIT_TAKE1("CacheDisable", add_cache_disable, NULL, RSRC_CONF|ACCESS_CONF,
2327 "A partial URL prefix below which caching is disabled"),
2328 AP_INIT_TAKE1("CacheMaxExpire", set_cache_maxex, NULL, RSRC_CONF|ACCESS_CONF,
2329 "The maximum time in seconds to cache a document"),
2330 AP_INIT_TAKE1("CacheMinExpire", set_cache_minex, NULL, RSRC_CONF|ACCESS_CONF,
2331 "The minimum time in seconds to cache a document"),
2332 AP_INIT_TAKE1("CacheDefaultExpire", set_cache_defex, NULL, RSRC_CONF|ACCESS_CONF,
2333 "The default time in seconds to cache a document"),
2334 AP_INIT_FLAG("CacheQuickHandler", set_cache_quick_handler, NULL,
2336 "Run the cache in the quick handler, default on"),
2337 AP_INIT_FLAG("CacheIgnoreNoLastMod", set_cache_ignore_no_last_mod, NULL,
2338 RSRC_CONF|ACCESS_CONF,
2339 "Ignore Responses where there is no Last Modified Header"),
2340 AP_INIT_FLAG("CacheIgnoreCacheControl", set_cache_ignore_cachecontrol,
2342 "Ignore requests from the client for uncached content"),
2343 AP_INIT_FLAG("CacheStoreExpired", set_cache_store_expired,
2344 NULL, RSRC_CONF|ACCESS_CONF,
2345 "Ignore expiration dates when populating cache, resulting in "
2346 "an If-Modified-Since request to the backend on retrieval"),
2347 AP_INIT_FLAG("CacheStorePrivate", set_cache_store_private,
2348 NULL, RSRC_CONF|ACCESS_CONF,
2349 "Ignore 'Cache-Control: private' and store private content"),
2350 AP_INIT_FLAG("CacheStoreNoStore", set_cache_store_nostore,
2351 NULL, RSRC_CONF|ACCESS_CONF,
2352 "Ignore 'Cache-Control: no-store' and store sensitive content"),
2353 AP_INIT_ITERATE("CacheIgnoreHeaders", add_ignore_header, NULL, RSRC_CONF,
2354 "A space separated list of headers that should not be "
2355 "stored by the cache"),
2356 AP_INIT_FLAG("CacheIgnoreQueryString", set_cache_ignore_querystring,
2358 "Ignore query-string when caching"),
2359 AP_INIT_ITERATE("CacheIgnoreURLSessionIdentifiers", add_ignore_session_id,
2360 NULL, RSRC_CONF, "A space separated list of session "
2361 "identifiers that should be ignored for creating the key "
2362 "of the cached entity."),
2363 AP_INIT_TAKE1("CacheLastModifiedFactor", set_cache_factor, NULL, RSRC_CONF|ACCESS_CONF,
2364 "The factor used to estimate Expires date from "
2365 "LastModified date"),
2366 AP_INIT_FLAG("CacheLock", set_cache_lock,
2368 "Enable or disable the thundering herd lock."),
2369 AP_INIT_TAKE1("CacheLockPath", set_cache_lock_path, NULL, RSRC_CONF,
2370 "The thundering herd lock path. Defaults to the '"
2371 DEFAULT_CACHE_LOCKPATH "' directory in the system "
2373 AP_INIT_TAKE1("CacheLockMaxAge", set_cache_lock_maxage, NULL, RSRC_CONF,
2374 "Maximum age of any thundering herd lock."),
2375 AP_INIT_FLAG("CacheHeader", set_cache_x_cache, NULL, RSRC_CONF | ACCESS_CONF,
2376 "Add a X-Cache header to responses. Default is off."),
2377 AP_INIT_FLAG("CacheDetailHeader", set_cache_x_cache_detail, NULL,
2378 RSRC_CONF | ACCESS_CONF,
2379 "Add a X-Cache-Detail header to responses. Default is off."),
2380 AP_INIT_TAKE1("CacheKeyBaseURL", set_cache_key_base_url, NULL, RSRC_CONF,
2381 "Override the base URL of reverse proxied cache keys."),
2382 AP_INIT_FLAG("CacheStaleOnError", set_cache_stale_on_error,
2383 NULL, RSRC_CONF|ACCESS_CONF,
2384 "Serve stale content on 5xx errors if present. Defaults to on."),
2388 static void register_hooks(apr_pool_t *p)
2390 /* cache initializer */
2391 /* cache quick handler */
2392 ap_hook_quick_handler(cache_quick_handler, NULL, NULL, APR_HOOK_FIRST);
2394 ap_hook_handler(cache_handler, NULL, NULL, APR_HOOK_REALLY_FIRST);
2396 cache_hook_cache_status(cache_status, NULL, NULL, APR_HOOK_MIDDLE);
2397 /* cache error handler */
2398 ap_hook_insert_error_filter(cache_insert_error_filter, NULL, NULL, APR_HOOK_MIDDLE);
2400 * XXX The cache filters need to run right after the handlers and before
2401 * any other filters. Consider creating AP_FTYPE_CACHE for this purpose.
2403 * Depending on the type of request (subrequest / main request) they
2404 * need to be run before AP_FTYPE_CONTENT_SET / after AP_FTYPE_CONTENT_SET
2405 * filters. Thus create two filter handles for each type:
2406 * cache_save_filter_handle / cache_out_filter_handle to be used by
2408 * cache_save_subreq_filter_handle / cache_out_subreq_filter_handle
2409 * to be run by subrequest
2412 * CACHE is placed into the filter chain at an admin specified location,
2413 * and when the cache_handler is run, the CACHE filter is swapped with
2414 * the CACHE_OUT filter, or CACHE_SAVE filter as appropriate. This has
2415 * the effect of offering optional fine control of where the cache is
2416 * inserted into the filter chain.
2418 cache_filter_handle =
2419 ap_register_output_filter("CACHE",
2424 * CACHE_SAVE must go into the filter chain after a possible DEFLATE
2425 * filter to ensure that the compressed content is stored.
2426 * Incrementing filter type by 1 ensures this happens.
2428 cache_save_filter_handle =
2429 ap_register_output_filter("CACHE_SAVE",
2432 AP_FTYPE_CONTENT_SET+1);
2434 * CACHE_SAVE_SUBREQ must go into the filter chain before SUBREQ_CORE to
2435 * handle subrequsts. Decrementing filter type by 1 ensures this
2438 cache_save_subreq_filter_handle =
2439 ap_register_output_filter("CACHE_SAVE_SUBREQ",
2442 AP_FTYPE_CONTENT_SET-1);
2444 * CACHE_OUT must go into the filter chain after a possible DEFLATE
2445 * filter to ensure that already compressed cache objects do not
2446 * get compressed again. Incrementing filter type by 1 ensures
2449 cache_out_filter_handle =
2450 ap_register_output_filter("CACHE_OUT",
2453 AP_FTYPE_CONTENT_SET+1);
2455 * CACHE_OUT_SUBREQ must go into the filter chain before SUBREQ_CORE to
2456 * handle subrequsts. Decrementing filter type by 1 ensures this
2459 cache_out_subreq_filter_handle =
2460 ap_register_output_filter("CACHE_OUT_SUBREQ",
2463 AP_FTYPE_CONTENT_SET-1);
2464 /* CACHE_REMOVE_URL has to be a protocol filter to ensure that is
2465 * run even if the response is a canned error message, which
2466 * removes the content filters.
2468 cache_remove_url_filter_handle =
2469 ap_register_output_filter("CACHE_REMOVE_URL",
2470 cache_remove_url_filter,
2473 ap_hook_post_config(cache_post_config, NULL, NULL, APR_HOOK_REALLY_FIRST);
2476 AP_DECLARE_MODULE(cache) =
2478 STANDARD20_MODULE_STUFF,
2479 create_dir_config, /* create per-directory config structure */
2480 merge_dir_config, /* merge per-directory config structures */
2481 create_cache_config, /* create per-server config structure */
2482 merge_cache_config, /* merge per-server config structures */
2483 cache_cmds, /* command apr_table_t */
2488 APR_HOOK_LINK(cache_status)
2491 APR_IMPLEMENT_EXTERNAL_HOOK_RUN_ALL(cache, CACHE, int, cache_status,
2492 (cache_handle_t *h, request_rec *r,
2493 apr_table_t *headers, ap_cache_status_e status,
2494 const char *reason), (h, r, headers, status, reason),