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);
296 return ap_pass_brigade_fchk(r, out,
297 "cache_quick_handler(%s): ap_pass_brigade returned",
298 cache->provider_name);
302 * If the two filter handles are present within the filter chain, replace
303 * the last instance of the first filter with the last instance of the
304 * second filter, and return true. If the second filter is not present at
305 * all, the first filter is removed, and false is returned. If neither
306 * filter is present, false is returned and this function does nothing.
307 * If a stop filter is specified, processing will stop once this filter is
310 static int cache_replace_filter(ap_filter_t *next, ap_filter_rec_t *from,
311 ap_filter_rec_t *to, ap_filter_rec_t *stop) {
312 ap_filter_t *ffrom = NULL, *fto = NULL;
313 while (next && next->frec != stop) {
314 if (next->frec == from) {
317 if (next->frec == to) {
323 ffrom->frec = fto->frec;
324 ffrom->ctx = fto->ctx;
325 ap_remove_output_filter(fto);
329 ap_remove_output_filter(ffrom);
335 * Find the given filter, and return it if found, or NULL otherwise.
337 static ap_filter_t *cache_get_filter(ap_filter_t *next, ap_filter_rec_t *rec) {
339 if (next->frec == rec && next->ctx) {
348 * The cache handler is functionally similar to the cache_quick_hander,
349 * however a number of steps that are required by the quick handler are
350 * not required here, as the normal httpd processing has already handled
353 static int cache_handler(request_rec *r)
356 cache_provider_list *providers;
357 cache_request_rec *cache;
358 apr_bucket_brigade *out;
361 ap_filter_rec_t *cache_out_handle;
362 ap_filter_rec_t *cache_save_handle;
363 cache_server_conf *conf;
365 conf = (cache_server_conf *) ap_get_module_config(r->server->module_config,
368 /* only run if the quick handler is disabled */
374 * Which cache module (if any) should handle this request?
376 if (!(providers = cache_get_providers(r, conf, r->parsed_uri))) {
380 /* make space for the per request config */
381 cache = apr_pcalloc(r->pool, sizeof(cache_request_rec));
383 cache->out = apr_brigade_create(r->pool, r->connection->bucket_alloc);
385 /* save away the possible providers */
386 cache->providers = providers;
388 /* Are we something other than GET or HEAD? If so, invalidate
389 * the cached entities.
391 if (r->method_number != M_GET) {
393 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r,
394 "Invalidating all cached entities in response to '%s' request for %s",
397 cache_invalidate(cache, r);
399 /* we've got a cache invalidate! tell everyone who cares */
400 cache_run_cache_status(cache->handle, r, r->headers_out,
401 AP_CACHE_INVALIDATE, apr_psprintf(r->pool,
402 "cache invalidated by %s", r->method));
409 * Try to serve this request from the cache.
411 * If no existing cache file (DECLINED)
412 * add cache_save filter
413 * If cached file (OK)
415 * add cache_out filter
418 rv = cache_select(cache, r);
420 if (rv == DECLINED) {
422 /* try to obtain a cache lock at this point. if we succeed,
423 * we are the first to try and cache this url. if we fail,
424 * it means someone else is already trying to cache this
425 * url, and we should just let the request through to the
426 * backend without any attempt to cache. this stops
427 * duplicated simultaneous attempts to cache an entity.
429 rv = cache_try_lock(conf, cache, r);
430 if (APR_SUCCESS == rv) {
433 * Add cache_save filter to cache this request. Choose
434 * the correct filter by checking if we are a subrequest
438 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS,
439 r, "Adding CACHE_SAVE_SUBREQ filter for %s",
441 cache_save_handle = cache_save_subreq_filter_handle;
444 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS,
445 r, "Adding CACHE_SAVE filter for %s",
447 cache_save_handle = cache_save_filter_handle;
449 ap_add_output_filter_handle(cache_save_handle, cache, r,
453 * Did the user indicate the precise location of the
454 * CACHE_SAVE filter by inserting the CACHE filter as a
457 * If so, we get cunning and replace CACHE with the
458 * CACHE_SAVE filter. This has the effect of inserting
459 * the CACHE_SAVE filter at the precise location where
460 * the admin wants to cache the content. All filters that
461 * lie before and after the original location of the CACHE
462 * filter will remain in place.
464 if (cache_replace_filter(r->output_filters,
465 cache_filter_handle, cache_save_handle,
466 ap_get_input_filter_handle("SUBREQ_CORE"))) {
467 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS,
468 r, "Replacing CACHE with CACHE_SAVE "
469 "filter for %s", r->uri);
472 /* save away the save filter stack */
473 cache->save_filter = cache_get_filter(r->output_filters,
474 cache_save_filter_handle);
476 apr_pool_userdata_setn(cache, CACHE_CTX_KEY, NULL, r->pool);
478 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r,
479 "Adding CACHE_REMOVE_URL filter for %s",
482 /* Add cache_remove_url filter to this request to remove a
483 * stale cache entry if needed. Also put the current cache
484 * request rec in the filter context, as the request that
485 * is available later during running the filter may be
486 * different due to an internal redirect.
488 cache->remove_url_filter
489 = ap_add_output_filter_handle(
490 cache_remove_url_filter_handle, cache, r,
495 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv,
496 r, "Cache locked for url, not caching "
497 "response: %s", r->uri);
507 /* we've got a cache hit! tell everyone who cares */
508 cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_HIT,
511 rv = ap_meets_conditions(r);
516 /* Serve up the content */
519 * Add cache_out filter to serve this request. Choose
520 * the correct filter by checking if we are a subrequest
524 cache_out_handle = cache_out_subreq_filter_handle;
527 cache_out_handle = cache_out_filter_handle;
529 ap_add_output_filter_handle(cache_out_handle, cache, r, r->connection);
532 * Did the user indicate the precise location of the CACHE_OUT filter by
533 * inserting the CACHE filter as a marker?
535 * If so, we get cunning and replace CACHE with the CACHE_OUT filters.
536 * This has the effect of inserting the CACHE_OUT filter at the precise
537 * location where the admin wants to cache the content. All filters that
538 * lie *after* the original location of the CACHE filter will remain in
541 if (cache_replace_filter(r->output_filters, cache_filter_handle,
542 cache_out_handle, ap_get_input_filter_handle("SUBREQ_CORE"))) {
543 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS,
544 r, "Replacing CACHE with CACHE_OUT filter for %s",
549 * Remove all filters that are before the cache_out filter. This ensures
550 * that we kick off the filter stack with our cache_out filter being the
551 * first in the chain. This make sense because we want to restore things
552 * in the same manner as we saved them.
553 * There may be filters before our cache_out filter, because
555 * 1. We call ap_set_content_type during cache_select. This causes
556 * Content-Type specific filters to be added.
557 * 2. We call the insert_filter hook. This causes filters e.g. like
558 * the ones set with SetOutputFilter to be added.
560 next = r->output_filters;
561 while (next && (next->frec != cache_out_handle)) {
562 ap_remove_output_filter(next);
566 /* kick off the filter stack */
567 out = apr_brigade_create(r->pool, r->connection->bucket_alloc);
568 e = apr_bucket_eos_create(out->bucket_alloc);
569 APR_BRIGADE_INSERT_TAIL(out, e);
570 return ap_pass_brigade_fchk(r, out, "cache(%s): ap_pass_brigade returned",
571 cache->provider_name);
578 * Deliver cached content (headers and body) up the stack.
580 static int cache_out_filter(ap_filter_t *f, apr_bucket_brigade *in)
582 request_rec *r = f->r;
584 cache_request_rec *cache = (cache_request_rec *)f->ctx;
587 /* user likely configured CACHE_OUT manually; they should use mod_cache
588 * configuration to do that */
589 ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
590 "CACHE/CACHE_OUT filter enabled while caching is disabled, ignoring");
591 ap_remove_output_filter(f);
592 return ap_pass_brigade(f->next, in);
595 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r,
596 "cache: running CACHE_OUT filter");
598 /* clean out any previous response up to EOS, if any */
599 for (e = APR_BRIGADE_FIRST(in);
600 e != APR_BRIGADE_SENTINEL(in);
601 e = APR_BUCKET_NEXT(e))
603 if (APR_BUCKET_IS_EOS(e)) {
604 apr_bucket_brigade *bb = apr_brigade_create(r->pool,
605 r->connection->bucket_alloc);
607 /* restore status of cached response */
608 r->status = cache->handle->cache_obj->info.status;
610 /* recall_headers() was called in cache_select() */
611 cache->provider->recall_body(cache->handle, r->pool, bb);
612 APR_BRIGADE_PREPEND(in, bb);
614 /* This filter is done once it has served up its content */
615 ap_remove_output_filter(f);
617 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r,
618 "cache: serving %s", r->uri);
619 return ap_pass_brigade(f->next, in);
622 apr_bucket_delete(e);
629 * Having jumped through all the hoops and decided to cache the
630 * response, call store_body() for each brigade, handling the
631 * case where the provider can't swallow the full brigade. In this
632 * case, we write the brigade we were passed out downstream, and
633 * loop around to try and cache some more until the in brigade is
634 * completely empty. As soon as the out brigade contains eos, call
635 * commit_entity() to finalise the cached element.
637 static int cache_save_store(ap_filter_t *f, apr_bucket_brigade *in,
638 cache_server_conf *conf, cache_request_rec *cache)
640 int rv = APR_SUCCESS;
643 /* pass the brigade in into the cache provider, which is then
644 * expected to move cached buckets to the out brigade, for us
645 * to pass up the filter stack. repeat until in is empty, or
648 while (APR_SUCCESS == rv && !APR_BRIGADE_EMPTY(in)) {
650 rv = cache->provider->store_body(cache->handle, f->r, in, cache->out);
651 if (rv != APR_SUCCESS) {
652 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, f->r,
653 "cache: Cache provider's store_body failed!");
654 ap_remove_output_filter(f);
656 /* give someone else the chance to cache the file */
657 cache_remove_lock(conf, cache, f->r, NULL);
659 /* give up trying to cache, just step out the way */
660 APR_BRIGADE_PREPEND(in, cache->out);
661 return ap_pass_brigade(f->next, in);
665 /* does the out brigade contain eos? if so, we're done, commit! */
666 for (e = APR_BRIGADE_FIRST(cache->out);
667 e != APR_BRIGADE_SENTINEL(cache->out);
668 e = APR_BUCKET_NEXT(e))
670 if (APR_BUCKET_IS_EOS(e)) {
671 rv = cache->provider->commit_entity(cache->handle, f->r);
676 /* conditionally remove the lock as soon as we see the eos bucket */
677 cache_remove_lock(conf, cache, f->r, cache->out);
679 if (APR_BRIGADE_EMPTY(cache->out)) {
680 if (APR_BRIGADE_EMPTY(in)) {
681 /* cache provider wants more data before passing the brigade
682 * upstream, oblige the provider by leaving to fetch more.
687 /* oops, no data out, but not all data read in either, be
688 * safe and stand down to prevent a spin.
690 ap_log_rerror(APLOG_MARK, APLOG_WARNING, rv, f->r,
691 "cache: Cache provider's store_body returned an "
692 "empty brigade, but didn't consume all of the"
693 "input brigade, standing down to prevent a spin");
694 ap_remove_output_filter(f);
696 /* give someone else the chance to cache the file */
697 cache_remove_lock(conf, cache, f->r, NULL);
699 return ap_pass_brigade(f->next, in);
703 rv = ap_pass_brigade(f->next, cache->out);
713 * Decide whether or not this content should be cached.
714 * If we decide no it should not:
715 * remove the filter from the chain
716 * If we decide yes it should:
717 * Have we already started saving the response?
718 * If we have started, pass the data to the storage manager via store_body
720 * Check to see if we *can* save this particular response.
721 * If we can, call cache_create_entity() and save the headers and body
722 * Finally, pass the data to the next filter (the network or whatever)
724 * After the various failure cases, the cache lock is proactively removed, so
725 * that another request is given the opportunity to attempt to cache without
726 * waiting for a potentially slow client to acknowledge the failure.
729 static int cache_save_filter(ap_filter_t *f, apr_bucket_brigade *in)
732 request_rec *r = f->r;
733 cache_request_rec *cache = (cache_request_rec *)f->ctx;
734 cache_server_conf *conf;
735 cache_dir_conf *dconf;
736 cache_control_t control;
737 const char *cc_out, *cl, *pragma;
738 const char *exps, *lastmods, *dates, *etag;
739 apr_time_t exp, date, lastmod, now;
741 cache_info *info = NULL;
745 apr_table_t *headers;
747 conf = (cache_server_conf *) ap_get_module_config(r->server->module_config,
750 /* Setup cache_request_rec */
752 /* user likely configured CACHE_SAVE manually; they should really use
753 * mod_cache configuration to do that
755 ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
756 "CACHE/CACHE_SAVE filter enabled while caching is disabled, ignoring");
757 ap_remove_output_filter(f);
758 return ap_pass_brigade(f->next, in);
766 * This section passes the brigades into the cache modules, but only
767 * if the setup section (see below) is complete.
769 if (cache->block_response) {
770 /* We've already sent down the response and EOS. So, ignore
771 * whatever comes now.
776 /* have we already run the cacheability check and set up the
777 * cached file handle?
779 if (cache->in_checked) {
780 return cache_save_store(f, in, conf, cache);
784 * Setup Data in Cache
785 * -------------------
786 * This section opens the cache entity and sets various caching
787 * parameters, and decides whether this URL should be cached at
788 * all. This section is* run before the above section.
791 dconf = ap_get_module_config(r->per_dir_config, &cache_module);
793 /* RFC2616 13.8 Errors or Incomplete Response Cache Behavior:
794 * If a cache receives a 5xx response while attempting to revalidate an
795 * entry, it MAY either forward this response to the requesting client,
796 * or act as if the server failed to respond. In the latter case, it MAY
797 * return a previously received response unless the cached entry
798 * includes the "must-revalidate" cache-control directive (see section
801 * This covers the case where an error was generated behind us, for example
802 * by a backend server via mod_proxy.
804 if (dconf->stale_on_error && r->status >= HTTP_INTERNAL_SERVER_ERROR) {
806 ap_remove_output_filter(cache->remove_url_filter);
808 if (cache->stale_handle
809 && !cache->stale_handle->cache_obj->info.control.must_revalidate
810 && !cache->stale_handle->cache_obj->info.control.proxy_revalidate) {
811 const char *warn_head;
813 /* morph the current save filter into the out filter, and serve from
816 cache->handle = cache->stale_handle;
818 f->frec = cache_out_subreq_filter_handle;
821 f->frec = cache_out_filter_handle;
824 r->headers_out = cache->stale_handle->resp_hdrs;
826 ap_set_content_type(r, apr_table_get(
827 cache->stale_handle->resp_hdrs, "Content-Type"));
829 /* add a revalidation warning */
830 warn_head = apr_table_get(r->err_headers_out, "Warning");
831 if ((warn_head == NULL) || ((warn_head != NULL)
832 && (ap_strstr_c(warn_head, "111") == NULL))) {
833 apr_table_mergen(r->err_headers_out, "Warning",
834 "111 Revalidation failed");
837 cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_HIT,
838 apr_psprintf(r->pool,
839 "cache hit: %d status; stale content returned",
842 /* give someone else the chance to cache the file */
843 cache_remove_lock(conf, cache, f->r, NULL);
845 /* pass brigade to our morphed out filter */
846 return ap_pass_brigade(f, in);
850 /* read expiry date; if a bad date, then leave it so the client can
853 exps = apr_table_get(r->err_headers_out, "Expires");
855 exps = apr_table_get(r->headers_out, "Expires");
858 exp = apr_date_parse_http(exps);
864 /* read the last-modified date; if the date is bad, then delete it */
865 lastmods = apr_table_get(r->err_headers_out, "Last-Modified");
866 if (lastmods == NULL) {
867 lastmods = apr_table_get(r->headers_out, "Last-Modified");
869 if (lastmods != NULL) {
870 lastmod = apr_date_parse_http(lastmods);
871 if (lastmod == APR_DATE_BAD) {
876 lastmod = APR_DATE_BAD;
879 /* read the etag and cache-control from the entity */
880 etag = apr_table_get(r->err_headers_out, "Etag");
882 etag = apr_table_get(r->headers_out, "Etag");
884 cc_out = apr_table_get(r->err_headers_out, "Cache-Control");
885 pragma = apr_table_get(r->err_headers_out, "Pragma");
886 headers = r->err_headers_out;
887 if (!cc_out && !pragma) {
888 cc_out = apr_table_get(r->headers_out, "Cache-Control");
889 pragma = apr_table_get(r->headers_out, "Pragma");
890 headers = r->headers_out;
893 /* Have we received a 304 response without any headers at all? Fall back to
894 * the original headers in the original cached request.
896 if (r->status == HTTP_NOT_MODIFIED && cache->stale_handle && !cc_out
898 cc_out = apr_table_get(cache->stale_handle->resp_hdrs, "Cache-Control");
899 pragma = apr_table_get(cache->stale_handle->resp_hdrs, "Pragma");
902 /* Parse the cache control header */
903 memset(&control, 0, sizeof(cache_control_t));
904 ap_cache_control(r, &control, cc_out, pragma, headers);
907 * what responses should we not cache?
909 * At this point we decide based on the response headers whether it
910 * is appropriate _NOT_ to cache the data from the server. There are
911 * a whole lot of conditions that prevent us from caching this data.
912 * They are tested here one by one to be clear and unambiguous.
914 if (r->status != HTTP_OK && r->status != HTTP_NON_AUTHORITATIVE
915 && r->status != HTTP_PARTIAL_CONTENT
916 && r->status != HTTP_MULTIPLE_CHOICES
917 && r->status != HTTP_MOVED_PERMANENTLY
918 && r->status != HTTP_NOT_MODIFIED) {
919 /* RFC2616 13.4 we are allowed to cache 200, 203, 206, 300, 301 or 410
920 * We allow the caching of 206, but a cache implementation might choose
921 * to decline to cache a 206 if it doesn't know how to.
922 * We include 304 Not Modified here too as this is the origin server
923 * telling us to serve the cached copy.
925 if (exps != NULL || cc_out != NULL) {
926 /* We are also allowed to cache any response given that it has a
927 * valid Expires or Cache Control header. If we find a either of
928 * those here, we pass request through the rest of the tests. From
931 * A response received with any other status code (e.g. status
932 * codes 302 and 307) MUST NOT be returned in a reply to a
933 * subsequent request unless there are cache-control directives or
934 * another header(s) that explicitly allow it. For example, these
935 * include the following: an Expires header (section 14.21); a
936 * "max-age", "s-maxage", "must-revalidate", "proxy-revalidate",
937 * "public" or "private" cache-control directive (section 14.9).
941 reason = apr_psprintf(p, "Response status %d", r->status);
948 else if (exps != NULL && exp == APR_DATE_BAD) {
949 /* if a broken Expires header is present, don't cache it */
950 reason = apr_pstrcat(p, "Broken expires header: ", exps, NULL);
952 else if (!dconf->store_expired && exp != APR_DATE_BAD
953 && exp < r->request_time) {
954 /* if a Expires header is in the past, don't cache it */
955 reason = "Expires header already expired; not cacheable";
957 else if (!dconf->store_expired && (control.must_revalidate
958 || control.proxy_revalidate) && (!control.s_maxage_value
959 || (!control.s_maxage && !control.max_age_value)) && lastmods
960 == NULL && etag == NULL) {
961 /* if we're already stale, but can never revalidate, don't cache it */
963 = "s-maxage or max-age zero and no Last-Modified or Etag; not cacheable";
965 else if (!conf->ignorequerystring && r->parsed_uri.query && exps == NULL
966 && !control.max_age && !control.s_maxage) {
967 /* if a query string is present but no explicit expiration time,
968 * don't cache it (RFC 2616/13.9 & 13.2.1)
970 reason = "Query string present but no explicit expiration time";
972 else if (r->status == HTTP_NOT_MODIFIED &&
973 !cache->handle && !cache->stale_handle) {
974 /* if the server said 304 Not Modified but we have no cache
975 * file - pass this untouched to the user agent, it's not for us.
977 reason = "HTTP Status 304 Not Modified";
979 else if (r->status == HTTP_OK && lastmods == NULL && etag == NULL && (exps
980 == NULL) && (dconf->no_last_mod_ignore == 0) && !control.max_age
981 && !control.s_maxage) {
982 /* 200 OK response from HTTP/1.0 and up without Last-Modified,
983 * Etag, Expires, Cache-Control:max-age, or Cache-Control:s-maxage
986 /* Note: mod-include clears last_modified/expires/etags - this
987 * is why we have an optional function for a key-gen ;-)
989 reason = "No Last-Modified; Etag; Expires; Cache-Control:max-age or Cache-Control:s-maxage headers";
991 else if (!dconf->store_nostore && control.no_store) {
992 /* RFC2616 14.9.2 Cache-Control: no-store response
993 * indicating do not cache, or stop now if you are
994 * trying to cache it.
996 reason = "Cache-Control: no-store present";
998 else if (!dconf->store_private && control.private) {
999 /* RFC2616 14.9.1 Cache-Control: private response
1000 * this object is marked for this user's eyes only. Behave
1003 reason = "Cache-Control: private present";
1005 else if (apr_table_get(r->headers_in, "Authorization")
1006 && !(control.s_maxage || control.must_revalidate
1007 || control.proxy_revalidate || control.public)) {
1008 /* RFC2616 14.8 Authorisation:
1009 * if authorisation is included in the request, we don't cache,
1010 * but we can cache if the following exceptions are true:
1011 * 1) If Cache-Control: s-maxage is included
1012 * 2) If Cache-Control: must-revalidate is included
1013 * 3) If Cache-Control: public is included
1015 reason = "Authorization required";
1017 else if (ap_cache_liststr(NULL,
1018 apr_table_get(r->headers_out, "Vary"),
1020 reason = "Vary header contains '*'";
1022 else if (apr_table_get(r->subprocess_env, "no-cache") != NULL) {
1023 reason = "environment variable 'no-cache' is set";
1025 else if (r->no_cache) {
1026 /* or we've been asked not to cache it above */
1027 reason = "r->no_cache present";
1030 /* Hold the phone. Some servers might allow us to cache a 2xx, but
1031 * then make their 304 responses non cacheable. This leaves us in a
1032 * sticky position. If the 304 is in answer to our own conditional
1033 * request, we cannot send this 304 back to the client because the
1034 * client isn't expecting it. Instead, our only option is to respect
1035 * the answer to the question we asked (has it changed, answer was
1036 * no) and return the cached item to the client, and then respect
1037 * the uncacheable nature of this 304 by allowing the remove_url
1038 * filter to kick in and remove the cached entity.
1040 if (reason && r->status == HTTP_NOT_MODIFIED &&
1041 cache->stale_handle) {
1042 apr_bucket_brigade *bb;
1046 cache->handle = cache->stale_handle;
1047 info = &cache->handle->cache_obj->info;
1049 /* Load in the saved status and clear the status line. */
1050 r->status = info->status;
1051 r->status_line = NULL;
1053 bb = apr_brigade_create(r->pool, r->connection->bucket_alloc);
1055 r->headers_in = cache->stale_headers;
1056 status = ap_meets_conditions(r);
1060 bkt = apr_bucket_flush_create(bb->bucket_alloc);
1061 APR_BRIGADE_INSERT_TAIL(bb, bkt);
1064 /* RFC 2616 10.3.5 states that entity headers are not supposed
1065 * to be in the 304 response. Therefore, we need to combine the
1066 * response headers with the cached headers *before* we update
1067 * the cached headers.
1069 * However, before doing that, we need to first merge in
1070 * err_headers_out and we also need to strip any hop-by-hop
1071 * headers that might have snuck in.
1073 r->headers_out = ap_cache_cacheable_headers_out(r);
1075 /* Merge in our cached headers. However, keep any updated values. */
1076 cache_accept_headers(cache->handle, r, 1);
1078 cache->provider->recall_body(cache->handle, r->pool, bb);
1080 bkt = apr_bucket_eos_create(bb->bucket_alloc);
1081 APR_BRIGADE_INSERT_TAIL(bb, bkt);
1084 cache->block_response = 1;
1086 /* we've got a cache conditional hit! tell anyone who cares */
1087 cache_run_cache_status(
1091 AP_CACHE_REVALIDATE,
1094 "conditional cache hit: 304 was uncacheable though (%s); entity removed",
1097 /* let someone else attempt to cache */
1098 cache_remove_lock(conf, cache, r, NULL);
1100 return ap_pass_brigade(f->next, bb);
1104 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
1105 "cache: %s not cached. Reason: %s", r->unparsed_uri,
1108 /* we've got a cache miss! tell anyone who cares */
1109 cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
1112 /* remove this filter from the chain */
1113 ap_remove_output_filter(f);
1115 /* remove the lock file unconditionally */
1116 cache_remove_lock(conf, cache, r, NULL);
1118 /* ship the data up the stack */
1119 return ap_pass_brigade(f->next, in);
1122 /* Make it so that we don't execute this path again. */
1123 cache->in_checked = 1;
1125 /* Set the content length if known.
1127 cl = apr_table_get(r->err_headers_out, "Content-Length");
1129 cl = apr_table_get(r->headers_out, "Content-Length");
1133 if (apr_strtoff(&size, cl, &errp, 10) || *errp || size < 0) {
1134 cl = NULL; /* parse error, see next 'if' block */
1139 /* if we don't get the content-length, see if we have all the
1140 * buckets and use their length to calculate the size
1142 int all_buckets_here=0;
1144 for (e = APR_BRIGADE_FIRST(in);
1145 e != APR_BRIGADE_SENTINEL(in);
1146 e = APR_BUCKET_NEXT(e))
1148 if (APR_BUCKET_IS_EOS(e)) {
1152 if (APR_BUCKET_IS_FLUSH(e)) {
1155 if (e->length == (apr_size_t)-1) {
1160 if (!all_buckets_here) {
1165 /* remember content length to check response size against later */
1168 /* It's safe to cache the response.
1170 * There are two possiblities at this point:
1171 * - cache->handle == NULL. In this case there is no previously
1172 * cached entity anywhere on the system. We must create a brand
1173 * new entity and store the response in it.
1174 * - cache->stale_handle != NULL. In this case there is a stale
1175 * entity in the system which needs to be replaced by new
1176 * content (unless the result was 304 Not Modified, which means
1177 * the cached entity is actually fresh, and we should update
1181 /* Did we have a stale cache entry that really is stale?
1183 if (cache->stale_handle) {
1184 if (r->status == HTTP_NOT_MODIFIED) {
1185 /* Oh, hey. It isn't that stale! Yay! */
1186 cache->handle = cache->stale_handle;
1187 info = &cache->handle->cache_obj->info;
1191 /* Oh, well. Toss it. */
1192 cache->provider->remove_entity(cache->stale_handle);
1193 /* Treat the request as if it wasn't conditional. */
1194 cache->stale_handle = NULL;
1196 * Restore the original request headers as they may be needed
1197 * by further output filters like the byterange filter to make
1198 * the correct decisions.
1200 r->headers_in = cache->stale_headers;
1204 /* no cache handle, create a new entity */
1205 if (!cache->handle) {
1206 rv = cache_create_entity(cache, r, size, in);
1207 info = apr_pcalloc(r->pool, sizeof(cache_info));
1208 /* We only set info->status upon the initial creation. */
1209 info->status = r->status;
1213 /* we've got a cache miss! tell anyone who cares */
1214 cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
1215 "cache miss: create_entity failed");
1217 /* Caching layer declined the opportunity to cache the response */
1218 ap_remove_output_filter(f);
1219 cache_remove_lock(conf, cache, r, NULL);
1220 return ap_pass_brigade(f->next, in);
1223 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
1224 "cache: Caching url: %s", r->unparsed_uri);
1226 /* We are actually caching this response. So it does not
1227 * make sense to remove this entity any more.
1229 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
1230 "cache: Removing CACHE_REMOVE_URL filter.");
1231 ap_remove_output_filter(cache->remove_url_filter);
1234 * We now want to update the cache file header information with
1235 * the new date, last modified, expire and content length and write
1236 * it away to our cache file. First, we determine these values from
1237 * the response, using heuristics if appropriate.
1239 * In addition, we make HTTP/1.1 age calculations and write them away
1243 /* store away the previously parsed cache control headers */
1244 memcpy(&info->control, &control, sizeof(cache_control_t));
1246 /* Read the date. Generate one if one is not supplied */
1247 dates = apr_table_get(r->err_headers_out, "Date");
1248 if (dates == NULL) {
1249 dates = apr_table_get(r->headers_out, "Date");
1251 if (dates != NULL) {
1252 info->date = apr_date_parse_http(dates);
1255 info->date = APR_DATE_BAD;
1258 now = apr_time_now();
1259 if (info->date == APR_DATE_BAD) { /* No, or bad date */
1260 /* no date header (or bad header)! */
1265 /* set response_time for HTTP/1.1 age calculations */
1266 info->response_time = now;
1268 /* get the request time */
1269 info->request_time = r->request_time;
1271 /* check last-modified date */
1272 if (lastmod != APR_DATE_BAD && lastmod > date) {
1273 /* if it's in the future, then replace by date */
1275 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0,
1276 r, "cache: Last modified is in the future, "
1277 "replacing with now");
1280 /* if no expiry date then
1281 * if Cache-Control: max-age
1282 * expiry date = date + max-age
1284 * expiry date = date + min((date - lastmod) * factor, maxexpire)
1286 * expire date = date + defaultexpire
1288 if (exp == APR_DATE_BAD) {
1290 if (control.max_age) {
1294 x = control.max_age_value;
1299 x = x * MSEC_ONE_SEC;
1301 if (x < dconf->minex) {
1304 if (x > dconf->maxex) {
1309 else if ((lastmod != APR_DATE_BAD) && (lastmod < date)) {
1310 /* if lastmod == date then you get 0*conf->factor which results in
1311 * an expiration time of now. This causes some problems with
1312 * freshness calculations, so we choose the else path...
1314 apr_time_t x = (apr_time_t) ((date - lastmod) * dconf->factor);
1316 if (x < dconf->minex) {
1319 if (x > dconf->maxex) {
1325 exp = date + dconf->defex;
1330 /* We found a stale entry which wasn't really stale. */
1331 if (cache->stale_handle) {
1332 /* Load in the saved status and clear the status line. */
1333 r->status = info->status;
1334 r->status_line = NULL;
1336 /* RFC 2616 10.3.5 states that entity headers are not supposed
1337 * to be in the 304 response. Therefore, we need to combine the
1338 * response headers with the cached headers *before* we update
1339 * the cached headers.
1341 * However, before doing that, we need to first merge in
1342 * err_headers_out and we also need to strip any hop-by-hop
1343 * headers that might have snuck in.
1345 r->headers_out = ap_cache_cacheable_headers_out(r);
1347 /* Merge in our cached headers. However, keep any updated values. */
1348 cache_accept_headers(cache->handle, r, 1);
1351 /* Write away header information to cache. It is possible that we are
1352 * trying to update headers for an entity which has already been cached.
1354 * This may fail, due to an unwritable cache area. E.g. filesystem full,
1355 * permissions problems or a read-only (re)mount. This must be handled
1358 rv = cache->provider->store_headers(cache->handle, r, info);
1360 /* Did we just update the cached headers on a revalidated response?
1362 * If so, we can now decide what to serve to the client. This is done in
1363 * the same way as with a regular response, but conditions are now checked
1364 * against the cached or merged response headers.
1366 if (cache->stale_handle) {
1367 apr_bucket_brigade *bb;
1371 /* We're just saving response headers, so we are done. Commit
1372 * the response at this point, unless there was a previous error.
1374 if (rv == APR_SUCCESS) {
1375 rv = cache->provider->commit_entity(cache->handle, r);
1378 bb = apr_brigade_create(r->pool, r->connection->bucket_alloc);
1380 /* Restore the original request headers and see if we need to
1381 * return anything else than the cached response (ie. the original
1382 * request was conditional).
1384 r->headers_in = cache->stale_headers;
1385 status = ap_meets_conditions(r);
1389 bkt = apr_bucket_flush_create(bb->bucket_alloc);
1390 APR_BRIGADE_INSERT_TAIL(bb, bkt);
1393 cache->provider->recall_body(cache->handle, r->pool, bb);
1395 bkt = apr_bucket_eos_create(bb->bucket_alloc);
1396 APR_BRIGADE_INSERT_TAIL(bb, bkt);
1399 cache->block_response = 1;
1401 /* Before returning we need to handle the possible case of an
1402 * unwritable cache. Rather than leaving the entity in the cache
1403 * and having it constantly re-validated, now that we have recalled
1404 * the body it is safe to try and remove the url from the cache.
1406 if (rv != APR_SUCCESS) {
1407 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r,
1408 "cache: updating headers with store_headers failed. "
1409 "Removing cached url.");
1411 rv = cache->provider->remove_url(cache->stale_handle, r);
1413 /* Probably a mod_cache_disk cache area has been (re)mounted
1414 * read-only, or that there is a permissions problem.
1416 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r,
1417 "cache: attempt to remove url from cache unsuccessful.");
1420 /* we've got a cache conditional hit! tell anyone who cares */
1421 cache_run_cache_status(cache->handle, r, r->headers_out,
1422 AP_CACHE_REVALIDATE,
1423 "conditional cache hit: entity refresh failed");
1428 /* we've got a cache conditional hit! tell anyone who cares */
1429 cache_run_cache_status(cache->handle, r, r->headers_out,
1430 AP_CACHE_REVALIDATE,
1431 "conditional cache hit: entity refreshed");
1435 /* let someone else attempt to cache */
1436 cache_remove_lock(conf, cache, r, NULL);
1438 return ap_pass_brigade(f->next, bb);
1441 if (rv != APR_SUCCESS) {
1442 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r,
1443 "cache: store_headers failed");
1445 /* we've got a cache miss! tell anyone who cares */
1446 cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
1447 "cache miss: store_headers failed");
1449 ap_remove_output_filter(f);
1450 cache_remove_lock(conf, cache, r, NULL);
1451 return ap_pass_brigade(f->next, in);
1454 /* we've got a cache miss! tell anyone who cares */
1455 cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
1456 "cache miss: attempting entity save");
1458 return cache_save_store(f, in, conf, cache);
1462 * CACHE_REMOVE_URL filter
1463 * -----------------------
1465 * This filter gets added in the quick handler every time the CACHE_SAVE filter
1466 * gets inserted. Its purpose is to remove a confirmed stale cache entry from
1469 * CACHE_REMOVE_URL has to be a protocol filter to ensure that is run even if
1470 * the response is a canned error message, which removes the content filters
1471 * and thus the CACHE_SAVE filter from the chain.
1473 * CACHE_REMOVE_URL expects cache request rec within its context because the
1474 * request this filter runs on can be different from the one whose cache entry
1475 * should be removed, due to internal redirects.
1477 * Note that CACHE_SAVE_URL (as a content-set filter, hence run before the
1478 * protocol filters) will remove this filter if it decides to cache the file.
1479 * Therefore, if this filter is left in, it must mean we need to toss any
1482 static int cache_remove_url_filter(ap_filter_t *f, apr_bucket_brigade *in)
1484 request_rec *r = f->r;
1485 cache_request_rec *cache;
1487 /* Setup cache_request_rec */
1488 cache = (cache_request_rec *) f->ctx;
1491 /* user likely configured CACHE_REMOVE_URL manually; they should really
1492 * use mod_cache configuration to do that. So:
1493 * 1. Remove ourselves
1494 * 2. Do nothing and bail out
1496 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
1497 "cache: CACHE_REMOVE_URL enabled unexpectedly");
1498 ap_remove_output_filter(f);
1499 return ap_pass_brigade(f->next, in);
1502 /* Now remove this cache entry from the cache */
1503 cache_remove_url(cache, r);
1505 /* remove ourselves */
1506 ap_remove_output_filter(f);
1507 return ap_pass_brigade(f->next, in);
1514 * This filter can be optionally inserted into the filter chain by the admin as
1515 * a marker representing the precise location within the filter chain where
1516 * caching is to be performed.
1518 * When the filter chain is set up in the non-quick version of the URL handler,
1519 * the CACHE filter is replaced by the CACHE_OUT or CACHE_SAVE filter,
1520 * effectively inserting the caching filters at the point indicated by the
1521 * admin. The CACHE filter is then removed.
1523 * This allows caching to be performed before the content is passed to the
1524 * INCLUDES filter, or to a filter that might perform transformations unique
1525 * to the specific request and that would otherwise be non-cacheable.
1527 static int cache_filter(ap_filter_t *f, apr_bucket_brigade *in)
1532 (cache_server_conf *) ap_get_module_config(f->r->server->module_config,
1535 /* was the quick handler enabled */
1537 ap_log_rerror(APLOG_MARK, APLOG_WARNING, 0, f->r,
1538 "cache: CACHE filter was added in quick handler mode and "
1539 "will be ignored: %s", f->r->unparsed_uri);
1541 /* otherwise we may have been bypassed, nothing to see here */
1543 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, f->r,
1544 "cache: CACHE filter was added twice, or was added where "
1545 "the cache has been bypassed and will be ignored: %s",
1546 f->r->unparsed_uri);
1549 /* we are just a marker, so let's just remove ourselves */
1550 ap_remove_output_filter(f);
1551 return ap_pass_brigade(f->next, in);
1555 * If configured, add the status of the caching attempt to the subprocess
1556 * environment, and if configured, to headers in the response.
1558 * The status is saved below the broad category of the status (hit, miss,
1559 * revalidate), as well as a single cache-status key. This can be used for
1560 * conditional logging.
1562 * The status is optionally saved to an X-Cache header, and the detail of
1563 * why a particular cache entry was cached (or not cached) is optionally
1564 * saved to an X-Cache-Detail header. This extra detail is useful for
1565 * service developers who may need to know whether their Cache-Control headers
1566 * are working correctly.
1568 static int cache_status(cache_handle_t *h, request_rec *r,
1569 apr_table_t *headers, ap_cache_status_e status, const char *reason)
1573 (cache_server_conf *) ap_get_module_config(r->server->module_config,
1576 cache_dir_conf *dconf = ap_get_module_config(r->per_dir_config, &cache_module);
1577 int x_cache = 0, x_cache_detail = 0;
1580 case AP_CACHE_HIT: {
1581 apr_table_setn(r->subprocess_env, AP_CACHE_HIT_ENV, reason);
1584 case AP_CACHE_REVALIDATE: {
1585 apr_table_setn(r->subprocess_env, AP_CACHE_REVALIDATE_ENV, reason);
1588 case AP_CACHE_MISS: {
1589 apr_table_setn(r->subprocess_env, AP_CACHE_MISS_ENV, reason);
1592 case AP_CACHE_INVALIDATE: {
1593 apr_table_setn(r->subprocess_env, AP_CACHE_INVALIDATE_ENV, reason);
1598 apr_table_setn(r->subprocess_env, AP_CACHE_STATUS_ENV, reason);
1600 if (dconf && dconf->x_cache_set) {
1601 x_cache = dconf->x_cache;
1604 x_cache = conf->x_cache;
1607 apr_table_setn(headers, "X-Cache", apr_psprintf(r->pool, "%s from %s",
1608 status == AP_CACHE_HIT ? "HIT"
1609 : status == AP_CACHE_REVALIDATE ? "REVALIDATE" : status
1610 == AP_CACHE_INVALIDATE ? "INVALIDATE" : "MISS",
1611 r->server->server_hostname));
1614 if (dconf && dconf->x_cache_detail_set) {
1615 x_cache_detail = dconf->x_cache_detail;
1618 x_cache_detail = conf->x_cache_detail;
1620 if (x_cache_detail) {
1621 apr_table_setn(headers, "X-Cache-Detail", apr_psprintf(r->pool,
1622 "\"%s\" from %s", reason, r->server->server_hostname));
1629 * If an error has occurred, but we have a stale cached entry, restore the
1630 * filter stack from the save filter onwards. The canned error message will
1631 * be discarded in the process, and replaced with the cached response.
1633 static void cache_insert_error_filter(request_rec *r)
1636 cache_dir_conf *dconf;
1638 /* ignore everything except for 5xx errors */
1639 if (r->status < HTTP_INTERNAL_SERVER_ERROR) {
1643 dconf = ap_get_module_config(r->per_dir_config, &cache_module);
1645 if (!dconf->stale_on_error) {
1649 /* RFC2616 13.8 Errors or Incomplete Response Cache Behavior:
1650 * If a cache receives a 5xx response while attempting to revalidate an
1651 * entry, it MAY either forward this response to the requesting client,
1652 * or act as if the server failed to respond. In the latter case, it MAY
1653 * return a previously received response unless the cached entry
1654 * includes the "must-revalidate" cache-control directive (see section
1657 * This covers the case where the error was generated by our server via
1660 apr_pool_userdata_get(&dummy, CACHE_CTX_KEY, r->pool);
1662 cache_request_rec *cache = (cache_request_rec *) dummy;
1664 ap_remove_output_filter(cache->remove_url_filter);
1666 if (cache->stale_handle && cache->save_filter
1667 && !cache->stale_handle->cache_obj->info.control.must_revalidate
1668 && !cache->stale_handle->cache_obj->info.control.proxy_revalidate) {
1669 const char *warn_head;
1672 (cache_server_conf *) ap_get_module_config(r->server->module_config,
1675 /* morph the current save filter into the out filter, and serve from
1678 cache->handle = cache->stale_handle;
1680 cache->save_filter->frec = cache_out_subreq_filter_handle;
1683 cache->save_filter->frec = cache_out_filter_handle;
1686 r->output_filters = cache->save_filter;
1688 r->err_headers_out = cache->stale_handle->resp_hdrs;
1690 /* add a revalidation warning */
1691 warn_head = apr_table_get(r->err_headers_out, "Warning");
1692 if ((warn_head == NULL) || ((warn_head != NULL)
1693 && (ap_strstr_c(warn_head, "111") == NULL))) {
1694 apr_table_mergen(r->err_headers_out, "Warning",
1695 "111 Revalidation failed");
1698 cache_run_cache_status(
1705 "cache hit: %d status; stale content returned",
1708 /* give someone else the chance to cache the file */
1709 cache_remove_lock(conf, cache, r, NULL);
1717 /* -------------------------------------------------------------- */
1718 /* Setup configurable data */
1720 static void *create_dir_config(apr_pool_t *p, char *dummy)
1722 cache_dir_conf *dconf = apr_pcalloc(p, sizeof(cache_dir_conf));
1724 dconf->no_last_mod_ignore = 0;
1725 dconf->store_expired = 0;
1726 dconf->store_private = 0;
1727 dconf->store_nostore = 0;
1729 /* maximum time to cache a document */
1730 dconf->maxex = DEFAULT_CACHE_MAXEXPIRE;
1731 dconf->minex = DEFAULT_CACHE_MINEXPIRE;
1732 /* default time to cache a document */
1733 dconf->defex = DEFAULT_CACHE_EXPIRE;
1735 /* factor used to estimate Expires date from LastModified date */
1736 dconf->factor = DEFAULT_CACHE_LMFACTOR;
1738 dconf->x_cache = DEFAULT_X_CACHE;
1739 dconf->x_cache_detail = DEFAULT_X_CACHE_DETAIL;
1741 dconf->stale_on_error = DEFAULT_CACHE_STALE_ON_ERROR;
1743 /* array of providers for this URL space */
1744 dconf->cacheenable = apr_array_make(p, 10, sizeof(struct cache_enable));
1749 static void *merge_dir_config(apr_pool_t *p, void *basev, void *addv) {
1750 cache_dir_conf *new = (cache_dir_conf *) apr_pcalloc(p, sizeof(cache_dir_conf));
1751 cache_dir_conf *add = (cache_dir_conf *) addv;
1752 cache_dir_conf *base = (cache_dir_conf *) basev;
1754 new->no_last_mod_ignore = (add->no_last_mod_ignore_set == 0) ? base->no_last_mod_ignore : add->no_last_mod_ignore;
1755 new->no_last_mod_ignore_set = add->no_last_mod_ignore_set || base->no_last_mod_ignore_set;
1757 new->store_expired = (add->store_expired_set == 0) ? base->store_expired : add->store_expired;
1758 new->store_expired_set = add->store_expired_set || base->store_expired_set;
1759 new->store_private = (add->store_private_set == 0) ? base->store_private : add->store_private;
1760 new->store_private_set = add->store_private_set || base->store_private_set;
1761 new->store_nostore = (add->store_nostore_set == 0) ? base->store_nostore : add->store_nostore;
1762 new->store_nostore_set = add->store_nostore_set || base->store_nostore_set;
1764 /* maximum time to cache a document */
1765 new->maxex = (add->maxex_set == 0) ? base->maxex : add->maxex;
1766 new->maxex_set = add->maxex_set || base->maxex_set;
1767 new->minex = (add->minex_set == 0) ? base->minex : add->minex;
1768 new->minex_set = add->minex_set || base->minex_set;
1770 /* default time to cache a document */
1771 new->defex = (add->defex_set == 0) ? base->defex : add->defex;
1772 new->defex_set = add->defex_set || base->defex_set;
1774 /* factor used to estimate Expires date from LastModified date */
1775 new->factor = (add->factor_set == 0) ? base->factor : add->factor;
1776 new->factor_set = add->factor_set || base->factor_set;
1778 new->x_cache = (add->x_cache_set == 0) ? base->x_cache : add->x_cache;
1779 new->x_cache_set = add->x_cache_set || base->x_cache_set;
1780 new->x_cache_detail = (add->x_cache_detail_set == 0) ? base->x_cache_detail
1781 : add->x_cache_detail;
1782 new->x_cache_detail_set = add->x_cache_detail_set
1783 || base->x_cache_detail_set;
1785 new->stale_on_error = (add->stale_on_error_set == 0) ? base->stale_on_error
1786 : add->stale_on_error;
1787 new->stale_on_error_set = add->stale_on_error_set
1788 || base->stale_on_error_set;
1790 new->cacheenable = add->enable_set ? apr_array_append(p, base->cacheenable,
1791 add->cacheenable) : base->cacheenable;
1792 new->enable_set = add->enable_set || base->enable_set;
1793 new->disable = (add->disable_set == 0) ? base->disable : add->disable;
1794 new->disable_set = add->disable_set || base->disable_set;
1799 static void * create_cache_config(apr_pool_t *p, server_rec *s)
1801 const char *tmppath;
1802 cache_server_conf *ps = apr_pcalloc(p, sizeof(cache_server_conf));
1804 /* array of URL prefixes for which caching is enabled */
1805 ps->cacheenable = apr_array_make(p, 10, sizeof(struct cache_enable));
1806 /* array of URL prefixes for which caching is disabled */
1807 ps->cachedisable = apr_array_make(p, 10, sizeof(struct cache_disable));
1808 ps->ignorecachecontrol = 0;
1809 ps->ignorecachecontrol_set = 0;
1810 /* array of headers that should not be stored in cache */
1811 ps->ignore_headers = apr_array_make(p, 10, sizeof(char *));
1812 ps->ignore_headers_set = CACHE_IGNORE_HEADERS_UNSET;
1813 /* flag indicating that query-string should be ignored when caching */
1814 ps->ignorequerystring = 0;
1815 ps->ignorequerystring_set = 0;
1816 /* by default, run in the quick handler */
1819 /* array of identifiers that should not be used for key calculation */
1820 ps->ignore_session_id = apr_array_make(p, 10, sizeof(char *));
1821 ps->ignore_session_id_set = CACHE_IGNORE_SESSION_ID_UNSET;
1822 ps->lock = 0; /* thundering herd lock defaults to off */
1824 apr_temp_dir_get(&tmppath, p);
1826 ps->lockpath = apr_pstrcat(p, tmppath, DEFAULT_CACHE_LOCKPATH, NULL);
1828 ps->lockmaxage = apr_time_from_sec(DEFAULT_CACHE_MAXAGE);
1829 ps->x_cache = DEFAULT_X_CACHE;
1830 ps->x_cache_detail = DEFAULT_X_CACHE_DETAIL;
1834 static void * merge_cache_config(apr_pool_t *p, void *basev, void *overridesv)
1836 cache_server_conf *ps = apr_pcalloc(p, sizeof(cache_server_conf));
1837 cache_server_conf *base = (cache_server_conf *) basev;
1838 cache_server_conf *overrides = (cache_server_conf *) overridesv;
1840 /* array of URL prefixes for which caching is disabled */
1841 ps->cachedisable = apr_array_append(p,
1843 overrides->cachedisable);
1844 /* array of URL prefixes for which caching is enabled */
1845 ps->cacheenable = apr_array_append(p,
1847 overrides->cacheenable);
1849 ps->ignorecachecontrol =
1850 (overrides->ignorecachecontrol_set == 0)
1851 ? base->ignorecachecontrol
1852 : overrides->ignorecachecontrol;
1853 ps->ignore_headers =
1854 (overrides->ignore_headers_set == CACHE_IGNORE_HEADERS_UNSET)
1855 ? base->ignore_headers
1856 : overrides->ignore_headers;
1857 ps->ignorequerystring =
1858 (overrides->ignorequerystring_set == 0)
1859 ? base->ignorequerystring
1860 : overrides->ignorequerystring;
1861 ps->ignore_session_id =
1862 (overrides->ignore_session_id_set == CACHE_IGNORE_SESSION_ID_UNSET)
1863 ? base->ignore_session_id
1864 : overrides->ignore_session_id;
1866 (overrides->lock_set == 0)
1870 (overrides->lockpath_set == 0)
1872 : overrides->lockpath;
1874 (overrides->lockmaxage_set == 0)
1876 : overrides->lockmaxage;
1878 (overrides->quick_set == 0)
1882 (overrides->x_cache_set == 0)
1884 : overrides->x_cache;
1885 ps->x_cache_detail =
1886 (overrides->x_cache_detail_set == 0)
1887 ? base->x_cache_detail
1888 : overrides->x_cache_detail;
1890 (overrides->base_uri_set == 0)
1892 : overrides->base_uri;
1896 static const char *set_cache_quick_handler(cmd_parms *parms, void *dummy,
1899 cache_server_conf *conf;
1902 (cache_server_conf *)ap_get_module_config(parms->server->module_config
1906 conf->quick_set = 1;
1911 static const char *set_cache_ignore_no_last_mod(cmd_parms *parms, void *dummy,
1914 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
1916 dconf->no_last_mod_ignore = flag;
1917 dconf->no_last_mod_ignore_set = 1;
1922 static const char *set_cache_ignore_cachecontrol(cmd_parms *parms,
1923 void *dummy, int flag)
1925 cache_server_conf *conf;
1928 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
1930 conf->ignorecachecontrol = flag;
1931 conf->ignorecachecontrol_set = 1;
1935 static const char *set_cache_store_expired(cmd_parms *parms, void *dummy,
1938 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
1940 dconf->store_expired = flag;
1941 dconf->store_expired_set = 1;
1945 static const char *set_cache_store_private(cmd_parms *parms, void *dummy,
1948 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
1950 dconf->store_private = flag;
1951 dconf->store_private_set = 1;
1955 static const char *set_cache_store_nostore(cmd_parms *parms, void *dummy,
1958 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
1960 dconf->store_nostore = flag;
1961 dconf->store_nostore_set = 1;
1965 static const char *add_ignore_header(cmd_parms *parms, void *dummy,
1968 cache_server_conf *conf;
1972 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
1974 if (!strcasecmp(header, "None")) {
1975 /* if header None is listed clear array */
1976 conf->ignore_headers->nelts = 0;
1979 if ((conf->ignore_headers_set == CACHE_IGNORE_HEADERS_UNSET) ||
1980 (conf->ignore_headers->nelts)) {
1981 /* Only add header if no "None" has been found in header list
1983 * (When 'None' is passed, IGNORE_HEADERS_SET && nelts == 0.)
1985 new = (char **)apr_array_push(conf->ignore_headers);
1986 (*new) = (char *)header;
1989 conf->ignore_headers_set = CACHE_IGNORE_HEADERS_SET;
1993 static const char *add_ignore_session_id(cmd_parms *parms, void *dummy,
1994 const char *identifier)
1996 cache_server_conf *conf;
2000 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2002 if (!strcasecmp(identifier, "None")) {
2003 /* if identifier None is listed clear array */
2004 conf->ignore_session_id->nelts = 0;
2007 if ((conf->ignore_session_id_set == CACHE_IGNORE_SESSION_ID_UNSET) ||
2008 (conf->ignore_session_id->nelts)) {
2010 * Only add identifier if no "None" has been found in identifier
2013 new = (char **)apr_array_push(conf->ignore_session_id);
2014 (*new) = (char *)identifier;
2017 conf->ignore_session_id_set = CACHE_IGNORE_SESSION_ID_SET;
2021 static const char *add_cache_enable(cmd_parms *parms, void *dummy,
2025 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2026 cache_server_conf *conf;
2027 struct cache_enable *new;
2029 const char *err = ap_check_cmd_context(parms,
2030 NOT_IN_DIRECTORY|NOT_IN_LIMIT|NOT_IN_FILES);
2036 return apr_psprintf(parms->pool,
2037 "provider (%s) starts with a '/'. Are url and provider switched?",
2045 return apr_psprintf(parms->pool,
2046 "CacheEnable provider (%s) is missing an URL.", type);
2048 if (parms->path && strncmp(parms->path, url, strlen(parms->path))) {
2049 return "When in a Location, CacheEnable must specify a path or an URL below "
2054 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2058 new = apr_array_push(dconf->cacheenable);
2059 dconf->enable_set = 1;
2062 new = apr_array_push(conf->cacheenable);
2066 if (apr_uri_parse(parms->pool, url, &(new->url))) {
2069 if (new->url.path) {
2070 new->pathlen = strlen(new->url.path);
2073 new->url.path = "/";
2078 static const char *add_cache_disable(cmd_parms *parms, void *dummy,
2081 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2082 cache_server_conf *conf;
2083 struct cache_disable *new;
2085 const char *err = ap_check_cmd_context(parms,
2086 NOT_IN_DIRECTORY|NOT_IN_LIMIT|NOT_IN_FILES);
2092 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2096 if (!strcmp(url, "on")) {
2098 dconf->disable_set = 1;
2102 return "CacheDisable must be followed by the word 'on' when in a Location.";
2106 if (!url || (url[0] != '/' && !ap_strchr_c(url, ':'))) {
2107 return "CacheDisable must specify a path or an URL.";
2110 new = apr_array_push(conf->cachedisable);
2111 if (apr_uri_parse(parms->pool, url, &(new->url))) {
2114 if (new->url.path) {
2115 new->pathlen = strlen(new->url.path);
2118 new->url.path = "/";
2123 static const char *set_cache_maxex(cmd_parms *parms, void *dummy,
2126 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2128 dconf->maxex = (apr_time_t) (atol(arg) * MSEC_ONE_SEC);
2129 dconf->maxex_set = 1;
2133 static const char *set_cache_minex(cmd_parms *parms, void *dummy,
2136 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2138 dconf->minex = (apr_time_t) (atol(arg) * MSEC_ONE_SEC);
2139 dconf->minex_set = 1;
2143 static const char *set_cache_defex(cmd_parms *parms, void *dummy,
2146 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2148 dconf->defex = (apr_time_t) (atol(arg) * MSEC_ONE_SEC);
2149 dconf->defex_set = 1;
2153 static const char *set_cache_factor(cmd_parms *parms, void *dummy,
2156 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2159 if (sscanf(arg, "%lg", &val) != 1) {
2160 return "CacheLastModifiedFactor value must be a float";
2162 dconf->factor = val;
2163 dconf->factor_set = 1;
2167 static const char *set_cache_ignore_querystring(cmd_parms *parms, void *dummy,
2170 cache_server_conf *conf;
2173 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2175 conf->ignorequerystring = flag;
2176 conf->ignorequerystring_set = 1;
2180 static const char *set_cache_lock(cmd_parms *parms, void *dummy,
2183 cache_server_conf *conf;
2186 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2193 static const char *set_cache_lock_path(cmd_parms *parms, void *dummy,
2196 cache_server_conf *conf;
2199 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2202 conf->lockpath = ap_server_root_relative(parms->pool, arg);
2203 if (!conf->lockpath) {
2204 return apr_pstrcat(parms->pool, "Invalid CacheLockPath path ",
2207 conf->lockpath_set = 1;
2211 static const char *set_cache_lock_maxage(cmd_parms *parms, void *dummy,
2214 cache_server_conf *conf;
2215 apr_int64_t seconds;
2218 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2220 seconds = apr_atoi64(arg);
2222 return "CacheLockMaxAge value must be a non-zero positive integer";
2224 conf->lockmaxage = apr_time_from_sec(seconds);
2225 conf->lockmaxage_set = 1;
2229 static const char *set_cache_x_cache(cmd_parms *parms, void *dummy, int flag)
2233 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2235 dconf->x_cache = flag;
2236 dconf->x_cache_set = 1;
2240 cache_server_conf *conf =
2241 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2244 conf->x_cache = flag;
2245 conf->x_cache_set = 1;
2252 static const char *set_cache_x_cache_detail(cmd_parms *parms, void *dummy, int flag)
2256 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2258 dconf->x_cache_detail = flag;
2259 dconf->x_cache_detail_set = 1;
2263 cache_server_conf *conf =
2264 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2267 conf->x_cache_detail = flag;
2268 conf->x_cache_detail_set = 1;
2275 static const char *set_cache_key_base_url(cmd_parms *parms, void *dummy,
2278 cache_server_conf *conf;
2282 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2284 conf->base_uri = apr_pcalloc(parms->pool, sizeof(apr_uri_t));
2285 rv = apr_uri_parse(parms->pool, arg, conf->base_uri);
2286 if (rv != APR_SUCCESS) {
2287 return apr_psprintf(parms->pool, "Could not parse '%s' as an URL.", arg);
2289 else if (!conf->base_uri->scheme && !conf->base_uri->hostname &&
2290 !conf->base_uri->port_str) {
2291 return apr_psprintf(parms->pool, "URL '%s' must contain at least one of a scheme, a hostname or a port.", arg);
2293 conf->base_uri_set = 1;
2297 static const char *set_cache_stale_on_error(cmd_parms *parms, void *dummy,
2300 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2302 dconf->stale_on_error = flag;
2303 dconf->stale_on_error_set = 1;
2307 static int cache_post_config(apr_pool_t *p, apr_pool_t *plog,
2308 apr_pool_t *ptemp, server_rec *s)
2310 /* This is the means by which unusual (non-unix) os's may find alternate
2311 * means to run a given command (e.g. shebang/registry parsing on Win32)
2313 cache_generate_key = APR_RETRIEVE_OPTIONAL_FN(ap_cache_generate_key);
2314 if (!cache_generate_key) {
2315 cache_generate_key = cache_generate_key_default;
2321 static const command_rec cache_cmds[] =
2324 * Consider a new config directive that enables loading specific cache
2325 * implememtations (like mod_cache_mem, mod_cache_file, etc.).
2326 * Rather than using a LoadModule directive, admin would use something
2327 * like CacheModule mem_cache_module | file_cache_module, etc,
2328 * which would cause the approprpriate cache module to be loaded.
2329 * This is more intuitive that requiring a LoadModule directive.
2332 AP_INIT_TAKE12("CacheEnable", add_cache_enable, NULL, RSRC_CONF|ACCESS_CONF,
2333 "A cache type and partial URL prefix below which "
2334 "caching is enabled"),
2335 AP_INIT_TAKE1("CacheDisable", add_cache_disable, NULL, RSRC_CONF|ACCESS_CONF,
2336 "A partial URL prefix below which caching is disabled"),
2337 AP_INIT_TAKE1("CacheMaxExpire", set_cache_maxex, NULL, RSRC_CONF|ACCESS_CONF,
2338 "The maximum time in seconds to cache a document"),
2339 AP_INIT_TAKE1("CacheMinExpire", set_cache_minex, NULL, RSRC_CONF|ACCESS_CONF,
2340 "The minimum time in seconds to cache a document"),
2341 AP_INIT_TAKE1("CacheDefaultExpire", set_cache_defex, NULL, RSRC_CONF|ACCESS_CONF,
2342 "The default time in seconds to cache a document"),
2343 AP_INIT_FLAG("CacheQuickHandler", set_cache_quick_handler, NULL,
2345 "Run the cache in the quick handler, default on"),
2346 AP_INIT_FLAG("CacheIgnoreNoLastMod", set_cache_ignore_no_last_mod, NULL,
2347 RSRC_CONF|ACCESS_CONF,
2348 "Ignore Responses where there is no Last Modified Header"),
2349 AP_INIT_FLAG("CacheIgnoreCacheControl", set_cache_ignore_cachecontrol,
2351 "Ignore requests from the client for uncached content"),
2352 AP_INIT_FLAG("CacheStoreExpired", set_cache_store_expired,
2353 NULL, RSRC_CONF|ACCESS_CONF,
2354 "Ignore expiration dates when populating cache, resulting in "
2355 "an If-Modified-Since request to the backend on retrieval"),
2356 AP_INIT_FLAG("CacheStorePrivate", set_cache_store_private,
2357 NULL, RSRC_CONF|ACCESS_CONF,
2358 "Ignore 'Cache-Control: private' and store private content"),
2359 AP_INIT_FLAG("CacheStoreNoStore", set_cache_store_nostore,
2360 NULL, RSRC_CONF|ACCESS_CONF,
2361 "Ignore 'Cache-Control: no-store' and store sensitive content"),
2362 AP_INIT_ITERATE("CacheIgnoreHeaders", add_ignore_header, NULL, RSRC_CONF,
2363 "A space separated list of headers that should not be "
2364 "stored by the cache"),
2365 AP_INIT_FLAG("CacheIgnoreQueryString", set_cache_ignore_querystring,
2367 "Ignore query-string when caching"),
2368 AP_INIT_ITERATE("CacheIgnoreURLSessionIdentifiers", add_ignore_session_id,
2369 NULL, RSRC_CONF, "A space separated list of session "
2370 "identifiers that should be ignored for creating the key "
2371 "of the cached entity."),
2372 AP_INIT_TAKE1("CacheLastModifiedFactor", set_cache_factor, NULL, RSRC_CONF|ACCESS_CONF,
2373 "The factor used to estimate Expires date from "
2374 "LastModified date"),
2375 AP_INIT_FLAG("CacheLock", set_cache_lock,
2377 "Enable or disable the thundering herd lock."),
2378 AP_INIT_TAKE1("CacheLockPath", set_cache_lock_path, NULL, RSRC_CONF,
2379 "The thundering herd lock path. Defaults to the '"
2380 DEFAULT_CACHE_LOCKPATH "' directory in the system "
2382 AP_INIT_TAKE1("CacheLockMaxAge", set_cache_lock_maxage, NULL, RSRC_CONF,
2383 "Maximum age of any thundering herd lock."),
2384 AP_INIT_FLAG("CacheHeader", set_cache_x_cache, NULL, RSRC_CONF | ACCESS_CONF,
2385 "Add a X-Cache header to responses. Default is off."),
2386 AP_INIT_FLAG("CacheDetailHeader", set_cache_x_cache_detail, NULL,
2387 RSRC_CONF | ACCESS_CONF,
2388 "Add a X-Cache-Detail header to responses. Default is off."),
2389 AP_INIT_TAKE1("CacheKeyBaseURL", set_cache_key_base_url, NULL, RSRC_CONF,
2390 "Override the base URL of reverse proxied cache keys."),
2391 AP_INIT_FLAG("CacheStaleOnError", set_cache_stale_on_error,
2392 NULL, RSRC_CONF|ACCESS_CONF,
2393 "Serve stale content on 5xx errors if present. Defaults to on."),
2397 static void register_hooks(apr_pool_t *p)
2399 /* cache initializer */
2400 /* cache quick handler */
2401 ap_hook_quick_handler(cache_quick_handler, NULL, NULL, APR_HOOK_FIRST);
2403 ap_hook_handler(cache_handler, NULL, NULL, APR_HOOK_REALLY_FIRST);
2405 cache_hook_cache_status(cache_status, NULL, NULL, APR_HOOK_MIDDLE);
2406 /* cache error handler */
2407 ap_hook_insert_error_filter(cache_insert_error_filter, NULL, NULL, APR_HOOK_MIDDLE);
2409 * XXX The cache filters need to run right after the handlers and before
2410 * any other filters. Consider creating AP_FTYPE_CACHE for this purpose.
2412 * Depending on the type of request (subrequest / main request) they
2413 * need to be run before AP_FTYPE_CONTENT_SET / after AP_FTYPE_CONTENT_SET
2414 * filters. Thus create two filter handles for each type:
2415 * cache_save_filter_handle / cache_out_filter_handle to be used by
2417 * cache_save_subreq_filter_handle / cache_out_subreq_filter_handle
2418 * to be run by subrequest
2421 * CACHE is placed into the filter chain at an admin specified location,
2422 * and when the cache_handler is run, the CACHE filter is swapped with
2423 * the CACHE_OUT filter, or CACHE_SAVE filter as appropriate. This has
2424 * the effect of offering optional fine control of where the cache is
2425 * inserted into the filter chain.
2427 cache_filter_handle =
2428 ap_register_output_filter("CACHE",
2433 * CACHE_SAVE must go into the filter chain after a possible DEFLATE
2434 * filter to ensure that the compressed content is stored.
2435 * Incrementing filter type by 1 ensures this happens.
2437 cache_save_filter_handle =
2438 ap_register_output_filter("CACHE_SAVE",
2441 AP_FTYPE_CONTENT_SET+1);
2443 * CACHE_SAVE_SUBREQ must go into the filter chain before SUBREQ_CORE to
2444 * handle subrequsts. Decrementing filter type by 1 ensures this
2447 cache_save_subreq_filter_handle =
2448 ap_register_output_filter("CACHE_SAVE_SUBREQ",
2451 AP_FTYPE_CONTENT_SET-1);
2453 * CACHE_OUT must go into the filter chain after a possible DEFLATE
2454 * filter to ensure that already compressed cache objects do not
2455 * get compressed again. Incrementing filter type by 1 ensures
2458 cache_out_filter_handle =
2459 ap_register_output_filter("CACHE_OUT",
2462 AP_FTYPE_CONTENT_SET+1);
2464 * CACHE_OUT_SUBREQ must go into the filter chain before SUBREQ_CORE to
2465 * handle subrequsts. Decrementing filter type by 1 ensures this
2468 cache_out_subreq_filter_handle =
2469 ap_register_output_filter("CACHE_OUT_SUBREQ",
2472 AP_FTYPE_CONTENT_SET-1);
2473 /* CACHE_REMOVE_URL has to be a protocol filter to ensure that is
2474 * run even if the response is a canned error message, which
2475 * removes the content filters.
2477 cache_remove_url_filter_handle =
2478 ap_register_output_filter("CACHE_REMOVE_URL",
2479 cache_remove_url_filter,
2482 ap_hook_post_config(cache_post_config, NULL, NULL, APR_HOOK_REALLY_FIRST);
2485 AP_DECLARE_MODULE(cache) =
2487 STANDARD20_MODULE_STUFF,
2488 create_dir_config, /* create per-directory config structure */
2489 merge_dir_config, /* merge per-directory config structures */
2490 create_cache_config, /* create per-server config structure */
2491 merge_cache_config, /* merge per-server config structures */
2492 cache_cmds, /* command apr_table_t */
2497 APR_HOOK_LINK(cache_status)
2500 APR_IMPLEMENT_EXTERNAL_HOOK_RUN_ALL(cache, CACHE, int, cache_status,
2501 (cache_handle_t *h, request_rec *r,
2502 apr_table_t *headers, ap_cache_status_e status,
2503 const char *reason), (h, r, headers, status, reason),