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)
972 /* if a Expires header is in the past, don't cache it */
973 reason = "Expires header already expired; not cacheable";
975 else if (!conf->ignorequerystring && r->parsed_uri.query && exps == NULL
976 && !control.max_age && !control.s_maxage) {
977 /* if a query string is present but no explicit expiration time,
978 * don't cache it (RFC 2616/13.9 & 13.2.1)
980 reason = "Query string present but no explicit expiration time";
982 else if (r->status == HTTP_NOT_MODIFIED &&
983 !cache->handle && !cache->stale_handle) {
984 /* if the server said 304 Not Modified but we have no cache
985 * file - pass this untouched to the user agent, it's not for us.
987 reason = "HTTP Status 304 Not Modified";
989 else if (r->status == HTTP_OK && lastmods == NULL && etag == NULL && (exps
990 == NULL) && (dconf->no_last_mod_ignore == 0) && !control.max_age
991 && !control.s_maxage) {
992 /* 200 OK response from HTTP/1.0 and up without Last-Modified,
993 * Etag, Expires, Cache-Control:max-age, or Cache-Control:s-maxage
996 /* Note: mod-include clears last_modified/expires/etags - this
997 * is why we have an optional function for a key-gen ;-)
999 reason = "No Last-Modified; Etag; Expires; Cache-Control:max-age or Cache-Control:s-maxage headers";
1001 else if (!dconf->store_nostore && control.no_store) {
1002 /* RFC2616 14.9.2 Cache-Control: no-store response
1003 * indicating do not cache, or stop now if you are
1004 * trying to cache it.
1006 reason = "Cache-Control: no-store present";
1008 else if (!dconf->store_private && control.private) {
1009 /* RFC2616 14.9.1 Cache-Control: private response
1010 * this object is marked for this user's eyes only. Behave
1013 reason = "Cache-Control: private present";
1015 else if (apr_table_get(r->headers_in, "Authorization")
1016 && !(control.s_maxage || control.must_revalidate
1017 || control.proxy_revalidate || control.public)) {
1018 /* RFC2616 14.8 Authorisation:
1019 * if authorisation is included in the request, we don't cache,
1020 * but we can cache if the following exceptions are true:
1021 * 1) If Cache-Control: s-maxage is included
1022 * 2) If Cache-Control: must-revalidate is included
1023 * 3) If Cache-Control: public is included
1025 reason = "Authorization required";
1027 else if (ap_cache_liststr(NULL,
1028 apr_table_get(r->headers_out, "Vary"),
1030 reason = "Vary header contains '*'";
1032 else if (apr_table_get(r->subprocess_env, "no-cache") != NULL) {
1033 reason = "environment variable 'no-cache' is set";
1035 else if (r->no_cache) {
1036 /* or we've been asked not to cache it above */
1037 reason = "r->no_cache present";
1040 /* Hold the phone. Some servers might allow us to cache a 2xx, but
1041 * then make their 304 responses non cacheable. This leaves us in a
1042 * sticky position. If the 304 is in answer to our own conditional
1043 * request, we cannot send this 304 back to the client because the
1044 * client isn't expecting it. Instead, our only option is to respect
1045 * the answer to the question we asked (has it changed, answer was
1046 * no) and return the cached item to the client, and then respect
1047 * the uncacheable nature of this 304 by allowing the remove_url
1048 * filter to kick in and remove the cached entity.
1050 if (reason && r->status == HTTP_NOT_MODIFIED &&
1051 cache->stale_handle) {
1052 apr_bucket_brigade *bb;
1056 cache->handle = cache->stale_handle;
1057 info = &cache->handle->cache_obj->info;
1059 /* Load in the saved status and clear the status line. */
1060 r->status = info->status;
1061 r->status_line = NULL;
1063 bb = apr_brigade_create(r->pool, r->connection->bucket_alloc);
1065 r->headers_in = cache->stale_headers;
1066 status = ap_meets_conditions(r);
1070 bkt = apr_bucket_flush_create(bb->bucket_alloc);
1071 APR_BRIGADE_INSERT_TAIL(bb, bkt);
1074 cache->provider->recall_body(cache->handle, r->pool, bb);
1076 bkt = apr_bucket_eos_create(bb->bucket_alloc);
1077 APR_BRIGADE_INSERT_TAIL(bb, bkt);
1080 cache->block_response = 1;
1082 /* we've got a cache conditional hit! tell anyone who cares */
1083 cache_run_cache_status(
1087 AP_CACHE_REVALIDATE,
1090 "conditional cache hit: 304 was uncacheable though (%s); entity removed",
1093 /* let someone else attempt to cache */
1094 cache_remove_lock(conf, cache, r, NULL);
1096 return ap_pass_brigade(f->next, bb);
1100 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
1101 "cache: %s not cached. Reason: %s", r->unparsed_uri,
1104 /* we've got a cache miss! tell anyone who cares */
1105 cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
1108 /* remove this filter from the chain */
1109 ap_remove_output_filter(f);
1111 /* remove the lock file unconditionally */
1112 cache_remove_lock(conf, cache, r, NULL);
1114 /* ship the data up the stack */
1115 return ap_pass_brigade(f->next, in);
1118 /* Make it so that we don't execute this path again. */
1119 cache->in_checked = 1;
1121 /* Set the content length if known.
1123 cl = apr_table_get(r->err_headers_out, "Content-Length");
1125 cl = apr_table_get(r->headers_out, "Content-Length");
1129 if (apr_strtoff(&size, cl, &errp, 10) || *errp || size < 0) {
1130 cl = NULL; /* parse error, see next 'if' block */
1135 /* if we don't get the content-length, see if we have all the
1136 * buckets and use their length to calculate the size
1138 int all_buckets_here=0;
1140 for (e = APR_BRIGADE_FIRST(in);
1141 e != APR_BRIGADE_SENTINEL(in);
1142 e = APR_BUCKET_NEXT(e))
1144 if (APR_BUCKET_IS_EOS(e)) {
1148 if (APR_BUCKET_IS_FLUSH(e)) {
1151 if (e->length == (apr_size_t)-1) {
1156 if (!all_buckets_here) {
1161 /* remember content length to check response size against later */
1164 /* It's safe to cache the response.
1166 * There are two possiblities at this point:
1167 * - cache->handle == NULL. In this case there is no previously
1168 * cached entity anywhere on the system. We must create a brand
1169 * new entity and store the response in it.
1170 * - cache->stale_handle != NULL. In this case there is a stale
1171 * entity in the system which needs to be replaced by new
1172 * content (unless the result was 304 Not Modified, which means
1173 * the cached entity is actually fresh, and we should update
1177 /* Did we have a stale cache entry that really is stale?
1179 if (cache->stale_handle) {
1180 if (r->status == HTTP_NOT_MODIFIED) {
1181 /* Oh, hey. It isn't that stale! Yay! */
1182 cache->handle = cache->stale_handle;
1183 info = &cache->handle->cache_obj->info;
1187 /* Oh, well. Toss it. */
1188 cache->provider->remove_entity(cache->stale_handle);
1189 /* Treat the request as if it wasn't conditional. */
1190 cache->stale_handle = NULL;
1192 * Restore the original request headers as they may be needed
1193 * by further output filters like the byterange filter to make
1194 * the correct decisions.
1196 r->headers_in = cache->stale_headers;
1200 /* no cache handle, create a new entity */
1201 if (!cache->handle) {
1202 rv = cache_create_entity(cache, r, size, in);
1203 info = apr_pcalloc(r->pool, sizeof(cache_info));
1204 /* We only set info->status upon the initial creation. */
1205 info->status = r->status;
1209 /* we've got a cache miss! tell anyone who cares */
1210 cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
1211 "cache miss: create_entity failed");
1213 /* Caching layer declined the opportunity to cache the response */
1214 ap_remove_output_filter(f);
1215 cache_remove_lock(conf, cache, r, NULL);
1216 return ap_pass_brigade(f->next, in);
1219 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
1220 "cache: Caching url: %s", r->unparsed_uri);
1222 /* We are actually caching this response. So it does not
1223 * make sense to remove this entity any more.
1225 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
1226 "cache: Removing CACHE_REMOVE_URL filter.");
1227 ap_remove_output_filter(cache->remove_url_filter);
1230 * We now want to update the cache file header information with
1231 * the new date, last modified, expire and content length and write
1232 * it away to our cache file. First, we determine these values from
1233 * the response, using heuristics if appropriate.
1235 * In addition, we make HTTP/1.1 age calculations and write them away
1239 /* store away the previously parsed cache control headers */
1240 memcpy(&info->control, &control, sizeof(cache_control_t));
1242 /* Read the date. Generate one if one is not supplied */
1243 dates = apr_table_get(r->err_headers_out, "Date");
1244 if (dates == NULL) {
1245 dates = apr_table_get(r->headers_out, "Date");
1247 if (dates != NULL) {
1248 info->date = apr_date_parse_http(dates);
1251 info->date = APR_DATE_BAD;
1254 now = apr_time_now();
1255 if (info->date == APR_DATE_BAD) { /* No, or bad date */
1256 /* no date header (or bad header)! */
1261 /* set response_time for HTTP/1.1 age calculations */
1262 info->response_time = now;
1264 /* get the request time */
1265 info->request_time = r->request_time;
1267 /* check last-modified date */
1268 if (lastmod != APR_DATE_BAD && lastmod > date) {
1269 /* if it's in the future, then replace by date */
1272 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0,
1273 r, "cache: Last modified is in the future, "
1274 "replacing with now");
1277 /* if no expiry date then
1278 * if Cache-Control: max-age
1279 * expiry date = date + max-age
1281 * expiry date = date + min((date - lastmod) * factor, maxexpire)
1283 * expire date = date + defaultexpire
1285 if (exp == APR_DATE_BAD) {
1287 if (control.max_age) {
1291 x = control.max_age_value;
1296 x = x * MSEC_ONE_SEC;
1298 if (x < dconf->minex) {
1301 if (x > dconf->maxex) {
1306 else if ((lastmod != APR_DATE_BAD) && (lastmod < date)) {
1307 /* if lastmod == date then you get 0*conf->factor which results in
1308 * an expiration time of now. This causes some problems with
1309 * freshness calculations, so we choose the else path...
1311 apr_time_t x = (apr_time_t) ((date - lastmod) * dconf->factor);
1313 if (x < dconf->minex) {
1316 if (x > dconf->maxex) {
1322 exp = date + dconf->defex;
1327 /* We found a stale entry which wasn't really stale. */
1328 if (cache->stale_handle) {
1329 /* Load in the saved status and clear the status line. */
1330 r->status = info->status;
1331 r->status_line = NULL;
1333 /* RFC 2616 10.3.5 states that entity headers are not supposed
1334 * to be in the 304 response. Therefore, we need to combine the
1335 * response headers with the cached headers *before* we update
1336 * the cached headers.
1338 * However, before doing that, we need to first merge in
1339 * err_headers_out and we also need to strip any hop-by-hop
1340 * headers that might have snuck in.
1342 r->headers_out = ap_cache_cacheable_headers_out(r);
1344 /* Merge in our cached headers. However, keep any updated values. */
1345 cache_accept_headers(cache->handle, r, 1);
1348 /* Write away header information to cache. It is possible that we are
1349 * trying to update headers for an entity which has already been cached.
1351 * This may fail, due to an unwritable cache area. E.g. filesystem full,
1352 * permissions problems or a read-only (re)mount. This must be handled
1355 rv = cache->provider->store_headers(cache->handle, r, info);
1357 /* Did we just update the cached headers on a revalidated response?
1359 * If so, we can now decide what to serve to the client. This is done in
1360 * the same way as with a regular response, but conditions are now checked
1361 * against the cached or merged response headers.
1363 if (cache->stale_handle) {
1364 apr_bucket_brigade *bb;
1368 /* We're just saving response headers, so we are done. Commit
1369 * the response at this point, unless there was a previous error.
1371 if (rv == APR_SUCCESS) {
1372 rv = cache->provider->commit_entity(cache->handle, r);
1375 bb = apr_brigade_create(r->pool, r->connection->bucket_alloc);
1377 /* Restore the original request headers and see if we need to
1378 * return anything else than the cached response (ie. the original
1379 * request was conditional).
1381 r->headers_in = cache->stale_headers;
1382 status = ap_meets_conditions(r);
1386 bkt = apr_bucket_flush_create(bb->bucket_alloc);
1387 APR_BRIGADE_INSERT_TAIL(bb, bkt);
1390 cache->provider->recall_body(cache->handle, r->pool, bb);
1392 bkt = apr_bucket_eos_create(bb->bucket_alloc);
1393 APR_BRIGADE_INSERT_TAIL(bb, bkt);
1396 cache->block_response = 1;
1398 /* Before returning we need to handle the possible case of an
1399 * unwritable cache. Rather than leaving the entity in the cache
1400 * and having it constantly re-validated, now that we have recalled
1401 * the body it is safe to try and remove the url from the cache.
1403 if (rv != APR_SUCCESS) {
1404 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r,
1405 "cache: updating headers with store_headers failed. "
1406 "Removing cached url.");
1408 rv = cache->provider->remove_url(cache->stale_handle, r);
1410 /* Probably a mod_cache_disk cache area has been (re)mounted
1411 * read-only, or that there is a permissions problem.
1413 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r,
1414 "cache: attempt to remove url from cache unsuccessful.");
1417 /* we've got a cache conditional hit! tell anyone who cares */
1418 cache_run_cache_status(cache->handle, r, r->headers_out,
1419 AP_CACHE_REVALIDATE,
1420 "conditional cache hit: entity refresh failed");
1425 /* we've got a cache conditional hit! tell anyone who cares */
1426 cache_run_cache_status(cache->handle, r, r->headers_out,
1427 AP_CACHE_REVALIDATE,
1428 "conditional cache hit: entity refreshed");
1432 /* let someone else attempt to cache */
1433 cache_remove_lock(conf, cache, r, NULL);
1435 return ap_pass_brigade(f->next, bb);
1438 if (rv != APR_SUCCESS) {
1439 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r,
1440 "cache: store_headers failed");
1442 /* we've got a cache miss! tell anyone who cares */
1443 cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
1444 "cache miss: store_headers failed");
1446 ap_remove_output_filter(f);
1447 cache_remove_lock(conf, cache, r, NULL);
1448 return ap_pass_brigade(f->next, in);
1451 /* we've got a cache miss! tell anyone who cares */
1452 cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
1453 "cache miss: attempting entity save");
1455 return cache_save_store(f, in, conf, cache);
1459 * CACHE_REMOVE_URL filter
1460 * -----------------------
1462 * This filter gets added in the quick handler every time the CACHE_SAVE filter
1463 * gets inserted. Its purpose is to remove a confirmed stale cache entry from
1466 * CACHE_REMOVE_URL has to be a protocol filter to ensure that is run even if
1467 * the response is a canned error message, which removes the content filters
1468 * and thus the CACHE_SAVE filter from the chain.
1470 * CACHE_REMOVE_URL expects cache request rec within its context because the
1471 * request this filter runs on can be different from the one whose cache entry
1472 * should be removed, due to internal redirects.
1474 * Note that CACHE_SAVE_URL (as a content-set filter, hence run before the
1475 * protocol filters) will remove this filter if it decides to cache the file.
1476 * Therefore, if this filter is left in, it must mean we need to toss any
1479 static int cache_remove_url_filter(ap_filter_t *f, apr_bucket_brigade *in)
1481 request_rec *r = f->r;
1482 cache_request_rec *cache;
1484 /* Setup cache_request_rec */
1485 cache = (cache_request_rec *) f->ctx;
1488 /* user likely configured CACHE_REMOVE_URL manually; they should really
1489 * use mod_cache configuration to do that. So:
1490 * 1. Remove ourselves
1491 * 2. Do nothing and bail out
1493 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
1494 "cache: CACHE_REMOVE_URL enabled unexpectedly");
1495 ap_remove_output_filter(f);
1496 return ap_pass_brigade(f->next, in);
1499 /* Now remove this cache entry from the cache */
1500 cache_remove_url(cache, r);
1502 /* remove ourselves */
1503 ap_remove_output_filter(f);
1504 return ap_pass_brigade(f->next, in);
1511 * This filter can be optionally inserted into the filter chain by the admin as
1512 * a marker representing the precise location within the filter chain where
1513 * caching is to be performed.
1515 * When the filter chain is set up in the non-quick version of the URL handler,
1516 * the CACHE filter is replaced by the CACHE_OUT or CACHE_SAVE filter,
1517 * effectively inserting the caching filters at the point indicated by the
1518 * admin. The CACHE filter is then removed.
1520 * This allows caching to be performed before the content is passed to the
1521 * INCLUDES filter, or to a filter that might perform transformations unique
1522 * to the specific request and that would otherwise be non-cacheable.
1524 static int cache_filter(ap_filter_t *f, apr_bucket_brigade *in)
1526 /* we are just a marker, so let's just remove ourselves */
1527 ap_log_rerror(APLOG_MARK, APLOG_WARNING, 0, f->r,
1528 "cache: CACHE filter was added twice, or was added in quick "
1529 "handler mode and will be ignored.");
1530 ap_remove_output_filter(f);
1531 return ap_pass_brigade(f->next, in);
1535 * If configured, add the status of the caching attempt to the subprocess
1536 * environment, and if configured, to headers in the response.
1538 * The status is saved below the broad category of the status (hit, miss,
1539 * revalidate), as well as a single cache-status key. This can be used for
1540 * conditional logging.
1542 * The status is optionally saved to an X-Cache header, and the detail of
1543 * why a particular cache entry was cached (or not cached) is optionally
1544 * saved to an X-Cache-Detail header. This extra detail is useful for
1545 * service developers who may need to know whether their Cache-Control headers
1546 * are working correctly.
1548 static int cache_status(cache_handle_t *h, request_rec *r,
1549 apr_table_t *headers, ap_cache_status_e status, const char *reason)
1553 (cache_server_conf *) ap_get_module_config(r->server->module_config,
1556 cache_dir_conf *dconf = ap_get_module_config(r->per_dir_config, &cache_module);
1557 int x_cache = 0, x_cache_detail = 0;
1560 case AP_CACHE_HIT: {
1561 apr_table_setn(r->subprocess_env, AP_CACHE_HIT_ENV, reason);
1564 case AP_CACHE_REVALIDATE: {
1565 apr_table_setn(r->subprocess_env, AP_CACHE_REVALIDATE_ENV, reason);
1568 case AP_CACHE_MISS: {
1569 apr_table_setn(r->subprocess_env, AP_CACHE_MISS_ENV, reason);
1572 case AP_CACHE_INVALIDATE: {
1573 apr_table_setn(r->subprocess_env, AP_CACHE_INVALIDATE_ENV, reason);
1578 apr_table_setn(r->subprocess_env, AP_CACHE_STATUS_ENV, reason);
1580 if (dconf && dconf->x_cache_set) {
1581 x_cache = dconf->x_cache;
1584 x_cache = conf->x_cache;
1587 apr_table_setn(headers, "X-Cache", apr_psprintf(r->pool, "%s from %s",
1588 status == AP_CACHE_HIT ? "HIT"
1589 : status == AP_CACHE_REVALIDATE ? "REVALIDATE" : status
1590 == AP_CACHE_INVALIDATE ? "INVALIDATE" : "MISS",
1591 r->server->server_hostname));
1594 if (dconf && dconf->x_cache_detail_set) {
1595 x_cache_detail = dconf->x_cache_detail;
1598 x_cache_detail = conf->x_cache_detail;
1600 if (x_cache_detail) {
1601 apr_table_setn(headers, "X-Cache-Detail", apr_psprintf(r->pool,
1602 "\"%s\" from %s", reason, r->server->server_hostname));
1609 * If an error has occurred, but we have a stale cached entry, restore the
1610 * filter stack from the save filter onwards. The canned error message will
1611 * be discarded in the process, and replaced with the cached response.
1613 static void cache_insert_error_filter(request_rec *r)
1616 cache_dir_conf *dconf;
1618 /* ignore everything except for 5xx errors */
1619 if (r->status < HTTP_INTERNAL_SERVER_ERROR) {
1623 dconf = ap_get_module_config(r->per_dir_config, &cache_module);
1625 if (!dconf->stale_on_error) {
1629 /* RFC2616 13.8 Errors or Incomplete Response Cache Behavior:
1630 * If a cache receives a 5xx response while attempting to revalidate an
1631 * entry, it MAY either forward this response to the requesting client,
1632 * or act as if the server failed to respond. In the latter case, it MAY
1633 * return a previously received response unless the cached entry
1634 * includes the "must-revalidate" cache-control directive (see section
1637 * This covers the case where the error was generated by our server via
1640 apr_pool_userdata_get(&dummy, CACHE_CTX_KEY, r->pool);
1642 cache_request_rec *cache = (cache_request_rec *) dummy;
1644 ap_remove_output_filter(cache->remove_url_filter);
1646 if (cache->stale_handle && cache->save_filter
1647 && !cache->stale_handle->cache_obj->info.control.must_revalidate
1648 && !cache->stale_handle->cache_obj->info.control.proxy_revalidate) {
1649 const char *warn_head;
1652 (cache_server_conf *) ap_get_module_config(r->server->module_config,
1655 /* morph the current save filter into the out filter, and serve from
1658 cache->handle = cache->stale_handle;
1660 cache->save_filter->frec = cache_out_subreq_filter_handle;
1663 cache->save_filter->frec = cache_out_filter_handle;
1666 r->output_filters = cache->save_filter;
1668 r->err_headers_out = cache->stale_handle->resp_hdrs;
1670 /* add a revalidation warning */
1671 warn_head = apr_table_get(r->err_headers_out, "Warning");
1672 if ((warn_head == NULL) || ((warn_head != NULL)
1673 && (ap_strstr_c(warn_head, "111") == NULL))) {
1674 apr_table_mergen(r->err_headers_out, "Warning",
1675 "111 Revalidation failed");
1678 cache_run_cache_status(
1685 "cache hit: %d status; stale content returned",
1688 /* give someone else the chance to cache the file */
1689 cache_remove_lock(conf, cache, r, NULL);
1697 /* -------------------------------------------------------------- */
1698 /* Setup configurable data */
1700 static void *create_dir_config(apr_pool_t *p, char *dummy)
1702 cache_dir_conf *dconf = apr_pcalloc(p, sizeof(cache_dir_conf));
1704 dconf->no_last_mod_ignore = 0;
1705 dconf->store_expired = 0;
1706 dconf->store_private = 0;
1707 dconf->store_nostore = 0;
1709 /* maximum time to cache a document */
1710 dconf->maxex = DEFAULT_CACHE_MAXEXPIRE;
1711 dconf->minex = DEFAULT_CACHE_MINEXPIRE;
1712 /* default time to cache a document */
1713 dconf->defex = DEFAULT_CACHE_EXPIRE;
1715 /* factor used to estimate Expires date from LastModified date */
1716 dconf->factor = DEFAULT_CACHE_LMFACTOR;
1718 dconf->x_cache = DEFAULT_X_CACHE;
1719 dconf->x_cache_detail = DEFAULT_X_CACHE_DETAIL;
1721 dconf->stale_on_error = DEFAULT_CACHE_STALE_ON_ERROR;
1723 /* array of providers for this URL space */
1724 dconf->cacheenable = apr_array_make(p, 10, sizeof(struct cache_enable));
1729 static void *merge_dir_config(apr_pool_t *p, void *basev, void *addv) {
1730 cache_dir_conf *new = (cache_dir_conf *) apr_pcalloc(p, sizeof(cache_dir_conf));
1731 cache_dir_conf *add = (cache_dir_conf *) addv;
1732 cache_dir_conf *base = (cache_dir_conf *) basev;
1734 new->no_last_mod_ignore = (add->no_last_mod_ignore_set == 0) ? base->no_last_mod_ignore : add->no_last_mod_ignore;
1735 new->no_last_mod_ignore_set = add->no_last_mod_ignore_set || base->no_last_mod_ignore_set;
1737 new->store_expired = (add->store_expired_set == 0) ? base->store_expired : add->store_expired;
1738 new->store_expired_set = add->store_expired_set || base->store_expired_set;
1739 new->store_private = (add->store_private_set == 0) ? base->store_private : add->store_private;
1740 new->store_private_set = add->store_private_set || base->store_private_set;
1741 new->store_nostore = (add->store_nostore_set == 0) ? base->store_nostore : add->store_nostore;
1742 new->store_nostore_set = add->store_nostore_set || base->store_nostore_set;
1744 /* maximum time to cache a document */
1745 new->maxex = (add->maxex_set == 0) ? base->maxex : add->maxex;
1746 new->maxex_set = add->maxex_set || base->maxex_set;
1747 new->minex = (add->minex_set == 0) ? base->minex : add->minex;
1748 new->minex_set = add->minex_set || base->minex_set;
1750 /* default time to cache a document */
1751 new->defex = (add->defex_set == 0) ? base->defex : add->defex;
1752 new->defex_set = add->defex_set || base->defex_set;
1754 /* factor used to estimate Expires date from LastModified date */
1755 new->factor = (add->factor_set == 0) ? base->factor : add->factor;
1756 new->factor_set = add->factor_set || base->factor_set;
1758 new->x_cache = (add->x_cache_set == 0) ? base->x_cache : add->x_cache;
1759 new->x_cache_set = add->x_cache_set || base->x_cache_set;
1760 new->x_cache_detail = (add->x_cache_detail_set == 0) ? base->x_cache_detail
1761 : add->x_cache_detail;
1762 new->x_cache_detail_set = add->x_cache_detail_set
1763 || base->x_cache_detail_set;
1765 new->stale_on_error = (add->stale_on_error_set == 0) ? base->stale_on_error
1766 : add->stale_on_error;
1767 new->stale_on_error_set = add->stale_on_error_set
1768 || base->stale_on_error_set;
1770 new->cacheenable = add->enable_set ? apr_array_append(p, base->cacheenable,
1771 add->cacheenable) : base->cacheenable;
1772 new->enable_set = add->enable_set || base->enable_set;
1773 new->disable = (add->disable_set == 0) ? base->disable : add->disable;
1774 new->disable_set = add->disable_set || base->disable_set;
1779 static void * create_cache_config(apr_pool_t *p, server_rec *s)
1781 const char *tmppath;
1782 cache_server_conf *ps = apr_pcalloc(p, sizeof(cache_server_conf));
1784 /* array of URL prefixes for which caching is enabled */
1785 ps->cacheenable = apr_array_make(p, 10, sizeof(struct cache_enable));
1786 /* array of URL prefixes for which caching is disabled */
1787 ps->cachedisable = apr_array_make(p, 10, sizeof(struct cache_disable));
1788 ps->ignorecachecontrol = 0;
1789 ps->ignorecachecontrol_set = 0;
1790 /* array of headers that should not be stored in cache */
1791 ps->ignore_headers = apr_array_make(p, 10, sizeof(char *));
1792 ps->ignore_headers_set = CACHE_IGNORE_HEADERS_UNSET;
1793 /* flag indicating that query-string should be ignored when caching */
1794 ps->ignorequerystring = 0;
1795 ps->ignorequerystring_set = 0;
1796 /* by default, run in the quick handler */
1799 /* array of identifiers that should not be used for key calculation */
1800 ps->ignore_session_id = apr_array_make(p, 10, sizeof(char *));
1801 ps->ignore_session_id_set = CACHE_IGNORE_SESSION_ID_UNSET;
1802 ps->lock = 0; /* thundering herd lock defaults to off */
1804 apr_temp_dir_get(&tmppath, p);
1806 ps->lockpath = apr_pstrcat(p, tmppath, DEFAULT_CACHE_LOCKPATH, NULL);
1808 ps->lockmaxage = apr_time_from_sec(DEFAULT_CACHE_MAXAGE);
1809 ps->x_cache = DEFAULT_X_CACHE;
1810 ps->x_cache_detail = DEFAULT_X_CACHE_DETAIL;
1814 static void * merge_cache_config(apr_pool_t *p, void *basev, void *overridesv)
1816 cache_server_conf *ps = apr_pcalloc(p, sizeof(cache_server_conf));
1817 cache_server_conf *base = (cache_server_conf *) basev;
1818 cache_server_conf *overrides = (cache_server_conf *) overridesv;
1820 /* array of URL prefixes for which caching is disabled */
1821 ps->cachedisable = apr_array_append(p,
1823 overrides->cachedisable);
1824 /* array of URL prefixes for which caching is enabled */
1825 ps->cacheenable = apr_array_append(p,
1827 overrides->cacheenable);
1829 ps->ignorecachecontrol =
1830 (overrides->ignorecachecontrol_set == 0)
1831 ? base->ignorecachecontrol
1832 : overrides->ignorecachecontrol;
1833 ps->ignore_headers =
1834 (overrides->ignore_headers_set == CACHE_IGNORE_HEADERS_UNSET)
1835 ? base->ignore_headers
1836 : overrides->ignore_headers;
1837 ps->ignorequerystring =
1838 (overrides->ignorequerystring_set == 0)
1839 ? base->ignorequerystring
1840 : overrides->ignorequerystring;
1841 ps->ignore_session_id =
1842 (overrides->ignore_session_id_set == CACHE_IGNORE_SESSION_ID_UNSET)
1843 ? base->ignore_session_id
1844 : overrides->ignore_session_id;
1846 (overrides->lock_set == 0)
1850 (overrides->lockpath_set == 0)
1852 : overrides->lockpath;
1854 (overrides->lockmaxage_set == 0)
1856 : overrides->lockmaxage;
1858 (overrides->quick_set == 0)
1862 (overrides->x_cache_set == 0)
1864 : overrides->x_cache;
1865 ps->x_cache_detail =
1866 (overrides->x_cache_detail_set == 0)
1867 ? base->x_cache_detail
1868 : overrides->x_cache_detail;
1870 (overrides->base_uri_set == 0)
1872 : overrides->base_uri;
1876 static const char *set_cache_quick_handler(cmd_parms *parms, void *dummy,
1879 cache_server_conf *conf;
1882 (cache_server_conf *)ap_get_module_config(parms->server->module_config
1886 conf->quick_set = 1;
1891 static const char *set_cache_ignore_no_last_mod(cmd_parms *parms, void *dummy,
1894 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
1896 dconf->no_last_mod_ignore = flag;
1897 dconf->no_last_mod_ignore_set = 1;
1902 static const char *set_cache_ignore_cachecontrol(cmd_parms *parms,
1903 void *dummy, int flag)
1905 cache_server_conf *conf;
1908 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
1910 conf->ignorecachecontrol = flag;
1911 conf->ignorecachecontrol_set = 1;
1915 static const char *set_cache_store_expired(cmd_parms *parms, void *dummy,
1918 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
1920 dconf->store_expired = flag;
1921 dconf->store_expired_set = 1;
1925 static const char *set_cache_store_private(cmd_parms *parms, void *dummy,
1928 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
1930 dconf->store_private = flag;
1931 dconf->store_private_set = 1;
1935 static const char *set_cache_store_nostore(cmd_parms *parms, void *dummy,
1938 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
1940 dconf->store_nostore = flag;
1941 dconf->store_nostore_set = 1;
1945 static const char *add_ignore_header(cmd_parms *parms, void *dummy,
1948 cache_server_conf *conf;
1952 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
1954 if (!strcasecmp(header, "None")) {
1955 /* if header None is listed clear array */
1956 conf->ignore_headers->nelts = 0;
1959 if ((conf->ignore_headers_set == CACHE_IGNORE_HEADERS_UNSET) ||
1960 (conf->ignore_headers->nelts)) {
1961 /* Only add header if no "None" has been found in header list
1963 * (When 'None' is passed, IGNORE_HEADERS_SET && nelts == 0.)
1965 new = (char **)apr_array_push(conf->ignore_headers);
1966 (*new) = (char *)header;
1969 conf->ignore_headers_set = CACHE_IGNORE_HEADERS_SET;
1973 static const char *add_ignore_session_id(cmd_parms *parms, void *dummy,
1974 const char *identifier)
1976 cache_server_conf *conf;
1980 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
1982 if (!strcasecmp(identifier, "None")) {
1983 /* if identifier None is listed clear array */
1984 conf->ignore_session_id->nelts = 0;
1987 if ((conf->ignore_session_id_set == CACHE_IGNORE_SESSION_ID_UNSET) ||
1988 (conf->ignore_session_id->nelts)) {
1990 * Only add identifier if no "None" has been found in identifier
1993 new = (char **)apr_array_push(conf->ignore_session_id);
1994 (*new) = (char *)identifier;
1997 conf->ignore_session_id_set = CACHE_IGNORE_SESSION_ID_SET;
2001 static const char *add_cache_enable(cmd_parms *parms, void *dummy,
2005 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2006 cache_server_conf *conf;
2007 struct cache_enable *new;
2009 const char *err = ap_check_cmd_context(parms,
2010 NOT_IN_DIRECTORY|NOT_IN_LIMIT|NOT_IN_FILES);
2016 return apr_psprintf(parms->pool,
2017 "provider (%s) starts with a '/'. Are url and provider switched?",
2025 return apr_psprintf(parms->pool,
2026 "CacheEnable provider (%s) is missing an URL.", type);
2028 if (parms->path && strncmp(parms->path, url, strlen(parms->path))) {
2029 return "When in a Location, CacheEnable must specify a path or an URL below "
2034 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2038 new = apr_array_push(dconf->cacheenable);
2039 dconf->enable_set = 1;
2042 new = apr_array_push(conf->cacheenable);
2046 if (apr_uri_parse(parms->pool, url, &(new->url))) {
2049 if (new->url.path) {
2050 new->pathlen = strlen(new->url.path);
2053 new->url.path = "/";
2058 static const char *add_cache_disable(cmd_parms *parms, void *dummy,
2061 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2062 cache_server_conf *conf;
2063 struct cache_disable *new;
2065 const char *err = ap_check_cmd_context(parms,
2066 NOT_IN_DIRECTORY|NOT_IN_LIMIT|NOT_IN_FILES);
2071 if (parms->path && !strcmp(url, "on")) {
2074 if (url[0] != '/' && !ap_strchr_c(url, ':')) {
2075 return "CacheDisable must specify a path or an URL, or when in a Location, "
2079 if (parms->path && strncmp(parms->path, url, strlen(parms->path))) {
2080 return "When in a Location, CacheDisable must specify a path or an URL below "
2085 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2090 dconf->disable_set = 1;
2094 new = apr_array_push(conf->cachedisable);
2095 if (apr_uri_parse(parms->pool, url, &(new->url))) {
2098 if (new->url.path) {
2099 new->pathlen = strlen(new->url.path);
2102 new->url.path = "/";
2107 static const char *set_cache_maxex(cmd_parms *parms, void *dummy,
2110 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2112 dconf->maxex = (apr_time_t) (atol(arg) * MSEC_ONE_SEC);
2113 dconf->maxex_set = 1;
2117 static const char *set_cache_minex(cmd_parms *parms, void *dummy,
2120 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2122 dconf->minex = (apr_time_t) (atol(arg) * MSEC_ONE_SEC);
2123 dconf->minex_set = 1;
2127 static const char *set_cache_defex(cmd_parms *parms, void *dummy,
2130 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2132 dconf->defex = (apr_time_t) (atol(arg) * MSEC_ONE_SEC);
2133 dconf->defex_set = 1;
2137 static const char *set_cache_factor(cmd_parms *parms, void *dummy,
2140 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2143 if (sscanf(arg, "%lg", &val) != 1) {
2144 return "CacheLastModifiedFactor value must be a float";
2146 dconf->factor = val;
2147 dconf->factor_set = 1;
2151 static const char *set_cache_ignore_querystring(cmd_parms *parms, void *dummy,
2154 cache_server_conf *conf;
2157 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2159 conf->ignorequerystring = flag;
2160 conf->ignorequerystring_set = 1;
2164 static const char *set_cache_lock(cmd_parms *parms, void *dummy,
2167 cache_server_conf *conf;
2170 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2177 static const char *set_cache_lock_path(cmd_parms *parms, void *dummy,
2180 cache_server_conf *conf;
2183 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2186 conf->lockpath = ap_server_root_relative(parms->pool, arg);
2187 if (!conf->lockpath) {
2188 return apr_pstrcat(parms->pool, "Invalid CacheLockPath path ",
2191 conf->lockpath_set = 1;
2195 static const char *set_cache_lock_maxage(cmd_parms *parms, void *dummy,
2198 cache_server_conf *conf;
2199 apr_int64_t seconds;
2202 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2204 seconds = apr_atoi64(arg);
2206 return "CacheLockMaxAge value must be a non-zero positive integer";
2208 conf->lockmaxage = apr_time_from_sec(seconds);
2209 conf->lockmaxage_set = 1;
2213 static const char *set_cache_x_cache(cmd_parms *parms, void *dummy, int flag)
2217 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2219 dconf->x_cache = flag;
2220 dconf->x_cache_set = 1;
2224 cache_server_conf *conf =
2225 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2228 conf->x_cache = flag;
2229 conf->x_cache_set = 1;
2236 static const char *set_cache_x_cache_detail(cmd_parms *parms, void *dummy, int flag)
2240 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2242 dconf->x_cache_detail = flag;
2243 dconf->x_cache_detail_set = 1;
2247 cache_server_conf *conf =
2248 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2251 conf->x_cache_detail = flag;
2252 conf->x_cache_detail_set = 1;
2259 static const char *set_cache_key_base_url(cmd_parms *parms, void *dummy,
2262 cache_server_conf *conf;
2266 (cache_server_conf *)ap_get_module_config(parms->server->module_config,
2268 conf->base_uri = apr_pcalloc(parms->pool, sizeof(apr_uri_t));
2269 rv = apr_uri_parse(parms->pool, arg, conf->base_uri);
2270 if (rv != APR_SUCCESS) {
2271 return apr_psprintf(parms->pool, "Could not parse '%s' as an URL.", arg);
2273 else if (!conf->base_uri->scheme && !conf->base_uri->hostname &&
2274 !conf->base_uri->port_str) {
2275 return apr_psprintf(parms->pool, "URL '%s' must contain at least one of a scheme, a hostname or a port.", arg);
2277 conf->base_uri_set = 1;
2281 static const char *set_cache_stale_on_error(cmd_parms *parms, void *dummy,
2284 cache_dir_conf *dconf = (cache_dir_conf *)dummy;
2286 dconf->stale_on_error = flag;
2287 dconf->stale_on_error_set = 1;
2291 static int cache_post_config(apr_pool_t *p, apr_pool_t *plog,
2292 apr_pool_t *ptemp, server_rec *s)
2294 /* This is the means by which unusual (non-unix) os's may find alternate
2295 * means to run a given command (e.g. shebang/registry parsing on Win32)
2297 cache_generate_key = APR_RETRIEVE_OPTIONAL_FN(ap_cache_generate_key);
2298 if (!cache_generate_key) {
2299 cache_generate_key = cache_generate_key_default;
2305 static const command_rec cache_cmds[] =
2308 * Consider a new config directive that enables loading specific cache
2309 * implememtations (like mod_cache_mem, mod_cache_file, etc.).
2310 * Rather than using a LoadModule directive, admin would use something
2311 * like CacheModule mem_cache_module | file_cache_module, etc,
2312 * which would cause the approprpriate cache module to be loaded.
2313 * This is more intuitive that requiring a LoadModule directive.
2316 AP_INIT_TAKE12("CacheEnable", add_cache_enable, NULL, RSRC_CONF|ACCESS_CONF,
2317 "A cache type and partial URL prefix below which "
2318 "caching is enabled"),
2319 AP_INIT_TAKE1("CacheDisable", add_cache_disable, NULL, RSRC_CONF|ACCESS_CONF,
2320 "A partial URL prefix below which caching is disabled"),
2321 AP_INIT_TAKE1("CacheMaxExpire", set_cache_maxex, NULL, RSRC_CONF|ACCESS_CONF,
2322 "The maximum time in seconds to cache a document"),
2323 AP_INIT_TAKE1("CacheMinExpire", set_cache_minex, NULL, RSRC_CONF|ACCESS_CONF,
2324 "The minimum time in seconds to cache a document"),
2325 AP_INIT_TAKE1("CacheDefaultExpire", set_cache_defex, NULL, RSRC_CONF|ACCESS_CONF,
2326 "The default time in seconds to cache a document"),
2327 AP_INIT_FLAG("CacheQuickHandler", set_cache_quick_handler, NULL,
2329 "Run the cache in the quick handler, default on"),
2330 AP_INIT_FLAG("CacheIgnoreNoLastMod", set_cache_ignore_no_last_mod, NULL,
2331 RSRC_CONF|ACCESS_CONF,
2332 "Ignore Responses where there is no Last Modified Header"),
2333 AP_INIT_FLAG("CacheIgnoreCacheControl", set_cache_ignore_cachecontrol,
2335 "Ignore requests from the client for uncached content"),
2336 AP_INIT_FLAG("CacheStoreExpired", set_cache_store_expired,
2337 NULL, RSRC_CONF|ACCESS_CONF,
2338 "Ignore expiration dates when populating cache, resulting in "
2339 "an If-Modified-Since request to the backend on retrieval"),
2340 AP_INIT_FLAG("CacheStorePrivate", set_cache_store_private,
2341 NULL, RSRC_CONF|ACCESS_CONF,
2342 "Ignore 'Cache-Control: private' and store private content"),
2343 AP_INIT_FLAG("CacheStoreNoStore", set_cache_store_nostore,
2344 NULL, RSRC_CONF|ACCESS_CONF,
2345 "Ignore 'Cache-Control: no-store' and store sensitive content"),
2346 AP_INIT_ITERATE("CacheIgnoreHeaders", add_ignore_header, NULL, RSRC_CONF,
2347 "A space separated list of headers that should not be "
2348 "stored by the cache"),
2349 AP_INIT_FLAG("CacheIgnoreQueryString", set_cache_ignore_querystring,
2351 "Ignore query-string when caching"),
2352 AP_INIT_ITERATE("CacheIgnoreURLSessionIdentifiers", add_ignore_session_id,
2353 NULL, RSRC_CONF, "A space separated list of session "
2354 "identifiers that should be ignored for creating the key "
2355 "of the cached entity."),
2356 AP_INIT_TAKE1("CacheLastModifiedFactor", set_cache_factor, NULL, RSRC_CONF|ACCESS_CONF,
2357 "The factor used to estimate Expires date from "
2358 "LastModified date"),
2359 AP_INIT_FLAG("CacheLock", set_cache_lock,
2361 "Enable or disable the thundering herd lock."),
2362 AP_INIT_TAKE1("CacheLockPath", set_cache_lock_path, NULL, RSRC_CONF,
2363 "The thundering herd lock path. Defaults to the '"
2364 DEFAULT_CACHE_LOCKPATH "' directory in the system "
2366 AP_INIT_TAKE1("CacheLockMaxAge", set_cache_lock_maxage, NULL, RSRC_CONF,
2367 "Maximum age of any thundering herd lock."),
2368 AP_INIT_FLAG("CacheHeader", set_cache_x_cache, NULL, RSRC_CONF | ACCESS_CONF,
2369 "Add a X-Cache header to responses. Default is off."),
2370 AP_INIT_FLAG("CacheDetailHeader", set_cache_x_cache_detail, NULL,
2371 RSRC_CONF | ACCESS_CONF,
2372 "Add a X-Cache-Detail header to responses. Default is off."),
2373 AP_INIT_TAKE1("CacheKeyBaseURL", set_cache_key_base_url, NULL, RSRC_CONF,
2374 "Override the base URL of reverse proxied cache keys."),
2375 AP_INIT_FLAG("CacheStaleOnError", set_cache_stale_on_error,
2376 NULL, RSRC_CONF|ACCESS_CONF,
2377 "Serve stale content on 5xx errors if present. Defaults to on."),
2381 static void register_hooks(apr_pool_t *p)
2383 /* cache initializer */
2384 /* cache quick handler */
2385 ap_hook_quick_handler(cache_quick_handler, NULL, NULL, APR_HOOK_FIRST);
2387 ap_hook_handler(cache_handler, NULL, NULL, APR_HOOK_REALLY_FIRST);
2389 cache_hook_cache_status(cache_status, NULL, NULL, APR_HOOK_MIDDLE);
2390 /* cache error handler */
2391 ap_hook_insert_error_filter(cache_insert_error_filter, NULL, NULL, APR_HOOK_MIDDLE);
2393 * XXX The cache filters need to run right after the handlers and before
2394 * any other filters. Consider creating AP_FTYPE_CACHE for this purpose.
2396 * Depending on the type of request (subrequest / main request) they
2397 * need to be run before AP_FTYPE_CONTENT_SET / after AP_FTYPE_CONTENT_SET
2398 * filters. Thus create two filter handles for each type:
2399 * cache_save_filter_handle / cache_out_filter_handle to be used by
2401 * cache_save_subreq_filter_handle / cache_out_subreq_filter_handle
2402 * to be run by subrequest
2405 * CACHE is placed into the filter chain at an admin specified location,
2406 * and when the cache_handler is run, the CACHE filter is swapped with
2407 * the CACHE_OUT filter, or CACHE_SAVE filter as appropriate. This has
2408 * the effect of offering optional fine control of where the cache is
2409 * inserted into the filter chain.
2411 cache_filter_handle =
2412 ap_register_output_filter("CACHE",
2417 * CACHE_SAVE must go into the filter chain after a possible DEFLATE
2418 * filter to ensure that the compressed content is stored.
2419 * Incrementing filter type by 1 ensures this happens.
2421 cache_save_filter_handle =
2422 ap_register_output_filter("CACHE_SAVE",
2425 AP_FTYPE_CONTENT_SET+1);
2427 * CACHE_SAVE_SUBREQ must go into the filter chain before SUBREQ_CORE to
2428 * handle subrequsts. Decrementing filter type by 1 ensures this
2431 cache_save_subreq_filter_handle =
2432 ap_register_output_filter("CACHE_SAVE_SUBREQ",
2435 AP_FTYPE_CONTENT_SET-1);
2437 * CACHE_OUT must go into the filter chain after a possible DEFLATE
2438 * filter to ensure that already compressed cache objects do not
2439 * get compressed again. Incrementing filter type by 1 ensures
2442 cache_out_filter_handle =
2443 ap_register_output_filter("CACHE_OUT",
2446 AP_FTYPE_CONTENT_SET+1);
2448 * CACHE_OUT_SUBREQ must go into the filter chain before SUBREQ_CORE to
2449 * handle subrequsts. Decrementing filter type by 1 ensures this
2452 cache_out_subreq_filter_handle =
2453 ap_register_output_filter("CACHE_OUT_SUBREQ",
2456 AP_FTYPE_CONTENT_SET-1);
2457 /* CACHE_REMOVE_URL has to be a protocol filter to ensure that is
2458 * run even if the response is a canned error message, which
2459 * removes the content filters.
2461 cache_remove_url_filter_handle =
2462 ap_register_output_filter("CACHE_REMOVE_URL",
2463 cache_remove_url_filter,
2466 ap_hook_post_config(cache_post_config, NULL, NULL, APR_HOOK_REALLY_FIRST);
2469 AP_DECLARE_MODULE(cache) =
2471 STANDARD20_MODULE_STUFF,
2472 create_dir_config, /* create per-directory config structure */
2473 merge_dir_config, /* merge per-directory config structures */
2474 create_cache_config, /* create per-server config structure */
2475 merge_cache_config, /* merge per-server config structures */
2476 cache_cmds, /* command apr_table_t */
2481 APR_HOOK_LINK(cache_status)
2484 APR_IMPLEMENT_EXTERNAL_HOOK_RUN_ALL(cache, CACHE, int, cache_status,
2485 (cache_handle_t *h, request_rec *r,
2486 apr_table_t *headers, ap_cache_status_e status,
2487 const char *reason), (h, r, headers, status, reason),