cache_provider_list *providers;
cache_request_rec *cache;
apr_bucket_brigade *out;
+ apr_bucket *e;
ap_filter_t *next;
ap_filter_rec_t *cache_out_handle;
cache_server_conf *conf;
r->server,
"Adding CACHE_SAVE_SUBREQ filter for %s",
r->uri);
- ap_add_output_filter_handle(cache_save_subreq_filter_handle,
- cache, r, r->connection);
+ cache->save_filter = ap_add_output_filter_handle(
+ cache_save_subreq_filter_handle, cache, r,
+ r->connection);
}
else {
ap_log_error(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS,
r->server, "Adding CACHE_SAVE filter for %s",
r->uri);
- ap_add_output_filter_handle(cache_save_filter_handle,
- cache, r, r->connection);
+ cache->save_filter = ap_add_output_filter_handle(
+ cache_save_filter_handle, cache, r,
+ r->connection);
}
+ apr_pool_userdata_setn(cache, CACHE_CTX_KEY, NULL, r->pool);
+
ap_log_error(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r->server,
"Adding CACHE_REMOVE_URL filter for %s",
r->uri);
}
/* we've got a cache hit! tell everyone who cares */
- cache_run_cache_status(cache->handle, r, AP_CACHE_HIT, "cache hit");
+ cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_HIT,
+ "cache hit");
/* if we are a lookup, we are exiting soon one way or another; Restore
* the headers. */
/* kick off the filter stack */
out = apr_brigade_create(r->pool, r->connection->bucket_alloc);
+ e = apr_bucket_eos_create(out->bucket_alloc);
+ APR_BRIGADE_INSERT_TAIL(out, e);
rv = ap_pass_brigade(r->output_filters, out);
if (rv != APR_SUCCESS) {
if (rv != AP_FILTER_ERROR) {
return 0;
}
+/**
+ * Find the given filter, and return it if found, or NULL otherwise.
+ */
+static ap_filter_t *cache_get_filter(ap_filter_t *next, ap_filter_rec_t *rec) {
+ while (next) {
+ if (next->frec == rec && next->ctx) {
+ break;
+ }
+ next = next->next;
+ }
+ return next;
+}
+
/**
* The cache handler is functionally similar to the cache_quick_hander,
* however a number of steps that are required by the quick handler are
cache_provider_list *providers;
cache_request_rec *cache;
apr_bucket_brigade *out;
+ apr_bucket *e;
ap_filter_t *next;
ap_filter_rec_t *cache_out_handle;
ap_filter_rec_t *cache_save_handle;
r->uri);
cache_save_handle = cache_save_filter_handle;
}
- ap_add_output_filter_handle(cache_save_handle,
- cache, r, r->connection);
+ ap_add_output_filter_handle(cache_save_handle, cache, r,
+ r->connection);
/*
* Did the user indicate the precise location of the
"filter for %s", r->uri);
}
+ /* save away the save filter stack */
+ cache->save_filter = cache_get_filter(r->output_filters,
+ cache_save_filter_handle);
+
+ apr_pool_userdata_setn(cache, CACHE_CTX_KEY, NULL, r->pool);
+
ap_log_error(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r->server,
"Adding CACHE_REMOVE_URL filter for %s",
r->uri);
}
/* we've got a cache hit! tell everyone who cares */
- cache_run_cache_status(cache->handle, r, AP_CACHE_HIT, "cache hit");
+ cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_HIT,
+ "cache hit");
rv = ap_meets_conditions(r);
if (rv != OK) {
/* kick off the filter stack */
out = apr_brigade_create(r->pool, r->connection->bucket_alloc);
+ e = apr_bucket_eos_create(out->bucket_alloc);
+ APR_BRIGADE_INSERT_TAIL(out, e);
rv = ap_pass_brigade(r->output_filters, out);
if (rv != APR_SUCCESS) {
if (rv != AP_FILTER_ERROR) {
static int cache_out_filter(ap_filter_t *f, apr_bucket_brigade *bb)
{
request_rec *r = f->r;
+ apr_bucket *e;
cache_request_rec *cache = (cache_request_rec *)f->ctx;
if (!cache) {
ap_log_error(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r->server,
"cache: running CACHE_OUT filter");
- /* restore status of cached response */
- /* XXX: This exposes a bug in mem_cache, since it does not
- * restore the status into it's handle. */
- r->status = cache->handle->cache_obj->info.status;
+ /* clean out any previous response up to EOS, if any */
+ for (e = APR_BRIGADE_FIRST(bb);
+ e != APR_BRIGADE_SENTINEL(bb);
+ e = APR_BUCKET_NEXT(e))
+ {
+ if (APR_BUCKET_IS_EOS(e)) {
- /* recall_headers() was called in cache_select() */
- cache->provider->recall_body(cache->handle, r->pool, bb);
+ /* restore status of cached response */
+ r->status = cache->handle->cache_obj->info.status;
- /* This filter is done once it has served up its content */
- ap_remove_output_filter(f);
+ /* recall_headers() was called in cache_select() */
+ cache->provider->recall_body(cache->handle, r->pool, bb);
- ap_log_error(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r->server,
- "cache: serving %s", r->uri);
- return ap_pass_brigade(f->next, bb);
+ /* This filter is done once it has served up its content */
+ ap_remove_output_filter(f);
+
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r->server,
+ "cache: serving %s", r->uri);
+ return ap_pass_brigade(f->next, bb);
+
+ }
+ apr_bucket_delete(e);
+ }
+
+ return APR_SUCCESS;
}
/*
}
else {
cache->provider->recall_body(cache->handle, r->pool, bb);
+
+ bkt = apr_bucket_eos_create(bb->bucket_alloc);
+ APR_BRIGADE_INSERT_TAIL(bb, bkt);
}
cache->block_response = 1;
cache_run_cache_status(
cache->handle,
r,
+ r->headers_out,
AP_CACHE_REVALIDATE,
apr_psprintf(
r->pool,
reason);
/* we've got a cache miss! tell anyone who cares */
- cache_run_cache_status(cache->handle, r, AP_CACHE_MISS, reason);
+ cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
+ reason);
/* remove this filter from the chain */
ap_remove_output_filter(f);
if (rv != OK) {
/* we've got a cache miss! tell anyone who cares */
- cache_run_cache_status(cache->handle, r, AP_CACHE_MISS,
+ cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
"cache miss: create_entity failed");
/* Caching layer declined the opportunity to cache the response */
}
else {
cache->provider->recall_body(cache->handle, r->pool, bb);
+
+ bkt = apr_bucket_eos_create(bb->bucket_alloc);
+ APR_BRIGADE_INSERT_TAIL(bb, bkt);
}
cache->block_response = 1;
}
/* we've got a cache conditional hit! tell anyone who cares */
- cache_run_cache_status(cache->handle, r, AP_CACHE_REVALIDATE,
+ cache_run_cache_status(cache->handle, r, r->headers_out,
+ AP_CACHE_REVALIDATE,
"conditional cache hit: entity refresh failed");
}
else {
/* we've got a cache conditional hit! tell anyone who cares */
- cache_run_cache_status(cache->handle, r, AP_CACHE_REVALIDATE,
+ cache_run_cache_status(cache->handle, r, r->headers_out,
+ AP_CACHE_REVALIDATE,
"conditional cache hit: entity refreshed");
}
"cache: store_headers failed");
/* we've got a cache miss! tell anyone who cares */
- cache_run_cache_status(cache->handle, r, AP_CACHE_MISS,
+ cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
"cache miss: store_headers failed");
ap_remove_output_filter(f);
}
/* we've got a cache miss! tell anyone who cares */
- cache_run_cache_status(cache->handle, r, AP_CACHE_MISS,
+ cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
"cache miss: attempting entity save");
return cache_save_store(f, in, conf, cache);
* service developers who may need to know whether their Cache-Control headers
* are working correctly.
*/
-static int cache_status(cache_handle_t *h, request_rec *r, ap_cache_status_e status,
- const char *reason)
+static int cache_status(cache_handle_t *h, request_rec *r,
+ apr_table_t *headers, ap_cache_status_e status, const char *reason)
{
cache_server_conf
*conf =
x_cache = conf->x_cache;
}
if (x_cache) {
- apr_table_setn(r->headers_out, "X-Cache", apr_psprintf(r->pool, "%s from %s",
- status == AP_CACHE_HIT ? "HIT" : status == AP_CACHE_REVALIDATE ?
- "REVALIDATE" : "MISS", r->server->server_hostname));
+ apr_table_setn(headers, "X-Cache",
+ apr_psprintf(r->pool, "%s from %s",
+ status == AP_CACHE_HIT ? "HIT" : status
+ == AP_CACHE_REVALIDATE ? "REVALIDATE" : "MISS",
+ r->server->server_hostname));
}
if (dconf && dconf->x_cache_detail_set) {
x_cache_detail = conf->x_cache_detail;
}
if (x_cache_detail) {
- apr_table_setn(r->headers_out, "X-Cache-Detail", apr_psprintf(r->pool,
+ apr_table_setn(headers, "X-Cache-Detail", apr_psprintf(r->pool,
"\"%s\" from %s", reason, r->server->server_hostname));
}
return OK;
}
+/**
+ * If an error has occurred, but we have a stale cached entry, restore the
+ * filter stack from the save filter onwards. The canned error message will
+ * be discarded in the process, and replaced with the cached response.
+ */
+static void cache_insert_error_filter(request_rec *r)
+{
+ void *dummy;
+ cache_dir_conf *dconf;
+
+ /* ignore everything except for 5xx errors */
+ if (r->status < HTTP_INTERNAL_SERVER_ERROR) {
+ return;
+ }
+
+ dconf = ap_get_module_config(r->per_dir_config, &cache_module);
+
+ if (!dconf->stale_on_error) {
+ return;
+ }
+
+ /* RFC2616 13.8 Errors or Incomplete Response Cache Behavior:
+ * If a cache receives a 5xx response while attempting to revalidate an
+ * entry, it MAY either forward this response to the requesting client,
+ * or act as if the server failed to respond. In the latter case, it MAY
+ * return a previously received response unless the cached entry
+ * includes the "must-revalidate" cache-control directive (see section
+ * 14.9).
+ */
+ apr_pool_userdata_get(&dummy, CACHE_CTX_KEY, r->pool);
+ if (dummy) {
+ cache_request_rec *cache = (cache_request_rec *) dummy;
+
+ if (cache->stale_handle && cache->save_filter && !ap_cache_liststr(
+ NULL, apr_table_get(cache->stale_handle->resp_hdrs,
+ "Cache-Control"), "must-revalidate", NULL)) {
+ const char *warn_head;
+
+ /* morph the current save filter into the out filter, and serve from
+ * cache.
+ */
+ cache->handle = cache->stale_handle;
+ if (r->main) {
+ cache->save_filter->frec = cache_out_subreq_filter_handle;
+ }
+ else {
+ cache->save_filter->frec = cache_out_filter_handle;
+ }
+
+ r->output_filters = cache->save_filter;
+
+ r->err_headers_out = cache->stale_handle->resp_hdrs;
+
+ /* add a stale warning */
+ warn_head = apr_table_get(r->err_headers_out, "Warning");
+ if ((warn_head == NULL) || ((warn_head != NULL)
+ && (ap_strstr_c(warn_head, "110") == NULL))) {
+ apr_table_mergen(r->err_headers_out, "Warning",
+ "110 Response is stale");
+ }
+
+ ap_remove_output_filter(cache->remove_url_filter);
+
+ cache_run_cache_status(
+ cache->handle,
+ r,
+ r->err_headers_out,
+ AP_CACHE_HIT,
+ apr_psprintf(
+ r->pool,
+ "cache hit: %d status; stale content returned",
+ r->status));
+
+ }
+ }
+
+ return;
+}
+
/* -------------------------------------------------------------- */
/* Setup configurable data */
dconf->x_cache = DEFAULT_X_CACHE;
dconf->x_cache_detail = DEFAULT_X_CACHE_DETAIL;
+ dconf->stale_on_error = DEFAULT_CACHE_STALE_ON_ERROR;
+
return dconf;
}
new->x_cache_detail_set = add->x_cache_detail_set
|| base->x_cache_detail_set;
+ new->stale_on_error = (add->stale_on_error_set == 0) ? base->stale_on_error
+ : add->stale_on_error;
+ new->stale_on_error_set = add->stale_on_error_set
+ || base->stale_on_error_set;
+
return new;
}
return NULL;
}
+static const char *set_cache_stale_on_error(cmd_parms *parms, void *dummy,
+ int flag)
+{
+ cache_dir_conf *dconf = (cache_dir_conf *)dummy;
+
+ dconf->stale_on_error = flag;
+ dconf->stale_on_error_set = 1;
+ return NULL;
+}
+
static int cache_post_config(apr_pool_t *p, apr_pool_t *plog,
apr_pool_t *ptemp, server_rec *s)
{
"Add a X-Cache-Detail header to responses. Default is off."),
AP_INIT_TAKE1("CacheKeyBaseURL", set_cache_key_base_url, NULL, RSRC_CONF,
"Override the base URL of reverse proxied cache keys."),
+ AP_INIT_FLAG("CacheStaleOnError", set_cache_stale_on_error,
+ NULL, RSRC_CONF|ACCESS_CONF,
+ "Serve stale content on 5xx errors if present. Defaults to on."),
{NULL}
};
ap_hook_handler(cache_handler, NULL, NULL, APR_HOOK_REALLY_FIRST);
/* cache status */
cache_hook_cache_status(cache_status, NULL, NULL, APR_HOOK_MIDDLE);
+ /* cache error handler */
+ ap_hook_insert_error_filter(cache_insert_error_filter, NULL, NULL, APR_HOOK_MIDDLE);
/* cache filters
* XXX The cache filters need to run right after the handlers and before
* any other filters. Consider creating AP_FTYPE_CACHE for this purpose.
)
APR_IMPLEMENT_EXTERNAL_HOOK_RUN_ALL(cache, CACHE, int, cache_status,
- (cache_handle_t *h, request_rec *r,
- ap_cache_status_e status,
- const char *reason), (h, r, status, reason),
- OK, DECLINED)
+ (cache_handle_t *h, request_rec *r,
+ apr_table_t *headers, ap_cache_status_e status,
+ const char *reason), (h, r, headers, status, reason),
+ OK, DECLINED)
projects / thirdparty / apache / httpd.git / commitdiff
