Adding upstream version 2.4.57.upstream/2.4.57

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 790 insertions, 0 deletions

diff --git a/modules/cache/cache_storage.c b/modules/cache/cache_storage.c
new file mode 100644
index 0000000..dfda34b
--- /dev/null
+++ b/modules/cache/cache_storage.c
@@ -0,0 +1,790 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "mod_cache.h"
+
+#include "cache_storage.h"
+#include "cache_util.h"
+
+APLOG_USE_MODULE(cache);
+
+extern APR_OPTIONAL_FN_TYPE(ap_cache_generate_key) *cache_generate_key;
+
+extern module AP_MODULE_DECLARE_DATA cache_module;
+
+/* -------------------------------------------------------------- */
+
+/*
+ * delete all URL entities from the cache
+ *
+ */
+int cache_remove_url(cache_request_rec *cache, request_rec *r)
+{
+    cache_provider_list *list;
+    cache_handle_t *h;
+
+    list = cache->providers;
+
+    /* Remove the stale cache entry if present. If not, we're
+     * being called from outside of a request; remove the
+     * non-stale handle.
+     */
+    h = cache->stale_handle ? cache->stale_handle : cache->handle;
+    if (!h) {
+       return OK;
+    }
+    ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00691)
+                 "cache: Removing url %s from the cache", h->cache_obj->key);
+
+    /* for each specified cache type, delete the URL */
+    while (list) {
+        list->provider->remove_url(h, r);
+        list = list->next;
+    }
+    return OK;
+}
+
+
+/*
+ * create a new URL entity in the cache
+ *
+ * It is possible to store more than once entity per URL. This
+ * function will always create a new entity, regardless of whether
+ * other entities already exist for the same URL.
+ *
+ * The size of the entity is provided so that a cache module can
+ * decide whether or not it wants to cache this particular entity.
+ * If the size is unknown, a size of -1 should be set.
+ */
+int cache_create_entity(cache_request_rec *cache, request_rec *r,
+                        apr_off_t size, apr_bucket_brigade *in)
+{
+    cache_provider_list *list;
+    cache_handle_t *h = apr_pcalloc(r->pool, sizeof(cache_handle_t));
+    apr_status_t rv;
+
+    if (!cache) {
+        /* This should never happen */
+        ap_log_rerror(APLOG_MARK, APLOG_ERR, APR_EGENERAL, r, APLOGNO(00692)
+                "cache: No cache request information available for key"
+                " generation");
+        return APR_EGENERAL;
+    }
+
+    if (!cache->key) {
+        rv = cache_generate_key(r, r->pool, &cache->key);
+        if (rv != APR_SUCCESS) {
+            return rv;
+        }
+    }
+
+    list = cache->providers;
+    /* for each specified cache type, delete the URL */
+    while (list) {
+        switch (rv = list->provider->create_entity(h, r, cache->key, size, in)) {
+        case OK: {
+            cache->handle = h;
+            cache->provider = list->provider;
+            cache->provider_name = list->provider_name;
+            return OK;
+        }
+        case DECLINED: {
+            list = list->next;
+            continue;
+        }
+        default: {
+            return rv;
+        }
+        }
+    }
+    return DECLINED;
+}
+
+static int filter_header_do(void *v, const char *key, const char *val)
+{
+    if ((*key == 'W' || *key == 'w') && !ap_cstr_casecmp(key, "Warning")
+            && *val == '1') {
+        /* any stored Warning headers with warn-code 1xx (see section
+         * 14.46) MUST be deleted from the cache entry and the forwarded
+         * response.
+         */
+    }
+    else {
+        apr_table_addn(v, key, val);
+    }
+    return 1;
+}
+static int remove_header_do(void *v, const char *key, const char *val)
+{
+    if ((*key == 'W' || *key == 'w') && !ap_cstr_casecmp(key, "Warning")) {
+        /* any stored Warning headers with warn-code 2xx MUST be retained
+         * in the cache entry and the forwarded response.
+         */
+    }
+    else {
+        apr_table_unset(v, key);
+    }
+    return 1;
+}
+static int add_header_do(void *v, const char *key, const char *val)
+{
+    apr_table_addn(v, key, val);
+    return 1;
+}
+
+/**
+ * Take two sets of headers, sandwich them together, and apply the result to
+ * r->headers_out.
+ *
+ * To complicate this, a header may be duplicated in either table. Should a
+ * header exist in the top table, all matching headers will be removed from
+ * the bottom table before the headers are combined. The Warning headers are
+ * handled specially. Warnings are added rather than being replaced, while
+ * in the case of revalidation 1xx Warnings are stripped.
+ *
+ * The Content-Type and Last-Modified headers are then re-parsed and inserted
+ * into the request.
+ */
+void cache_accept_headers(cache_handle_t *h, request_rec *r, apr_table_t *top,
+        apr_table_t *bottom, int revalidation)
+{
+    const char *v;
+
+    if (revalidation) {
+        r->headers_out = apr_table_make(r->pool, 10);
+        apr_table_do(filter_header_do, r->headers_out, bottom, NULL);
+    }
+    else if (r->headers_out != bottom) {
+        r->headers_out = apr_table_copy(r->pool, bottom);
+    }
+    apr_table_do(remove_header_do, r->headers_out, top, NULL);
+    apr_table_do(add_header_do, r->headers_out, top, NULL);
+
+    v = apr_table_get(r->headers_out, "Content-Type");
+    if (v) {
+        ap_set_content_type(r, v);
+        /*
+         * Also unset possible Content-Type headers in r->headers_out and
+         * r->err_headers_out as they may be different to what we have received
+         * from the cache.
+         * Actually they are not needed as r->content_type set by
+         * ap_set_content_type above will be used in the store_headers functions
+         * of the storage providers as a fallback and the HTTP_HEADER filter
+         * does overwrite the Content-Type header with r->content_type anyway.
+         */
+        apr_table_unset(r->headers_out, "Content-Type");
+        apr_table_unset(r->err_headers_out, "Content-Type");
+    }
+
+    /* If the cache gave us a Last-Modified header, we can't just
+     * pass it on blindly because of restrictions on future values.
+     */
+    v = apr_table_get(r->headers_out, "Last-Modified");
+    if (v) {
+        ap_update_mtime(r, apr_date_parse_http(v));
+        ap_set_last_modified(r);
+    }
+
+}
+
+/*
+ * select a specific URL entity in the cache
+ *
+ * It is possible to store more than one entity per URL. Content
+ * negotiation is used to select an entity. Once an entity is
+ * selected, details of it are stored in the per request
+ * config to save time when serving the request later.
+ *
+ * This function returns OK if successful, DECLINED if no
+ * cached entity fits the bill.
+ */
+int cache_select(cache_request_rec *cache, request_rec *r)
+{
+    cache_provider_list *list;
+    apr_status_t rv;
+    cache_handle_t *h;
+
+    if (!cache) {
+        /* This should never happen */
+        ap_log_rerror(APLOG_MARK, APLOG_ERR, APR_EGENERAL, r, APLOGNO(00693)
+                "cache: No cache request information available for key"
+                " generation");
+        return DECLINED;
+    }
+
+    /* if no-cache, we can't serve from the cache, but we may store to the
+     * cache.
+     */
+    if (!ap_cache_check_no_cache(cache, r)) {
+        return DECLINED;
+    }
+
+    if (!cache->key) {
+        rv = cache_generate_key(r, r->pool, &cache->key);
+        if (rv != APR_SUCCESS) {
+            return DECLINED;
+        }
+    }
+
+    /* go through the cache types till we get a match */
+    h = apr_palloc(r->pool, sizeof(cache_handle_t));
+
+    list = cache->providers;
+
+    while (list) {
+        switch ((rv = list->provider->open_entity(h, r, cache->key))) {
+        case OK: {
+            char *vary = NULL;
+            int mismatch = 0;
+            char *last = NULL;
+
+            if (list->provider->recall_headers(h, r) != APR_SUCCESS) {
+                /* try again with next cache type */
+                list = list->next;
+                continue;
+            }
+
+            /*
+             * Check Content-Negotiation - Vary
+             *
+             * At this point we need to make sure that the object we found in
+             * the cache is the same object that would be delivered to the
+             * client, when the effects of content negotiation are taken into
+             * effect.
+             *
+             * In plain english, we want to make sure that a language-negotiated
+             * document in one language is not given to a client asking for a
+             * language negotiated document in a different language by mistake.
+             *
+             * This code makes the assumption that the storage manager will
+             * cache the req_hdrs if the response contains a Vary header.
+             *
+             * RFC2616 13.6 and 14.44 describe the Vary mechanism.
+             */
+            vary = cache_strqtok(
+                    apr_pstrdup(r->pool,
+                            cache_table_getm(r->pool, h->resp_hdrs, "Vary")),
+                    CACHE_SEPARATOR, &last);
+            while (vary) {
+                const char *h1, *h2;
+
+                /*
+                 * is this header in the request and the header in the cached
+                 * request identical? If not, we give up and do a straight get
+                 */
+                h1 = cache_table_getm(r->pool, r->headers_in, vary);
+                h2 = cache_table_getm(r->pool, h->req_hdrs, vary);
+                if (h1 == h2) {
+                    /* both headers NULL, so a match - do nothing */
+                }
+                else if (h1 && h2 && !strcmp(h1, h2)) {
+                    /* both headers exist and are equal - do nothing */
+                }
+                else {
+                    /* headers do not match, so Vary failed */
+                    ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS,
+                            r, APLOGNO(00694) "cache_select(): Vary header mismatch.");
+                    mismatch = 1;
+                    break;
+                }
+                vary = cache_strqtok(NULL, CACHE_SEPARATOR, &last);
+            }
+
+            /* no vary match, try next provider */
+            if (mismatch) {
+                /* try again with next cache type */
+                list = list->next;
+                continue;
+            }
+
+            cache->provider = list->provider;
+            cache->provider_name = list->provider_name;
+
+            /*
+             * RFC2616 13.3.4 Rules for When to Use Entity Tags and Last-Modified
+             * Dates: An HTTP/1.1 caching proxy, upon receiving a conditional request
+             * that includes both a Last-Modified date and one or more entity tags as
+             * cache validators, MUST NOT return a locally cached response to the
+             * client unless that cached response is consistent with all of the
+             * conditional header fields in the request.
+             */
+            if (ap_condition_if_match(r, h->resp_hdrs) == AP_CONDITION_NOMATCH
+                    || ap_condition_if_unmodified_since(r, h->resp_hdrs)
+                            == AP_CONDITION_NOMATCH
+                    || ap_condition_if_none_match(r, h->resp_hdrs)
+                            == AP_CONDITION_NOMATCH
+                    || ap_condition_if_modified_since(r, h->resp_hdrs)
+                            == AP_CONDITION_NOMATCH
+                    || ap_condition_if_range(r, h->resp_hdrs) == AP_CONDITION_NOMATCH) {
+                mismatch = 1;
+            }
+
+            /* Is our cached response fresh enough? */
+            if (mismatch || !cache_check_freshness(h, cache, r)) {
+                const char *etag, *lastmod;
+
+                /* Cache-Control: only-if-cached and revalidation required, try
+                 * the next provider
+                 */
+                if (cache->control_in.only_if_cached) {
+                    /* try again with next cache type */
+                    list = list->next;
+                    continue;
+                }
+
+                /* set aside the stale entry for accessing later */
+                cache->stale_headers = apr_table_copy(r->pool,
+                        r->headers_in);
+                cache->stale_handle = h;
+
+                /* if no existing conditionals, use conditionals of our own */
+                if (!mismatch) {
+
+                    ap_log_rerror(
+                            APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(00695) "Cached response for %s isn't fresh. Adding "
+                            "conditional request headers.", r->uri);
+
+                    /* Remove existing conditionals that might conflict with ours */
+                    apr_table_unset(r->headers_in, "If-Match");
+                    apr_table_unset(r->headers_in, "If-Modified-Since");
+                    apr_table_unset(r->headers_in, "If-None-Match");
+                    apr_table_unset(r->headers_in, "If-Range");
+                    apr_table_unset(r->headers_in, "If-Unmodified-Since");
+
+                    etag = apr_table_get(h->resp_hdrs, "ETag");
+                    lastmod = apr_table_get(h->resp_hdrs, "Last-Modified");
+
+                    if (etag || lastmod) {
+                        /* If we have a cached etag and/or Last-Modified add in
+                         * our own conditionals.
+                         */
+
+                        if (etag) {
+                            apr_table_set(r->headers_in, "If-None-Match", etag);
+                        }
+
+                        if (lastmod) {
+                            apr_table_set(r->headers_in, "If-Modified-Since",
+                                    lastmod);
+                        }
+
+                        /*
+                         * Do not do Range requests with our own conditionals: If
+                         * we get 304 the Range does not matter and otherwise the
+                         * entity changed and we want to have the complete entity
+                         */
+                        apr_table_unset(r->headers_in, "Range");
+
+                    }
+
+                }
+
+                /* ready to revalidate, pretend we were never here */
+                return DECLINED;
+            }
+
+            /* Okay, this response looks okay.  Merge in our stuff and go. */
+            cache_accept_headers(h, r, h->resp_hdrs, r->headers_out, 0);
+
+            cache->handle = h;
+            return OK;
+        }
+        case DECLINED: {
+            /* try again with next cache type */
+            list = list->next;
+            continue;
+        }
+        default: {
+            /* oo-er! an error */
+            return rv;
+        }
+        }
+    }
+
+    /* if Cache-Control: only-if-cached, and not cached, return 504 */
+    if (cache->control_in.only_if_cached) {
+        ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(00696)
+                "cache: 'only-if-cached' requested and no cached entity, "
+                "returning 504 Gateway Timeout for: %s", r->uri);
+        return HTTP_GATEWAY_TIME_OUT;
+    }
+
+    return DECLINED;
+}
+
+static apr_status_t cache_canonicalise_key(request_rec *r, apr_pool_t* p,
+                                           const char *path, const char *query,
+                                           apr_uri_t *parsed_uri,
+                                           const char **key)
+{
+    cache_server_conf *conf;
+    char *port_str, *hn, *lcs;
+    const char *hostname, *scheme;
+    int i;
+    const char *kpath;
+    const char *kquery;
+
+    if (*key) {
+        /*
+         * We have been here before during the processing of this request.
+         */
+        return APR_SUCCESS;
+    }
+
+    /*
+     * Get the module configuration. We need this for the CacheIgnoreQueryString
+     * option below.
+     */
+    conf = (cache_server_conf *) ap_get_module_config(r->server->module_config,
+            &cache_module);
+
+    /*
+     * Use the canonical name to improve cache hit rate, but only if this is
+     * not a proxy request or if this is a reverse proxy request.
+     * We need to handle both cases in the same manner as for the reverse proxy
+     * case we have the following situation:
+     *
+     * If a cached entry is looked up by mod_cache's quick handler r->proxyreq
+     * is still unset in the reverse proxy case as it only gets set in the
+     * translate name hook (either by ProxyPass or mod_rewrite) which is run
+     * after the quick handler hook. This is different to the forward proxy
+     * case where it gets set before the quick handler is run (in the
+     * post_read_request hook).
+     * If a cache entry is created by the CACHE_SAVE filter we always have
+     * r->proxyreq set correctly.
+     * So we must ensure that in the reverse proxy case we use the same code
+     * path and using the canonical name seems to be the right thing to do
+     * in the reverse proxy case.
+     */
+    if (!r->proxyreq || (r->proxyreq == PROXYREQ_REVERSE)) {
+        if (conf->base_uri && conf->base_uri->hostname) {
+            hostname = conf->base_uri->hostname;
+        }
+        else {
+            /* Use _default_ as the hostname if none present, as in mod_vhost */
+            hostname = ap_get_server_name(r);
+            if (!hostname) {
+                hostname = "_default_";
+            }
+        }
+    }
+    else if (parsed_uri->hostname) {
+        /* Copy the parsed uri hostname */
+        hn = apr_pstrdup(p, parsed_uri->hostname);
+        ap_str_tolower(hn);
+        /* const work-around */
+        hostname = hn;
+    }
+    else {
+        /* We are a proxied request, with no hostname. Unlikely
+         * to get very far - but just in case */
+        hostname = "_default_";
+    }
+
+    /*
+     * Copy the scheme, ensuring that it is lower case. If the parsed uri
+     * contains no string or if this is not a proxy request get the http
+     * scheme for this request. As r->parsed_uri.scheme is not set if this
+     * is a reverse proxy request, it is ensured that the cases
+     * "no proxy request" and "reverse proxy request" are handled in the same
+     * manner (see above why this is needed).
+     */
+    if (r->proxyreq && parsed_uri->scheme) {
+        /* Copy the scheme and lower-case it */
+        lcs = apr_pstrdup(p, parsed_uri->scheme);
+        ap_str_tolower(lcs);
+        /* const work-around */
+        scheme = lcs;
+    }
+    else {
+        if (conf->base_uri && conf->base_uri->scheme) {
+            scheme = conf->base_uri->scheme;
+        }
+        else {
+            scheme = ap_http_scheme(r);
+        }
+    }
+
+    /*
+     * If this is a proxy request, but not a reverse proxy request (see comment
+     * above why these cases must be handled in the same manner), copy the
+     * URI's port-string (which may be a service name). If the URI contains
+     * no port-string, use apr-util's notion of the default port for that
+     * scheme - if available. Otherwise use the port-number of the current
+     * server.
+     */
+    if (r->proxyreq && (r->proxyreq != PROXYREQ_REVERSE)) {
+        if (parsed_uri->port_str) {
+            port_str = apr_pcalloc(p, strlen(parsed_uri->port_str) + 2);
+            port_str[0] = ':';
+            for (i = 0; parsed_uri->port_str[i]; i++) {
+                port_str[i + 1] = apr_tolower(parsed_uri->port_str[i]);
+            }
+        }
+        else if (apr_uri_port_of_scheme(scheme)) {
+            port_str = apr_psprintf(p, ":%u", apr_uri_port_of_scheme(scheme));
+        }
+        else {
+            /* No port string given in the AbsoluteUri, and we have no
+             * idea what the default port for the scheme is. Leave it
+             * blank and live with the inefficiency of some extra cached
+             * entities.
+             */
+            port_str = "";
+        }
+    }
+    else {
+        if (conf->base_uri && conf->base_uri->port_str) {
+            port_str = apr_pstrcat(p, ":", conf->base_uri->port_str, NULL);
+        }
+        else if (conf->base_uri && conf->base_uri->hostname) {
+            port_str = "";
+        }
+        else {
+            /* Use the server port */
+            port_str = apr_psprintf(p, ":%u", ap_get_server_port(r));
+        }
+    }
+
+    /*
+     * Check if we need to ignore session identifiers in the URL and do so
+     * if needed.
+     */
+    kpath = path;
+    kquery = conf->ignorequerystring ? NULL : query;
+    if (conf->ignore_session_id->nelts) {
+        int i;
+        char **identifier;
+
+        identifier = (char **) conf->ignore_session_id->elts;
+        for (i = 0; i < conf->ignore_session_id->nelts; i++, identifier++) {
+            int len;
+            const char *param;
+
+            len = strlen(*identifier);
+            /*
+             * Check that we have a parameter separator in the last segment
+             * of the path and that the parameter matches our identifier
+             */
+            if ((param = ap_strrchr_c(kpath, ';'))
+                    && !strncmp(param + 1, *identifier, len)
+                    && (*(param + len + 1) == '=')
+                    && !ap_strchr_c(param + len + 2, '/')) {
+                kpath = apr_pstrmemdup(p, kpath, param - kpath);
+                continue;
+            }
+            /*
+             * Check if the identifier is in the query string and cut it out.
+             */
+            if (kquery && *kquery) {
+                /*
+                 * First check if the identifier is at the beginning of the
+                 * query string and followed by a '='
+                 */
+                if (!strncmp(kquery, *identifier, len) && kquery[len] == '=') {
+                    param = kquery;
+                }
+                else {
+                    char *complete;
+
+                    /*
+                     * In order to avoid subkey matching (PR 48401) prepend
+                     * identifier with a '&' and append a '='
+                     */
+                    complete = apr_pstrcat(p, "&", *identifier, "=", NULL);
+                    param = ap_strstr_c(kquery, complete);
+                    /* If we found something we are sitting on the '&' */
+                    if (param) {
+                        param++;
+                    }
+                }
+                if (param) {
+                    const char *amp;
+                    char *dup = NULL;
+
+                    if (kquery != param) {
+                        dup = apr_pstrmemdup(p, kquery, param - kquery);
+                        kquery = dup;
+                    }
+                    else {
+                        kquery = "";
+                    }
+
+                    if ((amp = ap_strchr_c(param + len + 1, '&'))) {
+                        kquery = apr_pstrcat(p, kquery, amp + 1, NULL);
+                    }
+                    else {
+                        /*
+                         * If query string is not "", then we have the case
+                         * that the identifier parameter we removed was the
+                         * last one in the original query string. Hence we have
+                         * a trailing '&' which needs to be removed.
+                         */
+                        if (dup) {
+                            dup[strlen(dup) - 1] = '\0';
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    /* Key format is a URI, optionally without the query-string (NULL
+     * per above if conf->ignorequerystring)
+     */
+    *key = apr_pstrcat(p, scheme, "://", hostname, port_str,
+                       kpath, "?", kquery, NULL);
+
+    /*
+     * Store the key in the request_config for the cache as r->parsed_uri
+     * might have changed in the time from our first visit here triggered by the
+     * quick handler and our possible second visit triggered by the CACHE_SAVE
+     * filter (e.g. r->parsed_uri got unescaped). In this case we would save the
+     * resource in the cache under a key where it is never found by the quick
+     * handler during following requests.
+     */
+    ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(00698)
+                  "cache: Key for entity %s?%s is %s", path, query, *key);
+
+    return APR_SUCCESS;
+}
+
+apr_status_t cache_generate_key_default(request_rec *r, apr_pool_t* p,
+                                        const char **key)
+{
+    /* In early processing (quick-handler, forward proxy), we want the initial
+     * query-string from r->parsed_uri, since any change before CACHE_SAVE
+     * shouldn't modify the key. Otherwise we want the actual query-string.
+     */
+    const char *path = r->uri;
+    const char *query = r->args;
+    if (cache_use_early_url(r)) {
+        path = r->parsed_uri.path;
+        query = r->parsed_uri.query;
+    }
+    return cache_canonicalise_key(r, p, path, query, &r->parsed_uri, key);
+}
+
+/*
+ * Invalidate a specific URL entity in all caches
+ *
+ * All cached entities for this URL are removed, usually in
+ * response to a POST/PUT or DELETE.
+ *
+ * This function returns OK if at least one entity was found and
+ * removed, and DECLINED if no cached entities were removed.
+ */
+int cache_invalidate(cache_request_rec *cache, request_rec *r)
+{
+    cache_provider_list *list;
+    apr_status_t rv, status = DECLINED;
+    cache_handle_t *h;
+    apr_uri_t location_uri;
+    apr_uri_t content_location_uri;
+
+    const char *location, *location_key = NULL;
+    const char *content_location, *content_location_key = NULL;
+
+    if (!cache) {
+        /* This should never happen */
+        ap_log_rerror(
+                APLOG_MARK, APLOG_ERR, APR_EGENERAL, r, APLOGNO(00697) "cache: No cache request information available for key"
+                " generation");
+        return DECLINED;
+    }
+
+    if (!cache->key) {
+        rv = cache_generate_key(r, r->pool, &cache->key);
+        if (rv != APR_SUCCESS) {
+            return DECLINED;
+        }
+    }
+
+    location = apr_table_get(r->headers_out, "Location");
+    if (location) {
+        if (apr_uri_parse(r->pool, location, &location_uri)
+                || cache_canonicalise_key(r, r->pool,
+                                          location_uri.path,
+                                          location_uri.query,
+                                          &location_uri, &location_key)
+                || !(r->parsed_uri.hostname
+                     && location_uri.hostname
+                     && !strcmp(r->parsed_uri.hostname,
+                                location_uri.hostname))) {
+            location_key = NULL;
+        }
+    }
+
+    content_location = apr_table_get(r->headers_out, "Content-Location");
+    if (content_location) {
+        if (apr_uri_parse(r->pool, content_location,
+                          &content_location_uri)
+                || cache_canonicalise_key(r, r->pool,
+                                          content_location_uri.path,
+                                          content_location_uri.query,
+                                          &content_location_uri,
+                                          &content_location_key)
+                || !(r->parsed_uri.hostname
+                     && content_location_uri.hostname
+                     && !strcmp(r->parsed_uri.hostname,
+                                content_location_uri.hostname))) {
+            content_location_key = NULL;
+        }
+    }
+
+    /* go through the cache types */
+    h = apr_palloc(r->pool, sizeof(cache_handle_t));
+
+    list = cache->providers;
+
+    while (list) {
+
+        /* invalidate the request uri */
+        rv = list->provider->open_entity(h, r, cache->key);
+        if (OK == rv) {
+            rv = list->provider->invalidate_entity(h, r);
+            status = OK;
+        }
+        ap_log_rerror(
+                APLOG_MARK, APLOG_DEBUG, rv, r, APLOGNO(02468) "cache: Attempted to invalidate cached entity with key: %s", cache->key);
+
+        /* invalidate the Location */
+        if (location_key) {
+            rv = list->provider->open_entity(h, r, location_key);
+            if (OK == rv) {
+                rv = list->provider->invalidate_entity(h, r);
+                status = OK;
+            }
+            ap_log_rerror(
+                    APLOG_MARK, APLOG_DEBUG, rv, r, APLOGNO(02469) "cache: Attempted to invalidate cached entity with key: %s", location_key);
+        }
+
+        /* invalidate the Content-Location */
+        if (content_location_key) {
+            rv = list->provider->open_entity(h, r, content_location_key);
+            if (OK == rv) {
+                rv = list->provider->invalidate_entity(h, r);
+                status = OK;
+            }
+            ap_log_rerror(
+                    APLOG_MARK, APLOG_DEBUG, rv, r, APLOGNO(02470) "cache: Attempted to invalidate cached entity with key: %s", content_location_key);
+        }
+
+        list = list->next;
+    }
+
+    return status;
+}