Merge r992625 from trunk:

mod_cache: Check the request to determine whether we are allowed
to return cached content at all, and respect a "Cache-Control:
no-cache" header from a client. Previously, "no-cache" would
behave like "max-age=0".

Submitted by: minfrin
Reviewed by: minfrin, jim, covener

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@1053600 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/CHANGES b/CHANGES
index 6c62e20602070b530eec974fe7b35973fd620ebd..ad5d4265fb67bffd79574139473bfa38e2d5922c 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -1,6 +1,11 @@
                                                          -*- coding: utf-8 -*-
 Changes with Apache 2.2.18
 
+  *) mod_cache: Check the request to determine whether we are allowed
+     to return cached content at all, and respect a "Cache-Control:
+     no-cache" header from a client. Previously, "no-cache" would
+     behave like "max-age=0". [Graham Leggett]
+
   *) mod_mem_cache: Add a debug msg when a streaming response exceeds
      MCacheMaxStreamingBuffer, since mod_cache will follow up with a scary
      'memory allocation failed' debug message. PR 49604. [Eric Covener]

diff --git a/STATUS b/STATUS
index fd789dd50a2a9ee398c0a2588eaf8b42d37aa3a0..e3d1d60210cbad8f1bae94949f31d79555979294 100644 (file)
--- a/STATUS
+++ b/STATUS
@@ -89,15 +89,6 @@ RELEASE SHOWSTOPPERS:
 PATCHES ACCEPTED TO BACKPORT FROM TRUNK:
   [ start all new proposals below, under PATCHES PROPOSED. ]
 
-   * mod_cache: Check the request to determine whether we are allowed
-     to return cached content at all, and respect a "Cache-Control:
-     no-cache" header from a client. Previously, "no-cache" would
-     behave like "max-age=0".
-     PR49200
-     Trunk patch: http://svn.apache.org/viewvc?view=revision&revision=992625
-     2.2.x patch: trunk patch works
-     +1: minfrin, jim
-     +1 covener (needs r996311 MMN bump)
 
 PATCHES PROPOSED TO BACKPORT FROM TRUNK:
   [ New proposals should be added at the end of the list ]

diff --git a/include/ap_mmn.h b/include/ap_mmn.h
index ba1ca0bfe6a6b1cc155097e6d8db52e0a697a1c1..3658fb73fa3d4bd4dcbaabe56e8121c98177b9d0 100644 (file)
--- a/include/ap_mmn.h
+++ b/include/ap_mmn.h
@@ -140,6 +140,7 @@
  *                      and conditional cmdtype member of piped_log struct
  * 20051115.24 (2.2.15) Add forward member to proxy_conn_rec
  * 20051115.25 (2.2.17) Add errstatuses member to proxy_balancer
+ * 20051115.26 (2.2.18) Add ap_cache_check_allowed()
  */
 
 #define MODULE_MAGIC_COOKIE 0x41503232UL /* "AP22" */
@@ -147,7 +148,7 @@
 #ifndef MODULE_MAGIC_NUMBER_MAJOR
 #define MODULE_MAGIC_NUMBER_MAJOR 20051115
 #endif
-#define MODULE_MAGIC_NUMBER_MINOR 25                    /* 0...n */
+#define MODULE_MAGIC_NUMBER_MINOR 26                    /* 0...n */
 
 /**
  * Determine if the server's current MODULE_MAGIC_NUMBER is at least a

diff --git a/modules/cache/cache_storage.c b/modules/cache/cache_storage.c
index f87f9c9ddb6bf0a8e1d61ef236892c2f96e63be8..c9d362719d7d93e488663031a5fc31e39664217b 100644 (file)
--- a/modules/cache/cache_storage.c
+++ b/modules/cache/cache_storage.c
@@ -193,6 +193,11 @@ int cache_select(request_rec *r)
     if (rv != APR_SUCCESS) {
         return rv;
     }
+
+    if (!ap_cache_check_allowed(r)) {
+        return DECLINED;
+    }
+
     /* go through the cache types till we get a match */
     h = apr_palloc(r->pool, sizeof(cache_handle_t));
 

diff --git a/modules/cache/cache_util.c b/modules/cache/cache_util.c
index cb3d56537d6427e00adcb6b67c922b3715f59e21..14c1165e0b6addf198bc04161edfe7fd8751d42d 100644 (file)
--- a/modules/cache/cache_util.c
+++ b/modules/cache/cache_util.c
@@ -338,6 +338,64 @@ CACHE_DECLARE(apr_status_t) ap_cache_remove_lock(cache_server_conf *conf,
     return apr_file_remove(lockname, r->pool);
 }
 
+CACHE_DECLARE(int) ap_cache_check_allowed(request_rec *r) {
+    const char *cc_req;
+    const char *pragma;
+    cache_server_conf *conf =
+      (cache_server_conf *)ap_get_module_config(r->server->module_config,
+                                                &cache_module);
+
+    /*
+     * At this point, we may have data cached, but the request may have
+     * specified that cached data may not be used in a response.
+     *
+     * This is covered under RFC2616 section 14.9.4 (Cache Revalidation and
+     * Reload Controls).
+     *
+     * - RFC2616 14.9.4 End to end reload, Cache-Control: no-cache, or Pragma:
+     * no-cache. The server MUST NOT use a cached copy when responding to such
+     * a request.
+     *
+     * - RFC2616 14.9.2 What May be Stored by Caches. If Cache-Control:
+     * no-store arrives, do not serve from the cache.
+     */
+
+    /* This value comes from the client's initial request. */
+    cc_req = apr_table_get(r->headers_in, "Cache-Control");
+    pragma = apr_table_get(r->headers_in, "Pragma");
+
+    if (ap_cache_liststr(NULL, pragma, "no-cache", NULL)
+        || ap_cache_liststr(NULL, cc_req, "no-cache", NULL)) {
+
+        if (!conf->ignorecachecontrol) {
+            return 0;
+        }
+        else {
+            ap_log_error(APLOG_MARK, APLOG_INFO, 0, r->server,
+                         "Incoming request is asking for an uncached version of "
+                         "%s, but we have been configured to ignore it and serve "
+                         "cached content anyway", r->unparsed_uri);
+        }
+    }
+
+    if (ap_cache_liststr(NULL, cc_req, "no-store", NULL)) {
+
+        if (!conf->ignorecachecontrol) {
+            /* We're not allowed to serve a cached copy */
+            return 0;
+        }
+        else {
+            ap_log_error(APLOG_MARK, APLOG_INFO, 0, r->server,
+                         "Incoming request is asking for a no-store version of "
+                         "%s, but we have been configured to ignore it and serve "
+                         "cached content anyway", r->unparsed_uri);
+        }
+    }
+
+    return 1;
+}
+
+
 CACHE_DECLARE(int) ap_cache_check_freshness(cache_handle_t *h,
                                             request_rec *r)
 {
@@ -360,10 +418,11 @@ CACHE_DECLARE(int) ap_cache_check_freshness(cache_handle_t *h,
      * We now want to check if our cached data is still fresh. This depends
      * on a few things, in this order:
      *
-     * - RFC2616 14.9.4 End to end reload, Cache-Control: no-cache. no-cache in
-     * either the request or the cached response means that we must
-     * revalidate the request unconditionally, overriding any expiration
-     * mechanism. It's equivalent to max-age=0,must-revalidate.
+     * - RFC2616 14.9.4 End to end reload, Cache-Control: no-cache. no-cache
+     * in either the request or the cached response means that we must
+     * perform the request unconditionally, and ignore cached content. We
+     * should never reach here, but if we do, mark the content as stale,
+     * as this is the best we can do.
      *
      * - RFC2616 14.32 Pragma: no-cache This is treated the same as
      * Cache-Control: no-cache.
@@ -403,7 +462,8 @@ CACHE_DECLARE(int) ap_cache_check_freshness(cache_handle_t *h,
 
         ap_log_error(APLOG_MARK, APLOG_INFO, 0, r->server,
                      "Incoming request is asking for a uncached version of "
-                     "%s, but we know better and are ignoring it",
+                     "%s, but we have been configured to ignore it and "
+                     "serve a cached response anyway",
                      r->unparsed_uri);
     }
 

diff --git a/modules/cache/mod_cache.h b/modules/cache/mod_cache.h
index eca42c01f066f4965a49758911d2b55f6eff3ddc..e20fa72e9c424013601ad01f8ca2e85ba3135095 100644 (file)
--- a/modules/cache/mod_cache.h
+++ b/modules/cache/mod_cache.h
@@ -270,6 +270,15 @@ CACHE_DECLARE(apr_time_t) ap_cache_current_age(cache_info *info, const apr_time_
  */
 CACHE_DECLARE(int) ap_cache_check_freshness(cache_handle_t *h, request_rec *r);
 
+/**
+ * Check the whether the request allows a cached object to be served as per RFC2616
+ * section 14.9.4 (Cache Revalidation and Reload Controls)
+ * @param h cache_handle_t
+ * @param r request_rec
+ * @return 0 ==> cache object may not be served, 1 ==> cache object may be served
+ */
+CACHE_DECLARE(int) ap_cache_check_allowed(request_rec *r);
+
 /**
  * Try obtain a cache wide lock on the given cache key.
  *