From: Yann Ylavic <ylavic@apache.org>
Date: Wed, 30 Apr 2014 14:43:27 +0000 (+0000)
Subject: mod_cache: Don't add cached/revalidated entity headers to a 304 response.
X-Git-Tag: 2.5.0-alpha~4232
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=75e24df9a8d0fc0286f5d95ee7065a4ac80a321d;p=apache

mod_cache: Don't add cached/revalidated entity headers to a 304 response.
           PR 55547.

When the conditional request meets the conditions of the stale then revalidated
entry, the forwarded 304 response includes the entity headers merged from the
cached headers (before updating the entry).
Strip them before returning a 304.

Since the entity headers are stripped elsewhere, factorize the code using a
new table (MOD_CACHE_ENTITY_HEADERS[]) containing these headers's names.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1591320 13f79535-47bb-0310-9956-ffa450edef68
---

diff --git a/CHANGES b/CHANGES
index 9a1b0c0ce4..0eafe9dc38 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,6 +1,9 @@
                                                          -*- coding: utf-8 -*-
 Changes with Apache 2.5.0
 
+  *) mod_cache: Don't add cached/revalidated entity headers to a 304 response.
+                PR 55547. [Yann Ylavic]
+
   *) mod_cache: Retry unconditional request with the full URL (including the
      query-string) when the origin server's 304 response does not match the
      conditions used to revalidate the stale entry.  [Yann Ylavic].
diff --git a/modules/cache/mod_cache.c b/modules/cache/mod_cache.c
index af8889a892..6908a0a232 100644
--- a/modules/cache/mod_cache.c
+++ b/modules/cache/mod_cache.c
@@ -36,6 +36,22 @@ static ap_filter_rec_t *cache_out_subreq_filter_handle;
 static ap_filter_rec_t *cache_remove_url_filter_handle;
 static ap_filter_rec_t *cache_invalidate_filter_handle;
 
+/**
+ * Entity headers' names
+ */
+static const char *MOD_CACHE_ENTITY_HEADERS[] = {
+    "Allow",
+    "Content-Encoding",
+    "Content-Language",
+    "Content-Length",
+    "Content-Location",
+    "Content-MD5",
+    "Content-Range",
+    "Content-Type",
+    "Last-Modified",
+    NULL
+};
+
 /*
  * CACHE handler
  * -------------
@@ -802,7 +818,7 @@ static apr_status_t cache_save_filter(ap_filter_t *f, apr_bucket_brigade *in)
     apr_time_t exp, date, lastmod, now;
     apr_off_t size = -1;
     cache_info *info = NULL;
-    const char *reason;
+    const char *reason, **eh;
     apr_pool_t *p;
     apr_bucket *e;
     apr_table_t *headers;
@@ -1150,14 +1166,9 @@ static apr_status_t cache_save_filter(ap_filter_t *f, apr_bucket_brigade *in)
      * inconsistencies between cached entity-bodies and updated headers.
      */
     if (r->status == HTTP_NOT_MODIFIED) {
-        apr_table_unset(r->headers_out, "Allow");
-        apr_table_unset(r->headers_out, "Content-Encoding");
-        apr_table_unset(r->headers_out, "Content-Language");
-        apr_table_unset(r->headers_out, "Content-Length");
-        apr_table_unset(r->headers_out, "Content-MD5");
-        apr_table_unset(r->headers_out, "Content-Range");
-        apr_table_unset(r->headers_out, "Content-Type");
-        apr_table_unset(r->headers_out, "Last-Modified");
+        for (eh = MOD_CACHE_ENTITY_HEADERS; *eh; ++eh) {
+            apr_table_unset(r->headers_out, *eh);
+        }
     }
 
     /* Hold the phone. Some servers might allow us to cache a 2xx, but
@@ -1494,6 +1505,13 @@ static apr_status_t cache_save_filter(ap_filter_t *f, apr_bucket_brigade *in)
         if (status != OK) {
             r->status = status;
 
+            /* Strip the entity headers merged from the cached headers before
+             * updating the entry (see cache_accept_headers() above).
+             */
+            for (eh = MOD_CACHE_ENTITY_HEADERS; *eh; ++eh) {
+                apr_table_unset(r->headers_out, *eh);
+            }
+
             bkt = apr_bucket_flush_create(bb->bucket_alloc);
             APR_BRIGADE_INSERT_TAIL(bb, bkt);
         }