Issue #1476810 by Spleshka, David_Rothstein, franz | Heine: Drupal_serve_page_from_cache can serve uncompressed data with Content-Encoding gzip header with page_cache_without_database = 1.

4 files changed, 25 insertions, 2 deletions

diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index 89c12caff..044b56dd1 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -1,6 +1,10 @@
 
 Drupal 7.25, xxxx-xx-xx (development version)
 -----------------------
+- Fixed a bug which caused cached pages to sometimes be sent to the browser
+  with incorrect compression. The fix adds a new 'page_compressed' key to the
+  $cache->data array returned by drupal_page_get_cache() (minor data structure
+  change).
 - Fixed broken tests on PHP 5.5.
 - Made the File and Image modules more robust when saving entities that have
   deleted files attached. The code in file_field_presave() will now remove the
diff --git a/includes/bootstrap.inc b/includes/bootstrap.inc
index 7a4493991..5511d7c5d 100644
--- a/includes/bootstrap.inc
+++ b/includes/bootstrap.inc
@@ -1278,7 +1278,7 @@ function drupal_page_header() {
  */
 function drupal_serve_page_from_cache(stdClass $cache) {
   // Negotiate whether to use compression.
-  $page_compression = variable_get('page_compression', TRUE) && extension_loaded('zlib');
+  $page_compression = !empty($cache->data['page_compressed']);
   $return_compressed = $page_compression && isset($_SERVER['HTTP_ACCEPT_ENCODING']) && strpos($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip') !== FALSE;
 
   // Get headers set in hook_boot(). Keys are lower-case.
diff --git a/includes/common.inc b/includes/common.inc
index 9cd73f4e2..38895c542 100644
--- a/includes/common.inc
+++ b/includes/common.inc
@@ -5176,6 +5176,10 @@ function drupal_page_set_cache() {
   global $base_root;
 
   if (drupal_page_is_cacheable()) {
+
+    // Check whether the current page might be compressed.
+    $page_compressed = variable_get('page_compression', TRUE) && extension_loaded('zlib');
+
     $cache = (object) array(
       'cid' => $base_root . request_uri(),
       'data' => array(
@@ -5183,6 +5187,9 @@ function drupal_page_set_cache() {
         'body' => ob_get_clean(),
         'title' => drupal_get_title(),
         'headers' => array(),
+        // We need to store whether page was compressed or not,
+        // because by the time it is read, the configuration might change.
+        'page_compressed' => $page_compressed,
       ),
       'expire' => CACHE_TEMPORARY,
       'created' => REQUEST_TIME,
@@ -5200,7 +5207,7 @@ function drupal_page_set_cache() {
     }
 
     if ($cache->data['body']) {
-      if (variable_get('page_compression', TRUE) && extension_loaded('zlib')) {
+      if ($page_compressed) {
         $cache->data['body'] = gzencode($cache->data['body'], 9, FORCE_GZIP);
       }
       cache_set($cache->cid, $cache->data, 'cache_page', $cache->expire);
diff --git a/modules/simpletest/tests/bootstrap.test b/modules/simpletest/tests/bootstrap.test
index 87b59608e..4fda15c8c 100644
--- a/modules/simpletest/tests/bootstrap.test
+++ b/modules/simpletest/tests/bootstrap.test
@@ -219,6 +219,18 @@ class BootstrapPageCacheTestCase extends DrupalWebTestCase {
     $this->assertFalse($this->drupalGetHeader('Content-Encoding'), 'A Content-Encoding header was not sent.');
     $this->assertTitle(t('Welcome to @site-name | @site-name', array('@site-name' => variable_get('site_name', 'Drupal'))), 'Site title matches.');
     $this->assertRaw('</html>', 'Page was not compressed.');
+
+    // Disable compression mode.
+    variable_set('page_compression', FALSE);
+
+    // Verify if cached page is still available for a client with compression support.
+    $this->drupalGet('', array(), array('Accept-Encoding: gzip,deflate'));
+    $this->drupalSetContent(gzinflate(substr($this->drupalGetContent(), 10, -8)));
+    $this->assertRaw('</html>', 'Page was delivered after compression mode is changed (compression support enabled).');
+
+    // Verify if cached page is still available for a client without compression support.
+    $this->drupalGet('');
+    $this->assertRaw('</html>', 'Page was delivered after compression mode is changed (compression support disabled).');
   }
 }