? 147310-100.patch
? 147310-94.patch
? 147310-95.patch
? 147310-96.patch
? 147310-97.patch
? cacheable.patch
? sites/all/modules
? sites/default/files
? sites/default/settings.php
Index: includes/bootstrap.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/bootstrap.inc,v
retrieving revision 1.263
diff -u -p -r1.263 bootstrap.inc
--- includes/bootstrap.inc	4 Jan 2009 16:15:54 -0000	1.263
+++ includes/bootstrap.inc	8 Jan 2009 10:31:53 -0000
@@ -720,10 +720,24 @@ function drupal_load($type, $name) {
  * @see page_set_cache()
  */
 function drupal_page_header() {
-  header("Expires: Sun, 19 Nov 1978 05:00:00 GMT");
-  header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
-  header("Cache-Control: store, no-cache, must-revalidate");
-  header("Cache-Control: post-check=0, pre-check=0", FALSE);
+  // Check if module_implements() exists to avoid problems during installation.
+  $send_uncacheable_headers = TRUE;
+  if (!defined('MAINTENANCE_MODE') && count(module_implements('http_expires'))) {
+    // Pass FALSE to hook_http_expires because the page isn't coming from cache.
+    $lifetime = min(module_invoke_all('http_expires', FALSE));
+    if ($lifetime > 0) {
+      $send_uncacheable_headers = FALSE;
+      header("Expires: " . gmdate(DATE_RFC1123, REQUEST_TIME + $lifetime));
+      header('Cache-Control: public, max-age=' . $lifetime);
+    }
+  }
+
+  if ($send_uncacheable_headers) {
+    header("Expires: Sun, 19 Nov 1978 05:00:00 GMT");
+    header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
+    header("Cache-Control: store, no-cache, must-revalidate");
+    header("Cache-Control: post-check=0, pre-check=0", FALSE);
+  }
 }
 
 /**
@@ -756,9 +770,24 @@ function drupal_page_cache_header($cache
   header("Last-Modified: " . gmdate(DATE_RFC1123, $cache->created));
   header("ETag: $etag");
 
-  // The following headers force validation of cache:
-  header("Expires: Sun, 19 Nov 1978 05:00:00 GMT");
-  header("Cache-Control: must-revalidate");
+  // The following allows modules to specify their own cache expiration time.
+  $send_uncacheable_headers = TRUE;
+  if (count(module_implements('http_expires'))) {
+    $lifetime = min(module_invoke_all('http_expires', TRUE));
+    $age = abs(REQUEST_TIME - $cache->created);
+    
+    if ($lifetime - $age > 0) {
+      $send_uncacheable_headers = FALSE;
+      header("Expires: " . gmdate(DATE_RFC1123, $cache->created + $lifetime));
+      header('Cache-Control: public, max-age=' . max(0, $lifetime - $age)); 
+    }
+  }
+
+  if ($send_uncacheable_headers) {
+    // Use the old header which does not get cached.
+    header("Expires: Sun, 19 Nov 1978 05:00:00 GMT");
+    header("Cache-Control: must-revalidate");
+  }
 
   if (variable_get('page_compression', TRUE)) {
     // Determine if the browser accepts gzipped data.
Index: modules/simpletest/tests/bootstrap.test
===================================================================
RCS file: /cvs/drupal/drupal/modules/simpletest/tests/bootstrap.test,v
retrieving revision 1.9
diff -u -p -r1.9 bootstrap.test
--- modules/simpletest/tests/bootstrap.test	3 Dec 2008 14:51:53 -0000	1.9
+++ modules/simpletest/tests/bootstrap.test	8 Jan 2009 10:31:54 -0000
@@ -94,6 +94,10 @@ class BootstrapPageCacheTestCase extends
     );
   }
 
+  function setUp() {
+    parent::setUp('system_test');
+  }
+
   /**
    * Enable cache and examine HTTP headers.
    */
@@ -104,6 +108,13 @@ class BootstrapPageCacheTestCase extends
     $this->drupalGet('');
 
     $this->drupalHead('');
+
+    // Test HTTP Expires header in cached state.
+    $expires_time = strtotime($this->drupalGetHeader('Expires'));
+    // allow 10 seconds for server response.
+    $assertion = $expires_time > $_SERVER['REQUEST_TIME'] + 600 && $expires_time < $_SERVER['REQUEST_TIME'] + 610;
+    $this->assertTrue($assertion, t('Expires header properly sent for 10 minutes in the future.'));
+
     $etag = $this->drupalGetHeader('ETag');
     $this->assertTrue($etag, t('An ETag header was sent, indicating that page was cached.'));
     $last_modified = $this->drupalGetHeader('Last-Modified');
@@ -130,6 +141,12 @@ class BootstrapPageCacheTestCase extends
     $this->drupalGet('', array(), array('If-Modified-Since: ' . $last_modified, 'If-None-Match: ' . $etag));
     $this->assertResponse(200, t('Conditional request returned 200 OK for authenticated user.'));
     $this->assertFalse($this->drupalGetHeader('ETag'), t('An ETag header was not sent, indicating that page was not cached.'));
+
+    // Test HTTP Expires header in uncached state.
+    $expires_time = strtotime($this->drupalGetHeader('Expires'));
+    // allow 10 seconds for server response.
+    $assertion = $expires_time > $_SERVER['REQUEST_TIME'] && $expires_time < $_SERVER['REQUEST_TIME'] + 10;
+    $this->assertTrue($assertion, t('Expires header properly sent for 1 second in the future.'));
   }
 
 }
Index: modules/simpletest/tests/system_test.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/simpletest/tests/system_test.module,v
retrieving revision 1.8
diff -u -p -r1.8 system_test.module
--- modules/simpletest/tests/system_test.module	9 Dec 2008 11:09:26 -0000	1.8
+++ modules/simpletest/tests/system_test.module	8 Jan 2009 10:31:54 -0000
@@ -204,3 +204,15 @@ function system_test_trigger_pdo_excepti
   define('SIMPLETEST_COLLECT_ERRORS', FALSE);
   db_query("SELECT * FROM bananas_are_awesome");
 }
+
+/**
+ * Implementation of hook_http expires to test custom expires times.
+ */
+function system_test_http_expires($page_is_cached) {
+  if ($page_is_cached) {
+    return 600; // 10 minutes.
+  }
+  else {
+    return 1; // 1 second.
+  }
+}
Index: modules/system/system.api.php
===================================================================
RCS file: /cvs/drupal/drupal/modules/system/system.api.php,v
retrieving revision 1.9
diff -u -p -r1.9 system.api.php
--- modules/system/system.api.php	4 Jan 2009 19:56:51 -0000	1.9
+++ modules/system/system.api.php	8 Jan 2009 10:31:55 -0000
@@ -164,6 +164,24 @@ function hook_footer($main = 0) {
   }
 }
 
+/** 
+ * Suggest an expiration time to send to the client as the expires HTTP header.
+ *
+ * Only use this hook if you need your pages to be cacheable by reverse proxies
+ * or CDNs. If multiple modules return a value for this function, the earliest
+ * timestamp is honored. The simplest implementation of this function would
+ * return the number of seconds to cache all pages. More advanced implementations
+ * could return a different value depending on the current page.
+ *
+ * @param $page_is_cached
+ *   Whether the response is from cache
+ * @return
+ *   Number of seconds before the current page expires.
+ */
+function hook_http_expires($page_is_cached) {
+  return 600; // 10 minutes.
+}
+
 /**
  * Perform necessary alterations to the JavaScript before it is presented on
  * the page.