Ticket #1323: wp-blog-header.diff

wp-blog-header.php

@@ -128 +128 @@
         @header('X-Pingback: ' . get_bloginfo('pingback_url'));
 
         // Support for Conditional GET
-        if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE'])) $client_last_modified = $_SERVER['HTTP_IF_MODIFIED_SINCE'];
-        else $client_last_modified = false;
         if (isset($_SERVER['HTTP_IF_NONE_MATCH'])) $client_etag = stripslashes($_SERVER['HTTP_IF_NONE_MATCH']);
         else $client_etag = false;
 
+        $client_last_modified = trim($_SERVER['HTTP_IF_MODIFIED_SINCE']);
+        // If string is empty, return 0. If not, attempt to parse into a timestamp
+        $client_modified_timestamp = $client_last_modified ? strtotime($client_last_modified) : 0;
+
+        // Make a timestamp for our most recent modification... 
+        $wp_modified_timestamp = strtotime($wp_last_modified);
+        
         if ( ($client_last_modified && $client_etag) ?
-                ((strtotime($client_last_modified) >= strtotime($wp_last_modified)) && ($client_etag == $wp_etag)) :
-                ((strtotime($client_last_modified) >= strtotime($wp_last_modified)) || ($client_etag == $wp_etag)) ) {
+                (($client_modified_timestamp >= $wp_modified_timestamp) && ($client_etag == $wp_etag)) :
+                (($client_modified_timestamp >= $wp_modified_timestamp) || ($client_etag == $wp_etag)) ) {
                 if ( preg_match('/cgi/',php_sapi_name()) ) {
                         header('Status: 304 Not Modified');
                         echo "\r\n\r\n";