Changeset 1036

Timestamp:

03/31/2004 03:54:58 AM (23 years ago)

Author:

michelvaldrighi

Message:

your aggregator will love you, feeds now support sending a 304 Not Modified header when needed

File:

• trunk/wp-blog-header.php (modified) (1 diff)

trunk/wp-blog-header.php

@@ -84 +84 @@
         @header ('X-Pingback: '. get_settings('siteurl') . '/xmlrpc.php');
 } else {
+
         // We're showing a feed, so WP is indeed the only thing that last changed
-        @header('Last Modified: ' . mysql2date("D, d M Y H:i:s", get_lastpostmodified('GMT')).' GMT');
+        $last_modified_date = mysql2date("D, d M Y H:i:s", get_lastpostmodified('GMT')).' GMT';
+        @header('Last Modified: '.$last_modified_date);
+        @header('ETag: "'.md5($last_modified_date).'"');
         @header ('X-Pingback: ' . get_settings('siteurl') . '/xmlrpc.php');
+
+        // Checking If-Modified-Since and If-None-Match,
+        // works only on Apache but should fail gracefully elsewhere
+        $request_headers = getallheaders();
+
+        if ( !empty($request_headers['If-Modified-Since']) OR !empty($request_headers['If-None-Match']) ) {
+
+          $_match_ifmodifiedsince = 0;
+          $_match_ifnonematch = 0;
+
+          if (!empty($request_headers['If-Modified-Since'])) {
+            if (strtotime($request_headers['If-Modified-Since']) <= strtotime($last_modified_date)) {
+              $_match_ifmodifiedsince = 1;
+            } else {
+              $_match_ifmodifiedsince = -1;
+            }
+          }
+          if (!empty($request_headers['If-None-Match'])) {
+            if ($request_headers['If-None-Match'] == md5($last_modified_date)) {
+              $_match_ifnonematch = 1;
+            } else {
+              $_match_ifnonematch = -1;
+            }
+          }
+
+          // if one element is present but doesn't match the header, the -1 makes this <=0
+          if ($_match_ifmodifiedsince + $_match_ifnonematch) {
+            header("HTTP/1.1 304 Not Modified\n\n");
+          }
+        }
 }