Changeset 23267 for trunk/wp-includes/functions.php

Timestamp:

01/04/2013 07:51:31 PM (12 years ago)

Author:

ryan

Message:

Try not to send Last-Modified, even with an empty value. Some servers interpret an empty value as the epoch.

Props nacin, slene, SergeyBiryukov, andy
see #23021 for trunk

File:

• trunk/wp-includes/functions.php (modified) (3 diffs)

trunk/wp-includes/functions.php

@@ -903 +903 @@
     $headers = array(
         'Expires' => 'Wed, 11 Jan 1984 05:00:00 GMT',
-        'Last-Modified' => '',
         'Cache-Control' => 'no-cache, must-revalidate, max-age=0',
         'Pragma' => 'no-cache',
@@ -911 +910 @@
         $headers = (array) apply_filters('nocache_headers', $headers);
     }
+    $headers['Last-Modified'] = false;
     return $headers;
 }
@@ -925 +925 @@
 function nocache_headers() {
     $headers = wp_get_nocache_headers();
+
+    unset( $headers['Last-Modified'] );
+
+    // In PHP 5.3+, make sure we are not sending a Last-Modified header.
+    if ( function_exists( 'header_remove' ) ) {
+        @header_remove( 'Last-Modified' );
+    } else {
+        // In PHP 5.2, send an empty Last-Modified header, but only as a
+        // last resort to override a header already sent. #WP23021
+        foreach ( headers_list() as $header ) {
+            if ( 0 === stripos( $header, 'Last-Modified' ) ) {
+                $headers['Last-Modified'] = '';
+                break;
+            }
+        }
+    }
+
     foreach( $headers as $name => $field_value )
         @header("{$name}: {$field_value}");
-    if ( empty( $headers['Last-Modified'] ) && function_exists( 'header_remove' ) )
-        @header_remove( 'Last-Modified' );
 }