Changeset 23267 for trunk/wp-includes/class-wp.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/class-wp.php (modified) (1 diff)

trunk/wp-includes/class-wp.php

@@ -379 +379 @@
         if ( ! empty( $status ) )
             status_header( $status );
+
+        // If Last-Modified is set to false, it should not be sent (no-cache situation).
+        if ( isset( $headers['Last-Modified'] ) && false === $headers['Last-Modified'] ) {
+            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( (array) $headers as $name => $field_value )
             @header("{$name}: {$field_value}");
-
-        if ( isset( $headers['Last-Modified'] ) && empty( $headers['Last-Modified'] ) && function_exists( 'header_remove' ) )
-            @header_remove( 'Last-Modified' );
 
         if ( $exit_required )