Ticket #5213: 5213.01.patch

bp-activity/bp-activity-classes.php

@@ -1270 +1270 @@
                 }
         }
 
-        /** OUTPUT ***************************************************************/
-
         /**
-         * Output the RSS feed.
+         * Sets various HTTP headers related to Content-Type and browser caching.
+         *
+         * Most of this class method is derived from {@link WP::send_headers()}.
+         *
+         * @since BuddyPress (1.9.0)
          *
          * @access protected
          */
-        protected function output() {
+        protected function http_headers() {
                 // set up some additional headers if not on a directory page
                 // this is done b/c BP uses pseudo-pages
                 if ( ! bp_is_directory() ) {
@@ -1287 +1289 @@
                         status_header( 200 );
                 }
 
-                header( 'Content-Type: text/xml; charset=' . get_option( 'blog_charset' ), true );
+                // Set content-type
+                @header( 'Content-Type: text/xml; charset=' . get_option( 'blog_charset' ), true );
+
+                // Cache-related variables
+                $last_modified      = mysql2date( 'D, d M Y H:i:s O', bp_activity_get_last_updated(), false );
+                $modified_timestamp = strtotime( $last_modified );
+                $etag               = md5( $last_modified );
+        
+                // Set cache-related headers
+                @header( 'Last-Modified: ' . $last_modified );
+                @header( 'Pragma: no-cache' );
+                @header( 'ETag: ' . '"' . $etag . '"' );
+        
+                // First commit of BuddyPress! (Easter egg)
+                @header( 'Expires: Tue, 25 Mar 2008 17:13:55 GMT');
+        
+                // Get ETag from supported user agents
+                if ( isset( $_SERVER['HTTP_IF_NONE_MATCH'] ) ) {
+                        $client_etag = wp_unslash( $_SERVER['HTTP_IF_NONE_MATCH'] );
+        
+                        // Remove quotes from ETag
+                        $client_etag = trim( $client_etag, '"' );
+        
+                        // Strip suffixes from ETag if they exist (eg. "-gzip")
+                        if ( $etag_suffix_pos = strpos( $client_etag, '-' ) ) {
+                                $client_etag = substr( $client_etag, 0, $etag_suffix_pos );
+                        }
+
+                // No ETag found
+                } else {
+                        $client_etag = false;
+                }
+        
+                // Get client last modified timestamp from supported user agents
+                $client_last_modified      = empty( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ? '' : trim( $_SERVER['HTTP_IF_MODIFIED_SINCE'] );
+                $client_modified_timestamp = $client_last_modified ? strtotime( $client_last_modified ) : 0;
+        
+                // Set 304 status if feed hasn't been updated since last fetch
+                if ( ( $client_last_modified && $client_etag ) ?
+                                 ( ( $client_modified_timestamp >= $modified_timestamp ) && ( $client_etag == $etag ) ) :
+                                 ( ( $client_modified_timestamp >= $modified_timestamp ) || ( $client_etag == $etag ) ) ) {
+                        $status = 304;
+                } else {
+                        $status = false;
+                }
+        
+                // If feed hasn't changed as reported by the user agent, set 304 status header
+                if ( ! empty( $status ) ) {
+                        status_header( $status );
+        
+                        // cached response, so stop now!
+                        if ( $status == 304 ) {
+                                exit();
+                        }
+                }
+        }
+
+        /** OUTPUT ***************************************************************/
+
+        /**
+         * Output the RSS feed.
+         *
+         * @access protected
+         */
+        protected function output() {
+                $this->http_headers();
                 echo '<?xml version="1.0" encoding="' . get_option( 'blog_charset' ) . '"?'.'>';
         ?>