ChangesFeed.php

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<?php
class ChangesFeed {
        public $format, $type, $titleMsg, $descMsg;

        public function __construct( $format, $type ) {
                $this->format = $format;
                $this->type = $type;
        }

        public function getFeedObject( $title, $description, $url ) {
                global $wgSitename, $wgLanguageCode, $wgFeedClasses;

                if ( !isset( $wgFeedClasses[$this->format] ) ) {
                        return false;
                }

                if( !array_key_exists( $this->format, $wgFeedClasses ) ) {
                        // falling back to atom
                        $this->format = 'atom';
                }

                $feedTitle = "$wgSitename  - {$title} [$wgLanguageCode]";
                return new $wgFeedClasses[$this->format](
                        $feedTitle, htmlspecialchars( $description ), $url );
        }

        public function execute( $feed, $rows, $lastmod, $opts ) {
                global $wgLang, $wgRenderHashAppend;

                if ( !FeedUtils::checkFeedOutput( $this->format ) ) {
                        return null;
                }

                $optionsHash = md5( serialize( $opts->getAllValues() ) ) . $wgRenderHashAppend;
                $timekey = wfMemcKey( $this->type, $this->format, $wgLang->getCode(), $optionsHash, 'timestamp' );
                $key = wfMemcKey( $this->type, $this->format, $wgLang->getCode(), $optionsHash );

                FeedUtils::checkPurge( $timekey, $key );

                $cachedFeed = $this->loadFromCache( $lastmod, $timekey, $key );
                if( is_string( $cachedFeed ) ) {
                        wfDebug( "RC: Outputting cached feed\n" );
                        $feed->httpHeaders();
                        echo $cachedFeed;
                } else {
                        wfDebug( "RC: rendering new feed and caching it\n" );
                        ob_start();
                        self::generateFeed( $rows, $feed );
                        $cachedFeed = ob_get_contents();
                        ob_end_flush();
                        $this->saveToCache( $cachedFeed, $timekey, $key );
                }
                return true;
        }

        public function saveToCache( $feed, $timekey, $key ) {
                global $messageMemc;
                $expire = 3600 * 24; # One day
                $messageMemc->set( $key, $feed, $expire );
                $messageMemc->set( $timekey, wfTimestamp( TS_MW ), $expire );
        }

        public function loadFromCache( $lastmod, $timekey, $key ) {
                global $wgFeedCacheTimeout, $wgOut, $messageMemc;

                $feedLastmod = $messageMemc->get( $timekey );

                if( ( $wgFeedCacheTimeout > 0 ) && $feedLastmod ) {
                        $feedAge = time() - wfTimestamp( TS_UNIX, $feedLastmod );
                        $feedLastmodUnix = wfTimestamp( TS_UNIX, $feedLastmod );
                        $lastmodUnix = wfTimestamp( TS_UNIX, $lastmod );

                        if( $feedAge < $wgFeedCacheTimeout || $feedLastmodUnix > $lastmodUnix) {
                                wfDebug( "RC: loading feed from cache ($key; $feedLastmod; $lastmod)...\n" );
                                if ( $feedLastmodUnix < $lastmodUnix ) {
                                        $wgOut->setLastModified( $feedLastmod ); // bug 21916
                                }
                                return $messageMemc->get( $key );
                        } else {
                                wfDebug( "RC: cached feed timestamp check failed ($feedLastmod; $lastmod)\n" );
                        }
                }
                return false;
        }

        public static function generateFeed( $rows, &$feed ) {
                wfProfileIn( __METHOD__ );

                $feed->outHeader();

                # Merge adjacent edits by one user
                $sorted = array();
                $n = 0;
                foreach( $rows as $obj ) {
                        if( $n > 0 &&
                                $obj->rc_type == RC_EDIT &&
                                $obj->rc_namespace >= 0 &&
                                $obj->rc_cur_id == $sorted[$n-1]->rc_cur_id &&
                                $obj->rc_user_text == $sorted[$n-1]->rc_user_text ) {
                                $sorted[$n-1]->rc_last_oldid = $obj->rc_last_oldid;
                        } else {
                                $sorted[$n] = $obj;
                                $n++;
                        }
                }

                foreach( $sorted as $obj ) {
                        $title = Title::makeTitle( $obj->rc_namespace, $obj->rc_title );
                        $talkpage = MWNamespace::canTalk( $obj->rc_namespace ) ? $title->getTalkPage()->getFullUrl() : '';
                        // Skip items with deleted content (avoids partially complete/inconsistent output)
                        if( $obj->rc_deleted ) continue;

                        if ( $obj->rc_this_oldid ) {
                                $url = $title->getFullURL(
                                        'diff=' . $obj->rc_this_oldid .
                                        '&oldid=' . $obj->rc_last_oldid
                                );
                        } else {
                                // log entry or something like that.
                                $url = $title->getFullURL();
                        }

                        $item = new FeedItem(
                                $title->getPrefixedText(),
                                FeedUtils::formatDiff( $obj ),
                                $url,
                                $obj->rc_timestamp,
                                ( $obj->rc_deleted & Revision::DELETED_USER ) ? wfMessage( 'rev-deleted-user' )->escaped() : $obj->rc_user_text,
                                $talkpage
                        );
                        $feed->outItem( $item );
                }
                $feed->outFooter();
                wfProfileOut( __METHOD__ );
        }

}