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( array(
                    '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__ );
    }

}