includes/ChangesFeed.php

   1 <?php
   2
   3 class ChangesFeed {
   4
   5         public $format, $type, $titleMsg, $descMsg;
   6
   7         public function __construct( $format, $type ) {
   8                 $this->format = $format;
   9                 $this->type = $type;
  10         }
  11
  12         public function getFeedObject( $title, $description ) {
  13                 global $wgSitename, $wgContLanguageCode, $wgFeedClasses, $wgTitle;
  14                 $feedTitle = "$wgSitename  - {$title} [$wgContLanguageCode]";
  15                 if( !isset($wgFeedClasses[$this->format] ) )
  16                         return false;
  17                 return new $wgFeedClasses[$this->format](
  18                         $feedTitle, htmlspecialchars( $description ), $wgTitle->getFullUrl() );
  19         }
  20
  21         public function execute( $feed, $rows, $limit=0, $hideminor=false, $lastmod=false, $target='' ) {
  22                 global $messageMemc, $wgFeedCacheTimeout;
  23                 global $wgSitename, $wgContLanguageCode;
  24
  25                 if ( !FeedUtils::checkFeedOutput( $this->format ) ) {
  26                         return;
  27                 }
  28
  29                 $timekey = wfMemcKey( $this->type, $this->format, 'timestamp' );
  30                 $key = wfMemcKey( $this->type, $this->format, $limit, $hideminor, $target );
  31
  32                 FeedUtils::checkPurge($timekey, $key);
  33
  34                 /*
  35                 * Bumping around loading up diffs can be pretty slow, so where
  36                 * possible we want to cache the feed output so the next visitor
  37                 * gets it quick too.
  38                 */
  39                 $cachedFeed = $this->loadFromCache( $lastmod, $timekey, $key );
  40                 if( is_string( $cachedFeed ) ) {
  41                         wfDebug( "RC: Outputting cached feed\n" );
  42                         $feed->httpHeaders();
  43                         echo $cachedFeed;
  44                 } else {
  45                         wfDebug( "RC: rendering new feed and caching it\n" );
  46                         ob_start();
  47                         self::generateFeed( $rows, $feed );
  48                         $cachedFeed = ob_get_contents();
  49                         ob_end_flush();
  50                         $this->saveToCache( $cachedFeed, $timekey, $key );
  51                 }
  52                 return true;
  53         }
  54
  55         public function saveToCache( $feed, $timekey, $key ) {
  56                 global $messageMemc;
  57                 $expire = 3600 * 24; # One day
  58                 $messageMemc->set( $key, $feed );
  59                 $messageMemc->set( $timekey, wfTimestamp( TS_MW ), $expire );
  60         }
  61
  62         public function loadFromCache( $lastmod, $timekey, $key ) {
  63                 global $wgFeedCacheTimeout, $messageMemc;
  64                 $feedLastmod = $messageMemc->get( $timekey );
  65
  66                 if( ( $wgFeedCacheTimeout > 0 ) && $feedLastmod ) {
  67                         /*
  68                         * If the cached feed was rendered very recently, we may
  69                         * go ahead and use it even if there have been edits made
  70                         * since it was rendered. This keeps a swarm of requests
  71                         * from being too bad on a super-frequently edited wiki.
  72                         */
  73
  74                         $feedAge = time() - wfTimestamp( TS_UNIX, $feedLastmod );
  75                         $feedLastmodUnix = wfTimestamp( TS_UNIX, $feedLastmod );
  76                         $lastmodUnix = wfTimestamp( TS_UNIX, $lastmod );
  77
  78                         if( $feedAge < $wgFeedCacheTimeout || $feedLastmodUnix > $lastmodUnix) {
  79                                 wfDebug( "RC: loading feed from cache ($key; $feedLastmod; $lastmod)...\n" );
  80                                 return $messageMemc->get( $key );
  81                         } else {
  82                                 wfDebug( "RC: cached feed timestamp check failed ($feedLastmod; $lastmod)\n" );
  83                         }
  84                 }
  85                 return false;
  86         }
  87
  88         /**
  89         * Generate the feed items given a row from the database.
  90         * @param $rows Database resource with recentchanges rows
  91         * @param $feed Feed object
  92         */
  93         public static function generateFeed( $rows, &$feed ) {
  94                 wfProfileIn( __METHOD__ );
  95
  96                 $feed->outHeader();
  97
  98                 # Merge adjacent edits by one user
  99                 $sorted = array();
 100                 $n = 0;
 101                 foreach( $rows as $obj ) {
 102                         if( $n > 0 &&
 103                                 $obj->rc_namespace >= 0 &&
 104                                 $obj->rc_cur_id == $sorted[$n-1]->rc_cur_id &&
 105                                 $obj->rc_user_text == $sorted[$n-1]->rc_user_text ) {
 106                                 $sorted[$n-1]->rc_last_oldid = $obj->rc_last_oldid;
 107                         } else {
 108                                 $sorted[$n] = $obj;
 109                                 $n++;
 110                         }
 111                 }
 112
 113                 foreach( $sorted as $obj ) {
 114                         $title = Title::makeTitle( $obj->rc_namespace, $obj->rc_title );
 115                         $talkpage = $title->getTalkPage();
 116                         // Skip items with deleted content (avoids partially complete/inconsistent output)
 117                         if( $obj->rc_deleted ) continue;
 118                         $item = new FeedItem(
 119                                 $title->getPrefixedText(),
 120                                 FeedUtils::formatDiff( $obj ),
 121                                 $title->getFullURL( 'diff=' . $obj->rc_this_oldid . '&oldid=prev' ),
 122                                 $obj->rc_timestamp,
 123                                 ($obj->rc_deleted & Revision::DELETED_USER) ? wfMsgHtml('rev-deleted-user') : $obj->rc_user_text,
 124                                 $talkpage->getFullURL()
 125                         );
 126                         $feed->outItem( $item );
 127                 }
 128                 $feed->outFooter();
 129                 wfProfileOut( __METHOD__ );
 130         }
 131
 132 }