includes/ChangesFeed.php

   1 <?php
   2
   3 /**
   4  * Feed to Special:RecentChanges and Special:RecentChangesLiked
   5  *
   6  * @ingroup Feed
   7  */
   8 class ChangesFeed {
   9         public $format, $type, $titleMsg, $descMsg;
  10
  11         /**
  12          * Constructor
  13          *
  14          * @param $format String: feed's format (either 'rss' or 'atom')
  15          * @param $type String: type of feed (for cache keys)
  16          */
  17         public function __construct( $format, $type ) {
  18                 $this->format = $format;
  19                 $this->type = $type;
  20         }
  21
  22         /**
  23          * Get a ChannelFeed subclass object to use
  24          *
  25          * @param $title String: feed's title
  26          * @param $description String: feed's description
  27          * @param $url String: url of origin page
  28          * @return ChannelFeed subclass or false on failure
  29          */
  30         public function getFeedObject( $title, $description, $url ) {
  31                 global $wgSitename, $wgLanguageCode, $wgFeedClasses;
  32
  33                 if ( !isset( $wgFeedClasses[$this->format] ) ) {
  34                         return false;
  35                 }
  36
  37                 if( !array_key_exists( $this->format, $wgFeedClasses ) ) {
  38                         // falling back to atom
  39                         $this->format = 'atom';
  40                 }
  41
  42                 $feedTitle = "$wgSitename  - {$title} [$wgLanguageCode]";
  43                 return new $wgFeedClasses[$this->format](
  44                         $feedTitle, htmlspecialchars( $description ), $url );
  45         }
  46
  47         /**
  48          * Generates feed's content
  49          *
  50          * @param $feed ChannelFeed subclass object (generally the one returned by getFeedObject())
  51          * @param $rows ResultWrapper object with rows in recentchanges table
  52          * @param $lastmod Integer: timestamp of the last item in the recentchanges table (only used for the cache key)
  53          * @param $opts FormOptions as in SpecialRecentChanges::getDefaultOptions()
  54          * @return null|bool True or null
  55          */
  56         public function execute( $feed, $rows, $lastmod, $opts ) {
  57                 global $wgLang, $wgRenderHashAppend;
  58
  59                 if ( !FeedUtils::checkFeedOutput( $this->format ) ) {
  60                         return null;
  61                 }
  62
  63                 $optionsHash = md5( serialize( $opts->getAllValues() ) ) . $wgRenderHashAppend;
  64                 $timekey = wfMemcKey( $this->type, $this->format, $wgLang->getCode(), $optionsHash, 'timestamp' );
  65                 $key = wfMemcKey( $this->type, $this->format, $wgLang->getCode(), $optionsHash );
  66
  67                 FeedUtils::checkPurge( $timekey, $key );
  68
  69                 /**
  70                  * Bumping around loading up diffs can be pretty slow, so where
  71                  * possible we want to cache the feed output so the next visitor
  72                  * gets it quick too.
  73                  */
  74                 $cachedFeed = $this->loadFromCache( $lastmod, $timekey, $key );
  75                 if( is_string( $cachedFeed ) ) {
  76                         wfDebug( "RC: Outputting cached feed\n" );
  77                         $feed->httpHeaders();
  78                         echo $cachedFeed;
  79                 } else {
  80                         wfDebug( "RC: rendering new feed and caching it\n" );
  81                         ob_start();
  82                         self::generateFeed( $rows, $feed );
  83                         $cachedFeed = ob_get_contents();
  84                         ob_end_flush();
  85                         $this->saveToCache( $cachedFeed, $timekey, $key );
  86                 }
  87                 return true;
  88         }
  89
  90         /**
  91          * Save to feed result to $messageMemc
  92          *
  93          * @param $feed String: feed's content
  94          * @param $timekey String: memcached key of the last modification
  95          * @param $key String: memcached key of the content
  96          */
  97         public function saveToCache( $feed, $timekey, $key ) {
  98                 global $messageMemc;
  99                 $expire = 3600 * 24; # One day
 100                 $messageMemc->set( $key, $feed, $expire );
 101                 $messageMemc->set( $timekey, wfTimestamp( TS_MW ), $expire );
 102         }
 103
 104         /**
 105          * Try to load the feed result from $messageMemc
 106          *
 107          * @param $lastmod Integer: timestamp of the last item in the recentchanges table
 108          * @param $timekey String: memcached key of the last modification
 109          * @param $key String: memcached key of the content
 110          * @return string|bool feed's content on cache hit or false on cache miss
 111          */
 112         public function loadFromCache( $lastmod, $timekey, $key ) {
 113                 global $wgFeedCacheTimeout, $wgOut, $messageMemc;
 114
 115                 $feedLastmod = $messageMemc->get( $timekey );
 116
 117                 if( ( $wgFeedCacheTimeout > 0 ) && $feedLastmod ) {
 118                     /**
 119                          * If the cached feed was rendered very recently, we may
 120                          * go ahead and use it even if there have been edits made
 121                          * since it was rendered. This keeps a swarm of requests
 122                          * from being too bad on a super-frequently edited wiki.
 123                          */
 124
 125                         $feedAge = time() - wfTimestamp( TS_UNIX, $feedLastmod );
 126                         $feedLastmodUnix = wfTimestamp( TS_UNIX, $feedLastmod );
 127                         $lastmodUnix = wfTimestamp( TS_UNIX, $lastmod );
 128
 129                         if( $feedAge < $wgFeedCacheTimeout || $feedLastmodUnix > $lastmodUnix) {
 130                                 wfDebug( "RC: loading feed from cache ($key; $feedLastmod; $lastmod)...\n" );
 131                                 if ( $feedLastmodUnix < $lastmodUnix ) {
 132                                         $wgOut->setLastModified( $feedLastmod ); // bug 21916
 133                                 }
 134                                 return $messageMemc->get( $key );
 135                         } else {
 136                                 wfDebug( "RC: cached feed timestamp check failed ($feedLastmod; $lastmod)\n" );
 137                         }
 138                 }
 139                 return false;
 140         }
 141
 142         /**
 143          * Generate the feed items given a row from the database.
 144          * @param $rows DatabaseBase resource with recentchanges rows
 145          * @param $feed Feed object
 146          */
 147         public static function generateFeed( $rows, &$feed ) {
 148                 wfProfileIn( __METHOD__ );
 149
 150                 $feed->outHeader();
 151
 152                 # Merge adjacent edits by one user
 153                 $sorted = array();
 154                 $n = 0;
 155                 foreach( $rows as $obj ) {
 156                         if( $n > 0 &&
 157                                 $obj->rc_type == RC_EDIT &&
 158                                 $obj->rc_namespace >= 0 &&
 159                                 $obj->rc_cur_id == $sorted[$n-1]->rc_cur_id &&
 160                                 $obj->rc_user_text == $sorted[$n-1]->rc_user_text ) {
 161                                 $sorted[$n-1]->rc_last_oldid = $obj->rc_last_oldid;
 162                         } else {
 163                                 $sorted[$n] = $obj;
 164                                 $n++;
 165                         }
 166                 }
 167
 168                 foreach( $sorted as $obj ) {
 169                         $title = Title::makeTitle( $obj->rc_namespace, $obj->rc_title );
 170                         $talkpage = MWNamespace::canTalk( $obj->rc_namespace ) ? $title->getTalkPage()->getFullUrl() : '';
 171                         // Skip items with deleted content (avoids partially complete/inconsistent output)
 172                         if( $obj->rc_deleted ) continue;
 173
 174                         if ( $obj->rc_this_oldid ) {
 175                                 $url = $title->getFullURL(
 176                                         'diff=' . $obj->rc_this_oldid .
 177                                         '&oldid=' . $obj->rc_last_oldid
 178                                 );
 179                         } else {
 180                                 // log entry or something like that.
 181                                 $url = $title->getFullURL();
 182                         }
 183
 184                         $item = new FeedItem(
 185                                 $title->getPrefixedText(),
 186                                 FeedUtils::formatDiff( $obj ),
 187                                 $url,
 188                                 $obj->rc_timestamp,
 189                                 ($obj->rc_deleted & Revision::DELETED_USER) ? wfMsgHtml('rev-deleted-user') : $obj->rc_user_text,
 190                                 $talkpage
 191                         );
 192                         $feed->outItem( $item );
 193                 }
 194                 $feed->outFooter();
 195                 wfProfileOut( __METHOD__ );
 196         }
 197
 198 }