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   1  <?php
   2  /**
   3   * Feed for list of changes.
   4   *
   5   * This program is free software; you can redistribute it and/or modify
   6   * it under the terms of the GNU General Public License as published by
   7   * the Free Software Foundation; either version 2 of the License, or
   8   * (at your option) any later version.
   9   *
  10   * This program is distributed in the hope that it will be useful,
  11   * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13   * GNU General Public License for more details.
  14   *
  15   * You should have received a copy of the GNU General Public License along
  16   * with this program; if not, write to the Free Software Foundation, Inc.,
  17   * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18   * http://www.gnu.org/copyleft/gpl.html
  19   *
  20   * @file
  21   */
  22  
  23  /**
  24   * Feed to Special:RecentChanges and Special:RecentChangesLiked
  25   *
  26   * @ingroup Feed
  27   */
  28  class ChangesFeed {
  29      public $format, $type, $titleMsg, $descMsg;
  30  
  31      /**
  32       * Constructor
  33       *
  34       * @param string $format Feed's format (either 'rss' or 'atom')
  35       * @param string $type Type of feed (for cache keys)
  36       */
  37  	public function __construct( $format, $type ) {
  38          $this->format = $format;
  39          $this->type = $type;
  40      }
  41  
  42      /**
  43       * Get a ChannelFeed subclass object to use
  44       *
  45       * @param string $title Feed's title
  46       * @param string $description Feed's description
  47       * @param string $url Url of origin page
  48       * @return ChannelFeed|bool ChannelFeed subclass or false on failure
  49       */
  50  	public function getFeedObject( $title, $description, $url ) {
  51          global $wgSitename, $wgLanguageCode, $wgFeedClasses;
  52  
  53          if ( !isset( $wgFeedClasses[$this->format] ) ) {
  54              return false;
  55          }
  56  
  57          if ( !array_key_exists( $this->format, $wgFeedClasses ) ) {
  58              // falling back to atom
  59              $this->format = 'atom';
  60          }
  61  
  62          $feedTitle = "$wgSitename  - {$title} [$wgLanguageCode]";
  63          return new $wgFeedClasses[$this->format](
  64              $feedTitle, htmlspecialchars( $description ), $url );
  65      }
  66  
  67      /**
  68       * Generates feed's content
  69       *
  70       * @param ChannelFeed $feed ChannelFeed subclass object (generally the one returned
  71       *   by getFeedObject())
  72       * @param ResultWrapper $rows ResultWrapper object with rows in recentchanges table
  73       * @param int $lastmod Timestamp of the last item in the recentchanges table (only
  74       *   used for the cache key)
  75       * @param FormOptions $opts As in SpecialRecentChanges::getDefaultOptions()
  76       * @return null|bool True or null
  77       */
  78  	public function execute( $feed, $rows, $lastmod, $opts ) {
  79          global $wgLang, $wgRenderHashAppend;
  80  
  81          if ( !FeedUtils::checkFeedOutput( $this->format ) ) {
  82              return null;
  83          }
  84  
  85          $optionsHash = md5( serialize( $opts->getAllValues() ) ) . $wgRenderHashAppend;
  86          $timekey = wfMemcKey( $this->type, $this->format, $wgLang->getCode(), $optionsHash, 'timestamp' );
  87          $key = wfMemcKey( $this->type, $this->format, $wgLang->getCode(), $optionsHash );
  88  
  89          FeedUtils::checkPurge( $timekey, $key );
  90  
  91          /**
  92           * Bumping around loading up diffs can be pretty slow, so where
  93           * possible we want to cache the feed output so the next visitor
  94           * gets it quick too.
  95           */
  96          $cachedFeed = $this->loadFromCache( $lastmod, $timekey, $key );
  97          if ( is_string( $cachedFeed ) ) {
  98              wfDebug( "RC: Outputting cached feed\n" );
  99              $feed->httpHeaders();
 100              echo $cachedFeed;
 101          } else {
 102              wfDebug( "RC: rendering new feed and caching it\n" );
 103              ob_start();
 104              self::generateFeed( $rows, $feed );
 105              $cachedFeed = ob_get_contents();
 106              ob_end_flush();
 107              $this->saveToCache( $cachedFeed, $timekey, $key );
 108          }
 109          return true;
 110      }
 111  
 112      /**
 113       * Save to feed result to $messageMemc
 114       *
 115       * @param string $feed Feed's content
 116       * @param string $timekey Memcached key of the last modification
 117       * @param string $key Memcached key of the content
 118       */
 119  	public function saveToCache( $feed, $timekey, $key ) {
 120          global $messageMemc;
 121          $expire = 3600 * 24; # One day
 122          $messageMemc->set( $key, $feed, $expire );
 123          $messageMemc->set( $timekey, wfTimestamp( TS_MW ), $expire );
 124      }
 125  
 126      /**
 127       * Try to load the feed result from $messageMemc
 128       *
 129       * @param int $lastmod Timestamp of the last item in the recentchanges table
 130       * @param string $timekey Memcached key of the last modification
 131       * @param string $key Memcached key of the content
 132       * @return string|bool Feed's content on cache hit or false on cache miss
 133       */
 134  	public function loadFromCache( $lastmod, $timekey, $key ) {
 135          global $wgFeedCacheTimeout, $wgOut, $messageMemc;
 136  
 137          $feedLastmod = $messageMemc->get( $timekey );
 138  
 139          if ( ( $wgFeedCacheTimeout > 0 ) && $feedLastmod ) {
 140              /**
 141               * If the cached feed was rendered very recently, we may
 142               * go ahead and use it even if there have been edits made
 143               * since it was rendered. This keeps a swarm of requests
 144               * from being too bad on a super-frequently edited wiki.
 145               */
 146  
 147              $feedAge = time() - wfTimestamp( TS_UNIX, $feedLastmod );
 148              $feedLastmodUnix = wfTimestamp( TS_UNIX, $feedLastmod );
 149              $lastmodUnix = wfTimestamp( TS_UNIX, $lastmod );
 150  
 151              if ( $feedAge < $wgFeedCacheTimeout || $feedLastmodUnix > $lastmodUnix ) {
 152                  wfDebug( "RC: loading feed from cache ($key; $feedLastmod; $lastmod)...\n" );
 153                  if ( $feedLastmodUnix < $lastmodUnix ) {
 154                      $wgOut->setLastModified( $feedLastmod ); // bug 21916
 155                  }
 156                  return $messageMemc->get( $key );
 157              } else {
 158                  wfDebug( "RC: cached feed timestamp check failed ($feedLastmod; $lastmod)\n" );
 159              }
 160          }
 161          return false;
 162      }
 163  
 164      /**
 165       * Generate the feed items given a row from the database, printing the feed.
 166       * @param object $rows DatabaseBase resource with recentchanges rows
 167       * @param Feed $feed
 168       */
 169  	public static function generateFeed( $rows, &$feed ) {
 170          wfProfileIn( __METHOD__ );
 171          $items = self::buildItems( $rows );
 172          $feed->outHeader();
 173          foreach ( $items as $item ) {
 174              $feed->outItem( $item );
 175          }
 176          $feed->outFooter();
 177          wfProfileOut( __METHOD__ );
 178      }
 179  
 180      /**
 181       * Generate the feed items given a row from the database.
 182       * @param object $rows DatabaseBase resource with recentchanges rows
 183       * @return array
 184       */
 185  	public static function buildItems( $rows ) {
 186          wfProfileIn( __METHOD__ );
 187          $items = array();
 188  
 189          # Merge adjacent edits by one user
 190          $sorted = array();
 191          $n = 0;
 192          foreach ( $rows as $obj ) {
 193              if ( $n > 0 &&
 194                  $obj->rc_type == RC_EDIT &&
 195                  $obj->rc_namespace >= 0 &&
 196                  $obj->rc_cur_id == $sorted[$n - 1]->rc_cur_id &&
 197                  $obj->rc_user_text == $sorted[$n - 1]->rc_user_text ) {
 198                  $sorted[$n - 1]->rc_last_oldid = $obj->rc_last_oldid;
 199              } else {
 200                  $sorted[$n] = $obj;
 201                  $n++;
 202              }
 203          }
 204  
 205          foreach ( $sorted as $obj ) {
 206              $title = Title::makeTitle( $obj->rc_namespace, $obj->rc_title );
 207              $talkpage = MWNamespace::canTalk( $obj->rc_namespace )
 208                  ? $title->getTalkPage()->getFullURL()
 209                  : '';
 210  
 211              // Skip items with deleted content (avoids partially complete/inconsistent output)
 212              if ( $obj->rc_deleted ) {
 213                  continue;
 214              }
 215  
 216              if ( $obj->rc_this_oldid ) {
 217                  $url = $title->getFullURL( array(
 218                      'diff' => $obj->rc_this_oldid,
 219                      'oldid' => $obj->rc_last_oldid,
 220                  ) );
 221              } else {
 222                  // log entry or something like that.
 223                  $url = $title->getFullURL();
 224              }
 225  
 226              $items[] = new FeedItem(
 227                  $title->getPrefixedText(),
 228                  FeedUtils::formatDiff( $obj ),
 229                  $url,
 230                  $obj->rc_timestamp,
 231                  ( $obj->rc_deleted & Revision::DELETED_USER )
 232                      ? wfMessage( 'rev-deleted-user' )->escaped() : $obj->rc_user_text,
 233                  $talkpage
 234              );
 235          }
 236  
 237          wfProfileOut( __METHOD__ );
 238          return $items;
 239      }
 240  }