includes/changes/ChangesFeed.php

   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 use Wikimedia\Rdbms\ResultWrapper;
  24
  25 /**
  26  * Feed to Special:RecentChanges and Special:RecentChangesLiked
  27  *
  28  * @ingroup Feed
  29  */
  30 class ChangesFeed {
  31         public $format, $type, $titleMsg, $descMsg;
  32
  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(
  87                         $this->type, $this->format, $wgLang->getCode(), $optionsHash, 'timestamp' );
  88                 $key = wfMemcKey( $this->type, $this->format, $wgLang->getCode(), $optionsHash );
  89
  90                 FeedUtils::checkPurge( $timekey, $key );
  91
  92                 /**
  93                  * Bumping around loading up diffs can be pretty slow, so where
  94                  * possible we want to cache the feed output so the next visitor
  95                  * gets it quick too.
  96                  */
  97                 $cachedFeed = $this->loadFromCache( $lastmod, $timekey, $key );
  98                 if ( is_string( $cachedFeed ) ) {
  99                         wfDebug( "RC: Outputting cached feed\n" );
 100                         $feed->httpHeaders();
 101                         echo $cachedFeed;
 102                 } else {
 103                         wfDebug( "RC: rendering new feed and caching it\n" );
 104                         ob_start();
 105                         self::generateFeed( $rows, $feed );
 106                         $cachedFeed = ob_get_contents();
 107                         ob_end_flush();
 108                         $this->saveToCache( $cachedFeed, $timekey, $key );
 109                 }
 110                 return true;
 111         }
 112
 113         /**
 114          * Save to feed result to cache
 115          *
 116          * @param string $feed Feed's content
 117          * @param string $timekey Memcached key of the last modification
 118          * @param string $key Memcached key of the content
 119          */
 120         public function saveToCache( $feed, $timekey, $key ) {
 121                 $cache = ObjectCache::getMainWANInstance();
 122                 $cache->set( $key, $feed, $cache::TTL_DAY );
 123                 $cache->set( $timekey, wfTimestamp( TS_MW ), $cache::TTL_DAY );
 124         }
 125
 126         /**
 127          * Try to load the feed result from cache
 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;
 136
 137                 $cache = ObjectCache::getMainWANInstance();
 138                 $feedLastmod = $cache->get( $timekey );
 139
 140                 if ( ( $wgFeedCacheTimeout > 0 ) && $feedLastmod ) {
 141                         /**
 142                          * If the cached feed was rendered very recently, we may
 143                          * go ahead and use it even if there have been edits made
 144                          * since it was rendered. This keeps a swarm of requests
 145                          * from being too bad on a super-frequently edited wiki.
 146                          */
 147
 148                         $feedAge = time() - wfTimestamp( TS_UNIX, $feedLastmod );
 149                         $feedLastmodUnix = wfTimestamp( TS_UNIX, $feedLastmod );
 150                         $lastmodUnix = wfTimestamp( TS_UNIX, $lastmod );
 151
 152                         if ( $feedAge < $wgFeedCacheTimeout || $feedLastmodUnix > $lastmodUnix ) {
 153                                 wfDebug( "RC: loading feed from cache ($key; $feedLastmod; $lastmod)...\n" );
 154                                 if ( $feedLastmodUnix < $lastmodUnix ) {
 155                                         $wgOut->setLastModified( $feedLastmod ); // T23916
 156                                 }
 157                                 return $cache->get( $key );
 158                         } else {
 159                                 wfDebug( "RC: cached feed timestamp check failed ($feedLastmod; $lastmod)\n" );
 160                         }
 161                 }
 162                 return false;
 163         }
 164
 165         /**
 166          * Generate the feed items given a row from the database, printing the feed.
 167          * @param object $rows IDatabase resource with recentchanges rows
 168          * @param ChannelFeed &$feed
 169          */
 170         public static function generateFeed( $rows, &$feed ) {
 171                 $items = self::buildItems( $rows );
 172                 $feed->outHeader();
 173                 foreach ( $items as $item ) {
 174                         $feed->outItem( $item );
 175                 }
 176                 $feed->outFooter();
 177         }
 178
 179         /**
 180          * Generate the feed items given a row from the database.
 181          * @param object $rows IDatabase resource with recentchanges rows
 182          * @return array
 183          */
 184         public static function buildItems( $rows ) {
 185                 $items = [];
 186
 187                 # Merge adjacent edits by one user
 188                 $sorted = [];
 189                 $n = 0;
 190                 foreach ( $rows as $obj ) {
 191                         if ( $obj->rc_type == RC_EXTERNAL ) {
 192                                 continue;
 193                         }
 194
 195                         if ( $n > 0 &&
 196                                 $obj->rc_type == RC_EDIT &&
 197                                 $obj->rc_namespace >= 0 &&
 198                                 $obj->rc_cur_id == $sorted[$n - 1]->rc_cur_id &&
 199                                 $obj->rc_user_text == $sorted[$n - 1]->rc_user_text ) {
 200                                 $sorted[$n - 1]->rc_last_oldid = $obj->rc_last_oldid;
 201                         } else {
 202                                 $sorted[$n] = $obj;
 203                                 $n++;
 204                         }
 205                 }
 206
 207                 foreach ( $sorted as $obj ) {
 208                         $title = Title::makeTitle( $obj->rc_namespace, $obj->rc_title );
 209                         $talkpage = MWNamespace::canTalk( $obj->rc_namespace )
 210                                 ? $title->getTalkPage()->getFullURL()
 211                                 : '';
 212
 213                         // Skip items with deleted content (avoids partially complete/inconsistent output)
 214                         if ( $obj->rc_deleted ) {
 215                                 continue;
 216                         }
 217
 218                         if ( $obj->rc_this_oldid ) {
 219                                 $url = $title->getFullURL( [
 220                                         'diff' => $obj->rc_this_oldid,
 221                                         'oldid' => $obj->rc_last_oldid,
 222                                 ] );
 223                         } else {
 224                                 // log entry or something like that.
 225                                 $url = $title->getFullURL();
 226                         }
 227
 228                         $items[] = new FeedItem(
 229                                 $title->getPrefixedText(),
 230                                 FeedUtils::formatDiff( $obj ),
 231                                 $url,
 232                                 $obj->rc_timestamp,
 233                                 ( $obj->rc_deleted & Revision::DELETED_USER )
 234                                         ? wfMessage( 'rev-deleted-user' )->escaped() : $obj->rc_user_text,
 235                                 $talkpage
 236                         );
 237                 }
 238
 239                 return $items;
 240         }
 241 }