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          * Constructor
  35          *
  36          * @param string $format Feed's format (either 'rss' or 'atom')
  37          * @param string $type Type of feed (for cache keys)
  38          */
  39         public function __construct( $format, $type ) {
  40                 $this->format = $format;
  41                 $this->type = $type;
  42         }
  43
  44         /**
  45          * Get a ChannelFeed subclass object to use
  46          *
  47          * @param string $title Feed's title
  48          * @param string $description Feed's description
  49          * @param string $url Url of origin page
  50          * @return ChannelFeed|bool ChannelFeed subclass or false on failure
  51          */
  52         public function getFeedObject( $title, $description, $url ) {
  53                 global $wgSitename, $wgLanguageCode, $wgFeedClasses;
  54
  55                 if ( !isset( $wgFeedClasses[$this->format] ) ) {
  56                         return false;
  57                 }
  58
  59                 if ( !array_key_exists( $this->format, $wgFeedClasses ) ) {
  60                         // falling back to atom
  61                         $this->format = 'atom';
  62                 }
  63
  64                 $feedTitle = "$wgSitename  - {$title} [$wgLanguageCode]";
  65                 return new $wgFeedClasses[$this->format](
  66                         $feedTitle, htmlspecialchars( $description ), $url );
  67         }
  68
  69         /**
  70          * Generates feed's content
  71          *
  72          * @param ChannelFeed $feed ChannelFeed subclass object (generally the one returned
  73          *   by getFeedObject())
  74          * @param ResultWrapper $rows ResultWrapper object with rows in recentchanges table
  75          * @param int $lastmod Timestamp of the last item in the recentchanges table (only
  76          *   used for the cache key)
  77          * @param FormOptions $opts As in SpecialRecentChanges::getDefaultOptions()
  78          * @return null|bool True or null
  79          */
  80         public function execute( $feed, $rows, $lastmod, $opts ) {
  81                 global $wgLang, $wgRenderHashAppend;
  82
  83                 if ( !FeedUtils::checkFeedOutput( $this->format ) ) {
  84                         return null;
  85                 }
  86
  87                 $optionsHash = md5( serialize( $opts->getAllValues() ) ) . $wgRenderHashAppend;
  88                 $timekey = wfMemcKey(
  89                         $this->type, $this->format, $wgLang->getCode(), $optionsHash, 'timestamp' );
  90                 $key = wfMemcKey( $this->type, $this->format, $wgLang->getCode(), $optionsHash );
  91
  92                 FeedUtils::checkPurge( $timekey, $key );
  93
  94                 /**
  95                  * Bumping around loading up diffs can be pretty slow, so where
  96                  * possible we want to cache the feed output so the next visitor
  97                  * gets it quick too.
  98                  */
  99                 $cachedFeed = $this->loadFromCache( $lastmod, $timekey, $key );
 100                 if ( is_string( $cachedFeed ) ) {
 101                         wfDebug( "RC: Outputting cached feed\n" );
 102                         $feed->httpHeaders();
 103                         echo $cachedFeed;
 104                 } else {
 105                         wfDebug( "RC: rendering new feed and caching it\n" );
 106                         ob_start();
 107                         self::generateFeed( $rows, $feed );
 108                         $cachedFeed = ob_get_contents();
 109                         ob_end_flush();
 110                         $this->saveToCache( $cachedFeed, $timekey, $key );
 111                 }
 112                 return true;
 113         }
 114
 115         /**
 116          * Save to feed result to cache
 117          *
 118          * @param string $feed Feed's content
 119          * @param string $timekey Memcached key of the last modification
 120          * @param string $key Memcached key of the content
 121          */
 122         public function saveToCache( $feed, $timekey, $key ) {
 123                 $cache = ObjectCache::getMainWANInstance();
 124                 $cache->set( $key, $feed, $cache::TTL_DAY );
 125                 $cache->set( $timekey, wfTimestamp( TS_MW ), $cache::TTL_DAY );
 126         }
 127
 128         /**
 129          * Try to load the feed result from cache
 130          *
 131          * @param int $lastmod Timestamp of the last item in the recentchanges table
 132          * @param string $timekey Memcached key of the last modification
 133          * @param string $key Memcached key of the content
 134          * @return string|bool Feed's content on cache hit or false on cache miss
 135          */
 136         public function loadFromCache( $lastmod, $timekey, $key ) {
 137                 global $wgFeedCacheTimeout, $wgOut;
 138
 139                 $cache = ObjectCache::getMainWANInstance();
 140                 $feedLastmod = $cache->get( $timekey );
 141
 142                 if ( ( $wgFeedCacheTimeout > 0 ) && $feedLastmod ) {
 143                         /**
 144                          * If the cached feed was rendered very recently, we may
 145                          * go ahead and use it even if there have been edits made
 146                          * since it was rendered. This keeps a swarm of requests
 147                          * from being too bad on a super-frequently edited wiki.
 148                          */
 149
 150                         $feedAge = time() - wfTimestamp( TS_UNIX, $feedLastmod );
 151                         $feedLastmodUnix = wfTimestamp( TS_UNIX, $feedLastmod );
 152                         $lastmodUnix = wfTimestamp( TS_UNIX, $lastmod );
 153
 154                         if ( $feedAge < $wgFeedCacheTimeout || $feedLastmodUnix > $lastmodUnix ) {
 155                                 wfDebug( "RC: loading feed from cache ($key; $feedLastmod; $lastmod)...\n" );
 156                                 if ( $feedLastmodUnix < $lastmodUnix ) {
 157                                         $wgOut->setLastModified( $feedLastmod ); // T23916
 158                                 }
 159                                 return $cache->get( $key );
 160                         } else {
 161                                 wfDebug( "RC: cached feed timestamp check failed ($feedLastmod; $lastmod)\n" );
 162                         }
 163                 }
 164                 return false;
 165         }
 166
 167         /**
 168          * Generate the feed items given a row from the database, printing the feed.
 169          * @param object $rows IDatabase resource with recentchanges rows
 170          * @param ChannelFeed $feed
 171          */
 172         public static function generateFeed( $rows, &$feed ) {
 173                 $items = self::buildItems( $rows );
 174                 $feed->outHeader();
 175                 foreach ( $items as $item ) {
 176                         $feed->outItem( $item );
 177                 }
 178                 $feed->outFooter();
 179         }
 180
 181         /**
 182          * Generate the feed items given a row from the database.
 183          * @param object $rows IDatabase resource with recentchanges rows
 184          * @return array
 185          */
 186         public static function buildItems( $rows ) {
 187                 $items = [];
 188
 189                 # Merge adjacent edits by one user
 190                 $sorted = [];
 191                 $n = 0;
 192                 foreach ( $rows as $obj ) {
 193                         if ( $obj->rc_type == RC_EXTERNAL ) {
 194                                 continue;
 195                         }
 196
 197                         if ( $n > 0 &&
 198                                 $obj->rc_type == RC_EDIT &&
 199                                 $obj->rc_namespace >= 0 &&
 200                                 $obj->rc_cur_id == $sorted[$n - 1]->rc_cur_id &&
 201                                 $obj->rc_user_text == $sorted[$n - 1]->rc_user_text ) {
 202                                 $sorted[$n - 1]->rc_last_oldid = $obj->rc_last_oldid;
 203                         } else {
 204                                 $sorted[$n] = $obj;
 205                                 $n++;
 206                         }
 207                 }
 208
 209                 foreach ( $sorted as $obj ) {
 210                         $title = Title::makeTitle( $obj->rc_namespace, $obj->rc_title );
 211                         $talkpage = MWNamespace::canTalk( $obj->rc_namespace )
 212                                 ? $title->getTalkPage()->getFullURL()
 213                                 : '';
 214
 215                         // Skip items with deleted content (avoids partially complete/inconsistent output)
 216                         if ( $obj->rc_deleted ) {
 217                                 continue;
 218                         }
 219
 220                         if ( $obj->rc_this_oldid ) {
 221                                 $url = $title->getFullURL( [
 222                                         'diff' => $obj->rc_this_oldid,
 223                                         'oldid' => $obj->rc_last_oldid,
 224                                 ] );
 225                         } else {
 226                                 // log entry or something like that.
 227                                 $url = $title->getFullURL();
 228                         }
 229
 230                         $items[] = new FeedItem(
 231                                 $title->getPrefixedText(),
 232                                 FeedUtils::formatDiff( $obj ),
 233                                 $url,
 234                                 $obj->rc_timestamp,
 235                                 ( $obj->rc_deleted & Revision::DELETED_USER )
 236                                         ? wfMessage( 'rev-deleted-user' )->escaped() : $obj->rc_user_text,
 237                                 $talkpage
 238                         );
 239                 }
 240
 241                 return $items;
 242         }
 243 }