includes/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 /**
  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 $format String: feed's format (either 'rss' or 'atom')
  35          * @param $type String: 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 $title String: feed's title
  46          * @param $description String: feed's description
  47          * @param $url String: url of origin page
  48          * @return 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 $feed ChannelFeed subclass object (generally the one returned by getFeedObject())
  71          * @param $rows ResultWrapper object with rows in recentchanges table
  72          * @param $lastmod Integer: timestamp of the last item in the recentchanges table (only used for the cache key)
  73          * @param $opts FormOptions as in SpecialRecentChanges::getDefaultOptions()
  74          * @return null|bool True or null
  75          */
  76         public function execute( $feed, $rows, $lastmod, $opts ) {
  77                 global $wgLang, $wgRenderHashAppend;
  78
  79                 if ( !FeedUtils::checkFeedOutput( $this->format ) ) {
  80                         return null;
  81                 }
  82
  83                 $optionsHash = md5( serialize( $opts->getAllValues() ) ) . $wgRenderHashAppend;
  84                 $timekey = wfMemcKey( $this->type, $this->format, $wgLang->getCode(), $optionsHash, 'timestamp' );
  85                 $key = wfMemcKey( $this->type, $this->format, $wgLang->getCode(), $optionsHash );
  86
  87                 FeedUtils::checkPurge( $timekey, $key );
  88
  89                 /**
  90                  * Bumping around loading up diffs can be pretty slow, so where
  91                  * possible we want to cache the feed output so the next visitor
  92                  * gets it quick too.
  93                  */
  94                 $cachedFeed = $this->loadFromCache( $lastmod, $timekey, $key );
  95                 if( is_string( $cachedFeed ) ) {
  96                         wfDebug( "RC: Outputting cached feed\n" );
  97                         $feed->httpHeaders();
  98                         echo $cachedFeed;
  99                 } else {
 100                         wfDebug( "RC: rendering new feed and caching it\n" );
 101                         ob_start();
 102                         self::generateFeed( $rows, $feed );
 103                         $cachedFeed = ob_get_contents();
 104                         ob_end_flush();
 105                         $this->saveToCache( $cachedFeed, $timekey, $key );
 106                 }
 107                 return true;
 108         }
 109
 110         /**
 111          * Save to feed result to $messageMemc
 112          *
 113          * @param $feed String: feed's content
 114          * @param $timekey String: memcached key of the last modification
 115          * @param $key String: memcached key of the content
 116          */
 117         public function saveToCache( $feed, $timekey, $key ) {
 118                 global $messageMemc;
 119                 $expire = 3600 * 24; # One day
 120                 $messageMemc->set( $key, $feed, $expire );
 121                 $messageMemc->set( $timekey, wfTimestamp( TS_MW ), $expire );
 122         }
 123
 124         /**
 125          * Try to load the feed result from $messageMemc
 126          *
 127          * @param $lastmod Integer: timestamp of the last item in the recentchanges table
 128          * @param $timekey String: memcached key of the last modification
 129          * @param $key String: memcached key of the content
 130          * @return string|bool feed's content on cache hit or false on cache miss
 131          */
 132         public function loadFromCache( $lastmod, $timekey, $key ) {
 133                 global $wgFeedCacheTimeout, $wgOut, $messageMemc;
 134
 135                 $feedLastmod = $messageMemc->get( $timekey );
 136
 137                 if( ( $wgFeedCacheTimeout > 0 ) && $feedLastmod ) {
 138                     /**
 139                          * If the cached feed was rendered very recently, we may
 140                          * go ahead and use it even if there have been edits made
 141                          * since it was rendered. This keeps a swarm of requests
 142                          * from being too bad on a super-frequently edited wiki.
 143                          */
 144
 145                         $feedAge = time() - wfTimestamp( TS_UNIX, $feedLastmod );
 146                         $feedLastmodUnix = wfTimestamp( TS_UNIX, $feedLastmod );
 147                         $lastmodUnix = wfTimestamp( TS_UNIX, $lastmod );
 148
 149                         if( $feedAge < $wgFeedCacheTimeout || $feedLastmodUnix > $lastmodUnix) {
 150                                 wfDebug( "RC: loading feed from cache ($key; $feedLastmod; $lastmod)...\n" );
 151                                 if ( $feedLastmodUnix < $lastmodUnix ) {
 152                                         $wgOut->setLastModified( $feedLastmod ); // bug 21916
 153                                 }
 154                                 return $messageMemc->get( $key );
 155                         } else {
 156                                 wfDebug( "RC: cached feed timestamp check failed ($feedLastmod; $lastmod)\n" );
 157                         }
 158                 }
 159                 return false;
 160         }
 161
 162         /**
 163          * Generate the feed items given a row from the database.
 164          * @param $rows DatabaseBase resource with recentchanges rows
 165          * @param $feed Feed object
 166          */
 167         public static function generateFeed( $rows, &$feed ) {
 168                 wfProfileIn( __METHOD__ );
 169
 170                 $feed->outHeader();
 171
 172                 # Merge adjacent edits by one user
 173                 $sorted = array();
 174                 $n = 0;
 175                 foreach( $rows as $obj ) {
 176                         if( $n > 0 &&
 177                                 $obj->rc_type == RC_EDIT &&
 178                                 $obj->rc_namespace >= 0 &&
 179                                 $obj->rc_cur_id == $sorted[$n-1]->rc_cur_id &&
 180                                 $obj->rc_user_text == $sorted[$n-1]->rc_user_text ) {
 181                                 $sorted[$n-1]->rc_last_oldid = $obj->rc_last_oldid;
 182                         } else {
 183                                 $sorted[$n] = $obj;
 184                                 $n++;
 185                         }
 186                 }
 187
 188                 foreach( $sorted as $obj ) {
 189                         $title = Title::makeTitle( $obj->rc_namespace, $obj->rc_title );
 190                         $talkpage = MWNamespace::canTalk( $obj->rc_namespace ) ? $title->getTalkPage()->getFullUrl() : '';
 191                         // Skip items with deleted content (avoids partially complete/inconsistent output)
 192                         if( $obj->rc_deleted ) continue;
 193
 194                         if ( $obj->rc_this_oldid ) {
 195                                 $url = $title->getFullURL(
 196                                         'diff=' . $obj->rc_this_oldid .
 197                                         '&oldid=' . $obj->rc_last_oldid
 198                                 );
 199                         } else {
 200                                 // log entry or something like that.
 201                                 $url = $title->getFullURL();
 202                         }
 203
 204                         $item = new FeedItem(
 205                                 $title->getPrefixedText(),
 206                                 FeedUtils::formatDiff( $obj ),
 207                                 $url,
 208                                 $obj->rc_timestamp,
 209                                 ( $obj->rc_deleted & Revision::DELETED_USER ) ? wfMessage( 'rev-deleted-user' )->escaped() : $obj->rc_user_text,
 210                                 $talkpage
 211                         );
 212                         $feed->outItem( $item );
 213                 }
 214                 $feed->outFooter();
 215                 wfProfileOut( __METHOD__ );
 216         }
 217
 218 }