includes/FeedUtils.php

   1 <?php
   2 /**
   3  * Helper functions for feeds.
   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  * @ingroup Feed
  22  */
  23
  24 /**
  25  * Helper functions for feeds
  26  *
  27  * @ingroup Feed
  28  */
  29 class FeedUtils {
  30
  31         /**
  32          * Check whether feed's cache should be cleared; for changes feeds
  33          * If the feed should be purged; $timekey and $key will be removed from cache
  34          *
  35          * @param string $timekey Cache key of the timestamp of the last item
  36          * @param string $key Cache key of feed's content
  37          */
  38         public static function checkPurge( $timekey, $key ) {
  39                 global $wgRequest, $wgUser;
  40
  41                 $purge = $wgRequest->getVal( 'action' ) === 'purge';
  42                 // Allow users with 'purge' right to clear feed caches
  43                 if ( $purge && $wgUser->isAllowed( 'purge' ) ) {
  44                         $cache = ObjectCache::getMainWANInstance();
  45                         $cache->delete( $timekey, 1 );
  46                         $cache->delete( $key, 1 );
  47                 }
  48         }
  49
  50         /**
  51          * Check whether feeds can be used and that $type is a valid feed type
  52          *
  53          * @param string $type Feed type, as requested by the user
  54          * @return bool
  55          */
  56         public static function checkFeedOutput( $type ) {
  57                 global $wgOut, $wgFeed, $wgFeedClasses;
  58
  59                 if ( !$wgFeed ) {
  60                         $wgOut->addWikiMsg( 'feed-unavailable' );
  61                         return false;
  62                 }
  63
  64                 if ( !isset( $wgFeedClasses[$type] ) ) {
  65                         $wgOut->addWikiMsg( 'feed-invalid' );
  66                         return false;
  67                 }
  68
  69                 return true;
  70         }
  71
  72         /**
  73          * Format a diff for the newsfeed
  74          *
  75          * @param object $row Row from the recentchanges table, including fields as
  76          *  appropriate for CommentStore
  77          * @return string
  78          */
  79         public static function formatDiff( $row ) {
  80                 $titleObj = Title::makeTitle( $row->rc_namespace, $row->rc_title );
  81                 $timestamp = wfTimestamp( TS_MW, $row->rc_timestamp );
  82                 $actiontext = '';
  83                 if ( $row->rc_type == RC_LOG ) {
  84                         $rcRow = (array)$row; // newFromRow() only accepts arrays for RC rows
  85                         $actiontext = LogFormatter::newFromRow( $rcRow )->getActionText();
  86                 }
  87                 return self::formatDiffRow( $titleObj,
  88                         $row->rc_last_oldid, $row->rc_this_oldid,
  89                         $timestamp,
  90                         $row->rc_deleted & Revision::DELETED_COMMENT
  91                                 ? wfMessage( 'rev-deleted-comment' )->escaped()
  92                                 : CommentStore::newKey( 'rc_comment' )
  93                                         // Legacy from RecentChange::selectFields() via ChangesListSpecialPage::doMainQuery()
  94                                         ->getCommentLegacy( wfGetDB( DB_REPLICA ), $row )->text,
  95                         $actiontext
  96                 );
  97         }
  98
  99         /**
 100          * Really format a diff for the newsfeed
 101          *
 102          * @param Title $title Title object
 103          * @param int $oldid Old revision's id
 104          * @param int $newid New revision's id
 105          * @param int $timestamp New revision's timestamp
 106          * @param string $comment New revision's comment
 107          * @param string $actiontext Text of the action; in case of log event
 108          * @return string
 109          */
 110         public static function formatDiffRow( $title, $oldid, $newid, $timestamp,
 111                 $comment, $actiontext = ''
 112         ) {
 113                 global $wgFeedDiffCutoff, $wgLang;
 114
 115                 // log entries
 116                 $completeText = '<p>' . implode( ' ',
 117                         array_filter(
 118                                 [
 119                                         $actiontext,
 120                                         Linker::formatComment( $comment ) ] ) ) . "</p>\n";
 121
 122                 // NOTE: Check permissions for anonymous users, not current user.
 123                 //       No "privileged" version should end up in the cache.
 124                 //       Most feed readers will not log in anyway.
 125                 $anon = new User();
 126                 $accErrors = $title->getUserPermissionsErrors( 'read', $anon, true );
 127
 128                 // Can't diff special pages, unreadable pages or pages with no new revision
 129                 // to compare against: just return the text.
 130                 if ( $title->getNamespace() < 0 || $accErrors || !$newid ) {
 131                         return $completeText;
 132                 }
 133
 134                 if ( $oldid ) {
 135                         $diffText = '';
 136                         // Don't bother generating the diff if we won't be able to show it
 137                         if ( $wgFeedDiffCutoff > 0 ) {
 138                                 $rev = Revision::newFromId( $oldid );
 139
 140                                 if ( !$rev ) {
 141                                         $diffText = false;
 142                                 } else {
 143                                         $context = clone RequestContext::getMain();
 144                                         $context->setTitle( $title );
 145
 146                                         $contentHandler = $rev->getContentHandler();
 147                                         $de = $contentHandler->createDifferenceEngine( $context, $oldid, $newid );
 148                                         $diffText = $de->getDiff(
 149                                                 wfMessage( 'previousrevision' )->text(), // hack
 150                                                 wfMessage( 'revisionasof',
 151                                                         $wgLang->timeanddate( $timestamp ),
 152                                                         $wgLang->date( $timestamp ),
 153                                                         $wgLang->time( $timestamp ) )->text() );
 154                                 }
 155                         }
 156
 157                         if ( $wgFeedDiffCutoff <= 0 || ( strlen( $diffText ) > $wgFeedDiffCutoff ) ) {
 158                                 // Omit large diffs
 159                                 $diffText = self::getDiffLink( $title, $newid, $oldid );
 160                         } elseif ( $diffText === false ) {
 161                                 // Error in diff engine, probably a missing revision
 162                                 $diffText = "<p>Can't load revision $newid</p>";
 163                         } else {
 164                                 // Diff output fine, clean up any illegal UTF-8
 165                                 $diffText = UtfNormal\Validator::cleanUp( $diffText );
 166                                 $diffText = self::applyDiffStyle( $diffText );
 167                         }
 168                 } else {
 169                         $rev = Revision::newFromId( $newid );
 170                         if ( $wgFeedDiffCutoff <= 0 || is_null( $rev ) ) {
 171                                 $newContent = ContentHandler::getForTitle( $title )->makeEmptyContent();
 172                         } else {
 173                                 $newContent = $rev->getContent();
 174                         }
 175
 176                         if ( $newContent instanceof TextContent ) {
 177                                 // only textual content has a "source view".
 178                                 $text = $newContent->getNativeData();
 179
 180                                 if ( $wgFeedDiffCutoff <= 0 || strlen( $text ) > $wgFeedDiffCutoff ) {
 181                                         $html = null;
 182                                 } else {
 183                                         $html = nl2br( htmlspecialchars( $text ) );
 184                                 }
 185                         } else {
 186                                 // XXX: we could get an HTML representation of the content via getParserOutput, but that may
 187                                 //     contain JS magic and generally may not be suitable for inclusion in a feed.
 188                                 //     Perhaps Content should have a getDescriptiveHtml method and/or a getSourceText method.
 189                                 // Compare also ApiFeedContributions::feedItemDesc
 190                                 $html = null;
 191                         }
 192
 193                         if ( $html === null ) {
 194                                 // Omit large new page diffs, T31110
 195                                 // Also use diff link for non-textual content
 196                                 $diffText = self::getDiffLink( $title, $newid );
 197                         } else {
 198                                 $diffText = '<p><b>' . wfMessage( 'newpage' )->text() . '</b></p>' .
 199                                         '<div>' . $html . '</div>';
 200                         }
 201                 }
 202                 $completeText .= $diffText;
 203
 204                 return $completeText;
 205         }
 206
 207         /**
 208          * Generates a diff link. Used when the full diff is not wanted for example
 209          * when $wgFeedDiffCutoff is 0.
 210          *
 211          * @param Title $title Title object: used to generate the diff URL
 212          * @param int $newid Newid for this diff
 213          * @param int|null $oldid Oldid for the diff. Null means it is a new article
 214          * @return string
 215          */
 216         protected static function getDiffLink( Title $title, $newid, $oldid = null ) {
 217                 $queryParameters = [ 'diff' => $newid ];
 218                 if ( $oldid != null ) {
 219                         $queryParameters['oldid'] = $oldid;
 220                 }
 221                 $diffUrl = $title->getFullURL( $queryParameters );
 222
 223                 $diffLink = Html::element( 'a', [ 'href' => $diffUrl ],
 224                         wfMessage( 'showdiff' )->inContentLanguage()->text() );
 225
 226                 return $diffLink;
 227         }
 228
 229         /**
 230          * Hacky application of diff styles for the feeds.
 231          * Might be 'cleaner' to use DOM or XSLT or something,
 232          * but *gack* it's a pain in the ass.
 233          *
 234          * @param string $text Diff's HTML output
 235          * @return string Modified HTML
 236          */
 237         public static function applyDiffStyle( $text ) {
 238                 $styles = [
 239                         'diff'             => 'background-color: white; color:black;',
 240                         'diff-otitle'      => 'background-color: white; color:black; text-align: center;',
 241                         'diff-ntitle'      => 'background-color: white; color:black; text-align: center;',
 242                         'diff-addedline'   => 'color:black; font-size: 88%; border-style: solid; '
 243                                 . 'border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; '
 244                                 . 'vertical-align: top; white-space: pre-wrap;',
 245                         'diff-deletedline' => 'color:black; font-size: 88%; border-style: solid; '
 246                                 . 'border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; '
 247                                 . 'vertical-align: top; white-space: pre-wrap;',
 248                         'diff-context'     => 'background-color: #f9f9f9; color: #333333; font-size: 88%; '
 249                                 . 'border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; '
 250                                 . 'border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;',
 251                         'diffchange'       => 'font-weight: bold; text-decoration: none;',
 252                 ];
 253
 254                 foreach ( $styles as $class => $style ) {
 255                         $text = preg_replace( "/(<[^>]+)class=(['\"])$class\\2([^>]*>)/",
 256                                 "\\1style=\"$style\"\\3", $text );
 257                 }
 258
 259                 return $text;
 260         }
 261
 262 }