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 use MediaWiki\MediaWikiServices;
  24
  25 /**
  26  * Helper functions for feeds
  27  *
  28  * @ingroup Feed
  29  */
  30 class FeedUtils {
  31
  32         /**
  33          * Check whether feed's cache should be cleared; for changes feeds
  34          * If the feed should be purged; $timekey and $key will be removed from cache
  35          *
  36          * @param string $timekey Cache key of the timestamp of the last item
  37          * @param string $key Cache key of feed's content
  38          */
  39         public static function checkPurge( $timekey, $key ) {
  40                 global $wgRequest, $wgUser;
  41
  42                 $purge = $wgRequest->getVal( 'action' ) === 'purge';
  43                 // Allow users with 'purge' right to clear feed caches
  44                 if ( $purge && $wgUser->isAllowed( 'purge' ) ) {
  45                         $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
  46                         $cache->delete( $timekey, 1 );
  47                         $cache->delete( $key, 1 );
  48                 }
  49         }
  50
  51         /**
  52          * Check whether feeds can be used and that $type is a valid feed type
  53          *
  54          * @param string $type Feed type, as requested by the user
  55          * @return bool
  56          */
  57         public static function checkFeedOutput( $type ) {
  58                 global $wgOut, $wgFeed, $wgFeedClasses;
  59
  60                 if ( !$wgFeed ) {
  61                         $wgOut->addWikiMsg( 'feed-unavailable' );
  62                         return false;
  63                 }
  64
  65                 if ( !isset( $wgFeedClasses[$type] ) ) {
  66                         $wgOut->addWikiMsg( 'feed-invalid' );
  67                         return false;
  68                 }
  69
  70                 return true;
  71         }
  72
  73         /**
  74          * Format a diff for the newsfeed
  75          *
  76          * @param object $row Row from the recentchanges table, including fields as
  77          *  appropriate for CommentStore
  78          * @return string
  79          */
  80         public static function formatDiff( $row ) {
  81                 $titleObj = Title::makeTitle( $row->rc_namespace, $row->rc_title );
  82                 $timestamp = wfTimestamp( TS_MW, $row->rc_timestamp );
  83                 $actiontext = '';
  84                 if ( $row->rc_type == RC_LOG ) {
  85                         $rcRow = (array)$row; // newFromRow() only accepts arrays for RC rows
  86                         $actiontext = LogFormatter::newFromRow( $rcRow )->getActionText();
  87                 }
  88                 return self::formatDiffRow( $titleObj,
  89                         $row->rc_last_oldid, $row->rc_this_oldid,
  90                         $timestamp,
  91                         $row->rc_deleted & Revision::DELETED_COMMENT
  92                                 ? wfMessage( 'rev-deleted-comment' )->escaped()
  93                                 : CommentStore::getStore()->getComment( 'rc_comment', $row )->text,
  94                         $actiontext
  95                 );
  96         }
  97
  98         /**
  99          * Really format a diff for the newsfeed
 100          *
 101          * @param Title $title
 102          * @param int $oldid Old revision's id
 103          * @param int $newid New revision's id
 104          * @param int $timestamp New revision's timestamp
 105          * @param string $comment New revision's comment
 106          * @param string $actiontext Text of the action; in case of log event
 107          * @return string
 108          */
 109         public static function formatDiffRow( $title, $oldid, $newid, $timestamp,
 110                 $comment, $actiontext = ''
 111         ) {
 112                 global $wgFeedDiffCutoff, $wgLang;
 113
 114                 // log entries
 115                 $completeText = '<p>' . implode( ' ',
 116                         array_filter(
 117                                 [
 118                                         $actiontext,
 119                                         Linker::formatComment( $comment ) ] ) ) . "</p>\n";
 120
 121                 // NOTE: Check permissions for anonymous users, not current user.
 122                 //       No "privileged" version should end up in the cache.
 123                 //       Most feed readers will not log in anyway.
 124                 $anon = new User();
 125                 $accErrors = $title->getUserPermissionsErrors( 'read', $anon, true );
 126
 127                 // Can't diff special pages, unreadable pages or pages with no new revision
 128                 // to compare against: just return the text.
 129                 if ( $title->getNamespace() < 0 || $accErrors || !$newid ) {
 130                         return $completeText;
 131                 }
 132
 133                 if ( $oldid ) {
 134                         $diffText = '';
 135                         // Don't bother generating the diff if we won't be able to show it
 136                         if ( $wgFeedDiffCutoff > 0 ) {
 137                                 $rev = Revision::newFromId( $oldid );
 138
 139                                 if ( !$rev ) {
 140                                         $diffText = false;
 141                                 } else {
 142                                         $context = clone RequestContext::getMain();
 143                                         $context->setTitle( $title );
 144
 145                                         $contentHandler = $rev->getContentHandler();
 146                                         $de = $contentHandler->createDifferenceEngine( $context, $oldid, $newid );
 147                                         $diffText = $de->getDiff(
 148                                                 wfMessage( 'previousrevision' )->text(), // hack
 149                                                 wfMessage( 'revisionasof',
 150                                                         $wgLang->timeanddate( $timestamp ),
 151                                                         $wgLang->date( $timestamp ),
 152                                                         $wgLang->time( $timestamp ) )->text() );
 153                                 }
 154                         }
 155
 156                         if ( $wgFeedDiffCutoff <= 0 || ( strlen( $diffText ) > $wgFeedDiffCutoff ) ) {
 157                                 // Omit large diffs
 158                                 $diffText = self::getDiffLink( $title, $newid, $oldid );
 159                         } elseif ( $diffText === false ) {
 160                                 // Error in diff engine, probably a missing revision
 161                                 $diffText = "<p>Can't load revision $newid</p>";
 162                         } else {
 163                                 // Diff output fine, clean up any illegal UTF-8
 164                                 $diffText = UtfNormal\Validator::cleanUp( $diffText );
 165                                 $diffText = self::applyDiffStyle( $diffText );
 166                         }
 167                 } else {
 168                         $rev = Revision::newFromId( $newid );
 169                         if ( $wgFeedDiffCutoff <= 0 || is_null( $rev ) ) {
 170                                 $newContent = ContentHandler::getForTitle( $title )->makeEmptyContent();
 171                         } else {
 172                                 $newContent = $rev->getContent();
 173                         }
 174
 175                         if ( $newContent instanceof TextContent ) {
 176                                 // only textual content has a "source view".
 177                                 $text = $newContent->getText();
 178
 179                                 if ( $wgFeedDiffCutoff <= 0 || strlen( $text ) > $wgFeedDiffCutoff ) {
 180                                         $html = null;
 181                                 } else {
 182                                         $html = nl2br( htmlspecialchars( $text ) );
 183                                 }
 184                         } else {
 185                                 // XXX: we could get an HTML representation of the content via getParserOutput, but that may
 186                                 //     contain JS magic and generally may not be suitable for inclusion in a feed.
 187                                 //     Perhaps Content should have a getDescriptiveHtml method and/or a getSourceText method.
 188                                 // Compare also ApiFeedContributions::feedItemDesc
 189                                 $html = null;
 190                         }
 191
 192                         if ( $html === null ) {
 193                                 // Omit large new page diffs, T31110
 194                                 // Also use diff link for non-textual content
 195                                 $diffText = self::getDiffLink( $title, $newid );
 196                         } else {
 197                                 $diffText = '<p><b>' . wfMessage( 'newpage' )->text() . '</b></p>' .
 198                                         '<div>' . $html . '</div>';
 199                         }
 200                 }
 201                 $completeText .= $diffText;
 202
 203                 return $completeText;
 204         }
 205
 206         /**
 207          * Generates a diff link. Used when the full diff is not wanted for example
 208          * when $wgFeedDiffCutoff is 0.
 209          *
 210          * @param Title $title Title object: used to generate the diff URL
 211          * @param int $newid Newid for this diff
 212          * @param int|null $oldid Oldid for the diff. Null means it is a new article
 213          * @return string
 214          */
 215         protected static function getDiffLink( Title $title, $newid, $oldid = null ) {
 216                 $queryParameters = [ 'diff' => $newid ];
 217                 if ( $oldid != null ) {
 218                         $queryParameters['oldid'] = $oldid;
 219                 }
 220                 $diffUrl = $title->getFullURL( $queryParameters );
 221
 222                 $diffLink = Html::element( 'a', [ 'href' => $diffUrl ],
 223                         wfMessage( 'showdiff' )->inContentLanguage()->text() );
 224
 225                 return $diffLink;
 226         }
 227
 228         /**
 229          * Hacky application of diff styles for the feeds.
 230          * Might be 'cleaner' to use DOM or XSLT or something,
 231          * but *gack* it's a pain in the ass.
 232          *
 233          * @param string $text Diff's HTML output
 234          * @return string Modified HTML
 235          */
 236         public static function applyDiffStyle( $text ) {
 237                 $styles = [
 238                         'diff'             => 'background-color: #fff; color: #222;',
 239                         'diff-otitle'      => 'background-color: #fff; color: #222; text-align: center;',
 240                         'diff-ntitle'      => 'background-color: #fff; color: #222; text-align: center;',
 241                         'diff-addedline'   => 'color: #222; font-size: 88%; border-style: solid; '
 242                                 . 'border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; '
 243                                 . 'vertical-align: top; white-space: pre-wrap;',
 244                         'diff-deletedline' => 'color: #222; font-size: 88%; border-style: solid; '
 245                                 . 'border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; '
 246                                 . 'vertical-align: top; white-space: pre-wrap;',
 247                         'diff-context'     => 'background-color: #f8f9fa; color: #222; font-size: 88%; '
 248                                 . 'border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; '
 249                                 . 'border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;',
 250                         'diffchange'       => 'font-weight: bold; text-decoration: none;',
 251                 ];
 252
 253                 foreach ( $styles as $class => $style ) {
 254                         $text = preg_replace( "/(<[^>]+)class=(['\"])$class\\2([^>]*>)/",
 255                                 "\\1style=\"$style\"\\3", $text );
 256                 }
 257
 258                 return $text;
 259         }
 260
 261 }