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