thumb.php

   1 <?php
   2 /**
   3  * PHP script to stream out an image thumbnail.
   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 Media
  22  */
  23
  24 use MediaWiki\Logger\LoggerFactory;
  25 use MediaWiki\MediaWikiServices;
  26
  27 define( 'MW_NO_OUTPUT_COMPRESSION', 1 );
  28 require __DIR__ . '/includes/WebStart.php';
  29
  30 // Don't use fancy MIME detection, just check the file extension for jpg/gif/png
  31 $wgTrivialMimeDetection = true;
  32
  33 if ( defined( 'THUMB_HANDLER' ) ) {
  34         // Called from thumb_handler.php via 404; extract params from the URI...
  35         wfThumbHandle404();
  36 } else {
  37         // Called directly, use $_GET params
  38         wfStreamThumb( $_GET );
  39 }
  40
  41 $mediawiki = new MediaWiki();
  42 $mediawiki->doPostOutputShutdown( 'fast' );
  43
  44 // --------------------------------------------------------------------------
  45
  46 /**
  47  * Handle a thumbnail request via thumbnail file URL
  48  *
  49  * @return void
  50  */
  51 function wfThumbHandle404() {
  52         global $wgArticlePath;
  53
  54         # Set action base paths so that WebRequest::getPathInfo()
  55         # recognizes the "X" as the 'title' in ../thumb_handler.php/X urls.
  56         # Note: If Custom per-extension repo paths are set, this may break.
  57         $repo = RepoGroup::singleton()->getLocalRepo();
  58         $oldArticlePath = $wgArticlePath;
  59         $wgArticlePath = $repo->getZoneUrl( 'thumb' ) . '/$1';
  60
  61         $matches = WebRequest::getPathInfo();
  62
  63         $wgArticlePath = $oldArticlePath;
  64
  65         if ( !isset( $matches['title'] ) ) {
  66                 wfThumbError( 404, 'Could not determine the name of the requested thumbnail.' );
  67                 return;
  68         }
  69
  70         $params = wfExtractThumbRequestInfo( $matches['title'] ); // basic wiki URL param extracting
  71         if ( $params == null ) {
  72                 wfThumbError( 400, 'The specified thumbnail parameters are not recognized.' );
  73                 return;
  74         }
  75
  76         wfStreamThumb( $params ); // stream the thumbnail
  77 }
  78
  79 /**
  80  * Stream a thumbnail specified by parameters
  81  *
  82  * @param array $params List of thumbnailing parameters. In addition to parameters
  83  *  passed to the MediaHandler, this may also includes the keys:
  84  *   f (for filename), archived (if archived file), temp (if temp file),
  85  *   w (alias for width), p (alias for page), r (ignored; historical),
  86  *   rel404 (path for render on 404 to verify hash path correct),
  87  *   thumbName (thumbnail name to potentially extract more parameters from
  88  *   e.g. 'lossy-page1-120px-Foo.tiff' would add page, lossy and width
  89  *   to the parameters)
  90  * @return void
  91  */
  92 function wfStreamThumb( array $params ) {
  93         global $wgVaryOnXFP;
  94
  95         $headers = []; // HTTP headers to send
  96
  97         $fileName = isset( $params['f'] ) ? $params['f'] : '';
  98
  99         // Backwards compatibility parameters
 100         if ( isset( $params['w'] ) ) {
 101                 $params['width'] = $params['w'];
 102                 unset( $params['w'] );
 103         }
 104         if ( isset( $params['width'] ) && substr( $params['width'], -2 ) == 'px' ) {
 105                 // strip the px (pixel) suffix, if found
 106                 $params['width'] = substr( $params['width'], 0, -2 );
 107         }
 108         if ( isset( $params['p'] ) ) {
 109                 $params['page'] = $params['p'];
 110         }
 111
 112         // Is this a thumb of an archived file?
 113         $isOld = ( isset( $params['archived'] ) && $params['archived'] );
 114         unset( $params['archived'] ); // handlers don't care
 115
 116         // Is this a thumb of a temp file?
 117         $isTemp = ( isset( $params['temp'] ) && $params['temp'] );
 118         unset( $params['temp'] ); // handlers don't care
 119
 120         // Some basic input validation
 121         $fileName = strtr( $fileName, '\\/', '__' );
 122
 123         // Actually fetch the image. Method depends on whether it is archived or not.
 124         if ( $isTemp ) {
 125                 $repo = RepoGroup::singleton()->getLocalRepo()->getTempRepo();
 126                 $img = new UnregisteredLocalFile( null, $repo,
 127                         # Temp files are hashed based on the name without the timestamp.
 128                         # The thumbnails will be hashed based on the entire name however.
 129                         # @todo fix this convention to actually be reasonable.
 130                         $repo->getZonePath( 'public' ) . '/' . $repo->getTempHashPath( $fileName ) . $fileName
 131                 );
 132         } elseif ( $isOld ) {
 133                 // Format is <timestamp>!<name>
 134                 $bits = explode( '!', $fileName, 2 );
 135                 if ( count( $bits ) != 2 ) {
 136                         wfThumbError( 404, wfMessage( 'badtitletext' )->parse() );
 137                         return;
 138                 }
 139                 $title = Title::makeTitleSafe( NS_FILE, $bits[1] );
 140                 if ( !$title ) {
 141                         wfThumbError( 404, wfMessage( 'badtitletext' )->parse() );
 142                         return;
 143                 }
 144                 $img = RepoGroup::singleton()->getLocalRepo()->newFromArchiveName( $title, $fileName );
 145         } else {
 146                 $img = wfLocalFile( $fileName );
 147         }
 148
 149         // Check the source file title
 150         if ( !$img ) {
 151                 wfThumbError( 404, wfMessage( 'badtitletext' )->parse() );
 152                 return;
 153         }
 154
 155         // Check permissions if there are read restrictions
 156         $varyHeader = [];
 157         if ( !in_array( 'read', User::getGroupPermissions( [ '*' ] ), true ) ) {
 158                 if ( !$img->getTitle() || !$img->getTitle()->userCan( 'read' ) ) {
 159                         wfThumbError( 403, 'Access denied. You do not have permission to access ' .
 160                                 'the source file.' );
 161                         return;
 162                 }
 163                 $headers[] = 'Cache-Control: private';
 164                 $varyHeader[] = 'Cookie';
 165         }
 166
 167         // Check if the file is hidden
 168         if ( $img->isDeleted( File::DELETED_FILE ) ) {
 169                 wfThumbErrorText( 404, "The source file '$fileName' does not exist." );
 170                 return;
 171         }
 172
 173         // Do rendering parameters extraction from thumbnail name.
 174         if ( isset( $params['thumbName'] ) ) {
 175                 $params = wfExtractThumbParams( $img, $params );
 176         }
 177         if ( $params == null ) {
 178                 wfThumbError( 400, 'The specified thumbnail parameters are not recognized.' );
 179                 return;
 180         }
 181
 182         // Check the source file storage path
 183         if ( !$img->exists() ) {
 184                 $redirectedLocation = false;
 185                 if ( !$isTemp ) {
 186                         // Check for file redirect
 187                         // Since redirects are associated with pages, not versions of files,
 188                         // we look for the most current version to see if its a redirect.
 189                         $possRedirFile = RepoGroup::singleton()->getLocalRepo()->findFile( $img->getName() );
 190                         if ( $possRedirFile && !is_null( $possRedirFile->getRedirected() ) ) {
 191                                 $redirTarget = $possRedirFile->getName();
 192                                 $targetFile = wfLocalFile( Title::makeTitleSafe( NS_FILE, $redirTarget ) );
 193                                 if ( $targetFile->exists() ) {
 194                                         $newThumbName = $targetFile->thumbName( $params );
 195                                         if ( $isOld ) {
 196                                                 /** @var array $bits */
 197                                                 $newThumbUrl = $targetFile->getArchiveThumbUrl(
 198                                                         $bits[0] . '!' . $targetFile->getName(), $newThumbName );
 199                                         } else {
 200                                                 $newThumbUrl = $targetFile->getThumbUrl( $newThumbName );
 201                                         }
 202                                         $redirectedLocation = wfExpandUrl( $newThumbUrl, PROTO_CURRENT );
 203                                 }
 204                         }
 205                 }
 206
 207                 if ( $redirectedLocation ) {
 208                         // File has been moved. Give redirect.
 209                         $response = RequestContext::getMain()->getRequest()->response();
 210                         $response->statusHeader( 302 );
 211                         $response->header( 'Location: ' . $redirectedLocation );
 212                         $response->header( 'Expires: ' .
 213                                 gmdate( 'D, d M Y H:i:s', time() + 12 * 3600 ) . ' GMT' );
 214                         if ( $wgVaryOnXFP ) {
 215                                 $varyHeader[] = 'X-Forwarded-Proto';
 216                         }
 217                         if ( count( $varyHeader ) ) {
 218                                 $response->header( 'Vary: ' . implode( ', ', $varyHeader ) );
 219                         }
 220                         $response->header( 'Content-Length: 0' );
 221                         return;
 222                 }
 223
 224                 // If its not a redirect that has a target as a local file, give 404.
 225                 wfThumbErrorText( 404, "The source file '$fileName' does not exist." );
 226                 return;
 227         } elseif ( $img->getPath() === false ) {
 228                 wfThumbErrorText( 400, "The source file '$fileName' is not locally accessible." );
 229                 return;
 230         }
 231
 232         // Check IMS against the source file
 233         // This means that clients can keep a cached copy even after it has been deleted on the server
 234         if ( !empty( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
 235                 // Fix IE brokenness
 236                 $imsString = preg_replace( '/;.*$/', '', $_SERVER["HTTP_IF_MODIFIED_SINCE"] );
 237                 // Calculate time
 238                 MediaWiki\suppressWarnings();
 239                 $imsUnix = strtotime( $imsString );
 240                 MediaWiki\restoreWarnings();
 241                 if ( wfTimestamp( TS_UNIX, $img->getTimestamp() ) <= $imsUnix ) {
 242                         HttpStatus::header( 304 );
 243                         return;
 244                 }
 245         }
 246
 247         $rel404 = isset( $params['rel404'] ) ? $params['rel404'] : null;
 248         unset( $params['r'] ); // ignore 'r' because we unconditionally pass File::RENDER
 249         unset( $params['f'] ); // We're done with 'f' parameter.
 250         unset( $params['rel404'] ); // moved to $rel404
 251
 252         // Get the normalized thumbnail name from the parameters...
 253         try {
 254                 $thumbName = $img->thumbName( $params );
 255                 if ( !strlen( $thumbName ) ) { // invalid params?
 256                         throw new MediaTransformInvalidParametersException(
 257                                 'Empty return from File::thumbName'
 258                         );
 259                 }
 260                 $thumbName2 = $img->thumbName( $params, File::THUMB_FULL_NAME ); // b/c; "long" style
 261         } catch ( MediaTransformInvalidParametersException $e ) {
 262                 wfThumbError(
 263                         400,
 264                         'The specified thumbnail parameters are not valid: ' . $e->getMessage()
 265                 );
 266                 return;
 267         } catch ( MWException $e ) {
 268                 wfThumbError( 500, $e->getHTML(), 'Exception caught while extracting thumb name',
 269                         [ 'exception' => $e ] );
 270                 return;
 271         }
 272
 273         // For 404 handled thumbnails, we only use the base name of the URI
 274         // for the thumb params and the parent directory for the source file name.
 275         // Check that the zone relative path matches up so squid caches won't pick
 276         // up thumbs that would not be purged on source file deletion (T36231).
 277         if ( $rel404 !== null ) { // thumbnail was handled via 404
 278                 if ( rawurldecode( $rel404 ) === $img->getThumbRel( $thumbName ) ) {
 279                         // Request for the canonical thumbnail name
 280                 } elseif ( rawurldecode( $rel404 ) === $img->getThumbRel( $thumbName2 ) ) {
 281                         // Request for the "long" thumbnail name; redirect to canonical name
 282                         $response = RequestContext::getMain()->getRequest()->response();
 283                         $response->statusHeader( 301 );
 284                         $response->header( 'Location: ' .
 285                                 wfExpandUrl( $img->getThumbUrl( $thumbName ), PROTO_CURRENT ) );
 286                         $response->header( 'Expires: ' .
 287                                 gmdate( 'D, d M Y H:i:s', time() + 7 * 86400 ) . ' GMT' );
 288                         if ( $wgVaryOnXFP ) {
 289                                 $varyHeader[] = 'X-Forwarded-Proto';
 290                         }
 291                         if ( count( $varyHeader ) ) {
 292                                 $response->header( 'Vary: ' . implode( ', ', $varyHeader ) );
 293                         }
 294                         return;
 295                 } else {
 296                         wfThumbErrorText( 404, "The given path of the specified thumbnail is incorrect;
 297                                 expected '" . $img->getThumbRel( $thumbName ) . "' but got '" .
 298                                 rawurldecode( $rel404 ) . "'." );
 299                         return;
 300                 }
 301         }
 302
 303         $dispositionType = isset( $params['download'] ) ? 'attachment' : 'inline';
 304
 305         // Suggest a good name for users downloading this thumbnail
 306         $headers[] =
 307                 "Content-Disposition: {$img->getThumbDisposition( $thumbName, $dispositionType )}";
 308
 309         if ( count( $varyHeader ) ) {
 310                 $headers[] = 'Vary: ' . implode( ', ', $varyHeader );
 311         }
 312
 313         // Stream the file if it exists already...
 314         $thumbPath = $img->getThumbPath( $thumbName );
 315         if ( $img->getRepo()->fileExists( $thumbPath ) ) {
 316                 $starttime = microtime( true );
 317                 $status = $img->getRepo()->streamFileWithStatus( $thumbPath, $headers );
 318                 $streamtime = microtime( true ) - $starttime;
 319
 320                 if ( $status->isOK() ) {
 321                         MediaWikiServices::getInstance()->getStatsdDataFactory()->timing(
 322                                 'media.thumbnail.stream', $streamtime
 323                         );
 324                 } else {
 325                         wfThumbError( 500, 'Could not stream the file', null, [ 'file' => $thumbName,
 326                                 'path' => $thumbPath, 'error' => $status->getWikiText( false, false, 'en' ) ] );
 327                 }
 328                 return;
 329         }
 330
 331         $user = RequestContext::getMain()->getUser();
 332         if ( !wfThumbIsStandard( $img, $params ) && $user->pingLimiter( 'renderfile-nonstandard' ) ) {
 333                 wfThumbError( 429, wfMessage( 'actionthrottledtext' )->parse() );
 334                 return;
 335         } elseif ( $user->pingLimiter( 'renderfile' ) ) {
 336                 wfThumbError( 429, wfMessage( 'actionthrottledtext' )->parse() );
 337                 return;
 338         }
 339
 340         list( $thumb, $errorMsg ) = wfGenerateThumbnail( $img, $params, $thumbName, $thumbPath );
 341
 342         /** @var MediaTransformOutput|MediaTransformError|bool $thumb */
 343
 344         // Check for thumbnail generation errors...
 345         $msg = wfMessage( 'thumbnail_error' );
 346         $errorCode = 500;
 347
 348         if ( !$thumb ) {
 349                 $errorMsg = $errorMsg ?: $msg->rawParams( 'File::transform() returned false' )->escaped();
 350                 if ( $errorMsg instanceof MessageSpecifier &&
 351                         $errorMsg->getKey() === 'thumbnail_image-failure-limit'
 352                 ) {
 353                         $errorCode = 429;
 354                 }
 355         } elseif ( $thumb->isError() ) {
 356                 $errorMsg = $thumb->getHtmlMsg();
 357                 $errorCode = $thumb->getHttpStatusCode();
 358         } elseif ( !$thumb->hasFile() ) {
 359                 $errorMsg = $msg->rawParams( 'No path supplied in thumbnail object' )->escaped();
 360         } elseif ( $thumb->fileIsSource() ) {
 361                 $errorMsg = $msg
 362                         ->rawParams( 'Image was not scaled, is the requested width bigger than the source?' )
 363                         ->escaped();
 364                 $errorCode = 400;
 365         }
 366
 367         if ( $errorMsg !== false ) {
 368                 wfThumbError( $errorCode, $errorMsg, null, [ 'file' => $thumbName, 'path' => $thumbPath ] );
 369         } else {
 370                 // Stream the file if there were no errors
 371                 $status = $thumb->streamFileWithStatus( $headers );
 372                 if ( !$status->isOK() ) {
 373                         wfThumbError( 500, 'Could not stream the file', null, [
 374                                 'file' => $thumbName, 'path' => $thumbPath,
 375                                 'error' => $status->getWikiText( false, false, 'en' ) ] );
 376                 }
 377         }
 378 }
 379
 380 /**
 381  * Actually try to generate a new thumbnail
 382  *
 383  * @param File $file
 384  * @param array $params
 385  * @param string $thumbName
 386  * @param string $thumbPath
 387  * @return array (MediaTransformOutput|bool, string|bool error message HTML)
 388  */
 389 function wfGenerateThumbnail( File $file, array $params, $thumbName, $thumbPath ) {
 390         global $wgAttemptFailureEpoch;
 391
 392         $cache = ObjectCache::getLocalClusterInstance();
 393         $key = $cache->makeKey(
 394                 'attempt-failures',
 395                 $wgAttemptFailureEpoch,
 396                 $file->getRepo()->getName(),
 397                 $file->getSha1(),
 398                 md5( $thumbName )
 399         );
 400
 401         // Check if this file keeps failing to render
 402         if ( $cache->get( $key ) >= 4 ) {
 403                 return [ false, wfMessage( 'thumbnail_image-failure-limit', 4 ) ];
 404         }
 405
 406         $done = false;
 407         // Record failures on PHP fatals in addition to caching exceptions
 408         register_shutdown_function( function () use ( $cache, &$done, $key ) {
 409                 if ( !$done ) { // transform() gave a fatal
 410                         // Randomize TTL to reduce stampedes
 411                         $cache->incrWithInit( $key, $cache::TTL_HOUR + mt_rand( 0, 300 ) );
 412                 }
 413         } );
 414
 415         $thumb = false;
 416         $errorHtml = false;
 417
 418         // guard thumbnail rendering with PoolCounter to avoid stampedes
 419         // expensive files use a separate PoolCounter config so it is possible
 420         // to set up a global limit on them
 421         if ( $file->isExpensiveToThumbnail() ) {
 422                 $poolCounterType = 'FileRenderExpensive';
 423         } else {
 424                 $poolCounterType = 'FileRender';
 425         }
 426
 427         // Thumbnail isn't already there, so create the new thumbnail...
 428         try {
 429                 $work = new PoolCounterWorkViaCallback( $poolCounterType, sha1( $file->getName() ),
 430                         [
 431                                 'doWork' => function () use ( $file, $params ) {
 432                                         return $file->transform( $params, File::RENDER_NOW );
 433                                 },
 434                                 'doCachedWork' => function () use ( $file, $params, $thumbPath ) {
 435                                         // If the worker that finished made this thumbnail then use it.
 436                                         // Otherwise, it probably made a different thumbnail for this file.
 437                                         return $file->getRepo()->fileExists( $thumbPath )
 438                                                 ? $file->transform( $params, File::RENDER_NOW )
 439                                                 : false; // retry once more in exclusive mode
 440                                 },
 441                                 'error' => function ( Status $status ) {
 442                                         return wfMessage( 'generic-pool-error' )->parse() . '<hr>' . $status->getHTML();
 443                                 }
 444                         ]
 445                 );
 446                 $result = $work->execute();
 447                 if ( $result instanceof MediaTransformOutput ) {
 448                         $thumb = $result;
 449                 } elseif ( is_string( $result ) ) { // error
 450                         $errorHtml = $result;
 451                 }
 452         } catch ( Exception $e ) {
 453                 // Tried to select a page on a non-paged file?
 454         }
 455
 456         /** @noinspection PhpUnusedLocalVariableInspection */
 457         $done = true; // no PHP fatal occured
 458
 459         if ( !$thumb || $thumb->isError() ) {
 460                 // Randomize TTL to reduce stampedes
 461                 $cache->incrWithInit( $key, $cache::TTL_HOUR + mt_rand( 0, 300 ) );
 462         }
 463
 464         return [ $thumb, $errorHtml ];
 465 }
 466
 467 /**
 468  * Convert pathinfo type parameter, into normal request parameters
 469  *
 470  * So for example, if the request was redirected from
 471  * /w/images/thumb/a/ab/Foo.png/120px-Foo.png. The $thumbRel parameter
 472  * of this function would be set to "a/ab/Foo.png/120px-Foo.png".
 473  * This method is responsible for turning that into an array
 474  * with the folowing keys:
 475  *  * f => the filename (Foo.png)
 476  *  * rel404 => the whole thing (a/ab/Foo.png/120px-Foo.png)
 477  *  * archived => 1 (If the request is for an archived thumb)
 478  *  * temp => 1 (If the file is in the "temporary" zone)
 479  *  * thumbName => the thumbnail name, including parameters (120px-Foo.png)
 480  *
 481  * Transform specific parameters are set later via wfExtractThumbParams().
 482  *
 483  * @param string $thumbRel Thumbnail path relative to the thumb zone
 484  * @return array|null Associative params array or null
 485  */
 486 function wfExtractThumbRequestInfo( $thumbRel ) {
 487         $repo = RepoGroup::singleton()->getLocalRepo();
 488
 489         $hashDirReg = $subdirReg = '';
 490         $hashLevels = $repo->getHashLevels();
 491         for ( $i = 0; $i < $hashLevels; $i++ ) {
 492                 $subdirReg .= '[0-9a-f]';
 493                 $hashDirReg .= "$subdirReg/";
 494         }
 495
 496         // Check if this is a thumbnail of an original in the local file repo
 497         if ( preg_match( "!^((archive/)?$hashDirReg([^/]*)/([^/]*))$!", $thumbRel, $m ) ) {
 498                 list( /*all*/, $rel, $archOrTemp, $filename, $thumbname ) = $m;
 499         // Check if this is a thumbnail of an temp file in the local file repo
 500         } elseif ( preg_match( "!^(temp/)($hashDirReg([^/]*)/([^/]*))$!", $thumbRel, $m ) ) {
 501                 list( /*all*/, $archOrTemp, $rel, $filename, $thumbname ) = $m;
 502         } else {
 503                 return null; // not a valid looking thumbnail request
 504         }
 505
 506         $params = [ 'f' => $filename, 'rel404' => $rel ];
 507         if ( $archOrTemp === 'archive/' ) {
 508                 $params['archived'] = 1;
 509         } elseif ( $archOrTemp === 'temp/' ) {
 510                 $params['temp'] = 1;
 511         }
 512
 513         $params['thumbName'] = $thumbname;
 514         return $params;
 515 }
 516
 517 /**
 518  * Convert a thumbnail name (122px-foo.png) to parameters, using
 519  * file handler.
 520  *
 521  * @param File $file File object for file in question
 522  * @param array $params Array of parameters so far
 523  * @return array Parameters array with more parameters
 524  */
 525 function wfExtractThumbParams( $file, $params ) {
 526         if ( !isset( $params['thumbName'] ) ) {
 527                 throw new InvalidArgumentException( "No thumbnail name passed to wfExtractThumbParams" );
 528         }
 529
 530         $thumbname = $params['thumbName'];
 531         unset( $params['thumbName'] );
 532
 533         // FIXME: Files in the temp zone don't set a MIME type, which means
 534         // they don't have a handler. Which means we can't parse the param
 535         // string. However, not a big issue as what good is a param string
 536         // if you have no handler to make use of the param string and
 537         // actually generate the thumbnail.
 538         $handler = $file->getHandler();
 539
 540         // Based on UploadStash::parseKey
 541         $fileNamePos = strrpos( $thumbname, $params['f'] );
 542         if ( $fileNamePos === false ) {
 543                 // Maybe using a short filename? (see FileRepo::nameForThumb)
 544                 $fileNamePos = strrpos( $thumbname, 'thumbnail' );
 545         }
 546
 547         if ( $handler && $fileNamePos !== false ) {
 548                 $paramString = substr( $thumbname, 0, $fileNamePos - 1 );
 549                 $extraParams = $handler->parseParamString( $paramString );
 550                 if ( $extraParams !== false ) {
 551                         return $params + $extraParams;
 552                 }
 553         }
 554
 555         // As a last ditch fallback, use the traditional common parameters
 556         if ( preg_match( '!^(page(\d*)-)*(\d*)px-[^/]*$!', $thumbname, $matches ) ) {
 557                 list( /* all */, /* pagefull */, $pagenum, $size ) = $matches;
 558                 $params['width'] = $size;
 559                 if ( $pagenum ) {
 560                         $params['page'] = $pagenum;
 561                 }
 562                 return $params; // valid thumbnail URL
 563         }
 564         return null;
 565 }
 566
 567 /**
 568  * Output a thumbnail generation error message
 569  *
 570  * @param int $status
 571  * @param string $msgText Plain text (will be html escaped)
 572  * @return void
 573  */
 574 function wfThumbErrorText( $status, $msgText ) {
 575         wfThumbError( $status, htmlspecialchars( $msgText ) );
 576 }
 577
 578 /**
 579  * Output a thumbnail generation error message
 580  *
 581  * @param int $status
 582  * @param string $msgHtml HTML
 583  * @param string $msgText Short error description, for internal logging. Defaults to $msgHtml.
 584  *   Only used for HTTP 500 errors.
 585  * @param array $context Error context, for internal logging. Only used for HTTP 500 errors.
 586  * @return void
 587  */
 588 function wfThumbError( $status, $msgHtml, $msgText = null, $context = [] ) {
 589         global $wgShowHostnames;
 590
 591         header( 'Cache-Control: no-cache' );
 592         header( 'Content-Type: text/html; charset=utf-8' );
 593         if ( $status == 400 || $status == 404 || $status == 429 ) {
 594                 HttpStatus::header( $status );
 595         } elseif ( $status == 403 ) {
 596                 HttpStatus::header( 403 );
 597                 header( 'Vary: Cookie' );
 598         } else {
 599                 LoggerFactory::getInstance( 'thumb' )->error( $msgText ?: $msgHtml, $context );
 600                 HttpStatus::header( 500 );
 601         }
 602         if ( $wgShowHostnames ) {
 603                 header( 'X-MW-Thumbnail-Renderer: ' . wfHostname() );
 604                 $url = htmlspecialchars(
 605                         isset( $_SERVER['REQUEST_URI'] ) ? $_SERVER['REQUEST_URI'] : ''
 606                 );
 607                 $hostname = htmlspecialchars( wfHostname() );
 608                 $debug = "<!-- $url -->\n<!-- $hostname -->\n";
 609         } else {
 610                 $debug = '';
 611         }
 612         $content = <<<EOT
 613 <!DOCTYPE html>
 614 <html><head>
 615 <meta charset="UTF-8" />
 616 <title>Error generating thumbnail</title>
 617 </head>
 618 <body>
 619 <h1>Error generating thumbnail</h1>
 620 <p>
 621 $msgHtml
 622 </p>
 623 $debug
 624 </body>
 625 </html>
 626
 627 EOT;
 628         header( 'Content-Length: ' . strlen( $content ) );
 629         echo $content;
 630 }