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
  26 define( 'MW_NO_OUTPUT_COMPRESSION', 1 );
  27 require __DIR__ . '/includes/WebStart.php';
  28
  29 // Don't use fancy MIME detection, just check the file extension for jpg/gif/png
  30 $wgTrivialMimeDetection = true;
  31
  32 if ( defined( 'THUMB_HANDLER' ) ) {
  33         // Called from thumb_handler.php via 404; extract params from the URI...
  34         wfThumbHandle404();
  35 } else {
  36         // Called directly, use $_GET params
  37         wfStreamThumb( $_GET );
  38 }
  39
  40 $mediawiki = new MediaWiki();
  41 $mediawiki->doPostOutputShutdown( 'fast' );
  42
  43 // --------------------------------------------------------------------------
  44
  45 /**
  46  * Handle a thumbnail request via thumbnail file URL
  47  *
  48  * @return void
  49  */
  50 function wfThumbHandle404() {
  51         global $wgArticlePath;
  52
  53         # Set action base paths so that WebRequest::getPathInfo()
  54         # recognizes the "X" as the 'title' in ../thumb_handler.php/X urls.
  55         # Note: If Custom per-extension repo paths are set, this may break.
  56         $repo = RepoGroup::singleton()->getLocalRepo();
  57         $oldArticlePath = $wgArticlePath;
  58         $wgArticlePath = $repo->getZoneUrl( 'thumb' ) . '/$1';
  59
  60         $matches = WebRequest::getPathInfo();
  61
  62         $wgArticlePath = $oldArticlePath;
  63
  64         if ( !isset( $matches['title'] ) ) {
  65                 wfThumbError( 404, 'Could not determine the name of the requested thumbnail.' );
  66                 return;
  67         }
  68
  69         $params = wfExtractThumbRequestInfo( $matches['title'] ); // basic wiki URL param extracting
  70         if ( $params == null ) {
  71                 wfThumbError( 400, 'The specified thumbnail parameters are not recognized.' );
  72                 return;
  73         }
  74
  75         wfStreamThumb( $params ); // stream the thumbnail
  76 }
  77
  78 /**
  79  * Stream a thumbnail specified by parameters
  80  *
  81  * @param array $params List of thumbnailing parameters. In addition to parameters
  82  *  passed to the MediaHandler, this may also includes the keys:
  83  *   f (for filename), archived (if archived file), temp (if temp file),
  84  *   w (alias for width), p (alias for page), r (ignored; historical),
  85  *   rel404 (path for render on 404 to verify hash path correct),
  86  *   thumbName (thumbnail name to potentially extract more parameters from
  87  *   e.g. 'lossy-page1-120px-Foo.tiff' would add page, lossy and width
  88  *   to the parameters)
  89  * @return void
  90  */
  91 function wfStreamThumb( array $params ) {
  92         global $wgVaryOnXFP;
  93
  94         $headers = array(); // HTTP headers to send
  95
  96         $fileName = isset( $params['f'] ) ? $params['f'] : '';
  97
  98         // Backwards compatibility parameters
  99         if ( isset( $params['w'] ) ) {
 100                 $params['width'] = $params['w'];
 101                 unset( $params['w'] );
 102         }
 103         if ( isset( $params['width'] ) && substr( $params['width'], -2 ) == 'px' ) {
 104                 // strip the px (pixel) suffix, if found
 105                 $params['width'] = substr( $params['width'], 0, -2 );
 106         }
 107         if ( isset( $params['p'] ) ) {
 108                 $params['page'] = $params['p'];
 109         }
 110
 111         // Is this a thumb of an archived file?
 112         $isOld = ( isset( $params['archived'] ) && $params['archived'] );
 113         unset( $params['archived'] ); // handlers don't care
 114
 115         // Is this a thumb of a temp file?
 116         $isTemp = ( isset( $params['temp'] ) && $params['temp'] );
 117         unset( $params['temp'] ); // handlers don't care
 118
 119         // Some basic input validation
 120         $fileName = strtr( $fileName, '\\/', '__' );
 121
 122         // Actually fetch the image. Method depends on whether it is archived or not.
 123         if ( $isTemp ) {
 124                 $repo = RepoGroup::singleton()->getLocalRepo()->getTempRepo();
 125                 $img = new UnregisteredLocalFile( null, $repo,
 126                         # Temp files are hashed based on the name without the timestamp.
 127                         # The thumbnails will be hashed based on the entire name however.
 128                         # @todo fix this convention to actually be reasonable.
 129                         $repo->getZonePath( 'public' ) . '/' . $repo->getTempHashPath( $fileName ) . $fileName
 130                 );
 131         } elseif ( $isOld ) {
 132                 // Format is <timestamp>!<name>
 133                 $bits = explode( '!', $fileName, 2 );
 134                 if ( count( $bits ) != 2 ) {
 135                         wfThumbError( 404, wfMessage( 'badtitletext' )->parse() );
 136                         return;
 137                 }
 138                 $title = Title::makeTitleSafe( NS_FILE, $bits[1] );
 139                 if ( !$title ) {
 140                         wfThumbError( 404, wfMessage( 'badtitletext' )->parse() );
 141                         return;
 142                 }
 143                 $img = RepoGroup::singleton()->getLocalRepo()->newFromArchiveName( $title, $fileName );
 144         } else {
 145                 $img = wfLocalFile( $fileName );
 146         }
 147
 148         // Check the source file title
 149         if ( !$img ) {
 150                 wfThumbError( 404, wfMessage( 'badtitletext' )->parse() );
 151                 return;
 152         }
 153
 154         // Check permissions if there are read restrictions
 155         $varyHeader = array();
 156         if ( !in_array( 'read', User::getGroupPermissions( array( '*' ) ), true ) ) {
 157                 if ( !$img->getTitle() || !$img->getTitle()->userCan( 'read' ) ) {
 158                         wfThumbError( 403, 'Access denied. You do not have permission to access ' .
 159                                 'the source file.' );
 160                         return;
 161                 }
 162                 $headers[] = 'Cache-Control: private';
 163                 $varyHeader[] = 'Cookie';
 164         }
 165
 166         // Check if the file is hidden
 167         if ( $img->isDeleted( File::DELETED_FILE ) ) {
 168                 wfThumbErrorText( 404, "The source file '$fileName' does not exist." );
 169                 return;
 170         }
 171
 172         // Do rendering parameters extraction from thumbnail name.
 173         if ( isset( $params['thumbName'] ) ) {
 174                 $params = wfExtractThumbParams( $img, $params );
 175         }
 176         if ( $params == null ) {
 177                 wfThumbError( 400, 'The specified thumbnail parameters are not recognized.' );
 178                 return;
 179         }
 180
 181         // Check the source file storage path
 182         if ( !$img->exists() ) {
 183                 $redirectedLocation = false;
 184                 if ( !$isTemp ) {
 185                         // Check for file redirect
 186                         // Since redirects are associated with pages, not versions of files,
 187                         // we look for the most current version to see if its a redirect.
 188                         $possRedirFile = RepoGroup::singleton()->getLocalRepo()->findFile( $img->getName() );
 189                         if ( $possRedirFile && !is_null( $possRedirFile->getRedirected() ) ) {
 190                                 $redirTarget = $possRedirFile->getName();
 191                                 $targetFile = wfLocalFile( Title::makeTitleSafe( NS_FILE, $redirTarget ) );
 192                                 if ( $targetFile->exists() ) {
 193                                         $newThumbName = $targetFile->thumbName( $params );
 194                                         if ( $isOld ) {
 195                                                 /** @var array $bits */
 196                                                 $newThumbUrl = $targetFile->getArchiveThumbUrl(
 197                                                         $bits[0] . '!' . $targetFile->getName(), $newThumbName );
 198                                         } else {
 199                                                 $newThumbUrl = $targetFile->getThumbUrl( $newThumbName );
 200                                         }
 201                                         $redirectedLocation = wfExpandUrl( $newThumbUrl, PROTO_CURRENT );
 202                                 }
 203                         }
 204                 }
 205
 206                 if ( $redirectedLocation ) {
 207                         // File has been moved. Give redirect.
 208                         $response = RequestContext::getMain()->getRequest()->response();
 209                         $response->statusHeader( 302 );
 210                         $response->header( 'Location: ' . $redirectedLocation );
 211                         $response->header( 'Expires: ' .
 212                                 gmdate( 'D, d M Y H:i:s', time() + 12 * 3600 ) . ' GMT' );
 213                         if ( $wgVaryOnXFP ) {
 214                                 $varyHeader[] = 'X-Forwarded-Proto';
 215                         }
 216                         if ( count( $varyHeader ) ) {
 217                                 $response->header( 'Vary: ' . implode( ', ', $varyHeader ) );
 218                         }
 219                         $response->header( 'Content-Length: 0' );
 220                         return;
 221                 }
 222
 223                 // If its not a redirect that has a target as a local file, give 404.
 224                 wfThumbErrorText( 404, "The source file '$fileName' does not exist." );
 225                 return;
 226         } elseif ( $img->getPath() === false ) {
 227                 wfThumbErrorText( 400, "The source file '$fileName' is not locally accessible." );
 228                 return;
 229         }
 230
 231         // Check IMS against the source file
 232         // This means that clients can keep a cached copy even after it has been deleted on the server
 233         if ( !empty( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
 234                 // Fix IE brokenness
 235                 $imsString = preg_replace( '/;.*$/', '', $_SERVER["HTTP_IF_MODIFIED_SINCE"] );
 236                 // Calculate time
 237                 MediaWiki\suppressWarnings();
 238                 $imsUnix = strtotime( $imsString );
 239                 MediaWiki\restoreWarnings();
 240                 if ( wfTimestamp( TS_UNIX, $img->getTimestamp() ) <= $imsUnix ) {
 241                         HttpStatus::header( 304 );
 242                         return;
 243                 }
 244         }
 245
 246         $rel404 = isset( $params['rel404'] ) ? $params['rel404'] : null;
 247         unset( $params['r'] ); // ignore 'r' because we unconditionally pass File::RENDER
 248         unset( $params['f'] ); // We're done with 'f' parameter.
 249         unset( $params['rel404'] ); // moved to $rel404
 250
 251         // Get the normalized thumbnail name from the parameters...
 252         try {
 253                 $thumbName = $img->thumbName( $params );
 254                 if ( !strlen( $thumbName ) ) { // invalid params?
 255                         throw new MediaTransformInvalidParametersException(
 256                                 'Empty return from File::thumbName'
 257                         );
 258                 }
 259                 $thumbName2 = $img->thumbName( $params, File::THUMB_FULL_NAME ); // b/c; "long" style
 260         } catch ( MediaTransformInvalidParametersException $e ) {
 261                 wfThumbError(
 262                         400,
 263                         'The specified thumbnail parameters are not valid: ' . $e->getMessage()
 264                 );
 265                 return;
 266         } catch ( MWException $e ) {
 267                 wfThumbError( 500, $e->getHTML(), 'Exception caught while extracting thumb name',
 268                         array( 'exception' => $e ) );
 269                 return;
 270         }
 271
 272         // For 404 handled thumbnails, we only use the base name of the URI
 273         // for the thumb params and the parent directory for the source file name.
 274         // Check that the zone relative path matches up so squid caches won't pick
 275         // up thumbs that would not be purged on source file deletion (bug 34231).
 276         if ( $rel404 !== null ) { // thumbnail was handled via 404
 277                 if ( rawurldecode( $rel404 ) === $img->getThumbRel( $thumbName ) ) {
 278                         // Request for the canonical thumbnail name
 279                 } elseif ( rawurldecode( $rel404 ) === $img->getThumbRel( $thumbName2 ) ) {
 280                         // Request for the "long" thumbnail name; redirect to canonical name
 281                         $response = RequestContext::getMain()->getRequest()->response();
 282                         $response->statusHeader( 301 );
 283                         $response->header( 'Location: ' .
 284                                 wfExpandUrl( $img->getThumbUrl( $thumbName ), PROTO_CURRENT ) );
 285                         $response->header( 'Expires: ' .
 286                                 gmdate( 'D, d M Y H:i:s', time() + 7 * 86400 ) . ' GMT' );
 287                         if ( $wgVaryOnXFP ) {
 288                                 $varyHeader[] = 'X-Forwarded-Proto';
 289                         }
 290                         if ( count( $varyHeader ) ) {
 291                                 $response->header( 'Vary: ' . implode( ', ', $varyHeader ) );
 292                         }
 293                         return;
 294                 } else {
 295                         wfThumbErrorText( 404, "The given path of the specified thumbnail is incorrect;
 296                                 expected '" . $img->getThumbRel( $thumbName ) . "' but got '" .
 297                                 rawurldecode( $rel404 ) . "'." );
 298                         return;
 299                 }
 300         }
 301
 302         $dispositionType = isset( $params['download'] ) ? 'attachment' : 'inline';
 303
 304         // Suggest a good name for users downloading this thumbnail
 305         $headers[] =
 306                 "Content-Disposition: {$img->getThumbDisposition( $thumbName, $dispositionType )}";
 307
 308         if ( count( $varyHeader ) ) {
 309                 $headers[] = 'Vary: ' . implode( ', ', $varyHeader );
 310         }
 311
 312         // Stream the file if it exists already...
 313         $thumbPath = $img->getThumbPath( $thumbName );
 314         if ( $img->getRepo()->fileExists( $thumbPath ) ) {
 315                 $starttime = microtime( true );
 316                 $status = $img->getRepo()->streamFileWithStatus( $thumbPath, $headers );
 317                 $streamtime = microtime( true ) - $starttime;
 318
 319                 if ( $status->isOK() ) {
 320                         RequestContext::getMain()->getStats()->timing( 'media.thumbnail.stream', $streamtime );
 321                 } else {
 322                         wfThumbError( 500, 'Could not stream the file', null, array( 'file' => $thumbName,
 323                                 'path' => $thumbPath, 'error' => $status->getWikiText() ) );
 324                 }
 325                 return;
 326         }
 327
 328         $user = RequestContext::getMain()->getUser();
 329         if ( !wfThumbIsStandard( $img, $params ) && $user->pingLimiter( 'renderfile-nonstandard' ) ) {
 330                 wfThumbError( 429, wfMessage( 'actionthrottledtext' )->parse() );
 331                 return;
 332         } elseif ( $user->pingLimiter( 'renderfile' ) ) {
 333                 wfThumbError( 429, wfMessage( 'actionthrottledtext' )->parse() );
 334                 return;
 335         }
 336
 337         list( $thumb, $errorMsg ) = wfGenerateThumbnail( $img, $params, $thumbName, $thumbPath );
 338
 339         /** @var MediaTransformOutput|MediaTransformError|bool $thumb */
 340
 341         // Check for thumbnail generation errors...
 342         $msg = wfMessage( 'thumbnail_error' );
 343         $errorCode = 500;
 344         if ( !$thumb ) {
 345                 $errorMsg = $errorMsg ?: $msg->rawParams( 'File::transform() returned false' )->escaped();
 346                 if ( $errorMsg instanceof MessageSpecifier &&
 347                         $errorMsg->getKey() === 'thumbnail_image-failure-limit'
 348                 ) {
 349                         $errorCode = 429;
 350                 }
 351         } elseif ( $thumb->isError() ) {
 352                 $errorMsg = $thumb->getHtmlMsg();
 353         } elseif ( !$thumb->hasFile() ) {
 354                 $errorMsg = $msg->rawParams( 'No path supplied in thumbnail object' )->escaped();
 355         } elseif ( $thumb->fileIsSource() ) {
 356                 $errorMsg = $msg
 357                         ->rawParams( 'Image was not scaled, is the requested width bigger than the source?' )
 358                         ->escaped();
 359                 $errorCode = 400;
 360         }
 361
 362         if ( $errorMsg !== false ) {
 363                 wfThumbError( $errorCode, $errorMsg, null, array( 'file' => $thumbName, 'path' => $thumbPath ) );
 364         } else {
 365                 // Stream the file if there were no errors
 366                 $status = $thumb->streamFileWithStatus( $headers );
 367                 if ( !$status->isOK() ) {
 368                         wfThumbError( 500, 'Could not stream the file', null, array(
 369                                 'file' => $thumbName, 'path' => $thumbPath, 'error' => $status->getWikiText() ) );
 370                 }
 371         }
 372 }
 373
 374 /**
 375  * Actually try to generate a new thumbnail
 376  *
 377  * @param File $file
 378  * @param array $params
 379  * @param string $thumbName
 380  * @param string $thumbPath
 381  * @return array (MediaTransformOutput|bool, string|bool error message HTML)
 382  */
 383 function wfGenerateThumbnail( File $file, array $params, $thumbName, $thumbPath ) {
 384         global $wgAttemptFailureEpoch;
 385
 386         $cache = ObjectCache::getLocalClusterInstance();
 387         $key = $cache->makeKey(
 388                 'attempt-failures',
 389                 $wgAttemptFailureEpoch,
 390                 $file->getRepo()->getName(),
 391                 $file->getSha1(),
 392                 md5( $thumbName )
 393         );
 394
 395         // Check if this file keeps failing to render
 396         if ( $cache->get( $key ) >= 4 ) {
 397                 return array( false, wfMessage( 'thumbnail_image-failure-limit', 4 ) );
 398         }
 399
 400         $done = false;
 401         // Record failures on PHP fatals in addition to caching exceptions
 402         register_shutdown_function( function () use ( $cache, &$done, $key ) {
 403                 if ( !$done ) { // transform() gave a fatal
 404                         // Randomize TTL to reduce stampedes
 405                         $cache->incrWithInit( $key, $cache::TTL_HOUR + mt_rand( 0, 300 ) );
 406                 }
 407         } );
 408
 409         $thumb = false;
 410         $errorHtml = false;
 411
 412         // guard thumbnail rendering with PoolCounter to avoid stampedes
 413         // expensive files use a separate PoolCounter config so it is possible
 414         // to set up a global limit on them
 415         if ( $file->isExpensiveToThumbnail() ) {
 416                 $poolCounterType = 'FileRenderExpensive';
 417         } else {
 418                 $poolCounterType = 'FileRender';
 419         }
 420
 421         // Thumbnail isn't already there, so create the new thumbnail...
 422         try {
 423                 $work = new PoolCounterWorkViaCallback( $poolCounterType, sha1( $file->getName() ),
 424                         array(
 425                                 'doWork' => function () use ( $file, $params ) {
 426                                         return $file->transform( $params, File::RENDER_NOW );
 427                                 },
 428                                 'doCachedWork' => function () use ( $file, $params, $thumbPath ) {
 429                                         // If the worker that finished made this thumbnail then use it.
 430                                         // Otherwise, it probably made a different thumbnail for this file.
 431                                         return $file->getRepo()->fileExists( $thumbPath )
 432                                                 ? $file->transform( $params, File::RENDER_NOW )
 433                                                 : false; // retry once more in exclusive mode
 434                                 },
 435                                 'error' => function ( Status $status ) {
 436                                         return wfMessage( 'generic-pool-error' )->parse() . '<hr>' . $status->getHTML();
 437                                 }
 438                         )
 439                 );
 440                 $result = $work->execute();
 441                 if ( $result instanceof MediaTransformOutput ) {
 442                         $thumb = $result;
 443                 } elseif ( is_string( $result ) ) { // error
 444                         $errorHtml = $result;
 445                 }
 446         } catch ( Exception $e ) {
 447                 // Tried to select a page on a non-paged file?
 448         }
 449
 450         /** @noinspection PhpUnusedLocalVariableInspection */
 451         $done = true; // no PHP fatal occured
 452
 453         if ( !$thumb || $thumb->isError() ) {
 454                 // Randomize TTL to reduce stampedes
 455                 $cache->incrWithInit( $key, $cache::TTL_HOUR + mt_rand( 0, 300 ) );
 456         }
 457
 458         return array( $thumb, $errorHtml );
 459 }
 460
 461 /**
 462  * Convert pathinfo type parameter, into normal request parameters
 463  *
 464  * So for example, if the request was redirected from
 465  * /w/images/thumb/a/ab/Foo.png/120px-Foo.png. The $thumbRel parameter
 466  * of this function would be set to "a/ab/Foo.png/120px-Foo.png".
 467  * This method is responsible for turning that into an array
 468  * with the folowing keys:
 469  *  * f => the filename (Foo.png)
 470  *  * rel404 => the whole thing (a/ab/Foo.png/120px-Foo.png)
 471  *  * archived => 1 (If the request is for an archived thumb)
 472  *  * temp => 1 (If the file is in the "temporary" zone)
 473  *  * thumbName => the thumbnail name, including parameters (120px-Foo.png)
 474  *
 475  * Transform specific parameters are set later via wfExtractThumbParams().
 476  *
 477  * @param string $thumbRel Thumbnail path relative to the thumb zone
 478  * @return array|null Associative params array or null
 479  */
 480 function wfExtractThumbRequestInfo( $thumbRel ) {
 481         $repo = RepoGroup::singleton()->getLocalRepo();
 482
 483         $hashDirReg = $subdirReg = '';
 484         $hashLevels = $repo->getHashLevels();
 485         for ( $i = 0; $i < $hashLevels; $i++ ) {
 486                 $subdirReg .= '[0-9a-f]';
 487                 $hashDirReg .= "$subdirReg/";
 488         }
 489
 490         // Check if this is a thumbnail of an original in the local file repo
 491         if ( preg_match( "!^((archive/)?$hashDirReg([^/]*)/([^/]*))$!", $thumbRel, $m ) ) {
 492                 list( /*all*/, $rel, $archOrTemp, $filename, $thumbname ) = $m;
 493         // Check if this is a thumbnail of an temp file in the local file repo
 494         } elseif ( preg_match( "!^(temp/)($hashDirReg([^/]*)/([^/]*))$!", $thumbRel, $m ) ) {
 495                 list( /*all*/, $archOrTemp, $rel, $filename, $thumbname ) = $m;
 496         } else {
 497                 return null; // not a valid looking thumbnail request
 498         }
 499
 500         $params = array( 'f' => $filename, 'rel404' => $rel );
 501         if ( $archOrTemp === 'archive/' ) {
 502                 $params['archived'] = 1;
 503         } elseif ( $archOrTemp === 'temp/' ) {
 504                 $params['temp'] = 1;
 505         }
 506
 507         $params['thumbName'] = $thumbname;
 508         return $params;
 509 }
 510
 511 /**
 512  * Convert a thumbnail name (122px-foo.png) to parameters, using
 513  * file handler.
 514  *
 515  * @param File $file File object for file in question
 516  * @param array $params Array of parameters so far
 517  * @return array Parameters array with more parameters
 518  */
 519 function wfExtractThumbParams( $file, $params ) {
 520         if ( !isset( $params['thumbName'] ) ) {
 521                 throw new InvalidArgumentException( "No thumbnail name passed to wfExtractThumbParams" );
 522         }
 523
 524         $thumbname = $params['thumbName'];
 525         unset( $params['thumbName'] );
 526
 527         // Do the hook first for older extensions that rely on it.
 528         if ( !Hooks::run( 'ExtractThumbParameters', array( $thumbname, &$params ) ) ) {
 529                 // Check hooks if parameters can be extracted
 530                 // Hooks return false if they manage to *resolve* the parameters
 531                 // This hook should be considered deprecated
 532                 wfDeprecated( 'ExtractThumbParameters', '1.22' );
 533                 return $params; // valid thumbnail URL (via extension or config)
 534         }
 535
 536         // FIXME: Files in the temp zone don't set a MIME type, which means
 537         // they don't have a handler. Which means we can't parse the param
 538         // string. However, not a big issue as what good is a param string
 539         // if you have no handler to make use of the param string and
 540         // actually generate the thumbnail.
 541         $handler = $file->getHandler();
 542
 543         // Based on UploadStash::parseKey
 544         $fileNamePos = strrpos( $thumbname, $params['f'] );
 545         if ( $fileNamePos === false ) {
 546                 // Maybe using a short filename? (see FileRepo::nameForThumb)
 547                 $fileNamePos = strrpos( $thumbname, 'thumbnail' );
 548         }
 549
 550         if ( $handler && $fileNamePos !== false ) {
 551                 $paramString = substr( $thumbname, 0, $fileNamePos - 1 );
 552                 $extraParams = $handler->parseParamString( $paramString );
 553                 if ( $extraParams !== false ) {
 554                         return $params + $extraParams;
 555                 }
 556         }
 557
 558         // As a last ditch fallback, use the traditional common parameters
 559         if ( preg_match( '!^(page(\d*)-)*(\d*)px-[^/]*$!', $thumbname, $matches ) ) {
 560                 list( /* all */, /* pagefull */, $pagenum, $size ) = $matches;
 561                 $params['width'] = $size;
 562                 if ( $pagenum ) {
 563                         $params['page'] = $pagenum;
 564                 }
 565                 return $params; // valid thumbnail URL
 566         }
 567         return null;
 568 }
 569
 570 /**
 571  * Output a thumbnail generation error message
 572  *
 573  * @param int $status
 574  * @param string $msgText Plain text (will be html escaped)
 575  * @return void
 576  */
 577 function wfThumbErrorText( $status, $msgText ) {
 578         wfThumbError( $status, htmlspecialchars( $msgText ) );
 579 }
 580
 581 /**
 582  * Output a thumbnail generation error message
 583  *
 584  * @param int $status
 585  * @param string $msgHtml HTML
 586  * @param string $msgText Short error description, for internal logging. Defaults to $msgHtml.
 587  *   Only used for HTTP 500 errors.
 588  * @param array $context Error context, for internal logging. Only used for HTTP 500 errors.
 589  * @return void
 590  */
 591 function wfThumbError( $status, $msgHtml, $msgText = null, $context = array() ) {
 592         global $wgShowHostnames;
 593
 594         header( 'Cache-Control: no-cache' );
 595         header( 'Content-Type: text/html; charset=utf-8' );
 596         if ( $status == 400 || $status == 404 || $status == 429 ) {
 597                 HttpStatus::header( $status );
 598         } elseif ( $status == 403 ) {
 599                 HttpStatus::header( 403 );
 600                 header( 'Vary: Cookie' );
 601         } else {
 602                 LoggerFactory::getInstance( 'thumb' )->error( $msgText ?: $msgHtml, $context );
 603                 HttpStatus::header( 500 );
 604         }
 605         if ( $wgShowHostnames ) {
 606                 header( 'X-MW-Thumbnail-Renderer: ' . wfHostname() );
 607                 $url = htmlspecialchars(
 608                         isset( $_SERVER['REQUEST_URI'] ) ? $_SERVER['REQUEST_URI'] : ''
 609                 );
 610                 $hostname = htmlspecialchars( wfHostname() );
 611                 $debug = "<!-- $url -->\n<!-- $hostname -->\n";
 612         } else {
 613                 $debug = '';
 614         }
 615         $content = <<<EOT
 616 <!DOCTYPE html>
 617 <html><head>
 618 <meta charset="UTF-8" />
 619 <title>Error generating thumbnail</title>
 620 </head>
 621 <body>
 622 <h1>Error generating thumbnail</h1>
 623 <p>
 624 $msgHtml
 625 </p>
 626 $debug
 627 </body>
 628 </html>
 629
 630 EOT;
 631         header( 'Content-Length: ' . strlen( $content ) );
 632         echo $content;
 633 }