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 define( 'MW_NO_OUTPUT_COMPRESSION', 1 );
  25 require __DIR__ . '/includes/WebStart.php';
  26
  27 // Don't use fancy MIME detection, just check the file extension for jpg/gif/png
  28 $wgTrivialMimeDetection = true;
  29
  30 if ( defined( 'THUMB_HANDLER' ) ) {
  31         // Called from thumb_handler.php via 404; extract params from the URI...
  32         wfThumbHandle404();
  33 } else {
  34         // Called directly, use $_GET params
  35         wfStreamThumb( $_GET );
  36 }
  37
  38 wfLogProfilingData();
  39 // Commit and close up!
  40 $factory = wfGetLBFactory();
  41 $factory->commitMasterChanges();
  42 $factory->shutdown();
  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
  96         $headers = array(); // HTTP headers to send
  97
  98         $fileName = isset( $params['f'] ) ? $params['f'] : '';
  99
 100         // Backwards compatibility parameters
 101         if ( isset( $params['w'] ) ) {
 102                 $params['width'] = $params['w'];
 103                 unset( $params['w'] );
 104         }
 105         if ( isset( $params['width'] ) && substr( $params['width'], -2 ) == 'px' ) {
 106                 // strip the px (pixel) suffix, if found
 107                 $params['width'] = substr( $params['width'], 0, -2 );
 108         }
 109         if ( isset( $params['p'] ) ) {
 110                 $params['page'] = $params['p'];
 111         }
 112
 113         // Is this a thumb of an archived file?
 114         $isOld = ( isset( $params['archived'] ) && $params['archived'] );
 115         unset( $params['archived'] ); // handlers don't care
 116
 117         // Is this a thumb of a temp file?
 118         $isTemp = ( isset( $params['temp'] ) && $params['temp'] );
 119         unset( $params['temp'] ); // handlers don't care
 120
 121         // Some basic input validation
 122         $fileName = strtr( $fileName, '\\/', '__' );
 123
 124         // Actually fetch the image. Method depends on whether it is archived or not.
 125         if ( $isTemp ) {
 126                 $repo = RepoGroup::singleton()->getLocalRepo()->getTempRepo();
 127                 $img = new UnregisteredLocalFile( null, $repo,
 128                         # Temp files are hashed based on the name without the timestamp.
 129                         # The thumbnails will be hashed based on the entire name however.
 130                         # @todo fix this convention to actually be reasonable.
 131                         $repo->getZonePath( 'public' ) . '/' . $repo->getTempHashPath( $fileName ) . $fileName
 132                 );
 133         } elseif ( $isOld ) {
 134                 // Format is <timestamp>!<name>
 135                 $bits = explode( '!', $fileName, 2 );
 136                 if ( count( $bits ) != 2 ) {
 137                         wfThumbError( 404, wfMessage( 'badtitletext' )->parse() );
 138                         return;
 139                 }
 140                 $title = Title::makeTitleSafe( NS_FILE, $bits[1] );
 141                 if ( !$title ) {
 142                         wfThumbError( 404, wfMessage( 'badtitletext' )->parse() );
 143                         return;
 144                 }
 145                 $img = RepoGroup::singleton()->getLocalRepo()->newFromArchiveName( $title, $fileName );
 146         } else {
 147                 $img = wfLocalFile( $fileName );
 148         }
 149
 150         // Check the source file title
 151         if ( !$img ) {
 152                 wfThumbError( 404, wfMessage( 'badtitletext' )->parse() );
 153                 return;
 154         }
 155
 156         // Check permissions if there are read restrictions
 157         $varyHeader = array();
 158         if ( !in_array( 'read', User::getGroupPermissions( array( '*' ) ), true ) ) {
 159                 if ( !$img->getTitle() || !$img->getTitle()->userCan( 'read' ) ) {
 160                         wfThumbError( 403, 'Access denied. You do not have permission to access ' .
 161                                 'the source file.' );
 162                         return;
 163                 }
 164                 $headers[] = 'Cache-Control: private';
 165                 $varyHeader[] = 'Cookie';
 166         }
 167
 168         // Check if the file is hidden
 169         if ( $img->isDeleted( File::DELETED_FILE ) ) {
 170                 wfThumbError( 404, "The source file '$fileName' does not exist." );
 171                 return;
 172         }
 173
 174         // Do rendering parameters extraction from thumbnail name.
 175         if ( isset( $params['thumbName'] ) ) {
 176                 $params = wfExtractThumbParams( $img, $params );
 177         }
 178         if ( $params == null ) {
 179                 wfThumbError( 400, 'The specified thumbnail parameters are not recognized.' );
 180                 return;
 181         }
 182
 183         // Check the source file storage path
 184         if ( !$img->exists() ) {
 185                 $redirectedLocation = false;
 186                 if ( !$isTemp ) {
 187                         // Check for file redirect
 188                         // Since redirects are associated with pages, not versions of files,
 189                         // we look for the most current version to see if its a redirect.
 190                         $possRedirFile = RepoGroup::singleton()->getLocalRepo()->findFile( $img->getName() );
 191                         if ( $possRedirFile && !is_null( $possRedirFile->getRedirected() ) ) {
 192                                 $redirTarget = $possRedirFile->getName();
 193                                 $targetFile = wfLocalFile( Title::makeTitleSafe( NS_FILE, $redirTarget ) );
 194                                 if ( $targetFile->exists() ) {
 195                                         $newThumbName = $targetFile->thumbName( $params );
 196                                         if ( $isOld ) {
 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->header( "HTTP/1.1 302 " . HttpStatus::getMessage( 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( ', ', $varyHeader ) );
 219                         }
 220                         return;
 221                 }
 222
 223                 // If its not a redirect that has a target as a local file, give 404.
 224                 wfThumbError( 404, "The source file '$fileName' does not exist." );
 225                 return;
 226         } elseif ( $img->getPath() === false ) {
 227                 wfThumbError( 500, "The source file '$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                 wfSuppressWarnings();
 238                 $imsUnix = strtotime( $imsString );
 239                 wfRestoreWarnings();
 240                 if ( wfTimestamp( TS_UNIX, $img->getTimestamp() ) <= $imsUnix ) {
 241                         header( 'HTTP/1.1 304 Not Modified' );
 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( 'Empty return from File::thumbName' );
 256                 }
 257                 $thumbName2 = $img->thumbName( $params, File::THUMB_FULL_NAME ); // b/c; "long" style
 258         } catch ( MediaTransformInvalidParametersException $e ) {
 259                 wfThumbError( 400, 'The specified thumbnail parameters are not valid: ' . $e->getMessage() );
 260                 return;
 261         } catch ( MWException $e ) {
 262                 wfThumbError( 500, $e->getHTML() );
 263                 return;
 264         }
 265
 266         // For 404 handled thumbnails, we only use the base name of the URI
 267         // for the thumb params and the parent directory for the source file name.
 268         // Check that the zone relative path matches up so squid caches won't pick
 269         // up thumbs that would not be purged on source file deletion (bug 34231).
 270         if ( $rel404 !== null ) { // thumbnail was handled via 404
 271                 if ( rawurldecode( $rel404 ) === $img->getThumbRel( $thumbName ) ) {
 272                         // Request for the canonical thumbnail name
 273                 } elseif ( rawurldecode( $rel404 ) === $img->getThumbRel( $thumbName2 ) ) {
 274                         // Request for the "long" thumbnail name; redirect to canonical name
 275                         $response = RequestContext::getMain()->getRequest()->response();
 276                         $response->header( "HTTP/1.1 301 " . HttpStatus::getMessage( 301 ) );
 277                         $response->header( 'Location: ' .
 278                                 wfExpandUrl( $img->getThumbUrl( $thumbName ), PROTO_CURRENT ) );
 279                         $response->header( 'Expires: ' .
 280                                 gmdate( 'D, d M Y H:i:s', time() + 7 * 86400 ) . ' GMT' );
 281                         if ( $wgVaryOnXFP ) {
 282                                 $varyHeader[] = 'X-Forwarded-Proto';
 283                         }
 284                         if ( count( $varyHeader ) ) {
 285                                 $response->header( 'Vary: ' . implode( ', ', $varyHeader ) );
 286                         }
 287                         return;
 288                 } else {
 289                         wfThumbError( 404, "The given path of the specified thumbnail is incorrect;
 290                                 expected '" . $img->getThumbRel( $thumbName ) . "' but got '" .
 291                                 rawurldecode( $rel404 ) . "'." );
 292                         return;
 293                 }
 294         }
 295
 296         $dispositionType = isset( $params['download'] ) ? 'attachment' : 'inline';
 297
 298         // Suggest a good name for users downloading this thumbnail
 299         $headers[] = "Content-Disposition: {$img->getThumbDisposition( $thumbName, $dispositionType )}";
 300
 301         if ( count( $varyHeader ) ) {
 302                 $headers[] = 'Vary: ' . implode( ', ', $varyHeader );
 303         }
 304
 305         // Stream the file if it exists already...
 306         $thumbPath = $img->getThumbPath( $thumbName );
 307         if ( $img->getRepo()->fileExists( $thumbPath ) ) {
 308                 $img->getRepo()->streamFile( $thumbPath, $headers );
 309                 return;
 310         }
 311
 312         $user = RequestContext::getMain()->getUser();
 313         if ( !wfThumbIsStandard( $img, $params ) && $user->pingLimiter( 'renderfile-nonstandard' ) ) {
 314                 wfThumbError( 500, wfMessage( 'actionthrottledtext' )->parse() );
 315                 return;
 316         } elseif ( $user->pingLimiter( 'renderfile' ) ) {
 317                 wfThumbError( 500, wfMessage( 'actionthrottledtext' )->parse() );
 318                 return;
 319         }
 320
 321         // Actually generate a new thumbnail
 322         list( $thumb, $errorMsg ) = wfGenerateThumbnail( $img, $params, $thumbName, $thumbPath );
 323
 324         // Check for thumbnail generation errors...
 325         $msg = wfMessage( 'thumbnail_error' );
 326         $errorCode = 500;
 327         if ( !$thumb ) {
 328                 $errorMsg = $errorMsg ?: $msg->rawParams( 'File::transform() returned false' )->escaped();
 329         } elseif ( $thumb->isError() ) {
 330                 $errorMsg = $thumb->getHtmlMsg();
 331         } elseif ( !$thumb->hasFile() ) {
 332                 $errorMsg = $msg->rawParams( 'No path supplied in thumbnail object' )->escaped();
 333         } elseif ( $thumb->fileIsSource() ) {
 334                 $errorMsg = $msg->
 335                         rawParams( 'Image was not scaled, is the requested width bigger than the source?' )->escaped();
 336                 $errorCode = 400;
 337         }
 338
 339         if ( $errorMsg !== false ) {
 340                 wfThumbError( $errorCode, $errorMsg );
 341         } else {
 342                 // Stream the file if there were no errors
 343                 $thumb->streamFile( $headers );
 344         }
 345 }
 346
 347 /**
 348  * Actually try to generate a new thumbnail
 349  *
 350  * @param File $file
 351  * @param array $params
 352  * @param string $thumbName
 353  * @param string $thumbPath
 354  * @return array (MediaTransformOutput|bool, string|bool error message HTML)
 355  */
 356 function wfGenerateThumbnail( File $file, array $params, $thumbName, $thumbPath ) {
 357         global $wgMemc, $wgAttemptFailureEpoch;
 358
 359         $key = wfMemcKey( 'attempt-failures', $wgAttemptFailureEpoch,
 360                 $file->getRepo()->getName(), $file->getSha1(), md5( $thumbName ) );
 361
 362         // Check if this file keeps failing to render
 363         if ( $wgMemc->get( $key ) >= 4 ) {
 364                 return array( false, wfMessage( 'thumbnail_image-failure-limit', 4 ) );
 365         }
 366
 367         $done = false;
 368         // Record failures on PHP fatals in addition to caching exceptions
 369         register_shutdown_function( function () use ( &$done, $key ) {
 370                 if ( !$done ) { // transform() gave a fatal
 371                         global $wgMemc;
 372                         // Randomize TTL to reduce stampedes
 373                         $wgMemc->incrWithInit( $key, 3600 + mt_rand( 0, 300 ) );
 374                 }
 375         } );
 376
 377         $thumb = false;
 378         $errorHtml = false;
 379
 380         // guard thumbnail rendering with PoolCounter to avoid stampedes
 381         // expensive files use a separate PoolCounter config so it is possible
 382         // to set up a global limit on them
 383         if ( $file->isExpensiveToThumbnail() ) {
 384                 $poolCounterType = 'FileRenderExpensive';
 385         } else {
 386                 $poolCounterType = 'FileRender';
 387         }
 388
 389         // Thumbnail isn't already there, so create the new thumbnail...
 390         try {
 391                 $work = new PoolCounterWorkViaCallback( $poolCounterType, sha1( $file->getName() ),
 392                         array(
 393                                 'doWork' => function () use ( $file, $params ) {
 394                                         return $file->transform( $params, File::RENDER_NOW );
 395                                 },
 396                                 'getCachedWork' => function () use ( $file, $params, $thumbPath ) {
 397                                         // If the worker that finished made this thumbnail then use it.
 398                                         // Otherwise, it probably made a different thumbnail for this file.
 399                                         return $file->getRepo()->fileExists( $thumbPath )
 400                                                 ? $file->transform( $params, File::RENDER_NOW )
 401                                                 : false; // retry once more in exclusive mode
 402                                 },
 403                                 'fallback' => function () {
 404                                         return wfMessage( 'generic-pool-error' )->parse();
 405                                 },
 406                                 'error' => function ( $status ) {
 407                                         return $status->getHTML();
 408                                 }
 409                         )
 410                 );
 411                 $result = $work->execute();
 412                 if ( $result instanceof MediaTransformOutput ) {
 413                         $thumb = $result;
 414                 } elseif ( is_string( $result ) ) { // error
 415                         $errorHtml = $result;
 416                 }
 417         } catch ( Exception $e ) {
 418                 // Tried to select a page on a non-paged file?
 419         }
 420
 421         $done = true; // no PHP fatal occured
 422
 423         if ( !$thumb || $thumb->isError() ) {
 424                 // Randomize TTL to reduce stampedes
 425                 $wgMemc->incrWithInit( $key, 3600 + mt_rand( 0, 300 ) );
 426         }
 427
 428         return array( $thumb, $errorHtml );
 429 }
 430
 431 /**
 432  * Returns true if this thumbnail is one that MediaWiki generates
 433  * links to on file description pages and possibly parser output.
 434  *
 435  * $params is considered non-standard if they involve a non-standard
 436  * width or any non-default parameters aside from width and page number.
 437  * The number of possible files with standard parameters is far less than
 438  * that of all combinations; rate-limiting for them can thus be more generious.
 439  *
 440  * @param File $file
 441  * @param array $params
 442  * @return bool
 443  */
 444 function wfThumbIsStandard( File $file, array $params ) {
 445         global $wgThumbLimits, $wgImageLimits;
 446
 447         $handler = $file->getHandler();
 448         if ( !$handler || !isset( $params['width'] ) ) {
 449                 return false;
 450         }
 451
 452         $basicParams = array();
 453         if ( isset( $params['page'] ) ) {
 454                 $basicParams['page'] = $params['page'];
 455         }
 456
 457         // Check if the width matches one of $wgThumbLimits
 458         if ( in_array( $params['width'], $wgThumbLimits ) ) {
 459                 $normalParams = $basicParams + array( 'width' => $params['width'] );
 460                 // Append any default values to the map (e.g. "lossy", "lossless", ...)
 461                 $handler->normaliseParams( $file, $normalParams );
 462         } else {
 463                 // If not, then check if the width matchs one of $wgImageLimits
 464                 $match = false;
 465                 foreach ( $wgImageLimits as $pair ) {
 466                         $normalParams = $basicParams + array( 'width' => $pair[0], 'height' => $pair[1] );
 467                         // Decide whether the thumbnail should be scaled on width or height.
 468                         // Also append any default values to the map (e.g. "lossy", "lossless", ...)
 469                         $handler->normaliseParams( $file, $normalParams );
 470                         // Check if this standard thumbnail size maps to the given width
 471                         if ( $normalParams['width'] == $params['width'] ) {
 472                                 $match = true;
 473                                 break;
 474                         }
 475                 }
 476                 if ( !$match ) {
 477                         return false; // not standard for description pages
 478                 }
 479         }
 480
 481         // Check that the given values for non-page, non-width, params are just defaults
 482         foreach ( $params as $key => $value ) {
 483                 if ( !isset( $normalParams[$key] ) || $normalParams[$key] != $value ) {
 484                         return false;
 485                 }
 486         }
 487
 488         return true;
 489 }
 490
 491 /**
 492  * Convert pathinfo type parameter, into normal request parameters
 493  *
 494  * So for example, if the request was redirected from
 495  * /w/images/thumb/a/ab/Foo.png/120px-Foo.png. The $thumbRel parameter
 496  * of this function would be set to "a/ab/Foo.png/120px-Foo.png".
 497  * This method is responsible for turning that into an array
 498  * with the folowing keys:
 499  *  * f => the filename (Foo.png)
 500  *  * rel404 => the whole thing (a/ab/Foo.png/120px-Foo.png)
 501  *  * archived => 1 (If the request is for an archived thumb)
 502  *  * temp => 1 (If the file is in the "temporary" zone)
 503  *  * thumbName => the thumbnail name, including parameters (120px-Foo.png)
 504  *
 505  * Transform specific parameters are set later via wfExtractThumbParams().
 506  *
 507  * @param string $thumbRel Thumbnail path relative to the thumb zone
 508  * @return array|null Associative params array or null
 509  */
 510 function wfExtractThumbRequestInfo( $thumbRel ) {
 511         $repo = RepoGroup::singleton()->getLocalRepo();
 512
 513         $hashDirReg = $subdirReg = '';
 514         $hashLevels = $repo->getHashLevels();
 515         for ( $i = 0; $i < $hashLevels; $i++ ) {
 516                 $subdirReg .= '[0-9a-f]';
 517                 $hashDirReg .= "$subdirReg/";
 518         }
 519
 520         // Check if this is a thumbnail of an original in the local file repo
 521         if ( preg_match( "!^((archive/)?$hashDirReg([^/]*)/([^/]*))$!", $thumbRel, $m ) ) {
 522                 list( /*all*/, $rel, $archOrTemp, $filename, $thumbname ) = $m;
 523         // Check if this is a thumbnail of an temp file in the local file repo
 524         } elseif ( preg_match( "!^(temp/)($hashDirReg([^/]*)/([^/]*))$!", $thumbRel, $m ) ) {
 525                 list( /*all*/, $archOrTemp, $rel, $filename, $thumbname ) = $m;
 526         } else {
 527                 return null; // not a valid looking thumbnail request
 528         }
 529
 530         $params = array( 'f' => $filename, 'rel404' => $rel );
 531         if ( $archOrTemp === 'archive/' ) {
 532                 $params['archived'] = 1;
 533         } elseif ( $archOrTemp === 'temp/' ) {
 534                 $params['temp'] = 1;
 535         }
 536
 537         $params['thumbName'] = $thumbname;
 538         return $params;
 539 }
 540
 541 /**
 542  * Convert a thumbnail name (122px-foo.png) to parameters, using
 543  * file handler.
 544  *
 545  * @param File $file File object for file in question
 546  * @param array $params Array of parameters so far
 547  * @return array Parameters array with more parameters
 548  */
 549 function wfExtractThumbParams( $file, $params ) {
 550         if ( !isset( $params['thumbName'] ) ) {
 551                 throw new MWException( "No thumbnail name passed to wfExtractThumbParams" );
 552         }
 553
 554         $thumbname = $params['thumbName'];
 555         unset( $params['thumbName'] );
 556
 557         // Do the hook first for older extensions that rely on it.
 558         if ( !wfRunHooks( 'ExtractThumbParameters', array( $thumbname, &$params ) ) ) {
 559                 // Check hooks if parameters can be extracted
 560                 // Hooks return false if they manage to *resolve* the parameters
 561                 // This hook should be considered deprecated
 562                 wfDeprecated( 'ExtractThumbParameters', '1.22' );
 563                 return $params; // valid thumbnail URL (via extension or config)
 564         }
 565
 566         // FIXME: Files in the temp zone don't set a MIME type, which means
 567         // they don't have a handler. Which means we can't parse the param
 568         // string. However, not a big issue as what good is a param string
 569         // if you have no handler to make use of the param string and
 570         // actually generate the thumbnail.
 571         $handler = $file->getHandler();
 572
 573         // Based on UploadStash::parseKey
 574         $fileNamePos = strrpos( $thumbname, $params['f'] );
 575         if ( $fileNamePos === false ) {
 576                 // Maybe using a short filename? (see FileRepo::nameForThumb)
 577                 $fileNamePos = strrpos( $thumbname, 'thumbnail' );
 578         }
 579
 580         if ( $handler && $fileNamePos !== false ) {
 581                 $paramString = substr( $thumbname, 0, $fileNamePos - 1 );
 582                 $extraParams = $handler->parseParamString( $paramString );
 583                 if ( $extraParams !== false ) {
 584                         return $params + $extraParams;
 585                 }
 586         }
 587
 588         // As a last ditch fallback, use the traditional common parameters
 589         if ( preg_match( '!^(page(\d*)-)*(\d*)px-[^/]*$!', $thumbname, $matches ) ) {
 590                 list( /* all */, $pagefull, $pagenum, $size ) = $matches;
 591                 $params['width'] = $size;
 592                 if ( $pagenum ) {
 593                         $params['page'] = $pagenum;
 594                 }
 595                 return $params; // valid thumbnail URL
 596         }
 597         return null;
 598 }
 599
 600 /**
 601  * Output a thumbnail generation error message
 602  *
 603  * @param int $status
 604  * @param string $msg HTML
 605  * @return void
 606  */
 607 function wfThumbError( $status, $msg ) {
 608         global $wgShowHostnames;
 609
 610         header( 'Cache-Control: no-cache' );
 611         header( 'Content-Type: text/html; charset=utf-8' );
 612         if ( $status == 400 ) {
 613                 header( 'HTTP/1.1 400 Bad request' );
 614         } elseif ( $status == 404 ) {
 615                 header( 'HTTP/1.1 404 Not found' );
 616         } elseif ( $status == 403 ) {
 617                 header( 'HTTP/1.1 403 Forbidden' );
 618                 header( 'Vary: Cookie' );
 619         } else {
 620                 header( 'HTTP/1.1 500 Internal server error' );
 621         }
 622         if ( $wgShowHostnames ) {
 623                 header( 'X-MW-Thumbnail-Renderer: ' . wfHostname() );
 624                 $url = htmlspecialchars( isset( $_SERVER['REQUEST_URI'] ) ? $_SERVER['REQUEST_URI'] : '' );
 625                 $hostname = htmlspecialchars( wfHostname() );
 626                 $debug = "<!-- $url -->\n<!-- $hostname -->\n";
 627         } else {
 628                 $debug = '';
 629         }
 630         echo <<<EOT
 631 <html><head><title>Error generating thumbnail</title></head>
 632 <body>
 633 <h1>Error generating thumbnail</h1>
 634 <p>
 635 $msg
 636 </p>
 637 $debug
 638 </body>
 639 </html>
 640
 641 EOT;
 642 }