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 define( 'MW_ENTRY_POINT', 'thumb' );
  29 require __DIR__ . '/includes/WebStart.php';
  30
  31 // Don't use fancy MIME detection, just check the file extension for jpg/gif/png
  32 $wgTrivialMimeDetection = true;
  33
  34 if ( defined( 'THUMB_HANDLER' ) ) {
  35         // Called from thumb_handler.php via 404; extract params from the URI...
  36         wfThumbHandle404();
  37 } else {
  38         // Called directly, use $_GET params
  39         wfStreamThumb( $wgRequest->getQueryValuesOnly() );
  40 }
  41
  42 $mediawiki = new MediaWiki();
  43 $mediawiki->doPostOutputShutdown( 'fast' );
  44
  45 // --------------------------------------------------------------------------
  46
  47 /**
  48  * Handle a thumbnail request via thumbnail file URL
  49  *
  50  * @return void
  51  */
  52 function wfThumbHandle404() {
  53         global $wgArticlePath;
  54
  55         # Set action base paths so that WebRequest::getPathInfo()
  56         # recognizes the "X" as the 'title' in ../thumb_handler.php/X urls.
  57         # Note: If Custom per-extension repo paths are set, this may break.
  58         $repo = RepoGroup::singleton()->getLocalRepo();
  59         $oldArticlePath = $wgArticlePath;
  60         $wgArticlePath = $repo->getZoneUrl( 'thumb' ) . '/$1';
  61
  62         $matches = WebRequest::getPathInfo();
  63
  64         $wgArticlePath = $oldArticlePath;
  65
  66         if ( !isset( $matches['title'] ) ) {
  67                 wfThumbError( 404, 'Could not determine the name of the requested thumbnail.' );
  68                 return;
  69         }
  70
  71         $params = wfExtractThumbRequestInfo( $matches['title'] ); // basic wiki URL param extracting
  72         if ( $params == null ) {
  73                 wfThumbError( 400, 'The specified thumbnail parameters are not recognized.' );
  74                 return;
  75         }
  76
  77         wfStreamThumb( $params ); // stream the thumbnail
  78 }
  79
  80 /**
  81  * Stream a thumbnail specified by parameters
  82  *
  83  * @param array $params List of thumbnailing parameters. In addition to parameters
  84  *  passed to the MediaHandler, this may also includes the keys:
  85  *   f (for filename), archived (if archived file), temp (if temp file),
  86  *   w (alias for width), p (alias for page), r (ignored; historical),
  87  *   rel404 (path for render on 404 to verify hash path correct),
  88  *   thumbName (thumbnail name to potentially extract more parameters from
  89  *   e.g. 'lossy-page1-120px-Foo.tiff' would add page, lossy and width
  90  *   to the parameters)
  91  * @return void
  92  */
  93 function wfStreamThumb( array $params ) {
  94         global $wgVaryOnXFP;
  95         $permissionManager = MediaWikiServices::getInstance()->getPermissionManager();
  96
  97         $headers = []; // HTTP headers to send
  98
  99         $fileName = $params['f'] ?? '';
 100
 101         // Backwards compatibility parameters
 102         if ( isset( $params['w'] ) ) {
 103                 $params['width'] = $params['w'];
 104                 unset( $params['w'] );
 105         }
 106         if ( isset( $params['width'] ) && substr( $params['width'], -2 ) == 'px' ) {
 107                 // strip the px (pixel) suffix, if found
 108                 $params['width'] = substr( $params['width'], 0, -2 );
 109         }
 110         if ( isset( $params['p'] ) ) {
 111                 $params['page'] = $params['p'];
 112         }
 113
 114         // Is this a thumb of an archived file?
 115         $isOld = ( isset( $params['archived'] ) && $params['archived'] );
 116         unset( $params['archived'] ); // handlers don't care
 117
 118         // Is this a thumb of a temp file?
 119         $isTemp = ( isset( $params['temp'] ) && $params['temp'] );
 120         unset( $params['temp'] ); // handlers don't care
 121
 122         // Some basic input validation
 123         $fileName = strtr( $fileName, '\\/', '__' );
 124
 125         // Actually fetch the image. Method depends on whether it is archived or not.
 126         if ( $isTemp ) {
 127                 $repo = RepoGroup::singleton()->getLocalRepo()->getTempRepo();
 128                 $img = new UnregisteredLocalFile( null, $repo,
 129                         # Temp files are hashed based on the name without the timestamp.
 130                         # The thumbnails will be hashed based on the entire name however.
 131                         # @todo fix this convention to actually be reasonable.
 132                         $repo->getZonePath( 'public' ) . '/' . $repo->getTempHashPath( $fileName ) . $fileName
 133                 );
 134         } elseif ( $isOld ) {
 135                 // Format is <timestamp>!<name>
 136                 $bits = explode( '!', $fileName, 2 );
 137                 if ( count( $bits ) != 2 ) {
 138                         wfThumbError( 404, wfMessage( 'badtitletext' )->parse() );
 139                         return;
 140                 }
 141                 $title = Title::makeTitleSafe( NS_FILE, $bits[1] );
 142                 if ( !$title ) {
 143                         wfThumbError( 404, wfMessage( 'badtitletext' )->parse() );
 144                         return;
 145                 }
 146                 $img = RepoGroup::singleton()->getLocalRepo()->newFromArchiveName( $title, $fileName );
 147         } else {
 148                 $img = wfLocalFile( $fileName );
 149         }
 150
 151         // Check the source file title
 152         if ( !$img ) {
 153                 wfThumbError( 404, wfMessage( 'badtitletext' )->parse() );
 154                 return;
 155         }
 156
 157         // Check permissions if there are read restrictions
 158         $varyHeader = [];
 159         if ( !in_array( 'read', $permissionManager->getGroupPermissions( [ '*' ] ), true ) ) {
 160                 $user = RequestContext::getMain()->getUser();
 161                 $imgTitle = $img->getTitle();
 162
 163                 if ( !$imgTitle || !$permissionManager->userCan( 'read', $user, $imgTitle ) ) {
 164                         wfThumbError( 403, 'Access denied. You do not have permission to access ' .
 165                                 'the source file.' );
 166                         return;
 167                 }
 168                 $headers[] = 'Cache-Control: private';
 169                 $varyHeader[] = 'Cookie';
 170         }
 171
 172         // Check if the file is hidden
 173         if ( $img->isDeleted( File::DELETED_FILE ) ) {
 174                 wfThumbErrorText( 404, "The source file '$fileName' does not exist." );
 175                 return;
 176         }
 177
 178         // Do rendering parameters extraction from thumbnail name.
 179         if ( isset( $params['thumbName'] ) ) {
 180                 $params = wfExtractThumbParams( $img, $params );
 181         }
 182         if ( $params == null ) {
 183                 wfThumbError( 400, 'The specified thumbnail parameters are not recognized.' );
 184                 return;
 185         }
 186
 187         // Check the source file storage path
 188         if ( !$img->exists() ) {
 189                 $redirectedLocation = false;
 190                 if ( !$isTemp ) {
 191                         // Check for file redirect
 192                         // Since redirects are associated with pages, not versions of files,
 193                         // we look for the most current version to see if its a redirect.
 194                         $possRedirFile = RepoGroup::singleton()->getLocalRepo()->findFile( $img->getName() );
 195                         if ( $possRedirFile && !is_null( $possRedirFile->getRedirected() ) ) {
 196                                 $redirTarget = $possRedirFile->getName();
 197                                 $targetFile = wfLocalFile( Title::makeTitleSafe( NS_FILE, $redirTarget ) );
 198                                 if ( $targetFile->exists() ) {
 199                                         $newThumbName = $targetFile->thumbName( $params );
 200                                         if ( $isOld ) {
 201                                                 /** @var array $bits */
 202                                                 $newThumbUrl = $targetFile->getArchiveThumbUrl(
 203                                                         $bits[0] . '!' . $targetFile->getName(), $newThumbName );
 204                                         } else {
 205                                                 $newThumbUrl = $targetFile->getThumbUrl( $newThumbName );
 206                                         }
 207                                         $redirectedLocation = wfExpandUrl( $newThumbUrl, PROTO_CURRENT );
 208                                 }
 209                         }
 210                 }
 211
 212                 if ( $redirectedLocation ) {
 213                         // File has been moved. Give redirect.
 214                         $response = RequestContext::getMain()->getRequest()->response();
 215                         $response->statusHeader( 302 );
 216                         $response->header( 'Location: ' . $redirectedLocation );
 217                         $response->header( 'Expires: ' .
 218                                 gmdate( 'D, d M Y H:i:s', time() + 12 * 3600 ) . ' GMT' );
 219                         if ( $wgVaryOnXFP ) {
 220                                 $varyHeader[] = 'X-Forwarded-Proto';
 221                         }
 222                         if ( count( $varyHeader ) ) {
 223                                 $response->header( 'Vary: ' . implode( ', ', $varyHeader ) );
 224                         }
 225                         $response->header( 'Content-Length: 0' );
 226                         return;
 227                 }
 228
 229                 // If its not a redirect that has a target as a local file, give 404.
 230                 wfThumbErrorText( 404, "The source file '$fileName' does not exist." );
 231                 return;
 232         } elseif ( $img->getPath() === false ) {
 233                 wfThumbErrorText( 400, "The source file '$fileName' is not locally accessible." );
 234                 return;
 235         }
 236
 237         // Check IMS against the source file
 238         // This means that clients can keep a cached copy even after it has been deleted on the server
 239         if ( !empty( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
 240                 // Fix IE brokenness
 241                 $imsString = preg_replace( '/;.*$/', '', $_SERVER["HTTP_IF_MODIFIED_SINCE"] );
 242                 // Calculate time
 243                 Wikimedia\suppressWarnings();
 244                 $imsUnix = strtotime( $imsString );
 245                 Wikimedia\restoreWarnings();
 246                 if ( wfTimestamp( TS_UNIX, $img->getTimestamp() ) <= $imsUnix ) {
 247                         HttpStatus::header( 304 );
 248                         return;
 249                 }
 250         }
 251
 252         $rel404 = $params['rel404'] ?? null;
 253         unset( $params['r'] ); // ignore 'r' because we unconditionally pass File::RENDER
 254         unset( $params['f'] ); // We're done with 'f' parameter.
 255         unset( $params['rel404'] ); // moved to $rel404
 256
 257         // Get the normalized thumbnail name from the parameters...
 258         try {
 259                 $thumbName = $img->thumbName( $params );
 260                 if ( !strlen( $thumbName ) ) { // invalid params?
 261                         throw new MediaTransformInvalidParametersException(
 262                                 'Empty return from File::thumbName'
 263                         );
 264                 }
 265                 $thumbName2 = $img->thumbName( $params, File::THUMB_FULL_NAME ); // b/c; "long" style
 266         } catch ( MediaTransformInvalidParametersException $e ) {
 267                 wfThumbError(
 268                         400,
 269                         'The specified thumbnail parameters are not valid: ' . $e->getMessage()
 270                 );
 271                 return;
 272         } catch ( MWException $e ) {
 273                 wfThumbError( 500, $e->getHTML(), 'Exception caught while extracting thumb name',
 274                         [ 'exception' => $e ] );
 275                 return;
 276         }
 277
 278         // For 404 handled thumbnails, we only use the base name of the URI
 279         // for the thumb params and the parent directory for the source file name.
 280         // Check that the zone relative path matches up so CDN caches won't pick
 281         // up thumbs that would not be purged on source file deletion (T36231).
 282         if ( $rel404 !== null ) { // thumbnail was handled via 404
 283                 if ( rawurldecode( $rel404 ) === $img->getThumbRel( $thumbName ) ) {
 284                         // Request for the canonical thumbnail name
 285                 } elseif ( rawurldecode( $rel404 ) === $img->getThumbRel( $thumbName2 ) ) {
 286                         // Request for the "long" thumbnail name; redirect to canonical name
 287                         $response = RequestContext::getMain()->getRequest()->response();
 288                         $response->statusHeader( 301 );
 289                         $response->header( 'Location: ' .
 290                                 wfExpandUrl( $img->getThumbUrl( $thumbName ), PROTO_CURRENT ) );
 291                         $response->header( 'Expires: ' .
 292                                 gmdate( 'D, d M Y H:i:s', time() + 7 * 86400 ) . ' GMT' );
 293                         if ( $wgVaryOnXFP ) {
 294                                 $varyHeader[] = 'X-Forwarded-Proto';
 295                         }
 296                         if ( count( $varyHeader ) ) {
 297                                 $response->header( 'Vary: ' . implode( ', ', $varyHeader ) );
 298                         }
 299                         return;
 300                 } else {
 301                         wfThumbErrorText( 404, "The given path of the specified thumbnail is incorrect;
 302                                 expected '" . $img->getThumbRel( $thumbName ) . "' but got '" .
 303                                 rawurldecode( $rel404 ) . "'." );
 304                         return;
 305                 }
 306         }
 307
 308         $dispositionType = isset( $params['download'] ) ? 'attachment' : 'inline';
 309
 310         // Suggest a good name for users downloading this thumbnail
 311         $headers[] =
 312                 "Content-Disposition: {$img->getThumbDisposition( $thumbName, $dispositionType )}";
 313
 314         if ( count( $varyHeader ) ) {
 315                 $headers[] = 'Vary: ' . implode( ', ', $varyHeader );
 316         }
 317
 318         // Stream the file if it exists already...
 319         $thumbPath = $img->getThumbPath( $thumbName );
 320         if ( $img->getRepo()->fileExists( $thumbPath ) ) {
 321                 $starttime = microtime( true );
 322                 $status = $img->getRepo()->streamFileWithStatus( $thumbPath, $headers );
 323                 $streamtime = microtime( true ) - $starttime;
 324
 325                 if ( $status->isOK() ) {
 326                         MediaWikiServices::getInstance()->getStatsdDataFactory()->timing(
 327                                 'media.thumbnail.stream', $streamtime
 328                         );
 329                 } else {
 330                         wfThumbError( 500, 'Could not stream the file', null, [ 'file' => $thumbName,
 331                                 'path' => $thumbPath, 'error' => $status->getWikiText( false, false, 'en' ) ] );
 332                 }
 333                 return;
 334         }
 335
 336         $user = RequestContext::getMain()->getUser();
 337         if ( !wfThumbIsStandard( $img, $params ) && $user->pingLimiter( 'renderfile-nonstandard' ) ) {
 338                 wfThumbError( 429, wfMessage( 'actionthrottledtext' )->parse() );
 339                 return;
 340         } elseif ( $user->pingLimiter( 'renderfile' ) ) {
 341                 wfThumbError( 429, wfMessage( 'actionthrottledtext' )->parse() );
 342                 return;
 343         }
 344
 345         $thumbProxyUrl = $img->getRepo()->getThumbProxyUrl();
 346
 347         if ( strlen( $thumbProxyUrl ) ) {
 348                 wfProxyThumbnailRequest( $img, $thumbName );
 349                 // No local fallback when in proxy mode
 350                 return;
 351         } else {
 352                 // Generate the thumbnail locally
 353                 list( $thumb, $errorMsg ) = wfGenerateThumbnail( $img, $params, $thumbName, $thumbPath );
 354         }
 355
 356         /** @var MediaTransformOutput|MediaTransformError|bool $thumb */
 357
 358         // Check for thumbnail generation errors...
 359         $msg = wfMessage( 'thumbnail_error' );
 360         $errorCode = 500;
 361
 362         if ( !$thumb ) {
 363                 $errorMsg = $errorMsg ?: $msg->rawParams( 'File::transform() returned false' )->escaped();
 364                 if ( $errorMsg instanceof MessageSpecifier &&
 365                         $errorMsg->getKey() === 'thumbnail_image-failure-limit'
 366                 ) {
 367                         $errorCode = 429;
 368                 }
 369         } elseif ( $thumb->isError() ) {
 370                 $errorMsg = $thumb->getHtmlMsg();
 371                 $errorCode = $thumb->getHttpStatusCode();
 372         } elseif ( !$thumb->hasFile() ) {
 373                 $errorMsg = $msg->rawParams( 'No path supplied in thumbnail object' )->escaped();
 374         } elseif ( $thumb->fileIsSource() ) {
 375                 $errorMsg = $msg
 376                         ->rawParams( 'Image was not scaled, is the requested width bigger than the source?' )
 377                         ->escaped();
 378                 $errorCode = 400;
 379         }
 380
 381         if ( $errorMsg !== false ) {
 382                 wfThumbError( $errorCode, $errorMsg, null, [ 'file' => $thumbName, 'path' => $thumbPath ] );
 383         } else {
 384                 // Stream the file if there were no errors
 385                 $status = $thumb->streamFileWithStatus( $headers );
 386                 if ( !$status->isOK() ) {
 387                         wfThumbError( 500, 'Could not stream the file', null, [
 388                                 'file' => $thumbName, 'path' => $thumbPath,
 389                                 'error' => $status->getWikiText( false, false, 'en' ) ] );
 390                 }
 391         }
 392 }
 393
 394 /**
 395  * Proxies thumbnail request to a service that handles thumbnailing
 396  *
 397  * @param File $img
 398  * @param string $thumbName
 399  */
 400 function wfProxyThumbnailRequest( $img, $thumbName ) {
 401         $thumbProxyUrl = $img->getRepo()->getThumbProxyUrl();
 402
 403         // Instead of generating the thumbnail ourselves, we proxy the request to another service
 404         $thumbProxiedUrl = $thumbProxyUrl . $img->getThumbRel( $thumbName );
 405
 406         $req = MWHttpRequest::factory( $thumbProxiedUrl );
 407         $secret = $img->getRepo()->getThumbProxySecret();
 408
 409         // Pass a secret key shared with the proxied service if any
 410         if ( strlen( $secret ) ) {
 411                 $req->setHeader( 'X-Swift-Secret', $secret );
 412         }
 413
 414         // Send request to proxied service
 415         $status = $req->execute();
 416
 417         MediaWiki\HeaderCallback::warnIfHeadersSent();
 418
 419         // Simply serve the response from the proxied service as-is
 420         header( 'HTTP/1.1 ' . $req->getStatus() );
 421
 422         $headers = $req->getResponseHeaders();
 423
 424         foreach ( $headers as $key => $values ) {
 425                 foreach ( $values as $value ) {
 426                         header( $key . ': ' . $value, false );
 427                 }
 428         }
 429
 430         echo $req->getContent();
 431 }
 432
 433 /**
 434  * Actually try to generate a new thumbnail
 435  *
 436  * @param File $file
 437  * @param array $params
 438  * @param string $thumbName
 439  * @param string $thumbPath
 440  * @return array (MediaTransformOutput|bool, string|bool error message HTML)
 441  */
 442 function wfGenerateThumbnail( File $file, array $params, $thumbName, $thumbPath ) {
 443         global $wgAttemptFailureEpoch;
 444
 445         $cache = ObjectCache::getLocalClusterInstance();
 446         $key = $cache->makeKey(
 447                 'attempt-failures',
 448                 $wgAttemptFailureEpoch,
 449                 $file->getRepo()->getName(),
 450                 $file->getSha1(),
 451                 md5( $thumbName )
 452         );
 453
 454         // Check if this file keeps failing to render
 455         if ( $cache->get( $key ) >= 4 ) {
 456                 return [ false, wfMessage( 'thumbnail_image-failure-limit', 4 ) ];
 457         }
 458
 459         $done = false;
 460         // Record failures on PHP fatals in addition to caching exceptions
 461         register_shutdown_function( function () use ( $cache, &$done, $key ) {
 462                 if ( !$done ) { // transform() gave a fatal
 463                         // Randomize TTL to reduce stampedes
 464                         $cache->incrWithInit( $key, $cache::TTL_HOUR + mt_rand( 0, 300 ) );
 465                 }
 466         } );
 467
 468         $thumb = false;
 469         $errorHtml = false;
 470
 471         // guard thumbnail rendering with PoolCounter to avoid stampedes
 472         // expensive files use a separate PoolCounter config so it is possible
 473         // to set up a global limit on them
 474         if ( $file->isExpensiveToThumbnail() ) {
 475                 $poolCounterType = 'FileRenderExpensive';
 476         } else {
 477                 $poolCounterType = 'FileRender';
 478         }
 479
 480         // Thumbnail isn't already there, so create the new thumbnail...
 481         try {
 482                 $work = new PoolCounterWorkViaCallback( $poolCounterType, sha1( $file->getName() ),
 483                         [
 484                                 'doWork' => function () use ( $file, $params ) {
 485                                         return $file->transform( $params, File::RENDER_NOW );
 486                                 },
 487                                 'doCachedWork' => function () use ( $file, $params, $thumbPath ) {
 488                                         // If the worker that finished made this thumbnail then use it.
 489                                         // Otherwise, it probably made a different thumbnail for this file.
 490                                         return $file->getRepo()->fileExists( $thumbPath )
 491                                                 ? $file->transform( $params, File::RENDER_NOW )
 492                                                 : false; // retry once more in exclusive mode
 493                                 },
 494                                 'error' => function ( Status $status ) {
 495                                         return wfMessage( 'generic-pool-error' )->parse() . '<hr>' . $status->getHTML();
 496                                 }
 497                         ]
 498                 );
 499                 $result = $work->execute();
 500                 if ( $result instanceof MediaTransformOutput ) {
 501                         $thumb = $result;
 502                 } elseif ( is_string( $result ) ) { // error
 503                         $errorHtml = $result;
 504                 }
 505         } catch ( Exception $e ) {
 506                 // Tried to select a page on a non-paged file?
 507         }
 508
 509         /** @noinspection PhpUnusedLocalVariableInspection */
 510         $done = true; // no PHP fatal occurred
 511
 512         if ( !$thumb || $thumb->isError() ) {
 513                 // Randomize TTL to reduce stampedes
 514                 $cache->incrWithInit( $key, $cache::TTL_HOUR + mt_rand( 0, 300 ) );
 515         }
 516
 517         return [ $thumb, $errorHtml ];
 518 }
 519
 520 /**
 521  * Convert pathinfo type parameter, into normal request parameters
 522  *
 523  * So for example, if the request was redirected from
 524  * /w/images/thumb/a/ab/Foo.png/120px-Foo.png. The $thumbRel parameter
 525  * of this function would be set to "a/ab/Foo.png/120px-Foo.png".
 526  * This method is responsible for turning that into an array
 527  * with the folowing keys:
 528  *  * f => the filename (Foo.png)
 529  *  * rel404 => the whole thing (a/ab/Foo.png/120px-Foo.png)
 530  *  * archived => 1 (If the request is for an archived thumb)
 531  *  * temp => 1 (If the file is in the "temporary" zone)
 532  *  * thumbName => the thumbnail name, including parameters (120px-Foo.png)
 533  *
 534  * Transform specific parameters are set later via wfExtractThumbParams().
 535  *
 536  * @param string $thumbRel Thumbnail path relative to the thumb zone
 537  * @return array|null Associative params array or null
 538  */
 539 function wfExtractThumbRequestInfo( $thumbRel ) {
 540         $repo = RepoGroup::singleton()->getLocalRepo();
 541
 542         $hashDirReg = $subdirReg = '';
 543         $hashLevels = $repo->getHashLevels();
 544         for ( $i = 0; $i < $hashLevels; $i++ ) {
 545                 $subdirReg .= '[0-9a-f]';
 546                 $hashDirReg .= "$subdirReg/";
 547         }
 548
 549         // Check if this is a thumbnail of an original in the local file repo
 550         if ( preg_match( "!^((archive/)?$hashDirReg([^/]*)/([^/]*))$!", $thumbRel, $m ) ) {
 551                 list( /*all*/, $rel, $archOrTemp, $filename, $thumbname ) = $m;
 552         // Check if this is a thumbnail of an temp file in the local file repo
 553         } elseif ( preg_match( "!^(temp/)($hashDirReg([^/]*)/([^/]*))$!", $thumbRel, $m ) ) {
 554                 list( /*all*/, $archOrTemp, $rel, $filename, $thumbname ) = $m;
 555         } else {
 556                 return null; // not a valid looking thumbnail request
 557         }
 558
 559         $params = [ 'f' => $filename, 'rel404' => $rel ];
 560         if ( $archOrTemp === 'archive/' ) {
 561                 $params['archived'] = 1;
 562         } elseif ( $archOrTemp === 'temp/' ) {
 563                 $params['temp'] = 1;
 564         }
 565
 566         $params['thumbName'] = $thumbname;
 567         return $params;
 568 }
 569
 570 /**
 571  * Convert a thumbnail name (122px-foo.png) to parameters, using
 572  * file handler.
 573  *
 574  * @param File $file File object for file in question
 575  * @param array $params Array of parameters so far
 576  * @return array Parameters array with more parameters
 577  */
 578 function wfExtractThumbParams( $file, $params ) {
 579         if ( !isset( $params['thumbName'] ) ) {
 580                 throw new InvalidArgumentException( "No thumbnail name passed to wfExtractThumbParams" );
 581         }
 582
 583         $thumbname = $params['thumbName'];
 584         unset( $params['thumbName'] );
 585
 586         // FIXME: Files in the temp zone don't set a MIME type, which means
 587         // they don't have a handler. Which means we can't parse the param
 588         // string. However, not a big issue as what good is a param string
 589         // if you have no handler to make use of the param string and
 590         // actually generate the thumbnail.
 591         $handler = $file->getHandler();
 592
 593         // Based on UploadStash::parseKey
 594         $fileNamePos = strrpos( $thumbname, $params['f'] );
 595         if ( $fileNamePos === false ) {
 596                 // Maybe using a short filename? (see FileRepo::nameForThumb)
 597                 $fileNamePos = strrpos( $thumbname, 'thumbnail' );
 598         }
 599
 600         if ( $handler && $fileNamePos !== false ) {
 601                 $paramString = substr( $thumbname, 0, $fileNamePos - 1 );
 602                 $extraParams = $handler->parseParamString( $paramString );
 603                 if ( $extraParams !== false ) {
 604                         return $params + $extraParams;
 605                 }
 606         }
 607
 608         // As a last ditch fallback, use the traditional common parameters
 609         if ( preg_match( '!^(page(\d*)-)*(\d*)px-[^/]*$!', $thumbname, $matches ) ) {
 610                 list( /* all */, /* pagefull */, $pagenum, $size ) = $matches;
 611                 $params['width'] = $size;
 612                 if ( $pagenum ) {
 613                         $params['page'] = $pagenum;
 614                 }
 615                 return $params; // valid thumbnail URL
 616         }
 617         return null;
 618 }
 619
 620 /**
 621  * Output a thumbnail generation error message
 622  *
 623  * @param int $status
 624  * @param string $msgText Plain text (will be html escaped)
 625  * @return void
 626  */
 627 function wfThumbErrorText( $status, $msgText ) {
 628         wfThumbError( $status, htmlspecialchars( $msgText, ENT_NOQUOTES ) );
 629 }
 630
 631 /**
 632  * Output a thumbnail generation error message
 633  *
 634  * @param int $status
 635  * @param string $msgHtml HTML
 636  * @param string|null $msgText Short error description, for internal logging. Defaults to $msgHtml.
 637  *   Only used for HTTP 500 errors.
 638  * @param array $context Error context, for internal logging. Only used for HTTP 500 errors.
 639  * @return void
 640  */
 641 function wfThumbError( $status, $msgHtml, $msgText = null, $context = [] ) {
 642         global $wgShowHostnames;
 643
 644         MediaWiki\HeaderCallback::warnIfHeadersSent();
 645
 646         header( 'Cache-Control: no-cache' );
 647         header( 'Content-Type: text/html; charset=utf-8' );
 648         if ( $status == 400 || $status == 404 || $status == 429 ) {
 649                 HttpStatus::header( $status );
 650         } elseif ( $status == 403 ) {
 651                 HttpStatus::header( 403 );
 652                 header( 'Vary: Cookie' );
 653         } else {
 654                 LoggerFactory::getInstance( 'thumb' )->error( $msgText ?: $msgHtml, $context );
 655                 HttpStatus::header( 500 );
 656         }
 657         if ( $wgShowHostnames ) {
 658                 header( 'X-MW-Thumbnail-Renderer: ' . wfHostname() );
 659                 $url = htmlspecialchars(
 660                         $_SERVER['REQUEST_URI'] ?? '',
 661                         ENT_NOQUOTES
 662                 );
 663                 $hostname = htmlspecialchars( wfHostname(), ENT_NOQUOTES );
 664                 $debug = "<!-- $url -->\n<!-- $hostname -->\n";
 665         } else {
 666                 $debug = '';
 667         }
 668         $content = <<<EOT
 669 <!DOCTYPE html>
 670 <html><head>
 671 <meta charset="UTF-8" />
 672 <title>Error generating thumbnail</title>
 673 </head>
 674 <body>
 675 <h1>Error generating thumbnail</h1>
 676 <p>
 677 $msgHtml
 678 </p>
 679 $debug
 680 </body>
 681 </html>
 682
 683 EOT;
 684         header( 'Content-Length: ' . strlen( $content ) );
 685         echo $content;
 686 }