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 // T241340: thumb.php is included by thumb_handler.php which already defined
  29 // MW_ENTRY_POINT to 'thumb_handler'
  30 if ( !defined( 'MW_ENTRY_POINT' ) ) {
  31         define( 'MW_ENTRY_POINT', 'thumb' );
  32 }
  33 require __DIR__ . '/includes/WebStart.php';
  34
  35 // Don't use fancy MIME detection, just check the file extension for jpg/gif/png
  36 $wgTrivialMimeDetection = true;
  37
  38 if ( defined( 'THUMB_HANDLER' ) ) {
  39         // Called from thumb_handler.php via 404; extract params from the URI...
  40         wfThumbHandle404();
  41 } else {
  42         // Called directly, use $_GET params
  43         wfStreamThumb( $wgRequest->getQueryValuesOnly() );
  44 }
  45
  46 $mediawiki = new MediaWiki();
  47 $mediawiki->doPostOutputShutdown( 'fast' );
  48
  49 // --------------------------------------------------------------------------
  50
  51 /**
  52  * Handle a thumbnail request via thumbnail file URL
  53  *
  54  * @return void
  55  */
  56 function wfThumbHandle404() {
  57         global $wgArticlePath;
  58
  59         # Set action base paths so that WebRequest::getPathInfo()
  60         # recognizes the "X" as the 'title' in ../thumb_handler.php/X urls.
  61         # Note: If Custom per-extension repo paths are set, this may break.
  62         $repo = RepoGroup::singleton()->getLocalRepo();
  63         $oldArticlePath = $wgArticlePath;
  64         $wgArticlePath = $repo->getZoneUrl( 'thumb' ) . '/$1';
  65
  66         $matches = WebRequest::getPathInfo();
  67
  68         $wgArticlePath = $oldArticlePath;
  69
  70         if ( !isset( $matches['title'] ) ) {
  71                 wfThumbError( 404, 'Could not determine the name of the requested thumbnail.' );
  72                 return;
  73         }
  74
  75         $params = wfExtractThumbRequestInfo( $matches['title'] ); // basic wiki URL param extracting
  76         if ( $params == null ) {
  77                 wfThumbError( 400, 'The specified thumbnail parameters are not recognized.' );
  78                 return;
  79         }
  80
  81         wfStreamThumb( $params ); // stream the thumbnail
  82 }
  83
  84 /**
  85  * Stream a thumbnail specified by parameters
  86  *
  87  * @param array $params List of thumbnailing parameters. In addition to parameters
  88  *  passed to the MediaHandler, this may also includes the keys:
  89  *   f (for filename), archived (if archived file), temp (if temp file),
  90  *   w (alias for width), p (alias for page), r (ignored; historical),
  91  *   rel404 (path for render on 404 to verify hash path correct),
  92  *   thumbName (thumbnail name to potentially extract more parameters from
  93  *   e.g. 'lossy-page1-120px-Foo.tiff' would add page, lossy and width
  94  *   to the parameters)
  95  * @return void
  96  */
  97 function wfStreamThumb( array $params ) {
  98         global $wgVaryOnXFP;
  99         $permissionManager = MediaWikiServices::getInstance()->getPermissionManager();
 100
 101         $headers = []; // HTTP headers to send
 102
 103         $fileName = $params['f'] ?? '';
 104
 105         // Backwards compatibility parameters
 106         if ( isset( $params['w'] ) ) {
 107                 $params['width'] = $params['w'];
 108                 unset( $params['w'] );
 109         }
 110         if ( isset( $params['width'] ) && substr( $params['width'], -2 ) == 'px' ) {
 111                 // strip the px (pixel) suffix, if found
 112                 $params['width'] = substr( $params['width'], 0, -2 );
 113         }
 114         if ( isset( $params['p'] ) ) {
 115                 $params['page'] = $params['p'];
 116         }
 117
 118         // Is this a thumb of an archived file?
 119         $isOld = ( isset( $params['archived'] ) && $params['archived'] );
 120         unset( $params['archived'] ); // handlers don't care
 121
 122         // Is this a thumb of a temp file?
 123         $isTemp = ( isset( $params['temp'] ) && $params['temp'] );
 124         unset( $params['temp'] ); // handlers don't care
 125
 126         // Some basic input validation
 127         $fileName = strtr( $fileName, '\\/', '__' );
 128
 129         // Actually fetch the image. Method depends on whether it is archived or not.
 130         if ( $isTemp ) {
 131                 $repo = RepoGroup::singleton()->getLocalRepo()->getTempRepo();
 132                 $img = new UnregisteredLocalFile( null, $repo,
 133                         # Temp files are hashed based on the name without the timestamp.
 134                         # The thumbnails will be hashed based on the entire name however.
 135                         # @todo fix this convention to actually be reasonable.
 136                         $repo->getZonePath( 'public' ) . '/' . $repo->getTempHashPath( $fileName ) . $fileName
 137                 );
 138         } elseif ( $isOld ) {
 139                 // Format is <timestamp>!<name>
 140                 $bits = explode( '!', $fileName, 2 );
 141                 if ( count( $bits ) != 2 ) {
 142                         wfThumbError( 404, wfMessage( 'badtitletext' )->parse() );
 143                         return;
 144                 }
 145                 $title = Title::makeTitleSafe( NS_FILE, $bits[1] );
 146                 if ( !$title ) {
 147                         wfThumbError( 404, wfMessage( 'badtitletext' )->parse() );
 148                         return;
 149                 }
 150                 $img = RepoGroup::singleton()->getLocalRepo()->newFromArchiveName( $title, $fileName );
 151         } else {
 152                 $img = wfLocalFile( $fileName );
 153         }
 154
 155         // Check the source file title
 156         if ( !$img ) {
 157                 wfThumbError( 404, wfMessage( 'badtitletext' )->parse() );
 158                 return;
 159         }
 160
 161         // Check permissions if there are read restrictions
 162         $varyHeader = [];
 163         if ( !in_array( 'read', $permissionManager->getGroupPermissions( [ '*' ] ), true ) ) {
 164                 $user = RequestContext::getMain()->getUser();
 165                 $imgTitle = $img->getTitle();
 166
 167                 if ( !$imgTitle || !$permissionManager->userCan( 'read', $user, $imgTitle ) ) {
 168                         wfThumbError( 403, 'Access denied. You do not have permission to access ' .
 169                                 'the source file.' );
 170                         return;
 171                 }
 172                 $headers[] = 'Cache-Control: private';
 173                 $varyHeader[] = 'Cookie';
 174         }
 175
 176         // Check if the file is hidden
 177         if ( $img->isDeleted( File::DELETED_FILE ) ) {
 178                 wfThumbErrorText( 404, "The source file '$fileName' does not exist." );
 179                 return;
 180         }
 181
 182         // Do rendering parameters extraction from thumbnail name.
 183         if ( isset( $params['thumbName'] ) ) {
 184                 $params = wfExtractThumbParams( $img, $params );
 185         }
 186         if ( $params == null ) {
 187                 wfThumbError( 400, 'The specified thumbnail parameters are not recognized.' );
 188                 return;
 189         }
 190
 191         // Check the source file storage path
 192         if ( !$img->exists() ) {
 193                 $redirectedLocation = false;
 194                 if ( !$isTemp ) {
 195                         // Check for file redirect
 196                         // Since redirects are associated with pages, not versions of files,
 197                         // we look for the most current version to see if its a redirect.
 198                         $possRedirFile = RepoGroup::singleton()->getLocalRepo()->findFile( $img->getName() );
 199                         if ( $possRedirFile && !is_null( $possRedirFile->getRedirected() ) ) {
 200                                 $redirTarget = $possRedirFile->getName();
 201                                 $targetFile = wfLocalFile( Title::makeTitleSafe( NS_FILE, $redirTarget ) );
 202                                 if ( $targetFile->exists() ) {
 203                                         $newThumbName = $targetFile->thumbName( $params );
 204                                         if ( $isOld ) {
 205                                                 /** @var array $bits */
 206                                                 $newThumbUrl = $targetFile->getArchiveThumbUrl(
 207                                                         $bits[0] . '!' . $targetFile->getName(), $newThumbName );
 208                                         } else {
 209                                                 $newThumbUrl = $targetFile->getThumbUrl( $newThumbName );
 210                                         }
 211                                         $redirectedLocation = wfExpandUrl( $newThumbUrl, PROTO_CURRENT );
 212                                 }
 213                         }
 214                 }
 215
 216                 if ( $redirectedLocation ) {
 217                         // File has been moved. Give redirect.
 218                         $response = RequestContext::getMain()->getRequest()->response();
 219                         $response->statusHeader( 302 );
 220                         $response->header( 'Location: ' . $redirectedLocation );
 221                         $response->header( 'Expires: ' .
 222                                 gmdate( 'D, d M Y H:i:s', time() + 12 * 3600 ) . ' GMT' );
 223                         if ( $wgVaryOnXFP ) {
 224                                 $varyHeader[] = 'X-Forwarded-Proto';
 225                         }
 226                         if ( count( $varyHeader ) ) {
 227                                 $response->header( 'Vary: ' . implode( ', ', $varyHeader ) );
 228                         }
 229                         $response->header( 'Content-Length: 0' );
 230                         return;
 231                 }
 232
 233                 // If its not a redirect that has a target as a local file, give 404.
 234                 wfThumbErrorText( 404, "The source file '$fileName' does not exist." );
 235                 return;
 236         } elseif ( $img->getPath() === false ) {
 237                 wfThumbErrorText( 400, "The source file '$fileName' is not locally accessible." );
 238                 return;
 239         }
 240
 241         // Check IMS against the source file
 242         // This means that clients can keep a cached copy even after it has been deleted on the server
 243         if ( !empty( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
 244                 // Fix IE brokenness
 245                 $imsString = preg_replace( '/;.*$/', '', $_SERVER["HTTP_IF_MODIFIED_SINCE"] );
 246                 // Calculate time
 247                 Wikimedia\suppressWarnings();
 248                 $imsUnix = strtotime( $imsString );
 249                 Wikimedia\restoreWarnings();
 250                 if ( wfTimestamp( TS_UNIX, $img->getTimestamp() ) <= $imsUnix ) {
 251                         HttpStatus::header( 304 );
 252                         return;
 253                 }
 254         }
 255
 256         $rel404 = $params['rel404'] ?? null;
 257         unset( $params['r'] ); // ignore 'r' because we unconditionally pass File::RENDER
 258         unset( $params['f'] ); // We're done with 'f' parameter.
 259         unset( $params['rel404'] ); // moved to $rel404
 260
 261         // Get the normalized thumbnail name from the parameters...
 262         try {
 263                 $thumbName = $img->thumbName( $params );
 264                 if ( !strlen( $thumbName ) ) { // invalid params?
 265                         throw new MediaTransformInvalidParametersException(
 266                                 'Empty return from File::thumbName'
 267                         );
 268                 }
 269                 $thumbName2 = $img->thumbName( $params, File::THUMB_FULL_NAME ); // b/c; "long" style
 270         } catch ( MediaTransformInvalidParametersException $e ) {
 271                 wfThumbError(
 272                         400,
 273                         'The specified thumbnail parameters are not valid: ' . $e->getMessage()
 274                 );
 275                 return;
 276         } catch ( MWException $e ) {
 277                 wfThumbError( 500, $e->getHTML(), 'Exception caught while extracting thumb name',
 278                         [ 'exception' => $e ] );
 279                 return;
 280         }
 281
 282         // For 404 handled thumbnails, we only use the base name of the URI
 283         // for the thumb params and the parent directory for the source file name.
 284         // Check that the zone relative path matches up so CDN caches won't pick
 285         // up thumbs that would not be purged on source file deletion (T36231).
 286         if ( $rel404 !== null ) { // thumbnail was handled via 404
 287                 if ( rawurldecode( $rel404 ) === $img->getThumbRel( $thumbName ) ) {
 288                         // Request for the canonical thumbnail name
 289                 } elseif ( rawurldecode( $rel404 ) === $img->getThumbRel( $thumbName2 ) ) {
 290                         // Request for the "long" thumbnail name; redirect to canonical name
 291                         $response = RequestContext::getMain()->getRequest()->response();
 292                         $response->statusHeader( 301 );
 293                         $response->header( 'Location: ' .
 294                                 wfExpandUrl( $img->getThumbUrl( $thumbName ), PROTO_CURRENT ) );
 295                         $response->header( 'Expires: ' .
 296                                 gmdate( 'D, d M Y H:i:s', time() + 7 * 86400 ) . ' GMT' );
 297                         if ( $wgVaryOnXFP ) {
 298                                 $varyHeader[] = 'X-Forwarded-Proto';
 299                         }
 300                         if ( count( $varyHeader ) ) {
 301                                 $response->header( 'Vary: ' . implode( ', ', $varyHeader ) );
 302                         }
 303                         return;
 304                 } else {
 305                         wfThumbErrorText( 404, "The given path of the specified thumbnail is incorrect;
 306                                 expected '" . $img->getThumbRel( $thumbName ) . "' but got '" .
 307                                 rawurldecode( $rel404 ) . "'." );
 308                         return;
 309                 }
 310         }
 311
 312         $dispositionType = isset( $params['download'] ) ? 'attachment' : 'inline';
 313
 314         // Suggest a good name for users downloading this thumbnail
 315         $headers[] =
 316                 "Content-Disposition: {$img->getThumbDisposition( $thumbName, $dispositionType )}";
 317
 318         if ( count( $varyHeader ) ) {
 319                 $headers[] = 'Vary: ' . implode( ', ', $varyHeader );
 320         }
 321
 322         // Stream the file if it exists already...
 323         $thumbPath = $img->getThumbPath( $thumbName );
 324         if ( $img->getRepo()->fileExists( $thumbPath ) ) {
 325                 $starttime = microtime( true );
 326                 $status = $img->getRepo()->streamFileWithStatus( $thumbPath, $headers );
 327                 $streamtime = microtime( true ) - $starttime;
 328
 329                 if ( $status->isOK() ) {
 330                         MediaWikiServices::getInstance()->getStatsdDataFactory()->timing(
 331                                 'media.thumbnail.stream', $streamtime
 332                         );
 333                 } else {
 334                         wfThumbError( 500, 'Could not stream the file', null, [ 'file' => $thumbName,
 335                                 'path' => $thumbPath, 'error' => $status->getWikiText( false, false, 'en' ) ] );
 336                 }
 337                 return;
 338         }
 339
 340         $user = RequestContext::getMain()->getUser();
 341         if ( !wfThumbIsStandard( $img, $params ) && $user->pingLimiter( 'renderfile-nonstandard' ) ) {
 342                 wfThumbError( 429, wfMessage( 'actionthrottledtext' )->parse() );
 343                 return;
 344         } elseif ( $user->pingLimiter( 'renderfile' ) ) {
 345                 wfThumbError( 429, wfMessage( 'actionthrottledtext' )->parse() );
 346                 return;
 347         }
 348
 349         $thumbProxyUrl = $img->getRepo()->getThumbProxyUrl();
 350
 351         if ( strlen( $thumbProxyUrl ) ) {
 352                 wfProxyThumbnailRequest( $img, $thumbName );
 353                 // No local fallback when in proxy mode
 354                 return;
 355         } else {
 356                 // Generate the thumbnail locally
 357                 list( $thumb, $errorMsg ) = wfGenerateThumbnail( $img, $params, $thumbName, $thumbPath );
 358         }
 359
 360         /** @var MediaTransformOutput|MediaTransformError|bool $thumb */
 361
 362         // Check for thumbnail generation errors...
 363         $msg = wfMessage( 'thumbnail_error' );
 364         $errorCode = 500;
 365
 366         if ( !$thumb ) {
 367                 $errorMsg = $errorMsg ?: $msg->rawParams( 'File::transform() returned false' )->escaped();
 368                 if ( $errorMsg instanceof MessageSpecifier &&
 369                         $errorMsg->getKey() === 'thumbnail_image-failure-limit'
 370                 ) {
 371                         $errorCode = 429;
 372                 }
 373         } elseif ( $thumb->isError() ) {
 374                 $errorMsg = $thumb->getHtmlMsg();
 375                 $errorCode = $thumb->getHttpStatusCode();
 376         } elseif ( !$thumb->hasFile() ) {
 377                 $errorMsg = $msg->rawParams( 'No path supplied in thumbnail object' )->escaped();
 378         } elseif ( $thumb->fileIsSource() ) {
 379                 $errorMsg = $msg
 380                         ->rawParams( 'Image was not scaled, is the requested width bigger than the source?' )
 381                         ->escaped();
 382                 $errorCode = 400;
 383         }
 384
 385         if ( $errorMsg !== false ) {
 386                 wfThumbError( $errorCode, $errorMsg, null, [ 'file' => $thumbName, 'path' => $thumbPath ] );
 387         } else {
 388                 // Stream the file if there were no errors
 389                 $status = $thumb->streamFileWithStatus( $headers );
 390                 if ( !$status->isOK() ) {
 391                         wfThumbError( 500, 'Could not stream the file', null, [
 392                                 'file' => $thumbName, 'path' => $thumbPath,
 393                                 'error' => $status->getWikiText( false, false, 'en' ) ] );
 394                 }
 395         }
 396 }
 397
 398 /**
 399  * Proxies thumbnail request to a service that handles thumbnailing
 400  *
 401  * @param File $img
 402  * @param string $thumbName
 403  */
 404 function wfProxyThumbnailRequest( $img, $thumbName ) {
 405         $thumbProxyUrl = $img->getRepo()->getThumbProxyUrl();
 406
 407         // Instead of generating the thumbnail ourselves, we proxy the request to another service
 408         $thumbProxiedUrl = $thumbProxyUrl . $img->getThumbRel( $thumbName );
 409
 410         $req = MWHttpRequest::factory( $thumbProxiedUrl );
 411         $secret = $img->getRepo()->getThumbProxySecret();
 412
 413         // Pass a secret key shared with the proxied service if any
 414         if ( strlen( $secret ) ) {
 415                 $req->setHeader( 'X-Swift-Secret', $secret );
 416         }
 417
 418         // Send request to proxied service
 419         $status = $req->execute();
 420
 421         MediaWiki\HeaderCallback::warnIfHeadersSent();
 422
 423         // Simply serve the response from the proxied service as-is
 424         header( 'HTTP/1.1 ' . $req->getStatus() );
 425
 426         $headers = $req->getResponseHeaders();
 427
 428         foreach ( $headers as $key => $values ) {
 429                 foreach ( $values as $value ) {
 430                         header( $key . ': ' . $value, false );
 431                 }
 432         }
 433
 434         echo $req->getContent();
 435 }
 436
 437 /**
 438  * Actually try to generate a new thumbnail
 439  *
 440  * @param File $file
 441  * @param array $params
 442  * @param string $thumbName
 443  * @param string $thumbPath
 444  * @return array (MediaTransformOutput|bool, string|bool error message HTML)
 445  */
 446 function wfGenerateThumbnail( File $file, array $params, $thumbName, $thumbPath ) {
 447         global $wgAttemptFailureEpoch;
 448
 449         $cache = ObjectCache::getLocalClusterInstance();
 450         $key = $cache->makeKey(
 451                 'attempt-failures',
 452                 $wgAttemptFailureEpoch,
 453                 $file->getRepo()->getName(),
 454                 $file->getSha1(),
 455                 md5( $thumbName )
 456         );
 457
 458         // Check if this file keeps failing to render
 459         if ( $cache->get( $key ) >= 4 ) {
 460                 return [ false, wfMessage( 'thumbnail_image-failure-limit', 4 ) ];
 461         }
 462
 463         $done = false;
 464         // Record failures on PHP fatals in addition to caching exceptions
 465         register_shutdown_function( function () use ( $cache, &$done, $key ) {
 466                 if ( !$done ) { // transform() gave a fatal
 467                         // Randomize TTL to reduce stampedes
 468                         $cache->incrWithInit( $key, $cache::TTL_HOUR + mt_rand( 0, 300 ) );
 469                 }
 470         } );
 471
 472         $thumb = false;
 473         $errorHtml = false;
 474
 475         // guard thumbnail rendering with PoolCounter to avoid stampedes
 476         // expensive files use a separate PoolCounter config so it is possible
 477         // to set up a global limit on them
 478         if ( $file->isExpensiveToThumbnail() ) {
 479                 $poolCounterType = 'FileRenderExpensive';
 480         } else {
 481                 $poolCounterType = 'FileRender';
 482         }
 483
 484         // Thumbnail isn't already there, so create the new thumbnail...
 485         try {
 486                 $work = new PoolCounterWorkViaCallback( $poolCounterType, sha1( $file->getName() ),
 487                         [
 488                                 'doWork' => function () use ( $file, $params ) {
 489                                         return $file->transform( $params, File::RENDER_NOW );
 490                                 },
 491                                 'doCachedWork' => function () use ( $file, $params, $thumbPath ) {
 492                                         // If the worker that finished made this thumbnail then use it.
 493                                         // Otherwise, it probably made a different thumbnail for this file.
 494                                         return $file->getRepo()->fileExists( $thumbPath )
 495                                                 ? $file->transform( $params, File::RENDER_NOW )
 496                                                 : false; // retry once more in exclusive mode
 497                                 },
 498                                 'error' => function ( Status $status ) {
 499                                         return wfMessage( 'generic-pool-error' )->parse() . '<hr>' . $status->getHTML();
 500                                 }
 501                         ]
 502                 );
 503                 $result = $work->execute();
 504                 if ( $result instanceof MediaTransformOutput ) {
 505                         $thumb = $result;
 506                 } elseif ( is_string( $result ) ) { // error
 507                         $errorHtml = $result;
 508                 }
 509         } catch ( Exception $e ) {
 510                 // Tried to select a page on a non-paged file?
 511         }
 512
 513         /** @noinspection PhpUnusedLocalVariableInspection */
 514         $done = true; // no PHP fatal occurred
 515
 516         if ( !$thumb || $thumb->isError() ) {
 517                 // Randomize TTL to reduce stampedes
 518                 $cache->incrWithInit( $key, $cache::TTL_HOUR + mt_rand( 0, 300 ) );
 519         }
 520
 521         return [ $thumb, $errorHtml ];
 522 }
 523
 524 /**
 525  * Convert pathinfo type parameter, into normal request parameters
 526  *
 527  * So for example, if the request was redirected from
 528  * /w/images/thumb/a/ab/Foo.png/120px-Foo.png. The $thumbRel parameter
 529  * of this function would be set to "a/ab/Foo.png/120px-Foo.png".
 530  * This method is responsible for turning that into an array
 531  * with the following keys:
 532  *  * f => the filename (Foo.png)
 533  *  * rel404 => the whole thing (a/ab/Foo.png/120px-Foo.png)
 534  *  * archived => 1 (If the request is for an archived thumb)
 535  *  * temp => 1 (If the file is in the "temporary" zone)
 536  *  * thumbName => the thumbnail name, including parameters (120px-Foo.png)
 537  *
 538  * Transform specific parameters are set later via wfExtractThumbParams().
 539  *
 540  * @param string $thumbRel Thumbnail path relative to the thumb zone
 541  * @return array|null Associative params array or null
 542  */
 543 function wfExtractThumbRequestInfo( $thumbRel ) {
 544         $repo = RepoGroup::singleton()->getLocalRepo();
 545
 546         $hashDirReg = $subdirReg = '';
 547         $hashLevels = $repo->getHashLevels();
 548         for ( $i = 0; $i < $hashLevels; $i++ ) {
 549                 $subdirReg .= '[0-9a-f]';
 550                 $hashDirReg .= "$subdirReg/";
 551         }
 552
 553         // Check if this is a thumbnail of an original in the local file repo
 554         if ( preg_match( "!^((archive/)?$hashDirReg([^/]*)/([^/]*))$!", $thumbRel, $m ) ) {
 555                 list( /*all*/, $rel, $archOrTemp, $filename, $thumbname ) = $m;
 556         // Check if this is a thumbnail of an temp file in the local file repo
 557         } elseif ( preg_match( "!^(temp/)($hashDirReg([^/]*)/([^/]*))$!", $thumbRel, $m ) ) {
 558                 list( /*all*/, $archOrTemp, $rel, $filename, $thumbname ) = $m;
 559         } else {
 560                 return null; // not a valid looking thumbnail request
 561         }
 562
 563         $params = [ 'f' => $filename, 'rel404' => $rel ];
 564         if ( $archOrTemp === 'archive/' ) {
 565                 $params['archived'] = 1;
 566         } elseif ( $archOrTemp === 'temp/' ) {
 567                 $params['temp'] = 1;
 568         }
 569
 570         $params['thumbName'] = $thumbname;
 571         return $params;
 572 }
 573
 574 /**
 575  * Convert a thumbnail name (122px-foo.png) to parameters, using
 576  * file handler.
 577  *
 578  * @param File $file File object for file in question
 579  * @param array $params Array of parameters so far
 580  * @return array Parameters array with more parameters
 581  */
 582 function wfExtractThumbParams( $file, $params ) {
 583         if ( !isset( $params['thumbName'] ) ) {
 584                 throw new InvalidArgumentException( "No thumbnail name passed to wfExtractThumbParams" );
 585         }
 586
 587         $thumbname = $params['thumbName'];
 588         unset( $params['thumbName'] );
 589
 590         // FIXME: Files in the temp zone don't set a MIME type, which means
 591         // they don't have a handler. Which means we can't parse the param
 592         // string. However, not a big issue as what good is a param string
 593         // if you have no handler to make use of the param string and
 594         // actually generate the thumbnail.
 595         $handler = $file->getHandler();
 596
 597         // Based on UploadStash::parseKey
 598         $fileNamePos = strrpos( $thumbname, $params['f'] );
 599         if ( $fileNamePos === false ) {
 600                 // Maybe using a short filename? (see FileRepo::nameForThumb)
 601                 $fileNamePos = strrpos( $thumbname, 'thumbnail' );
 602         }
 603
 604         if ( $handler && $fileNamePos !== false ) {
 605                 $paramString = substr( $thumbname, 0, $fileNamePos - 1 );
 606                 $extraParams = $handler->parseParamString( $paramString );
 607                 if ( $extraParams !== false ) {
 608                         return $params + $extraParams;
 609                 }
 610         }
 611
 612         // As a last ditch fallback, use the traditional common parameters
 613         if ( preg_match( '!^(page(\d*)-)*(\d*)px-[^/]*$!', $thumbname, $matches ) ) {
 614                 list( /* all */, /* pagefull */, $pagenum, $size ) = $matches;
 615                 $params['width'] = $size;
 616                 if ( $pagenum ) {
 617                         $params['page'] = $pagenum;
 618                 }
 619                 return $params; // valid thumbnail URL
 620         }
 621         return null;
 622 }
 623
 624 /**
 625  * Output a thumbnail generation error message
 626  *
 627  * @param int $status
 628  * @param string $msgText Plain text (will be html escaped)
 629  * @return void
 630  */
 631 function wfThumbErrorText( $status, $msgText ) {
 632         wfThumbError( $status, htmlspecialchars( $msgText, ENT_NOQUOTES ) );
 633 }
 634
 635 /**
 636  * Output a thumbnail generation error message
 637  *
 638  * @param int $status
 639  * @param string $msgHtml HTML
 640  * @param string|null $msgText Short error description, for internal logging. Defaults to $msgHtml.
 641  *   Only used for HTTP 500 errors.
 642  * @param array $context Error context, for internal logging. Only used for HTTP 500 errors.
 643  * @return void
 644  */
 645 function wfThumbError( $status, $msgHtml, $msgText = null, $context = [] ) {
 646         global $wgShowHostnames;
 647
 648         MediaWiki\HeaderCallback::warnIfHeadersSent();
 649
 650         header( 'Cache-Control: no-cache' );
 651         header( 'Content-Type: text/html; charset=utf-8' );
 652         if ( $status == 400 || $status == 404 || $status == 429 ) {
 653                 HttpStatus::header( $status );
 654         } elseif ( $status == 403 ) {
 655                 HttpStatus::header( 403 );
 656                 header( 'Vary: Cookie' );
 657         } else {
 658                 LoggerFactory::getInstance( 'thumb' )->error( $msgText ?: $msgHtml, $context );
 659                 HttpStatus::header( 500 );
 660         }
 661         if ( $wgShowHostnames ) {
 662                 header( 'X-MW-Thumbnail-Renderer: ' . wfHostname() );
 663                 $url = htmlspecialchars(
 664                         $_SERVER['REQUEST_URI'] ?? '',
 665                         ENT_NOQUOTES
 666                 );
 667                 $hostname = htmlspecialchars( wfHostname(), ENT_NOQUOTES );
 668                 $debug = "<!-- $url -->\n<!-- $hostname -->\n";
 669         } else {
 670                 $debug = '';
 671         }
 672         $content = <<<EOT
 673 <!DOCTYPE html>
 674 <html><head>
 675 <meta charset="UTF-8" />
 676 <title>Error generating thumbnail</title>
 677 </head>
 678 <body>
 679 <h1>Error generating thumbnail</h1>
 680 <p>
 681 $msgHtml
 682 </p>
 683 $debug
 684 </body>
 685 </html>
 686
 687 EOT;
 688         header( 'Content-Length: ' . strlen( $content ) );
 689         echo $content;
 690 }