thumb.php

   1 <?php
   2 /**
   3  * PHP script to stream out an image thumbnail.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Media
  22  */
  23
  24 use MediaWiki\Logger\LoggerFactory;
  25 use MediaWiki\MediaWikiServices;
  26
  27 define( 'MW_NO_OUTPUT_COMPRESSION', 1 );
  28 require __DIR__ . '/includes/WebStart.php';
  29
  30 // Don't use fancy MIME detection, just check the file extension for jpg/gif/png
  31 $wgTrivialMimeDetection = true;
  32
  33 if ( defined( 'THUMB_HANDLER' ) ) {
  34         // Called from thumb_handler.php via 404; extract params from the URI...
  35         wfThumbHandle404();
  36 } else {
  37         // Called directly, use $_GET params
  38         wfStreamThumb( $wgRequest->getQueryValues() );
  39 }
  40
  41 $mediawiki = new MediaWiki();
  42 $mediawiki->doPostOutputShutdown( 'fast' );
  43
  44 // --------------------------------------------------------------------------
  45
  46 /**
  47  * Handle a thumbnail request via thumbnail file URL
  48  *
  49  * @return void
  50  */
  51 function wfThumbHandle404() {
  52         global $wgArticlePath;
  53
  54         # Set action base paths so that WebRequest::getPathInfo()
  55         # recognizes the "X" as the 'title' in ../thumb_handler.php/X urls.
  56         # Note: If Custom per-extension repo paths are set, this may break.
  57         $repo = RepoGroup::singleton()->getLocalRepo();
  58         $oldArticlePath = $wgArticlePath;
  59         $wgArticlePath = $repo->getZoneUrl( 'thumb' ) . '/$1';
  60
  61         $matches = WebRequest::getPathInfo();
  62
  63         $wgArticlePath = $oldArticlePath;
  64
  65         if ( !isset( $matches['title'] ) ) {
  66                 wfThumbError( 404, 'Could not determine the name of the requested thumbnail.' );
  67                 return;
  68         }
  69
  70         $params = wfExtractThumbRequestInfo( $matches['title'] ); // basic wiki URL param extracting
  71         if ( $params == null ) {
  72                 wfThumbError( 400, 'The specified thumbnail parameters are not recognized.' );
  73                 return;
  74         }
  75
  76         wfStreamThumb( $params ); // stream the thumbnail
  77 }
  78
  79 /**
  80  * Stream a thumbnail specified by parameters
  81  *
  82  * @param array $params List of thumbnailing parameters. In addition to parameters
  83  *  passed to the MediaHandler, this may also includes the keys:
  84  *   f (for filename), archived (if archived file), temp (if temp file),
  85  *   w (alias for width), p (alias for page), r (ignored; historical),
  86  *   rel404 (path for render on 404 to verify hash path correct),
  87  *   thumbName (thumbnail name to potentially extract more parameters from
  88  *   e.g. 'lossy-page1-120px-Foo.tiff' would add page, lossy and width
  89  *   to the parameters)
  90  * @return void
  91  */
  92 function wfStreamThumb( array $params ) {
  93         global $wgVaryOnXFP;
  94         $permissionManager = MediaWikiServices::getInstance()->getPermissionManager();
  95
  96         $headers = []; // HTTP headers to send
  97
  98         $fileName = $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 = [];
 158         if ( !in_array( 'read', $permissionManager->getGroupPermissions( [ '*' ] ), true ) ) {
 159                 $user = RequestContext::getMain()->getUser();
 160                 $imgTitle = $img->getTitle();
 161
 162                 if ( !$imgTitle || !$permissionManager->userCan( 'read', $user, $imgTitle ) ) {
 163                         wfThumbError( 403, 'Access denied. You do not have permission to access ' .
 164                                 'the source file.' );
 165                         return;
 166                 }
 167                 $headers[] = 'Cache-Control: private';
 168                 $varyHeader[] = 'Cookie';
 169         }
 170
 171         // Check if the file is hidden
 172         if ( $img->isDeleted( File::DELETED_FILE ) ) {
 173                 wfThumbErrorText( 404, "The source file '$fileName' does not exist." );
 174                 return;
 175         }
 176
 177         // Do rendering parameters extraction from thumbnail name.
 178         if ( isset( $params['thumbName'] ) ) {
 179                 $params = wfExtractThumbParams( $img, $params );
 180         }
 181         if ( $params == null ) {
 182                 wfThumbError( 400, 'The specified thumbnail parameters are not recognized.' );
 183                 return;
 184         }
 185
 186         // Check the source file storage path
 187         if ( !$img->exists() ) {
 188                 $redirectedLocation = false;
 189                 if ( !$isTemp ) {
 190                         // Check for file redirect
 191                         // Since redirects are associated with pages, not versions of files,
 192                         // we look for the most current version to see if its a redirect.
 193                         $possRedirFile = RepoGroup::singleton()->getLocalRepo()->findFile( $img->getName() );
 194                         if ( $possRedirFile && !is_null( $possRedirFile->getRedirected() ) ) {
 195                                 $redirTarget = $possRedirFile->getName();
 196                                 $targetFile = wfLocalFile( Title::makeTitleSafe( NS_FILE, $redirTarget ) );
 197                                 if ( $targetFile->exists() ) {
 198                                         $newThumbName = $targetFile->thumbName( $params );
 199                                         if ( $isOld ) {
 200                                                 /** @var array $bits */
 201                                                 $newThumbUrl = $targetFile->getArchiveThumbUrl(
 202                                                         $bits[0] . '!' . $targetFile->getName(), $newThumbName );
 203                                         } else {
 204                                                 $newThumbUrl = $targetFile->getThumbUrl( $newThumbName );
 205                                         }
 206                                         $redirectedLocation = wfExpandUrl( $newThumbUrl, PROTO_CURRENT );
 207                                 }
 208                         }
 209                 }
 210
 211                 if ( $redirectedLocation ) {
 212                         // File has been moved. Give redirect.
 213                         $response = RequestContext::getMain()->getRequest()->response();
 214                         $response->statusHeader( 302 );
 215                         $response->header( 'Location: ' . $redirectedLocation );
 216                         $response->header( 'Expires: ' .
 217                                 gmdate( 'D, d M Y H:i:s', time() + 12 * 3600 ) . ' GMT' );
 218                         if ( $wgVaryOnXFP ) {
 219                                 $varyHeader[] = 'X-Forwarded-Proto';
 220                         }
 221                         if ( count( $varyHeader ) ) {
 222                                 $response->header( 'Vary: ' . implode( ', ', $varyHeader ) );
 223                         }
 224                         $response->header( 'Content-Length: 0' );
 225                         return;
 226                 }
 227
 228                 // If its not a redirect that has a target as a local file, give 404.
 229                 wfThumbErrorText( 404, "The source file '$fileName' does not exist." );
 230                 return;
 231         } elseif ( $img->getPath() === false ) {
 232                 wfThumbErrorText( 400, "The source file '$fileName' is not locally accessible." );
 233                 return;
 234         }
 235
 236         // Check IMS against the source file
 237         // This means that clients can keep a cached copy even after it has been deleted on the server
 238         if ( !empty( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
 239                 // Fix IE brokenness
 240                 $imsString = preg_replace( '/;.*$/', '', $_SERVER["HTTP_IF_MODIFIED_SINCE"] );
 241                 // Calculate time
 242                 Wikimedia\suppressWarnings();
 243                 $imsUnix = strtotime( $imsString );
 244                 Wikimedia\restoreWarnings();
 245                 if ( wfTimestamp( TS_UNIX, $img->getTimestamp() ) <= $imsUnix ) {
 246                         HttpStatus::header( 304 );
 247                         return;
 248                 }
 249         }
 250
 251         $rel404 = $params['rel404'] ?? null;
 252         unset( $params['r'] ); // ignore 'r' because we unconditionally pass File::RENDER
 253         unset( $params['f'] ); // We're done with 'f' parameter.
 254         unset( $params['rel404'] ); // moved to $rel404
 255
 256         // Get the normalized thumbnail name from the parameters...
 257         try {
 258                 $thumbName = $img->thumbName( $params );
 259                 if ( !strlen( $thumbName ) ) { // invalid params?
 260                         throw new MediaTransformInvalidParametersException(
 261                                 'Empty return from File::thumbName'
 262                         );
 263                 }
 264                 $thumbName2 = $img->thumbName( $params, File::THUMB_FULL_NAME ); // b/c; "long" style
 265         } catch ( MediaTransformInvalidParametersException $e ) {
 266                 wfThumbError(
 267                         400,
 268                         'The specified thumbnail parameters are not valid: ' . $e->getMessage()
 269                 );
 270                 return;
 271         } catch ( MWException $e ) {
 272                 wfThumbError( 500, $e->getHTML(), 'Exception caught while extracting thumb name',
 273                         [ 'exception' => $e ] );
 274                 return;
 275         }
 276
 277         // For 404 handled thumbnails, we only use the base name of the URI
 278         // for the thumb params and the parent directory for the source file name.
 279         // Check that the zone relative path matches up so CDN caches won't pick
 280         // up thumbs that would not be purged on source file deletion (T36231).
 281         if ( $rel404 !== null ) { // thumbnail was handled via 404
 282                 if ( rawurldecode( $rel404 ) === $img->getThumbRel( $thumbName ) ) {
 283                         // Request for the canonical thumbnail name
 284                 } elseif ( rawurldecode( $rel404 ) === $img->getThumbRel( $thumbName2 ) ) {
 285                         // Request for the "long" thumbnail name; redirect to canonical name
 286                         $response = RequestContext::getMain()->getRequest()->response();
 287                         $response->statusHeader( 301 );
 288                         $response->header( 'Location: ' .
 289                                 wfExpandUrl( $img->getThumbUrl( $thumbName ), PROTO_CURRENT ) );
 290                         $response->header( 'Expires: ' .
 291                                 gmdate( 'D, d M Y H:i:s', time() + 7 * 86400 ) . ' GMT' );
 292                         if ( $wgVaryOnXFP ) {
 293                                 $varyHeader[] = 'X-Forwarded-Proto';
 294                         }
 295                         if ( count( $varyHeader ) ) {
 296                                 $response->header( 'Vary: ' . implode( ', ', $varyHeader ) );
 297                         }
 298                         return;
 299                 } else {
 300                         wfThumbErrorText( 404, "The given path of the specified thumbnail is incorrect;
 301                                 expected '" . $img->getThumbRel( $thumbName ) . "' but got '" .
 302                                 rawurldecode( $rel404 ) . "'." );
 303                         return;
 304                 }
 305         }
 306
 307         $dispositionType = isset( $params['download'] ) ? 'attachment' : 'inline';
 308
 309         // Suggest a good name for users downloading this thumbnail
 310         $headers[] =
 311                 "Content-Disposition: {$img->getThumbDisposition( $thumbName, $dispositionType )}";
 312
 313         if ( count( $varyHeader ) ) {
 314                 $headers[] = 'Vary: ' . implode( ', ', $varyHeader );
 315         }
 316
 317         // Stream the file if it exists already...
 318         $thumbPath = $img->getThumbPath( $thumbName );
 319         if ( $img->getRepo()->fileExists( $thumbPath ) ) {
 320                 $starttime = microtime( true );
 321                 $status = $img->getRepo()->streamFileWithStatus( $thumbPath, $headers );
 322                 $streamtime = microtime( true ) - $starttime;
 323
 324                 if ( $status->isOK() ) {
 325                         MediaWikiServices::getInstance()->getStatsdDataFactory()->timing(
 326                                 'media.thumbnail.stream', $streamtime
 327                         );
 328                 } else {
 329                         wfThumbError( 500, 'Could not stream the file', null, [ 'file' => $thumbName,
 330                                 'path' => $thumbPath, 'error' => $status->getWikiText( false, false, 'en' ) ] );
 331                 }
 332                 return;
 333         }
 334
 335         $user = RequestContext::getMain()->getUser();
 336         if ( !wfThumbIsStandard( $img, $params ) && $user->pingLimiter( 'renderfile-nonstandard' ) ) {
 337                 wfThumbError( 429, wfMessage( 'actionthrottledtext' )->parse() );
 338                 return;
 339         } elseif ( $user->pingLimiter( 'renderfile' ) ) {
 340                 wfThumbError( 429, wfMessage( 'actionthrottledtext' )->parse() );
 341                 return;
 342         }
 343
 344         $thumbProxyUrl = $img->getRepo()->getThumbProxyUrl();
 345
 346         if ( strlen( $thumbProxyUrl ) ) {
 347                 wfProxyThumbnailRequest( $img, $thumbName );
 348                 // No local fallback when in proxy mode
 349                 return;
 350         } else {
 351                 // Generate the thumbnail locally
 352                 list( $thumb, $errorMsg ) = wfGenerateThumbnail( $img, $params, $thumbName, $thumbPath );
 353         }
 354
 355         /** @var MediaTransformOutput|MediaTransformError|bool $thumb */
 356
 357         // Check for thumbnail generation errors...
 358         $msg = wfMessage( 'thumbnail_error' );
 359         $errorCode = 500;
 360
 361         if ( !$thumb ) {
 362                 $errorMsg = $errorMsg ?: $msg->rawParams( 'File::transform() returned false' )->escaped();
 363                 if ( $errorMsg instanceof MessageSpecifier &&
 364                         $errorMsg->getKey() === 'thumbnail_image-failure-limit'
 365                 ) {
 366                         $errorCode = 429;
 367                 }
 368         } elseif ( $thumb->isError() ) {
 369                 $errorMsg = $thumb->getHtmlMsg();
 370                 $errorCode = $thumb->getHttpStatusCode();
 371         } elseif ( !$thumb->hasFile() ) {
 372                 $errorMsg = $msg->rawParams( 'No path supplied in thumbnail object' )->escaped();
 373         } elseif ( $thumb->fileIsSource() ) {
 374                 $errorMsg = $msg
 375                         ->rawParams( 'Image was not scaled, is the requested width bigger than the source?' )
 376                         ->escaped();
 377                 $errorCode = 400;
 378         }
 379
 380         if ( $errorMsg !== false ) {
 381                 wfThumbError( $errorCode, $errorMsg, null, [ 'file' => $thumbName, 'path' => $thumbPath ] );
 382         } else {
 383                 // Stream the file if there were no errors
 384                 $status = $thumb->streamFileWithStatus( $headers );
 385                 if ( !$status->isOK() ) {
 386                         wfThumbError( 500, 'Could not stream the file', null, [
 387                                 'file' => $thumbName, 'path' => $thumbPath,
 388                                 'error' => $status->getWikiText( false, false, 'en' ) ] );
 389                 }
 390         }
 391 }
 392
 393 /**
 394  * Proxies thumbnail request to a service that handles thumbnailing
 395  *
 396  * @param File $img
 397  * @param string $thumbName
 398  */
 399 function wfProxyThumbnailRequest( $img, $thumbName ) {
 400         $thumbProxyUrl = $img->getRepo()->getThumbProxyUrl();
 401
 402         // Instead of generating the thumbnail ourselves, we proxy the request to another service
 403         $thumbProxiedUrl = $thumbProxyUrl . $img->getThumbRel( $thumbName );
 404
 405         $req = MWHttpRequest::factory( $thumbProxiedUrl );
 406         $secret = $img->getRepo()->getThumbProxySecret();
 407
 408         // Pass a secret key shared with the proxied service if any
 409         if ( strlen( $secret ) ) {
 410                 $req->setHeader( 'X-Swift-Secret', $secret );
 411         }
 412
 413         // Send request to proxied service
 414         $status = $req->execute();
 415
 416         MediaWiki\HeaderCallback::warnIfHeadersSent();
 417
 418         // Simply serve the response from the proxied service as-is
 419         header( 'HTTP/1.1 ' . $req->getStatus() );
 420
 421         $headers = $req->getResponseHeaders();
 422
 423         foreach ( $headers as $key => $values ) {
 424                 foreach ( $values as $value ) {
 425                         header( $key . ': ' . $value, false );
 426                 }
 427         }
 428
 429         echo $req->getContent();
 430 }
 431
 432 /**
 433  * Actually try to generate a new thumbnail
 434  *
 435  * @param File $file
 436  * @param array $params
 437  * @param string $thumbName
 438  * @param string $thumbPath
 439  * @return array (MediaTransformOutput|bool, string|bool error message HTML)
 440  */
 441 function wfGenerateThumbnail( File $file, array $params, $thumbName, $thumbPath ) {
 442         global $wgAttemptFailureEpoch;
 443
 444         $cache = ObjectCache::getLocalClusterInstance();
 445         $key = $cache->makeKey(
 446                 'attempt-failures',
 447                 $wgAttemptFailureEpoch,
 448                 $file->getRepo()->getName(),
 449                 $file->getSha1(),
 450                 md5( $thumbName )
 451         );
 452
 453         // Check if this file keeps failing to render
 454         if ( $cache->get( $key ) >= 4 ) {
 455                 return [ false, wfMessage( 'thumbnail_image-failure-limit', 4 ) ];
 456         }
 457
 458         $done = false;
 459         // Record failures on PHP fatals in addition to caching exceptions
 460         register_shutdown_function( function () use ( $cache, &$done, $key ) {
 461                 if ( !$done ) { // transform() gave a fatal
 462                         // Randomize TTL to reduce stampedes
 463                         $cache->incrWithInit( $key, $cache::TTL_HOUR + mt_rand( 0, 300 ) );
 464                 }
 465         } );
 466
 467         $thumb = false;
 468         $errorHtml = false;
 469
 470         // guard thumbnail rendering with PoolCounter to avoid stampedes
 471         // expensive files use a separate PoolCounter config so it is possible
 472         // to set up a global limit on them
 473         if ( $file->isExpensiveToThumbnail() ) {
 474                 $poolCounterType = 'FileRenderExpensive';
 475         } else {
 476                 $poolCounterType = 'FileRender';
 477         }
 478
 479         // Thumbnail isn't already there, so create the new thumbnail...
 480         try {
 481                 $work = new PoolCounterWorkViaCallback( $poolCounterType, sha1( $file->getName() ),
 482                         [
 483                                 'doWork' => function () use ( $file, $params ) {
 484                                         return $file->transform( $params, File::RENDER_NOW );
 485                                 },
 486                                 'doCachedWork' => function () use ( $file, $params, $thumbPath ) {
 487                                         // If the worker that finished made this thumbnail then use it.
 488                                         // Otherwise, it probably made a different thumbnail for this file.
 489                                         return $file->getRepo()->fileExists( $thumbPath )
 490                                                 ? $file->transform( $params, File::RENDER_NOW )
 491                                                 : false; // retry once more in exclusive mode
 492                                 },
 493                                 'error' => function ( Status $status ) {
 494                                         return wfMessage( 'generic-pool-error' )->parse() . '<hr>' . $status->getHTML();
 495                                 }
 496                         ]
 497                 );
 498                 $result = $work->execute();
 499                 if ( $result instanceof MediaTransformOutput ) {
 500                         $thumb = $result;
 501                 } elseif ( is_string( $result ) ) { // error
 502                         $errorHtml = $result;
 503                 }
 504         } catch ( Exception $e ) {
 505                 // Tried to select a page on a non-paged file?
 506         }
 507
 508         /** @noinspection PhpUnusedLocalVariableInspection */
 509         $done = true; // no PHP fatal occurred
 510
 511         if ( !$thumb || $thumb->isError() ) {
 512                 // Randomize TTL to reduce stampedes
 513                 $cache->incrWithInit( $key, $cache::TTL_HOUR + mt_rand( 0, 300 ) );
 514         }
 515
 516         return [ $thumb, $errorHtml ];
 517 }
 518
 519 /**
 520  * Convert pathinfo type parameter, into normal request parameters
 521  *
 522  * So for example, if the request was redirected from
 523  * /w/images/thumb/a/ab/Foo.png/120px-Foo.png. The $thumbRel parameter
 524  * of this function would be set to "a/ab/Foo.png/120px-Foo.png".
 525  * This method is responsible for turning that into an array
 526  * with the folowing keys:
 527  *  * f => the filename (Foo.png)
 528  *  * rel404 => the whole thing (a/ab/Foo.png/120px-Foo.png)
 529  *  * archived => 1 (If the request is for an archived thumb)
 530  *  * temp => 1 (If the file is in the "temporary" zone)
 531  *  * thumbName => the thumbnail name, including parameters (120px-Foo.png)
 532  *
 533  * Transform specific parameters are set later via wfExtractThumbParams().
 534  *
 535  * @param string $thumbRel Thumbnail path relative to the thumb zone
 536  * @return array|null Associative params array or null
 537  */
 538 function wfExtractThumbRequestInfo( $thumbRel ) {
 539         $repo = RepoGroup::singleton()->getLocalRepo();
 540
 541         $hashDirReg = $subdirReg = '';
 542         $hashLevels = $repo->getHashLevels();
 543         for ( $i = 0; $i < $hashLevels; $i++ ) {
 544                 $subdirReg .= '[0-9a-f]';
 545                 $hashDirReg .= "$subdirReg/";
 546         }
 547
 548         // Check if this is a thumbnail of an original in the local file repo
 549         if ( preg_match( "!^((archive/)?$hashDirReg([^/]*)/([^/]*))$!", $thumbRel, $m ) ) {
 550                 list( /*all*/, $rel, $archOrTemp, $filename, $thumbname ) = $m;
 551         // Check if this is a thumbnail of an temp file in the local file repo
 552         } elseif ( preg_match( "!^(temp/)($hashDirReg([^/]*)/([^/]*))$!", $thumbRel, $m ) ) {
 553                 list( /*all*/, $archOrTemp, $rel, $filename, $thumbname ) = $m;
 554         } else {
 555                 return null; // not a valid looking thumbnail request
 556         }
 557
 558         $params = [ 'f' => $filename, 'rel404' => $rel ];
 559         if ( $archOrTemp === 'archive/' ) {
 560                 $params['archived'] = 1;
 561         } elseif ( $archOrTemp === 'temp/' ) {
 562                 $params['temp'] = 1;
 563         }
 564
 565         $params['thumbName'] = $thumbname;
 566         return $params;
 567 }
 568
 569 /**
 570  * Convert a thumbnail name (122px-foo.png) to parameters, using
 571  * file handler.
 572  *
 573  * @param File $file File object for file in question
 574  * @param array $params Array of parameters so far
 575  * @return array Parameters array with more parameters
 576  */
 577 function wfExtractThumbParams( $file, $params ) {
 578         if ( !isset( $params['thumbName'] ) ) {
 579                 throw new InvalidArgumentException( "No thumbnail name passed to wfExtractThumbParams" );
 580         }
 581
 582         $thumbname = $params['thumbName'];
 583         unset( $params['thumbName'] );
 584
 585         // FIXME: Files in the temp zone don't set a MIME type, which means
 586         // they don't have a handler. Which means we can't parse the param
 587         // string. However, not a big issue as what good is a param string
 588         // if you have no handler to make use of the param string and
 589         // actually generate the thumbnail.
 590         $handler = $file->getHandler();
 591
 592         // Based on UploadStash::parseKey
 593         $fileNamePos = strrpos( $thumbname, $params['f'] );
 594         if ( $fileNamePos === false ) {
 595                 // Maybe using a short filename? (see FileRepo::nameForThumb)
 596                 $fileNamePos = strrpos( $thumbname, 'thumbnail' );
 597         }
 598
 599         if ( $handler && $fileNamePos !== false ) {
 600                 $paramString = substr( $thumbname, 0, $fileNamePos - 1 );
 601                 $extraParams = $handler->parseParamString( $paramString );
 602                 if ( $extraParams !== false ) {
 603                         return $params + $extraParams;
 604                 }
 605         }
 606
 607         // As a last ditch fallback, use the traditional common parameters
 608         if ( preg_match( '!^(page(\d*)-)*(\d*)px-[^/]*$!', $thumbname, $matches ) ) {
 609                 list( /* all */, /* pagefull */, $pagenum, $size ) = $matches;
 610                 $params['width'] = $size;
 611                 if ( $pagenum ) {
 612                         $params['page'] = $pagenum;
 613                 }
 614                 return $params; // valid thumbnail URL
 615         }
 616         return null;
 617 }
 618
 619 /**
 620  * Output a thumbnail generation error message
 621  *
 622  * @param int $status
 623  * @param string $msgText Plain text (will be html escaped)
 624  * @return void
 625  */
 626 function wfThumbErrorText( $status, $msgText ) {
 627         wfThumbError( $status, htmlspecialchars( $msgText, ENT_NOQUOTES ) );
 628 }
 629
 630 /**
 631  * Output a thumbnail generation error message
 632  *
 633  * @param int $status
 634  * @param string $msgHtml HTML
 635  * @param string|null $msgText Short error description, for internal logging. Defaults to $msgHtml.
 636  *   Only used for HTTP 500 errors.
 637  * @param array $context Error context, for internal logging. Only used for HTTP 500 errors.
 638  * @return void
 639  */
 640 function wfThumbError( $status, $msgHtml, $msgText = null, $context = [] ) {
 641         global $wgShowHostnames;
 642
 643         MediaWiki\HeaderCallback::warnIfHeadersSent();
 644
 645         header( 'Cache-Control: no-cache' );
 646         header( 'Content-Type: text/html; charset=utf-8' );
 647         if ( $status == 400 || $status == 404 || $status == 429 ) {
 648                 HttpStatus::header( $status );
 649         } elseif ( $status == 403 ) {
 650                 HttpStatus::header( 403 );
 651                 header( 'Vary: Cookie' );
 652         } else {
 653                 LoggerFactory::getInstance( 'thumb' )->error( $msgText ?: $msgHtml, $context );
 654                 HttpStatus::header( 500 );
 655         }
 656         if ( $wgShowHostnames ) {
 657                 header( 'X-MW-Thumbnail-Renderer: ' . wfHostname() );
 658                 $url = htmlspecialchars(
 659                         $_SERVER['REQUEST_URI'] ?? '',
 660                         ENT_NOQUOTES
 661                 );
 662                 $hostname = htmlspecialchars( wfHostname(), ENT_NOQUOTES );
 663                 $debug = "<!-- $url -->\n<!-- $hostname -->\n";
 664         } else {
 665                 $debug = '';
 666         }
 667         $content = <<<EOT
 668 <!DOCTYPE html>
 669 <html><head>
 670 <meta charset="UTF-8" />
 671 <title>Error generating thumbnail</title>
 672 </head>
 673 <body>
 674 <h1>Error generating thumbnail</h1>
 675 <p>
 676 $msgHtml
 677 </p>
 678 $debug
 679 </body>
 680 </html>
 681
 682 EOT;
 683         header( 'Content-Length: ' . strlen( $content ) );
 684         echo $content;
 685 }