thumb.php

   1 <?php
   2 /**
   3  * PHP script to stream out an image thumbnail.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Media
  22  */
  23
  24 define( 'MW_NO_OUTPUT_COMPRESSION', 1 );
  25 require __DIR__ . '/includes/WebStart.php';
  26
  27 // Don't use fancy mime detection, just check the file extension for jpg/gif/png
  28 $wgTrivialMimeDetection = true;
  29
  30 if ( defined( 'THUMB_HANDLER' ) ) {
  31         // Called from thumb_handler.php via 404; extract params from the URI...
  32         wfThumbHandle404();
  33 } else {
  34         // Called directly, use $_GET params
  35         wfThumbHandleRequest();
  36 }
  37
  38 wfLogProfilingData();
  39
  40 //--------------------------------------------------------------------------
  41
  42 /**
  43  * Handle a thumbnail request via query parameters
  44  *
  45  * @return void
  46  */
  47 function wfThumbHandleRequest() {
  48         $params = get_magic_quotes_gpc()
  49                 ? array_map( 'stripslashes', $_GET )
  50                 : $_GET;
  51
  52         wfStreamThumb( $params ); // stream the thumbnail
  53 }
  54
  55 /**
  56  * Handle a thumbnail request via thumbnail file URL
  57  *
  58  * @return void
  59  */
  60 function wfThumbHandle404() {
  61         global $wgArticlePath;
  62
  63         # Set action base paths so that WebRequest::getPathInfo()
  64         # recognizes the "X" as the 'title' in ../thumb_handler.php/X urls.
  65         # Note: If Custom per-extension repo paths are set, this may break.
  66         $repo = RepoGroup::singleton()->getLocalRepo();
  67         $oldArticlePath = $wgArticlePath;
  68         $wgArticlePath = $repo->getZoneUrl( 'thumb' ) . '/$1';
  69
  70         $matches = WebRequest::getPathInfo();
  71
  72         $wgArticlePath = $oldArticlePath;
  73
  74         if ( !isset( $matches['title'] ) ) {
  75                 wfThumbError( 404, 'Could not determine the name of the requested thumbnail.' );
  76                 return;
  77         }
  78
  79         $params = wfExtractThumbRequestInfo( $matches['title'] ); // basic wiki URL param extracting
  80         if ( $params == null ) {
  81                 wfThumbError( 400, 'The specified thumbnail parameters are not recognized.' );
  82                 return;
  83         }
  84
  85         wfStreamThumb( $params ); // stream the thumbnail
  86 }
  87
  88 /**
  89  * Stream a thumbnail specified by parameters
  90  *
  91  * @param array $params List of thumbnailing parameters. In addition to parameters
  92  *  passed to the MediaHandler, this may also includes the keys:
  93  *   f (for filename), archived (if archived file), temp (if temp file),
  94  *   w (alias for width), p (alias for page), r (ignored; historical),
  95  *   rel404 (path for render on 404 to verify hash path correct),
  96  *   thumbName (thumbnail name to potentially extract more parameters from
  97  *   e.g. 'lossy-page1-120px-Foo.tiff' would add page, lossy and width
  98  *   to the parameters)
  99  * @return void
 100  */
 101 function wfStreamThumb( array $params ) {
 102         global $wgVaryOnXFP;
 103
 104         $section = new ProfileSection( __METHOD__ );
 105
 106         $headers = array(); // HTTP headers to send
 107
 108         $fileName = isset( $params['f'] ) ? $params['f'] : '';
 109
 110         // Backwards compatibility parameters
 111         if ( isset( $params['w'] ) ) {
 112                 $params['width'] = $params['w'];
 113                 unset( $params['w'] );
 114         }
 115         if ( isset( $params['p'] ) ) {
 116                 $params['page'] = $params['p'];
 117         }
 118
 119         // Is this a thumb of an archived file?
 120         $isOld = ( isset( $params['archived'] ) && $params['archived'] );
 121         unset( $params['archived'] ); // handlers don't care
 122
 123         // Is this a thumb of a temp file?
 124         $isTemp = ( isset( $params['temp'] ) && $params['temp'] );
 125         unset( $params['temp'] ); // handlers don't care
 126
 127         // Some basic input validation
 128         $fileName = strtr( $fileName, '\\/', '__' );
 129
 130         // Actually fetch the image. Method depends on whether it is archived or not.
 131         if ( $isTemp ) {
 132                 $repo = RepoGroup::singleton()->getLocalRepo()->getTempRepo();
 133                 $img = new UnregisteredLocalFile( null, $repo,
 134                         # Temp files are hashed based on the name without the timestamp.
 135                         # The thumbnails will be hashed based on the entire name however.
 136                         # @todo fix this convention to actually be reasonable.
 137                         $repo->getZonePath( 'public' ) . '/' . $repo->getTempHashPath( $fileName ) . $fileName
 138                 );
 139         } elseif ( $isOld ) {
 140                 // Format is <timestamp>!<name>
 141                 $bits = explode( '!', $fileName, 2 );
 142                 if ( count( $bits ) != 2 ) {
 143                         wfThumbError( 404, wfMessage( 'badtitletext' )->text() );
 144                         return;
 145                 }
 146                 $title = Title::makeTitleSafe( NS_FILE, $bits[1] );
 147                 if ( !$title ) {
 148                         wfThumbError( 404, wfMessage( 'badtitletext' )->text() );
 149                         return;
 150                 }
 151                 $img = RepoGroup::singleton()->getLocalRepo()->newFromArchiveName( $title, $fileName );
 152         } else {
 153                 $img = wfLocalFile( $fileName );
 154         }
 155
 156         // Check the source file title
 157         if ( !$img ) {
 158                 wfThumbError( 404, wfMessage( 'badtitletext' )->text() );
 159                 return;
 160         }
 161
 162         // Check if the file is hidden
 163         if ( $img->isDeleted( File::DELETED_FILE ) ) {
 164                 wfThumbError( 404, "The source file '$fileName' does not exist." );
 165                 return;
 166         }
 167
 168         // Check permissions if there are read restrictions
 169         $varyHeader = array();
 170         if ( !in_array( 'read', User::getGroupPermissions( array( '*' ) ), true ) ) {
 171                 if ( !$img->getTitle() || !$img->getTitle()->userCan( 'read' ) ) {
 172                         wfThumbError( 403, 'Access denied. You do not have permission to access ' .
 173                                 'the source file.' );
 174                         return;
 175                 }
 176                 $headers[] = 'Cache-Control: private';
 177                 $varyHeader[] = 'Cookie';
 178         }
 179
 180         // Do rendering parameters extraction from thumbnail name.
 181         if ( isset( $params['thumbName'] ) ) {
 182                 $params = wfExtractThumbParams( $img, $params );
 183         }
 184         if ( $params == null ) {
 185                 wfThumbError( 400, 'The specified thumbnail parameters are not recognized.' );
 186                 return;
 187         }
 188
 189         // Check the source file storage path
 190         if ( !$img->exists() ) {
 191                 $redirectedLocation = false;
 192                 if ( !$isTemp ) {
 193                         // Check for file redirect
 194                         // Since redirects are associated with pages, not versions of files,
 195                         // we look for the most current version to see if its a redirect.
 196                         $possRedirFile = RepoGroup::singleton()->getLocalRepo()->findFile( $img->getName() );
 197                         if ( $possRedirFile && !is_null( $possRedirFile->getRedirected() ) ) {
 198                                 $redirTarget = $possRedirFile->getName();
 199                                 $targetFile = wfLocalFile( Title::makeTitleSafe( NS_FILE, $redirTarget ) );
 200                                 if ( $targetFile->exists() ) {
 201                                         $newThumbName = $targetFile->thumbName( $params );
 202                                         if ( $isOld ) {
 203                                                 $newThumbUrl = $targetFile->getArchiveThumbUrl(
 204                                                         $bits[0] . '!' . $targetFile->getName(), $newThumbName );
 205                                         } else {
 206                                                 $newThumbUrl = $targetFile->getThumbUrl( $newThumbName );
 207                                         }
 208                                         $redirectedLocation = wfExpandUrl( $newThumbUrl, PROTO_CURRENT );
 209                                 }
 210                         }
 211                 }
 212
 213                 if ( $redirectedLocation ) {
 214                         // File has been moved. Give redirect.
 215                         $response = RequestContext::getMain()->getRequest()->response();
 216                         $response->header( "HTTP/1.1 302 " . HttpStatus::getMessage( 302 ) );
 217                         $response->header( 'Location: ' . $redirectedLocation );
 218                         $response->header( 'Expires: ' .
 219                                 gmdate( 'D, d M Y H:i:s', time() + 12 * 3600 ) . ' GMT' );
 220                         if ( $wgVaryOnXFP ) {
 221                                 $varyHeader[] = 'X-Forwarded-Proto';
 222                         }
 223                         if ( count( $varyHeader ) ) {
 224                                 $response->header( 'Vary: ' . implode( ', ', $varyHeader ) );
 225                         }
 226                         return;
 227                 }
 228
 229                 // If its not a redirect that has a target as a local file, give 404.
 230                 wfThumbError( 404, "The source file '$fileName' does not exist." );
 231                 return;
 232         } elseif ( $img->getPath() === false ) {
 233                 wfThumbError( 500, "The source file '$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                 wfSuppressWarnings();
 244                 $imsUnix = strtotime( $imsString );
 245                 wfRestoreWarnings();
 246                 if ( wfTimestamp( TS_UNIX, $img->getTimestamp() ) <= $imsUnix ) {
 247                         header( 'HTTP/1.1 304 Not Modified' );
 248                         return;
 249                 }
 250         }
 251
 252         $rel404 = isset( $params['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                         wfThumbError( 400, 'The specified thumbnail parameters are not valid.' );
 262                         return;
 263                 }
 264                 $thumbName2 = $img->thumbName( $params, File::THUMB_FULL_NAME ); // b/c; "long" style
 265         } catch ( MWException $e ) {
 266                 wfThumbError( 500, $e->getHTML() );
 267                 return;
 268         }
 269
 270         // For 404 handled thumbnails, we only use the the base name of the URI
 271         // for the thumb params and the parent directory for the source file name.
 272         // Check that the zone relative path matches up so squid caches won't pick
 273         // up thumbs that would not be purged on source file deletion (bug 34231).
 274         if ( $rel404 !== null ) { // thumbnail was handled via 404
 275                 if ( rawurldecode( $rel404 ) === $img->getThumbRel( $thumbName ) ) {
 276                         // Request for the canonical thumbnail name
 277                 } elseif ( rawurldecode( $rel404 ) === $img->getThumbRel( $thumbName2 ) ) {
 278                         // Request for the "long" thumbnail name; redirect to canonical name
 279                         $response = RequestContext::getMain()->getRequest()->response();
 280                         $response->header( "HTTP/1.1 301 " . HttpStatus::getMessage( 301 ) );
 281                         $response->header( 'Location: ' .
 282                                 wfExpandUrl( $img->getThumbUrl( $thumbName ), PROTO_CURRENT ) );
 283                         $response->header( 'Expires: ' .
 284                                 gmdate( 'D, d M Y H:i:s', time() + 7 * 86400 ) . ' GMT' );
 285                         if ( $wgVaryOnXFP ) {
 286                                 $varyHeader[] = 'X-Forwarded-Proto';
 287                         }
 288                         if ( count( $varyHeader ) ) {
 289                                 $response->header( 'Vary: ' . implode( ', ', $varyHeader ) );
 290                         }
 291                         return;
 292                 } else {
 293                         wfThumbError( 404, "The given path of the specified thumbnail is incorrect;
 294                                 expected '" . $img->getThumbRel( $thumbName ) . "' but got '" .
 295                                 rawurldecode( $rel404 ) . "'." );
 296                         return;
 297                 }
 298         }
 299
 300         $dispositionType = isset( $params['download'] ) ? 'attachment' : 'inline';
 301
 302         // Suggest a good name for users downloading this thumbnail
 303         $headers[] = "Content-Disposition: {$img->getThumbDisposition( $thumbName, $dispositionType )}";
 304
 305         if ( count( $varyHeader ) ) {
 306                 $headers[] = 'Vary: ' . implode( ', ', $varyHeader );
 307         }
 308
 309         // Stream the file if it exists already...
 310         $thumbPath = $img->getThumbPath( $thumbName );
 311         if ( $img->getRepo()->fileExists( $thumbPath ) ) {
 312                 $img->getRepo()->streamFile( $thumbPath, $headers );
 313                 return;
 314         }
 315
 316         $user = RequestContext::getMain()->getUser();
 317         if ( !wfThumbIsStandard( $img, $params ) && $user->pingLimiter( 'renderfile-nonstandard' ) ) {
 318                 wfThumbError( 500, wfMessage( 'actionthrottledtext' ) );
 319                 return;
 320         } elseif ( $user->pingLimiter( 'renderfile' ) ) {
 321                 wfThumbError( 500, wfMessage( 'actionthrottledtext' ) );
 322                 return;
 323         } elseif ( wfThumbIsAttemptThrottled( $img, $thumbName, 5 ) ) {
 324                 wfThumbError( 500, wfMessage( 'thumbnail_image-failure-limit', 5 ) );
 325                 return;
 326         }
 327
 328         // Thumbnail isn't already there, so create the new thumbnail...
 329         $thumb = null;
 330         try {
 331                 // Record failures on PHP fatals too
 332                 register_shutdown_function( function() use ( &$thumb, $img, $thumbName ) {
 333                         if ( $thumb === null ) { // transform() gave a fatal
 334                                 wfThumbIncrAttemptFailures( $img, $thumbName );
 335                         }
 336                 } );
 337                 $thumb = $img->transform( $params, File::RENDER_NOW );
 338         } catch ( Exception $ex ) {
 339                 // Tried to select a page on a non-paged file?
 340                 $thumb = false;
 341         }
 342
 343         // Check for thumbnail generation errors...
 344         $errorMsg = false;
 345         $msg = wfMessage( 'thumbnail_error' );
 346         if ( !$thumb ) {
 347                 $errorMsg = $msg->rawParams( 'File::transform() returned false' )->escaped();
 348         } elseif ( $thumb->isError() ) {
 349                 $errorMsg = $thumb->getHtmlMsg();
 350         } elseif ( !$thumb->hasFile() ) {
 351                 $errorMsg = $msg->rawParams( 'No path supplied in thumbnail object' )->escaped();
 352         } elseif ( $thumb->fileIsSource() ) {
 353                 $errorMsg = $msg->
 354                         rawParams( 'Image was not scaled, is the requested width bigger than the source?' )->escaped();
 355         }
 356
 357         if ( $errorMsg !== false ) {
 358                 wfThumbIncrAttemptFailures( $img, $thumbName );
 359                 wfThumbError( 500, $errorMsg );
 360         } else {
 361                 // Stream the file if there were no errors
 362                 $thumb->streamFile( $headers );
 363         }
 364 }
 365
 366 /**
 367  * Returns true if this thumbnail is one that MediaWiki generates
 368  * links to on file description pages and possibly parser output.
 369  *
 370  * $params is considered non-standard if they involve a non-standard
 371  * width or any parameter aside from width and page number. The number
 372  * of possible files with standard parameters is far less than that of all
 373  * possible combinations; rate-limiting for them can thus be more generious.
 374  *
 375  * @param File $img
 376  * @param array $params
 377  * @return bool
 378  */
 379 function wfThumbIsStandard( File $img, array $params ) {
 380         global $wgThumbLimits, $wgImageLimits;
 381         // @TODO: use polymorphism with media handler here
 382         if ( array_diff( array_keys( $params ), array( 'width', 'page' ) ) ) {
 383                 return false; // extra parameters present
 384         }
 385         if ( isset( $params['width'] ) ) {
 386                 $widths = $wgThumbLimits;
 387                 foreach ( $wgImageLimits as $pair ) {
 388                         $widths[] = $pair[0];
 389                 }
 390                 if ( !in_array( $params['width'], $widths ) ) {
 391                         return false;
 392                 }
 393         }
 394         return true;
 395 }
 396
 397 /**
 398  * @param File $img
 399  * @param string $thumbName
 400  * @param int $limit
 401  * @return int|bool
 402  */
 403 function wfThumbIsAttemptThrottled( File $img, $thumbName, $limit ) {
 404         global $wgMemc;
 405
 406         return ( $wgMemc->get( wfThumbAttemptKey( $img, $thumbName ) ) >= $limit );
 407 }
 408
 409 /**
 410  * @param File $img
 411  * @param string $thumbName
 412  */
 413 function wfThumbIncrAttemptFailures( File $img, $thumbName ) {
 414         global $wgMemc;
 415
 416         $key = wfThumbAttemptKey( $img, $thumbName );
 417         if ( !$wgMemc->incr( $key, 1 ) ) {
 418                 if ( !$wgMemc->add( $key, 1, 3600 ) ) {
 419                         $wgMemc->incr( $key, 1 );
 420                 }
 421         }
 422 }
 423
 424 /**
 425  * @param File $img
 426  * @param string $thumbName
 427  * @return string
 428  */
 429 function wfThumbAttemptKey( File $img, $thumbName ) {
 430         global $wgAttemptFailureEpoch;
 431
 432         return wfMemcKey( 'attempt-failures', $wgAttemptFailureEpoch,
 433                 $img->getRepo()->getName(), md5( $img->getName() ), md5( $thumbName ) );
 434 }
 435
 436 /**
 437  * Convert pathinfo type parameter, into normal request parameters
 438  *
 439  * So for example, if the request was redirected from
 440  * /w/images/thumb/a/ab/Foo.png/120px-Foo.png. The $thumbRel parameter
 441  * of this function would be set to "a/ab/Foo.png/120px-Foo.png".
 442  * This method is responsible for turning that into an array
 443  * with the folowing keys:
 444  *  * f => the filename (Foo.png)
 445  *  * rel404 => the whole thing (a/ab/Foo.png/120px-Foo.png)
 446  *  * archived => 1 (If the request is for an archived thumb)
 447  *  * temp => 1 (If the file is in the "temporary" zone)
 448  *  * thumbName => the thumbnail name, including parameters (120px-Foo.png)
 449  *
 450  * Transform specific parameters are set later via wfExtractThumbParams().
 451  *
 452  * @param string $thumbRel Thumbnail path relative to the thumb zone
 453  * @return array|null Associative params array or null
 454  */
 455 function wfExtractThumbRequestInfo( $thumbRel ) {
 456         $repo = RepoGroup::singleton()->getLocalRepo();
 457
 458         $hashDirReg = $subdirReg = '';
 459         for ( $i = 0; $i < $repo->getHashLevels(); $i++ ) {
 460                 $subdirReg .= '[0-9a-f]';
 461                 $hashDirReg .= "$subdirReg/";
 462         }
 463
 464         // Check if this is a thumbnail of an original in the local file repo
 465         if ( preg_match( "!^((archive/)?$hashDirReg([^/]*)/([^/]*))$!", $thumbRel, $m ) ) {
 466                 list( /*all*/, $rel, $archOrTemp, $filename, $thumbname ) = $m;
 467         // Check if this is a thumbnail of an temp file in the local file repo
 468         } elseif ( preg_match( "!^(temp/)($hashDirReg([^/]*)/([^/]*))$!", $thumbRel, $m ) ) {
 469                 list( /*all*/, $archOrTemp, $rel, $filename, $thumbname ) = $m;
 470         } else {
 471                 return null; // not a valid looking thumbnail request
 472         }
 473
 474         $params = array( 'f' => $filename, 'rel404' => $rel );
 475         if ( $archOrTemp === 'archive/' ) {
 476                 $params['archived'] = 1;
 477         } elseif ( $archOrTemp === 'temp/' ) {
 478                 $params['temp'] = 1;
 479         }
 480
 481         $params['thumbName'] = $thumbname;
 482         return $params;
 483 }
 484
 485 /**
 486  * Convert a thumbnail name (122px-foo.png) to parameters, using
 487  * file handler.
 488  *
 489  * @param File $file File object for file in question
 490  * @param array $param Array of parameters so far
 491  * @return array Parameters array with more parameters
 492  */
 493 function wfExtractThumbParams( $file, $params ) {
 494         if ( !isset( $params['thumbName'] ) ) {
 495                 throw new MWException( "No thumbnail name passed to wfExtractThumbParams" );
 496         }
 497
 498         $thumbname = $params['thumbName'];
 499         unset( $params['thumbName'] );
 500
 501         // Do the hook first for older extensions that rely on it.
 502         if ( !wfRunHooks( 'ExtractThumbParameters', array( $thumbname, &$params ) ) ) {
 503                 // Check hooks if parameters can be extracted
 504                 // Hooks return false if they manage to *resolve* the parameters
 505                 // This hook should be considered deprecated
 506                 wfDeprecated( 'ExtractThumbParameters', '1.22' );
 507                 return $params; // valid thumbnail URL (via extension or config)
 508         }
 509
 510         // FIXME: Files in the temp zone don't set a mime type, which means
 511         // they don't have a handler. Which means we can't parse the param
 512         // string. However, not a big issue as what good is a param string
 513         // if you have no handler to make use of the param string and
 514         // actually generate the thumbnail.
 515         $handler = $file->getHandler();
 516
 517         // Based on UploadStash::parseKey
 518         $fileNamePos = strrpos( $thumbname, $params['f'] );
 519         if ( $fileNamePos === false ) {
 520                 // Maybe using a short filename? (see FileRepo::nameForThumb)
 521                 $fileNamePos = strrpos( $thumbname, 'thumbnail' );
 522         }
 523
 524         if ( $handler && $fileNamePos !== false ) {
 525                 $paramString = substr( $thumbname, 0, $fileNamePos - 1 );
 526                 $extraParams = $handler->parseParamString( $paramString );
 527                 if ( $extraParams !== false ) {
 528                         return $params + $extraParams;
 529                 }
 530         }
 531
 532         // As a last ditch fallback, use the traditional common parameters
 533         if ( preg_match( '!^(page(\d*)-)*(\d*)px-[^/]*$!', $thumbname, $matches ) ) {
 534                 list( /* all */, $pagefull, $pagenum, $size ) = $matches;
 535                 $params['width'] = $size;
 536                 if ( $pagenum ) {
 537                         $params['page'] = $pagenum;
 538                 }
 539                 return $params; // valid thumbnail URL
 540         }
 541         return null;
 542 }
 543
 544 /**
 545  * Output a thumbnail generation error message
 546  *
 547  * @param int $status
 548  * @param string $msg
 549  * @return void
 550  */
 551 function wfThumbError( $status, $msg ) {
 552         global $wgShowHostnames;
 553
 554         header( 'Cache-Control: no-cache' );
 555         header( 'Content-Type: text/html; charset=utf-8' );
 556         if ( $status == 404 ) {
 557                 header( 'HTTP/1.1 404 Not found' );
 558         } elseif ( $status == 403 ) {
 559                 header( 'HTTP/1.1 403 Forbidden' );
 560                 header( 'Vary: Cookie' );
 561         } else {
 562                 header( 'HTTP/1.1 500 Internal server error' );
 563         }
 564         if ( $wgShowHostnames ) {
 565                 header( 'X-MW-Thumbnail-Renderer: ' . wfHostname() );
 566                 $url = htmlspecialchars( isset( $_SERVER['REQUEST_URI'] ) ? $_SERVER['REQUEST_URI'] : '' );
 567                 $hostname = htmlspecialchars( wfHostname() );
 568                 $debug = "<!-- $url -->\n<!-- $hostname -->\n";
 569         } else {
 570                 $debug = '';
 571         }
 572         echo <<<EOT
 573 <html><head><title>Error generating thumbnail</title></head>
 574 <body>
 575 <h1>Error generating thumbnail</h1>
 576 <p>
 577 $msg
 578 </p>
 579 $debug
 580 </body>
 581 </html>
 582
 583 EOT;
 584 }