includes/MimeMagic.php

   1 <?php
   2 /**
   3  * Module defining helper functions for detecting and dealing with mime types.
   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  */
  22
  23 /**
  24  * Defines a set of well known mime types
  25  * This is used as a fallback to mime.types files.
  26  * An extensive list of well known mime types is provided by
  27  * the file mime.types in the includes directory.
  28  *
  29  * This list concatenated with mime.types is used to create a mime <-> ext
  30  * map. Each line contains a mime type followed by a space separated list of
  31  * extensions. If multiple extensions for a single mime type exist or if
  32  * multiple mime types exist for a single extension then in most cases
  33  * MediaWiki assumes that the first extension following the mime type is the
  34  * canonical extension, and the first time a mime type appears for a certain
  35  * extension is considered the canonical mime type.
  36  *
  37  * (Note that appending $wgMimeTypeFile to the end of MM_WELL_KNOWN_MIME_TYPES
  38  * sucks because you can't redefine canonical types. This could be fixed by
  39  * appending MM_WELL_KNOWN_MIME_TYPES behind $wgMimeTypeFile, but who knows
  40  * what will break? In practice this probably isn't a problem anyway -- Bryan)
  41  */
  42 define( 'MM_WELL_KNOWN_MIME_TYPES', <<<END_STRING
  43 application/ogg ogx ogg ogm ogv oga spx
  44 application/pdf pdf
  45 application/vnd.oasis.opendocument.chart odc
  46 application/vnd.oasis.opendocument.chart-template otc
  47 application/vnd.oasis.opendocument.database odb
  48 application/vnd.oasis.opendocument.formula odf
  49 application/vnd.oasis.opendocument.formula-template otf
  50 application/vnd.oasis.opendocument.graphics odg
  51 application/vnd.oasis.opendocument.graphics-template otg
  52 application/vnd.oasis.opendocument.image odi
  53 application/vnd.oasis.opendocument.image-template oti
  54 application/vnd.oasis.opendocument.presentation odp
  55 application/vnd.oasis.opendocument.presentation-template otp
  56 application/vnd.oasis.opendocument.spreadsheet ods
  57 application/vnd.oasis.opendocument.spreadsheet-template ots
  58 application/vnd.oasis.opendocument.text odt
  59 application/vnd.oasis.opendocument.text-master otm
  60 application/vnd.oasis.opendocument.text-template ott
  61 application/vnd.oasis.opendocument.text-web oth
  62 application/x-javascript js
  63 application/x-shockwave-flash swf
  64 audio/midi mid midi kar
  65 audio/mpeg mpga mpa mp2 mp3
  66 audio/x-aiff aif aiff aifc
  67 audio/x-wav wav
  68 audio/ogg oga spx ogg
  69 image/x-bmp bmp
  70 image/gif gif
  71 image/jpeg jpeg jpg jpe
  72 image/png png
  73 image/svg+xml svg
  74 image/svg svg
  75 image/tiff tiff tif
  76 image/vnd.djvu djvu
  77 image/x.djvu djvu
  78 image/x-djvu djvu
  79 image/x-portable-pixmap ppm
  80 image/x-xcf xcf
  81 text/plain txt
  82 text/html html htm
  83 video/ogg ogv ogm ogg
  84 video/mpeg mpg mpeg
  85 END_STRING
  86 );
  87
  88 /**
  89  * Defines a set of well known mime info entries
  90  * This is used as a fallback to mime.info files.
  91  * An extensive list of well known mime types is provided by
  92  * the file mime.info in the includes directory.
  93  */
  94 define( 'MM_WELL_KNOWN_MIME_INFO', <<<END_STRING
  95 application/pdf [OFFICE]
  96 application/vnd.oasis.opendocument.chart [OFFICE]
  97 application/vnd.oasis.opendocument.chart-template [OFFICE]
  98 application/vnd.oasis.opendocument.database [OFFICE]
  99 application/vnd.oasis.opendocument.formula [OFFICE]
 100 application/vnd.oasis.opendocument.formula-template [OFFICE]
 101 application/vnd.oasis.opendocument.graphics [OFFICE]
 102 application/vnd.oasis.opendocument.graphics-template [OFFICE]
 103 application/vnd.oasis.opendocument.image [OFFICE]
 104 application/vnd.oasis.opendocument.image-template [OFFICE]
 105 application/vnd.oasis.opendocument.presentation [OFFICE]
 106 application/vnd.oasis.opendocument.presentation-template [OFFICE]
 107 application/vnd.oasis.opendocument.spreadsheet [OFFICE]
 108 application/vnd.oasis.opendocument.spreadsheet-template [OFFICE]
 109 application/vnd.oasis.opendocument.text [OFFICE]
 110 application/vnd.oasis.opendocument.text-template [OFFICE]
 111 application/vnd.oasis.opendocument.text-master [OFFICE]
 112 application/vnd.oasis.opendocument.text-web [OFFICE]
 113 text/javascript application/x-javascript [EXECUTABLE]
 114 application/x-shockwave-flash [MULTIMEDIA]
 115 audio/midi [AUDIO]
 116 audio/x-aiff [AUDIO]
 117 audio/x-wav [AUDIO]
 118 audio/mp3 audio/mpeg [AUDIO]
 119 application/ogg audio/ogg video/ogg [MULTIMEDIA]
 120 image/x-bmp image/x-ms-bmp image/bmp [BITMAP]
 121 image/gif [BITMAP]
 122 image/jpeg [BITMAP]
 123 image/png [BITMAP]
 124 image/svg+xml [DRAWING]
 125 image/tiff [BITMAP]
 126 image/vnd.djvu [BITMAP]
 127 image/x-xcf [BITMAP]
 128 image/x-portable-pixmap [BITMAP]
 129 text/plain [TEXT]
 130 text/html [TEXT]
 131 video/ogg [VIDEO]
 132 video/mpeg [VIDEO]
 133 unknown/unknown application/octet-stream application/x-empty [UNKNOWN]
 134 END_STRING
 135 );
 136
 137 /**
 138  * Implements functions related to mime types such as detection and mapping to
 139  * file extension.
 140  *
 141  * Instances of this class are stateless, there only needs to be one global instance
 142  * of MimeMagic. Please use MimeMagic::singleton() to get that instance.
 143  */
 144 class MimeMagic {
 145
 146         /**
 147          * Mapping of media types to arrays of mime types.
 148          * This is used by findMediaType and getMediaType, respectively
 149          */
 150         var $mMediaTypes = null;
 151
 152         /** Map of mime type aliases
 153          */
 154         var $mMimeTypeAliases = null;
 155
 156         /** map of mime types to file extensions (as a space separated list)
 157          */
 158         var $mMimeToExt = null;
 159
 160         /** map of file extensions types to mime types (as a space separated list)
 161          */
 162         var $mExtToMime = null;
 163
 164         /** IEContentAnalyzer instance
 165          */
 166         var $mIEAnalyzer;
 167
 168         /** The singleton instance
 169          */
 170         private static $instance = null;
 171
 172         /** Initializes the MimeMagic object. This is called by MimeMagic::singleton().
 173          *
 174          * This constructor parses the mime.types and mime.info files and build internal mappings.
 175          */
 176         function __construct() {
 177                 /**
 178                  *   --- load mime.types ---
 179                  */
 180
 181                 global $wgMimeTypeFile, $IP;
 182
 183                 $types = MM_WELL_KNOWN_MIME_TYPES;
 184
 185                 if ( $wgMimeTypeFile == 'includes/mime.types' ) {
 186                         $wgMimeTypeFile = "$IP/$wgMimeTypeFile";
 187                 }
 188
 189                 if ( $wgMimeTypeFile ) {
 190                         if ( is_file( $wgMimeTypeFile ) and is_readable( $wgMimeTypeFile ) ) {
 191                                 wfDebug( __METHOD__ . ": loading mime types from $wgMimeTypeFile\n" );
 192                                 $types .= "\n";
 193                                 $types .= file_get_contents( $wgMimeTypeFile );
 194                         } else {
 195                                 wfDebug( __METHOD__ . ": can't load mime types from $wgMimeTypeFile\n" );
 196                         }
 197                 } else {
 198                         wfDebug( __METHOD__ . ": no mime types file defined, using build-ins only.\n" );
 199                 }
 200
 201                 $types = str_replace( array( "\r\n", "\n\r", "\n\n", "\r\r", "\r" ), "\n", $types );
 202                 $types = str_replace( "\t", " ", $types );
 203
 204                 $this->mMimeToExt = array();
 205                 $this->mToMime = array();
 206
 207                 $lines = explode( "\n", $types );
 208                 foreach ( $lines as $s ) {
 209                         $s = trim( $s );
 210                         if ( empty( $s ) ) {
 211                                 continue;
 212                         }
 213                         if ( strpos( $s, '#' ) === 0 ) {
 214                                 continue;
 215                         }
 216
 217                         $s = strtolower( $s );
 218                         $i = strpos( $s, ' ' );
 219
 220                         if ( $i === false ) {
 221                                 continue;
 222                         }
 223
 224                         $mime = substr( $s, 0, $i );
 225                         $ext = trim( substr( $s, $i + 1 ) );
 226
 227                         if ( empty( $ext ) ) {
 228                                 continue;
 229                         }
 230
 231                         if ( !empty( $this->mMimeToExt[$mime] ) ) {
 232                                 $this->mMimeToExt[$mime] .= ' ' . $ext;
 233                         } else {
 234                                 $this->mMimeToExt[$mime] = $ext;
 235                         }
 236
 237                         $extensions = explode( ' ', $ext );
 238
 239                         foreach ( $extensions as $e ) {
 240                                 $e = trim( $e );
 241                                 if ( empty( $e ) ) {
 242                                         continue;
 243                                 }
 244
 245                                 if ( !empty( $this->mExtToMime[$e] ) ) {
 246                                         $this->mExtToMime[$e] .= ' ' . $mime;
 247                                 } else {
 248                                         $this->mExtToMime[$e] = $mime;
 249                                 }
 250                         }
 251                 }
 252
 253                 /**
 254                  *   --- load mime.info ---
 255                  */
 256
 257                 global $wgMimeInfoFile;
 258                 if ( $wgMimeInfoFile == 'includes/mime.info' ) {
 259                         $wgMimeInfoFile = "$IP/$wgMimeInfoFile";
 260                 }
 261
 262                 $info = MM_WELL_KNOWN_MIME_INFO;
 263
 264                 if ( $wgMimeInfoFile ) {
 265                         if ( is_file( $wgMimeInfoFile ) and is_readable( $wgMimeInfoFile ) ) {
 266                                 wfDebug( __METHOD__ . ": loading mime info from $wgMimeInfoFile\n" );
 267                                 $info .= "\n";
 268                                 $info .= file_get_contents( $wgMimeInfoFile );
 269                         } else {
 270                                 wfDebug( __METHOD__ . ": can't load mime info from $wgMimeInfoFile\n" );
 271                         }
 272                 } else {
 273                         wfDebug( __METHOD__ . ": no mime info file defined, using build-ins only.\n" );
 274                 }
 275
 276                 $info = str_replace( array( "\r\n", "\n\r", "\n\n", "\r\r", "\r" ), "\n", $info );
 277                 $info = str_replace( "\t", " ", $info );
 278
 279                 $this->mMimeTypeAliases = array();
 280                 $this->mMediaTypes = array();
 281
 282                 $lines = explode( "\n", $info );
 283                 foreach ( $lines as $s ) {
 284                         $s = trim( $s );
 285                         if ( empty( $s ) ) {
 286                                 continue;
 287                         }
 288                         if ( strpos( $s, '#' ) === 0 ) {
 289                                 continue;
 290                         }
 291
 292                         $s = strtolower( $s );
 293                         $i = strpos( $s, ' ' );
 294
 295                         if ( $i === false ) {
 296                                 continue;
 297                         }
 298
 299                         #print "processing MIME INFO line $s<br>";
 300
 301                         $match = array();
 302                         if ( preg_match( '!\[\s*(\w+)\s*\]!', $s, $match ) ) {
 303                                 $s = preg_replace( '!\[\s*(\w+)\s*\]!', '', $s );
 304                                 $mtype = trim( strtoupper( $match[1] ) );
 305                         } else {
 306                                 $mtype = MEDIATYPE_UNKNOWN;
 307                         }
 308
 309                         $m = explode( ' ', $s );
 310
 311                         if ( !isset( $this->mMediaTypes[$mtype] ) ) {
 312                                 $this->mMediaTypes[$mtype] = array();
 313                         }
 314
 315                         foreach ( $m as $mime ) {
 316                                 $mime = trim( $mime );
 317                                 if ( empty( $mime ) ) {
 318                                         continue;
 319                                 }
 320
 321                                 $this->mMediaTypes[$mtype][] = $mime;
 322                         }
 323
 324                         if ( count( $m ) > 1 ) {
 325                                 $main = $m[0];
 326                                 for ( $i = 1; $i < count( $m ); $i += 1 ) {
 327                                         $mime = $m[$i];
 328                                         $this->mMimeTypeAliases[$mime] = $main;
 329                                 }
 330                         }
 331                 }
 332
 333         }
 334
 335         /**
 336          * Get an instance of this class
 337          * @return MimeMagic
 338          */
 339         public static function singleton() {
 340                 if ( self::$instance === null ) {
 341                         self::$instance = new MimeMagic;
 342                 }
 343                 return self::$instance;
 344         }
 345
 346         /**
 347          * Returns a list of file extensions for a given mime type as a space
 348          * separated string or null if the mime type was unrecognized. Resolves
 349          * mime type aliases.
 350          *
 351          * @param $mime string
 352          * @return string|null
 353          */
 354         public function getExtensionsForType( $mime ) {
 355                 $mime = strtolower( $mime );
 356
 357                 // Check the mime-to-ext map
 358                 if ( isset( $this->mMimeToExt[$mime] ) ) {
 359                         return $this->mMimeToExt[$mime];
 360                 }
 361
 362                 // Resolve the mime type to the canonical type
 363                 if ( isset( $this->mMimeTypeAliases[$mime] ) ) {
 364                         $mime = $this->mMimeTypeAliases[$mime];
 365                         if ( isset( $this->mMimeToExt[$mime] ) ) {
 366                                 return $this->mMimeToExt[$mime];
 367                         }
 368                 }
 369
 370                 return null;
 371         }
 372
 373         /**
 374          * Returns a list of mime types for a given file extension as a space
 375          * separated string or null if the extension was unrecognized.
 376          *
 377          * @param $ext string
 378          * @return string|null
 379          */
 380         public function getTypesForExtension( $ext ) {
 381                 $ext = strtolower( $ext );
 382
 383                 $r = isset( $this->mExtToMime[$ext] ) ? $this->mExtToMime[$ext] : null;
 384                 return $r;
 385         }
 386
 387         /**
 388          * Returns a single mime type for a given file extension or null if unknown.
 389          * This is always the first type from the list returned by getTypesForExtension($ext).
 390          *
 391          * @param $ext string
 392          * @return string|null
 393          */
 394         public function guessTypesForExtension( $ext ) {
 395                 $m = $this->getTypesForExtension( $ext );
 396                 if ( is_null( $m ) ) {
 397                         return null;
 398                 }
 399
 400                 // TODO: Check if this is needed; strtok( $m, ' ' ) should be sufficient
 401                 $m = trim( $m );
 402                 $m = preg_replace( '/\s.*$/', '', $m );
 403
 404                 return $m;
 405         }
 406
 407         /**
 408          * Tests if the extension matches the given mime type. Returns true if a
 409          * match was found, null if the mime type is unknown, and false if the
 410          * mime type is known but no matches where found.
 411          *
 412          * @param $extension string
 413          * @param $mime string
 414          * @return bool|null
 415          */
 416         public function isMatchingExtension( $extension, $mime ) {
 417                 $ext = $this->getExtensionsForType( $mime );
 418
 419                 if ( !$ext ) {
 420                         return null; // Unknown mime type
 421                 }
 422
 423                 $ext = explode( ' ', $ext );
 424
 425                 $extension = strtolower( $extension );
 426                 return in_array( $extension, $ext );
 427         }
 428
 429         /**
 430          * Returns true if the mime type is known to represent an image format
 431          * supported by the PHP GD library.
 432          *
 433          * @param $mime string
 434          *
 435          * @return bool
 436          */
 437         public function isPHPImageType( $mime ) {
 438                 // As defined by imagegetsize and image_type_to_mime
 439                 static $types = array(
 440                         'image/gif', 'image/jpeg', 'image/png',
 441                         'image/x-bmp', 'image/xbm', 'image/tiff',
 442                         'image/jp2', 'image/jpeg2000', 'image/iff',
 443                         'image/xbm', 'image/x-xbitmap',
 444                         'image/vnd.wap.wbmp', 'image/vnd.xiff',
 445                         'image/x-photoshop',
 446                         'application/x-shockwave-flash',
 447                 );
 448
 449                 return in_array( $mime, $types );
 450         }
 451
 452         /**
 453          * Returns true if the extension represents a type which can
 454          * be reliably detected from its content. Use this to determine
 455          * whether strict content checks should be applied to reject
 456          * invalid uploads; if we can't identify the type we won't
 457          * be able to say if it's invalid.
 458          *
 459          * @todo Be more accurate when using fancy mime detector plugins;
 460          *       right now this is the bare minimum getimagesize() list.
 461          * @return bool
 462          */
 463         function isRecognizableExtension( $extension ) {
 464                 static $types = array(
 465                         // Types recognized by getimagesize()
 466                         'gif', 'jpeg', 'jpg', 'png', 'swf', 'psd',
 467                         'bmp', 'tiff', 'tif', 'jpc', 'jp2',
 468                         'jpx', 'jb2', 'swc', 'iff', 'wbmp',
 469                         'xbm',
 470
 471                         // Formats we recognize magic numbers for
 472                         'djvu', 'ogx', 'ogg', 'ogv', 'oga', 'spx',
 473                         'mid', 'pdf', 'wmf', 'xcf', 'webm', 'mkv', 'mka',
 474                         'webp',
 475
 476                         // XML formats we sure hope we recognize reliably
 477                         'svg',
 478                 );
 479                 return in_array( strtolower( $extension ), $types );
 480         }
 481
 482         /**
 483          * Improves a mime type using the file extension. Some file formats are very generic,
 484          * so their mime type is not very meaningful. A more useful mime type can be derived
 485          * by looking at the file extension. Typically, this method would be called on the
 486          * result of guessMimeType().
 487          *
 488          * Currently, this method does the following:
 489          *
 490          * If $mime is "unknown/unknown" and isRecognizableExtension( $ext ) returns false,
 491          * return the result of guessTypesForExtension($ext).
 492          *
 493          * If $mime is "application/x-opc+zip" and isMatchingExtension( $ext, $mime )
 494          * gives true, return the result of guessTypesForExtension($ext).
 495          *
 496          * @param string $mime the mime type, typically guessed from a file's content.
 497          * @param string $ext the file extension, as taken from the file name
 498          *
 499          * @return string the mime type
 500          */
 501         public function improveTypeFromExtension( $mime, $ext ) {
 502                 if ( $mime === 'unknown/unknown' ) {
 503                         if ( $this->isRecognizableExtension( $ext ) ) {
 504                                 wfDebug( __METHOD__ . ': refusing to guess mime type for .' .
 505                                         "$ext file, we should have recognized it\n" );
 506                         } else {
 507                                 // Not something we can detect, so simply
 508                                 // trust the file extension
 509                                 $mime = $this->guessTypesForExtension( $ext );
 510                         }
 511                 }
 512                 elseif ( $mime === 'application/x-opc+zip' ) {
 513                         if ( $this->isMatchingExtension( $ext, $mime ) ) {
 514                                 // A known file extension for an OPC file,
 515                                 // find the proper mime type for that file extension
 516                                 $mime = $this->guessTypesForExtension( $ext );
 517                         } else {
 518                                 wfDebug( __METHOD__ . ": refusing to guess better type for $mime file, " .
 519                                         ".$ext is not a known OPC extension.\n" );
 520                                 $mime = 'application/zip';
 521                         }
 522                 }
 523
 524                 if ( isset( $this->mMimeTypeAliases[$mime] ) ) {
 525                         $mime = $this->mMimeTypeAliases[$mime];
 526                 }
 527
 528                 wfDebug( __METHOD__ . ": improved mime type for .$ext: $mime\n" );
 529                 return $mime;
 530         }
 531
 532         /**
 533          * Mime type detection. This uses detectMimeType to detect the mime type
 534          * of the file, but applies additional checks to determine some well known
 535          * file formats that may be missed or misinterpreted by the default mime
 536          * detection (namely XML based formats like XHTML or SVG, as well as ZIP
 537          * based formats like OPC/ODF files).
 538          *
 539          * @param string $file the file to check
 540          * @param $ext Mixed: the file extension, or true (default) to extract it from the filename.
 541          *             Set it to false to ignore the extension. DEPRECATED! Set to false, use
 542          *             improveTypeFromExtension($mime, $ext) later to improve mime type.
 543          *
 544          * @return string the mime type of $file
 545          */
 546         public function guessMimeType( $file, $ext = true ) {
 547                 if ( $ext ) { // TODO: make $ext default to false. Or better, remove it.
 548                         wfDebug( __METHOD__ . ": WARNING: use of the \$ext parameter is deprecated. " .
 549                                 "Use improveTypeFromExtension(\$mime, \$ext) instead.\n" );
 550                 }
 551
 552                 $mime = $this->doGuessMimeType( $file, $ext );
 553
 554                 if ( !$mime ) {
 555                         wfDebug( __METHOD__ . ": internal type detection failed for $file (.$ext)...\n" );
 556                         $mime = $this->detectMimeType( $file, $ext );
 557                 }
 558
 559                 if ( isset( $this->mMimeTypeAliases[$mime] ) ) {
 560                         $mime = $this->mMimeTypeAliases[$mime];
 561                 }
 562
 563                 wfDebug( __METHOD__ . ": guessed mime type of $file: $mime\n" );
 564                 return $mime;
 565         }
 566
 567         /**
 568          * Guess the mime type from the file contents.
 569          *
 570          * @param string $file
 571          * @param mixed $ext
 572          * @return bool|string
 573          */
 574         private function doGuessMimeType( $file, $ext ) { // TODO: remove $ext param
 575                 // Read a chunk of the file
 576                 wfSuppressWarnings();
 577                 // @todo FIXME: Shouldn't this be rb?
 578                 $f = fopen( $file, 'rt' );
 579                 wfRestoreWarnings();
 580
 581                 if ( !$f ) {
 582                         return 'unknown/unknown';
 583                 }
 584                 $head = fread( $f, 1024 );
 585                 fseek( $f, -65558, SEEK_END );
 586                 $tail = fread( $f, 65558 ); // 65558 = maximum size of a zip EOCDR
 587                 fclose( $f );
 588
 589                 wfDebug( __METHOD__ . ": analyzing head and tail of $file for magic numbers.\n" );
 590
 591                 // Hardcode a few magic number checks...
 592                 $headers = array(
 593                         // Multimedia...
 594                         'MThd'             => 'audio/midi',
 595                         'OggS'             => 'application/ogg',
 596
 597                         // Image formats...
 598                         // Note that WMF may have a bare header, no magic number.
 599                         "\x01\x00\x09\x00" => 'application/x-msmetafile', // Possibly prone to false positives?
 600                         "\xd7\xcd\xc6\x9a" => 'application/x-msmetafile',
 601                         '%PDF'             => 'application/pdf',
 602                         'gimp xcf'         => 'image/x-xcf',
 603
 604                         // Some forbidden fruit...
 605                         'MZ'               => 'application/octet-stream', // DOS/Windows executable
 606                         "\xca\xfe\xba\xbe" => 'application/octet-stream', // Mach-O binary
 607                         "\x7fELF"          => 'application/octet-stream', // ELF binary
 608                 );
 609
 610                 foreach ( $headers as $magic => $candidate ) {
 611                         if ( strncmp( $head, $magic, strlen( $magic ) ) == 0 ) {
 612                                 wfDebug( __METHOD__ . ": magic header in $file recognized as $candidate\n" );
 613                                 return $candidate;
 614                         }
 615                 }
 616
 617                 /* Look for WebM and Matroska files */
 618                 if ( strncmp( $head, pack( "C4", 0x1a, 0x45, 0xdf, 0xa3 ), 4 ) == 0 ) {
 619                         $doctype = strpos( $head, "\x42\x82" );
 620                         if ( $doctype ) {
 621                                 // Next byte is datasize, then data (sizes larger than 1 byte are very stupid muxers)
 622                                 $data = substr( $head, $doctype + 3, 8 );
 623                                 if ( strncmp( $data, "matroska", 8 ) == 0 ) {
 624                                         wfDebug( __METHOD__ . ": recognized file as video/x-matroska\n" );
 625                                         return "video/x-matroska";
 626                                 } elseif ( strncmp( $data, "webm", 4 ) == 0 ) {
 627                                         wfDebug( __METHOD__ . ": recognized file as video/webm\n" );
 628                                         return "video/webm";
 629                                 }
 630                         }
 631                         wfDebug( __METHOD__ . ": unknown EBML file\n" );
 632                         return "unknown/unknown";
 633                 }
 634
 635                 /* Look for WebP */
 636                 if ( strncmp( $head, "RIFF", 4 ) == 0 && strncmp( substr( $head, 8, 8 ), "WEBPVP8 ", 8 ) == 0 ) {
 637                         wfDebug( __METHOD__ . ": recognized file as image/webp\n" );
 638                         return "image/webp";
 639                 }
 640
 641                 /**
 642                  * Look for PHP.  Check for this before HTML/XML...  Warning: this is a
 643                  * heuristic, and won't match a file with a lot of non-PHP before.  It
 644                  * will also match text files which could be PHP. :)
 645                  *
 646                  * @todo FIXME: For this reason, the check is probably useless -- an attacker
 647                  * could almost certainly just pad the file with a lot of nonsense to
 648                  * circumvent the check in any case where it would be a security
 649                  * problem.  On the other hand, it causes harmful false positives (bug
 650                  * 16583).  The heuristic has been cut down to exclude three-character
 651                  * strings like "<? ", but should it be axed completely?
 652                  */
 653                 if ( ( strpos( $head, '<?php' ) !== false ) ||
 654                         ( strpos( $head, "<\x00?\x00p\x00h\x00p" ) !== false ) ||
 655                         ( strpos( $head, "<\x00?\x00 " ) !== false ) ||
 656                         ( strpos( $head, "<\x00?\x00\n" ) !== false ) ||
 657                         ( strpos( $head, "<\x00?\x00\t" ) !== false ) ||
 658                         ( strpos( $head, "<\x00?\x00=" ) !== false ) ) {
 659
 660                         wfDebug( __METHOD__ . ": recognized $file as application/x-php\n" );
 661                         return 'application/x-php';
 662                 }
 663
 664                 /**
 665                  * look for XML formats (XHTML and SVG)
 666                  */
 667                 $xml = new XmlTypeCheck( $file );
 668                 if ( $xml->wellFormed ) {
 669                         global $wgXMLMimeTypes;
 670                         if ( isset( $wgXMLMimeTypes[$xml->getRootElement()] ) ) {
 671                                 return $wgXMLMimeTypes[$xml->getRootElement()];
 672                         } else {
 673                                 return 'application/xml';
 674                         }
 675                 }
 676
 677                 /**
 678                  * look for shell scripts
 679                  */
 680                 $script_type = null;
 681
 682                 # detect by shebang
 683                 if ( substr( $head, 0, 2 ) == "#!" ) {
 684                         $script_type = "ASCII";
 685                 } elseif ( substr( $head, 0, 5 ) == "\xef\xbb\xbf#!" ) {
 686                         $script_type = "UTF-8";
 687                 } elseif ( substr( $head, 0, 7 ) == "\xfe\xff\x00#\x00!" ) {
 688                         $script_type = "UTF-16BE";
 689                 } elseif ( substr( $head, 0, 7 ) == "\xff\xfe#\x00!" ) {
 690                         $script_type = "UTF-16LE";
 691                 }
 692
 693                 if ( $script_type ) {
 694                         if ( $script_type !== "UTF-8" && $script_type !== "ASCII" ) {
 695                                 // Quick and dirty fold down to ASCII!
 696                                 $pack = array( 'UTF-16BE' => 'n*', 'UTF-16LE' => 'v*' );
 697                                 $chars = unpack( $pack[$script_type], substr( $head, 2 ) );
 698                                 $head = '';
 699                                 foreach ( $chars as $codepoint ) {
 700                                         if ( $codepoint < 128 ) {
 701                                                 $head .= chr( $codepoint );
 702                                         } else {
 703                                                 $head .= '?';
 704                                         }
 705                                 }
 706                         }
 707
 708                         $match = array();
 709
 710                         if ( preg_match( '%/?([^\s]+/)(\w+)%', $head, $match ) ) {
 711                                 $mime = "application/x-{$match[2]}";
 712                                 wfDebug( __METHOD__ . ": shell script recognized as $mime\n" );
 713                                 return $mime;
 714                         }
 715                 }
 716
 717                 // Check for ZIP variants (before getimagesize)
 718                 if ( strpos( $tail, "PK\x05\x06" ) !== false ) {
 719                         wfDebug( __METHOD__ . ": ZIP header present in $file\n" );
 720                         return $this->detectZipType( $head, $tail, $ext );
 721                 }
 722
 723                 wfSuppressWarnings();
 724                 $gis = getimagesize( $file );
 725                 wfRestoreWarnings();
 726
 727                 if ( $gis && isset( $gis['mime'] ) ) {
 728                         $mime = $gis['mime'];
 729                         wfDebug( __METHOD__ . ": getimagesize detected $file as $mime\n" );
 730                         return $mime;
 731                 }
 732
 733                 // Also test DjVu
 734                 $deja = new DjVuImage( $file );
 735                 if ( $deja->isValid() ) {
 736                         wfDebug( __METHOD__ . ": detected $file as image/vnd.djvu\n" );
 737                         return 'image/vnd.djvu';
 738                 }
 739
 740                 return false;
 741         }
 742
 743         /**
 744          * Detect application-specific file type of a given ZIP file from its
 745          * header data.  Currently works for OpenDocument and OpenXML types...
 746          * If can't tell, returns 'application/zip'.
 747          *
 748          * @param string $header some reasonably-sized chunk of file header
 749          * @param $tail   String: the tail of the file
 750          * @param $ext Mixed: the file extension, or true to extract it from the filename.
 751          *             Set it to false (default) to ignore the extension. DEPRECATED! Set to false,
 752          *             use improveTypeFromExtension($mime, $ext) later to improve mime type.
 753          *
 754          * @return string
 755          */
 756         function detectZipType( $header, $tail = null, $ext = false ) {
 757                 if ( $ext ) { # TODO: remove $ext param
 758                         wfDebug( __METHOD__ . ": WARNING: use of the \$ext parameter is deprecated. " .
 759                                 "Use improveTypeFromExtension(\$mime, \$ext) instead.\n" );
 760                 }
 761
 762                 $mime = 'application/zip';
 763                 $opendocTypes = array(
 764                         'chart-template',
 765                         'chart',
 766                         'formula-template',
 767                         'formula',
 768                         'graphics-template',
 769                         'graphics',
 770                         'image-template',
 771                         'image',
 772                         'presentation-template',
 773                         'presentation',
 774                         'spreadsheet-template',
 775                         'spreadsheet',
 776                         'text-template',
 777                         'text-master',
 778                         'text-web',
 779                         'text' );
 780
 781                 // http://lists.oasis-open.org/archives/office/200505/msg00006.html
 782                 $types = '(?:' . implode( '|', $opendocTypes ) . ')';
 783                 $opendocRegex = "/^mimetype(application\/vnd\.oasis\.opendocument\.$types)/";
 784
 785                 $openxmlRegex = "/^\[Content_Types\].xml/";
 786
 787                 if ( preg_match( $opendocRegex, substr( $header, 30 ), $matches ) ) {
 788                         $mime = $matches[1];
 789                         wfDebug( __METHOD__ . ": detected $mime from ZIP archive\n" );
 790                 } elseif ( preg_match( $openxmlRegex, substr( $header, 30 ) ) ) {
 791                         $mime = "application/x-opc+zip";
 792                         # TODO: remove the block below, as soon as improveTypeFromExtension is used everywhere
 793                         if ( $ext !== true && $ext !== false ) {
 794                                 /** This is the mode used by getPropsFromPath
 795                                  * These mime's are stored in the database, where we don't really want
 796                                  * x-opc+zip, because we use it only for internal purposes
 797                                  */
 798                                 if ( $this->isMatchingExtension( $ext, $mime ) ) {
 799                                         /* A known file extension for an OPC file,
 800                                          * find the proper mime type for that file extension
 801                                          */
 802                                         $mime = $this->guessTypesForExtension( $ext );
 803                                 } else {
 804                                         $mime = "application/zip";
 805                                 }
 806                         }
 807                         wfDebug( __METHOD__ . ": detected an Open Packaging Conventions archive: $mime\n" );
 808                 } elseif ( substr( $header, 0, 8 ) == "\xd0\xcf\x11\xe0\xa1\xb1\x1a\xe1" &&
 809                                 ( $headerpos = strpos( $tail, "PK\x03\x04" ) ) !== false &&
 810                                 preg_match( $openxmlRegex, substr( $tail, $headerpos + 30 ) ) ) {
 811                         if ( substr( $header, 512, 4 ) == "\xEC\xA5\xC1\x00" ) {
 812                                 $mime = "application/msword";
 813                         }
 814                         switch ( substr( $header, 512, 6 ) ) {
 815                                 case "\xEC\xA5\xC1\x00\x0E\x00":
 816                                 case "\xEC\xA5\xC1\x00\x1C\x00":
 817                                 case "\xEC\xA5\xC1\x00\x43\x00":
 818                                         $mime = "application/vnd.ms-powerpoint";
 819                                         break;
 820                                 case "\xFD\xFF\xFF\xFF\x10\x00":
 821                                 case "\xFD\xFF\xFF\xFF\x1F\x00":
 822                                 case "\xFD\xFF\xFF\xFF\x22\x00":
 823                                 case "\xFD\xFF\xFF\xFF\x23\x00":
 824                                 case "\xFD\xFF\xFF\xFF\x28\x00":
 825                                 case "\xFD\xFF\xFF\xFF\x29\x00":
 826                                 case "\xFD\xFF\xFF\xFF\x10\x02":
 827                                 case "\xFD\xFF\xFF\xFF\x1F\x02":
 828                                 case "\xFD\xFF\xFF\xFF\x22\x02":
 829                                 case "\xFD\xFF\xFF\xFF\x23\x02":
 830                                 case "\xFD\xFF\xFF\xFF\x28\x02":
 831                                 case "\xFD\xFF\xFF\xFF\x29\x02":
 832                                         $mime = "application/vnd.msexcel";
 833                                         break;
 834                         }
 835
 836                         wfDebug( __METHOD__ . ": detected a MS Office document with OPC trailer\n" );
 837                 } else {
 838                         wfDebug( __METHOD__ . ": unable to identify type of ZIP archive\n" );
 839                 }
 840                 return $mime;
 841         }
 842
 843         /**
 844          * Internal mime type detection. Detection is done using an external
 845          * program, if $wgMimeDetectorCommand is set. Otherwise, the fileinfo
 846          * extension and mime_content_type are tried (in this order), if they
 847          * are available. If the detections fails and $ext is not false, the mime
 848          * type is guessed from the file extension, using guessTypesForExtension.
 849          *
 850          * If the mime type is still unknown, getimagesize is used to detect the
 851          * mime type if the file is an image. If no mime type can be determined,
 852          * this function returns 'unknown/unknown'.
 853          *
 854          * @param string $file the file to check
 855          * @param $ext Mixed: the file extension, or true (default) to extract it from the filename.
 856          *             Set it to false to ignore the extension. DEPRECATED! Set to false, use
 857          *             improveTypeFromExtension($mime, $ext) later to improve mime type.
 858          *
 859          * @return string the mime type of $file
 860          */
 861         private function detectMimeType( $file, $ext = true ) {
 862                 global $wgMimeDetectorCommand;
 863
 864                 if ( $ext ) { # TODO:  make $ext default to false. Or better, remove it.
 865                         wfDebug( __METHOD__ . ": WARNING: use of the \$ext parameter is deprecated. Use improveTypeFromExtension(\$mime, \$ext) instead.\n" );
 866                 }
 867
 868                 $m = null;
 869                 if ( $wgMimeDetectorCommand ) {
 870                         $args = wfEscapeShellArg( $file );
 871                         $m = wfShellExec( "$wgMimeDetectorCommand $args" );
 872                 } elseif ( function_exists( "finfo_open" ) && function_exists( "finfo_file" ) ) {
 873
 874                         # This required the fileinfo extension by PECL,
 875                         # see http://pecl.php.net/package/fileinfo
 876                         # This must be compiled into PHP
 877                         #
 878                         # finfo is the official replacement for the deprecated
 879                         # mime_content_type function, see below.
 880                         #
 881                         # If you may need to load the fileinfo extension at runtime, set
 882                         # $wgLoadFileinfoExtension in LocalSettings.php
 883
 884                         $mime_magic_resource = finfo_open( FILEINFO_MIME ); /* return mime type ala mimetype extension */
 885
 886                         if ( $mime_magic_resource ) {
 887                                 $m = finfo_file( $mime_magic_resource, $file );
 888                                 finfo_close( $mime_magic_resource );
 889                         } else {
 890                                 wfDebug( __METHOD__ . ": finfo_open failed on " . FILEINFO_MIME . "!\n" );
 891                         }
 892                 } elseif ( function_exists( "mime_content_type" ) ) {
 893
 894                         # NOTE: this function is available since PHP 4.3.0, but only if
 895                         # PHP was compiled with --with-mime-magic or, before 4.3.2, with --enable-mime-magic.
 896                         #
 897                         # On Windows, you must set mime_magic.magicfile in php.ini to point to the mime.magic file bundled with PHP;
 898                         # sometimes, this may even be needed under linus/unix.
 899                         #
 900                         # Also note that this has been DEPRECATED in favor of the fileinfo extension by PECL, see above.
 901                         # see http://www.php.net/manual/en/ref.mime-magic.php for details.
 902
 903                         $m = mime_content_type( $file );
 904                 } else {
 905                         wfDebug( __METHOD__ . ": no magic mime detector found!\n" );
 906                 }
 907
 908                 if ( $m ) {
 909                         # normalize
 910                         $m = preg_replace( '![;, ].*$!', '', $m ); #strip charset, etc
 911                         $m = trim( $m );
 912                         $m = strtolower( $m );
 913
 914                         if ( strpos( $m, 'unknown' ) !== false ) {
 915                                 $m = null;
 916                         } else {
 917                                 wfDebug( __METHOD__ . ": magic mime type of $file: $m\n" );
 918                                 return $m;
 919                         }
 920                 }
 921
 922                 // If desired, look at extension as a fallback.
 923                 if ( $ext === true ) {
 924                         $i = strrpos( $file, '.' );
 925                         $ext = strtolower( $i ? substr( $file, $i + 1 ) : '' );
 926                 }
 927                 if ( $ext ) {
 928                         if ( $this->isRecognizableExtension( $ext ) ) {
 929                                 wfDebug( __METHOD__ . ": refusing to guess mime type for .$ext file, we should have recognized it\n" );
 930                         } else {
 931                                 $m = $this->guessTypesForExtension( $ext );
 932                                 if ( $m ) {
 933                                         wfDebug( __METHOD__ . ": extension mime type of $file: $m\n" );
 934                                         return $m;
 935                                 }
 936                         }
 937                 }
 938
 939                 // Unknown type
 940                 wfDebug( __METHOD__ . ": failed to guess mime type for $file!\n" );
 941                 return 'unknown/unknown';
 942         }
 943
 944         /**
 945          * Determine the media type code for a file, using its mime type, name and
 946          * possibly its contents.
 947          *
 948          * This function relies on the findMediaType(), mapping extensions and mime
 949          * types to media types.
 950          *
 951          * @todo analyse file if need be
 952          * @todo look at multiple extension, separately and together.
 953          *
 954          * @param string $path full path to the image file, in case we have to look at the contents
 955          *        (if null, only the mime type is used to determine the media type code).
 956          * @param string $mime mime type. If null it will be guessed using guessMimeType.
 957          *
 958          * @return (int?string?) a value to be used with the MEDIATYPE_xxx constants.
 959          */
 960         function getMediaType( $path = null, $mime = null ) {
 961                 if ( !$mime && !$path ) {
 962                         return MEDIATYPE_UNKNOWN;
 963                 }
 964
 965                 // If mime type is unknown, guess it
 966                 if ( !$mime ) {
 967                         $mime = $this->guessMimeType( $path, false );
 968                 }
 969
 970                 // Special code for ogg - detect if it's video (theora),
 971                 // else label it as sound.
 972                 if ( $mime == 'application/ogg' && file_exists( $path ) ) {
 973
 974                         // Read a chunk of the file
 975                         $f = fopen( $path, "rt" );
 976                         if ( !$f ) {
 977                                 return MEDIATYPE_UNKNOWN;
 978                         }
 979                         $head = fread( $f, 256 );
 980                         fclose( $f );
 981
 982                         $head = strtolower( $head );
 983
 984                         // This is an UGLY HACK, file should be parsed correctly
 985                         if ( strpos( $head, 'theora' ) !== false ) {
 986                                 return MEDIATYPE_VIDEO;
 987                         } elseif ( strpos( $head, 'vorbis' ) !== false ) {
 988                                 return MEDIATYPE_AUDIO;
 989                         } elseif ( strpos( $head, 'flac' ) !== false ) {
 990                                 return MEDIATYPE_AUDIO;
 991                         } elseif ( strpos( $head, 'speex' ) !== false ) {
 992                                 return MEDIATYPE_AUDIO;
 993                         } else {
 994                                 return MEDIATYPE_MULTIMEDIA;
 995                         }
 996                 }
 997
 998                 // Check for entry for full mime type
 999                 if ( $mime ) {
1000                         $type = $this->findMediaType( $mime );
1001                         if ( $type !== MEDIATYPE_UNKNOWN ) {
1002                                 return $type;
1003                         }
1004                 }
1005
1006                 // Check for entry for file extension
1007                 if ( $path ) {
1008                         $i = strrpos( $path, '.' );
1009                         $e = strtolower( $i ? substr( $path, $i + 1 ) : '' );
1010
1011                         // TODO: look at multi-extension if this fails, parse from full path
1012                         $type = $this->findMediaType( '.' . $e );
1013                         if ( $type !== MEDIATYPE_UNKNOWN ) {
1014                                 return $type;
1015                         }
1016                 }
1017
1018                 // Check major mime type
1019                 if ( $mime ) {
1020                         $i = strpos( $mime, '/' );
1021                         if ( $i !== false ) {
1022                                 $major = substr( $mime, 0, $i );
1023                                 $type = $this->findMediaType( $major );
1024                                 if ( $type !== MEDIATYPE_UNKNOWN ) {
1025                                         return $type;
1026                                 }
1027                         }
1028                 }
1029
1030                 if ( !$type ) {
1031                         $type = MEDIATYPE_UNKNOWN;
1032                 }
1033
1034                 return $type;
1035         }
1036
1037         /**
1038          * Returns a media code matching the given mime type or file extension.
1039          * File extensions are represented by a string starting with a dot (.) to
1040          * distinguish them from mime types.
1041          *
1042          * This function relies on the mapping defined by $this->mMediaTypes
1043          * @access private
1044          * @return int|string
1045          */
1046         function findMediaType( $extMime ) {
1047                 if ( strpos( $extMime, '.' ) === 0 ) {
1048                         // If it's an extension, look up the mime types
1049                         $m = $this->getTypesForExtension( substr( $extMime, 1 ) );
1050                         if ( !$m ) {
1051                                 return MEDIATYPE_UNKNOWN;
1052                         }
1053
1054                         $m = explode( ' ', $m );
1055                 } else {
1056                         // Normalize mime type
1057                         if ( isset( $this->mMimeTypeAliases[$extMime] ) ) {
1058                                 $extMime = $this->mMimeTypeAliases[$extMime];
1059                         }
1060
1061                         $m = array( $extMime );
1062                 }
1063
1064                 foreach ( $m as $mime ) {
1065                         foreach ( $this->mMediaTypes as $type => $codes ) {
1066                                 if ( in_array( $mime, $codes, true ) ) {
1067                                         return $type;
1068                                 }
1069                         }
1070                 }
1071
1072                 return MEDIATYPE_UNKNOWN;
1073         }
1074
1075         /**
1076          * Get the MIME types that various versions of Internet Explorer would
1077          * detect from a chunk of the content.
1078          *
1079          * @param string $fileName the file name (unused at present)
1080          * @param string $chunk the first 256 bytes of the file
1081          * @param string $proposed the MIME type proposed by the server
1082          * @return Array
1083          */
1084         public function getIEMimeTypes( $fileName, $chunk, $proposed ) {
1085                 $ca = $this->getIEContentAnalyzer();
1086                 return $ca->getRealMimesFromData( $fileName, $chunk, $proposed );
1087         }
1088
1089         /**
1090          * Get a cached instance of IEContentAnalyzer
1091          *
1092          * @return IEContentAnalyzer
1093          */
1094         protected function getIEContentAnalyzer() {
1095                 if ( is_null( $this->mIEAnalyzer ) ) {
1096                         $this->mIEAnalyzer = new IEContentAnalyzer;
1097                 }
1098                 return $this->mIEAnalyzer;
1099         }
1100 }