includes/MimeMagic.php

   1 <?php
   2 /** Module defining helper functions for detecting and dealing with mime types.
   3  *
   4  * @package MediaWiki
   5  */
   6
   7  /** Defines a set of well known mime types
   8  * This is used as a fallback to mime.types files.
   9  * An extensive list of well known mime types is provided by
  10  * the file mime.types in the includes directory.
  11  */
  12 define('MM_WELL_KNOWN_MIME_TYPES',<<<END_STRING
  13 application/ogg ogg ogm
  14 application/pdf pdf
  15 application/x-javascript js
  16 application/x-shockwave-flash swf
  17 audio/midi mid midi kar
  18 audio/mpeg mpga mpa mp2 mp3
  19 audio/x-aiff aif aiff aifc
  20 audio/x-wav wav
  21 audio/ogg ogg
  22 image/x-bmp bmp
  23 image/gif gif
  24 image/jpeg jpeg jpg jpe
  25 image/png png
  26 image/svg+xml svg
  27 image/tiff tiff tif
  28 image/vnd.djvu djvu
  29 text/plain txt
  30 text/html html htm
  31 video/ogg ogm ogg
  32 video/mpeg mpg mpeg
  33 END_STRING
  34 );
  35
  36  /** Defines a set of well known mime info entries
  37  * This is used as a fallback to mime.info files.
  38  * An extensive list of well known mime types is provided by
  39  * the file mime.info in the includes directory.
  40  */
  41 define('MM_WELL_KNOWN_MIME_INFO', <<<END_STRING
  42 application/pdf [OFFICE]
  43 text/javascript application/x-javascript [EXECUTABLE]
  44 application/x-shockwave-flash [MULTIMEDIA]
  45 audio/midi [AUDIO]
  46 audio/x-aiff [AUDIO]
  47 audio/x-wav [AUDIO]
  48 audio/mp3 audio/mpeg [AUDIO]
  49 application/ogg audio/ogg video/ogg [MULTIMEDIA]
  50 image/x-bmp image/bmp [BITMAP]
  51 image/gif [BITMAP]
  52 image/jpeg [BITMAP]
  53 image/png [BITMAP]
  54 image/svg image/svg+xml [DRAWING]
  55 image/tiff [BITMAP]
  56 image/vnd.djvu [BITMAP]
  57 text/plain [TEXT]
  58 text/html [TEXT]
  59 video/ogg [VIDEO]
  60 video/mpeg [VIDEO]
  61 unknown/unknown application/octet-stream application/x-empty [UNKNOWN]
  62 END_STRING
  63 );
  64
  65 #note: because this file is possibly included by a function,
  66 #we need to access the global scope explicitely!
  67 global $wgLoadFileinfoExtension;
  68
  69 if ($wgLoadFileinfoExtension) {
  70         if(!extension_loaded('fileinfo')) dl('fileinfo.' . PHP_SHLIB_SUFFIX);
  71 }
  72
  73 /** Implements functions related to mime types such as detection and mapping to
  74 * file extension,
  75 *
  76 * Instances of this class are stateles, there only needs to be one global instance
  77 * of MimeMagic. Please use MimeMagic::singleton() to get that instance.
  78 * @package MediaWiki
  79 */
  80 class MimeMagic {
  81
  82         /**
  83         * Mapping of media types to arrays of mime types.
  84         * This is used by findMediaType and getMediaType, respectively
  85         */
  86         var $mMediaTypes= NULL;
  87
  88         /** Map of mime type aliases
  89         */
  90         var $mMimeTypeAliases= NULL;
  91
  92         /** map of mime types to file extensions (as a space seprarated list)
  93         */
  94         var $mMimeToExt= NULL;
  95
  96         /** map of file extensions types to mime types (as a space seprarated list)
  97         */
  98         var $mExtToMime= NULL;
  99
 100         /** The singleton instance
 101          */
 102         private static $instance;
 103
 104         /** Initializes the MimeMagic object. This is called by MimeMagic::singleton().
 105         *
 106         * This constructor parses the mime.types and mime.info files and build internal mappings.
 107         */
 108         function MimeMagic() {
 109                 /*
 110                 *   --- load mime.types ---
 111                 */
 112
 113                 global $wgMimeTypeFile;
 114
 115                 $types= MM_WELL_KNOWN_MIME_TYPES;
 116
 117                 if ($wgMimeTypeFile) {
 118                         if (is_file($wgMimeTypeFile) and is_readable($wgMimeTypeFile)) {
 119                                 wfDebug("MimeMagic::MimeMagic: loading mime types from $wgMimeTypeFile\n");
 120
 121                                 $types.= "\n";
 122                                 $types.= file_get_contents($wgMimeTypeFile);
 123                         }
 124                         else wfDebug("MimeMagic::MimeMagic: can't load mime types from $wgMimeTypeFile\n");
 125                 }
 126                 else wfDebug("MimeMagic::MimeMagic: no mime types file defined, using build-ins only.\n");
 127
 128                 $types= str_replace(array("\r\n","\n\r","\n\n","\r\r","\r"),"\n",$types);
 129                 $types= str_replace("\t"," ",$types);
 130
 131                 $this->mMimeToExt= array();
 132                 $this->mToMime= array();
 133
 134                 $lines= explode("\n",$types);
 135                 foreach ($lines as $s) {
 136                         $s= trim($s);
 137                         if (empty($s)) continue;
 138                         if (strpos($s,'#')===0) continue;
 139
 140                         $s= strtolower($s);
 141                         $i= strpos($s,' ');
 142
 143                         if ($i===false) continue;
 144
 145                         #print "processing MIME line $s<br>";
 146
 147                         $mime= substr($s,0,$i);
 148                         $ext= trim(substr($s,$i+1));
 149
 150                         if (empty($ext)) continue;
 151
 152                         if ( !empty($this->mMimeToExt[$mime])) $this->mMimeToExt[$mime] .= ' '.$ext;
 153                         else $this->mMimeToExt[$mime]= $ext;
 154
 155                         $extensions= explode(' ',$ext);
 156
 157                         foreach ($extensions as $e) {
 158                                 $e= trim($e);
 159                                 if (empty($e)) continue;
 160
 161                                 if ( !empty($this->mExtToMime[$e])) $this->mExtToMime[$e] .= ' '.$mime;
 162                                 else $this->mExtToMime[$e]= $mime;
 163                         }
 164                 }
 165
 166                 /*
 167                 *   --- load mime.info ---
 168                 */
 169
 170                 global $wgMimeInfoFile;
 171
 172                 $info= MM_WELL_KNOWN_MIME_INFO;
 173
 174                 if ($wgMimeInfoFile) {
 175                         if (is_file($wgMimeInfoFile) and is_readable($wgMimeInfoFile)) {
 176                                 wfDebug("MimeMagic::MimeMagic: loading mime info from $wgMimeInfoFile\n");
 177
 178                                 $info.= "\n";
 179                                 $info.= file_get_contents($wgMimeInfoFile);
 180                         }
 181                         else wfDebug("MimeMagic::MimeMagic: can't load mime info from $wgMimeInfoFile\n");
 182                 }
 183                 else wfDebug("MimeMagic::MimeMagic: no mime info file defined, using build-ins only.\n");
 184
 185                 $info= str_replace(array("\r\n","\n\r","\n\n","\r\r","\r"),"\n",$info);
 186                 $info= str_replace("\t"," ",$info);
 187
 188                 $this->mMimeTypeAliases= array();
 189                 $this->mMediaTypes= array();
 190
 191                 $lines= explode("\n",$info);
 192                 foreach ($lines as $s) {
 193                         $s= trim($s);
 194                         if (empty($s)) continue;
 195                         if (strpos($s,'#')===0) continue;
 196
 197                         $s= strtolower($s);
 198                         $i= strpos($s,' ');
 199
 200                         if ($i===false) continue;
 201
 202                         #print "processing MIME INFO line $s<br>";
 203
 204                         $match= array();
 205                         if (preg_match('!\[\s*(\w+)\s*\]!',$s,$match)) {
 206                                 $s= preg_replace('!\[\s*(\w+)\s*\]!','',$s);
 207                                 $mtype= trim(strtoupper($match[1]));
 208                         }
 209                         else $mtype= MEDIATYPE_UNKNOWN;
 210
 211                         $m= explode(' ',$s);
 212
 213                         if (!isset($this->mMediaTypes[$mtype])) $this->mMediaTypes[$mtype]= array();
 214
 215                         foreach ($m as $mime) {
 216                                 $mime= trim($mime);
 217                                 if (empty($mime)) continue;
 218
 219                                 $this->mMediaTypes[$mtype][]= $mime;
 220                         }
 221
 222                         if (sizeof($m)>1) {
 223                                 $main= $m[0];
 224                                 for ($i=1; $i<sizeof($m); $i+= 1) {
 225                                         $mime= $m[$i];
 226                                         $this->mMimeTypeAliases[$mime]= $main;
 227                                 }
 228                         }
 229                 }
 230
 231         }
 232
 233         /**
 234          * Get an instance of this class
 235          */
 236         static function &singleton() {
 237                 if ( !isset( self::$instance ) ) {
 238                         self::$instance = new MimeMagic;
 239                 }
 240                 return self::$instance;
 241         }
 242
 243         /** returns a list of file extensions for a given mime type
 244         * as a space separated string.
 245         */
 246         function getExtensionsForType($mime) {
 247                 $mime= strtolower($mime);
 248
 249                 $r= @$this->mMimeToExt[$mime];
 250
 251                 if (@!$r and isset($this->mMimeTypeAliases[$mime])) {
 252                         $mime= $this->mMimeTypeAliases[$mime];
 253                         $r= @$this->mMimeToExt[$mime];
 254                 }
 255
 256                 return $r;
 257         }
 258
 259         /** returns a list of mime types for a given file extension
 260         * as a space separated string.
 261         */
 262         function getTypesForExtension($ext) {
 263                 $ext= strtolower($ext);
 264
 265                 $r= @$this->mExtToMime[$ext];
 266                 return $r;
 267         }
 268
 269         /** returns a single mime type for a given file extension.
 270         * This is always the first type from the list returned by getTypesForExtension($ext).
 271         */
 272         function guessTypesForExtension($ext) {
 273                 $m= $this->getTypesForExtension( $ext );
 274                 if( is_null($m) ) return NULL;
 275
 276                 $m= trim( $m );
 277                 $m= preg_replace('/\s.*$/','',$m);
 278
 279                 return $m;
 280         }
 281
 282
 283         /** tests if the extension matches the given mime type.
 284         * returns true if a match was found, NULL if the mime type is unknown,
 285         * and false if the mime type is known but no matches where found.
 286         */
 287         function isMatchingExtension($extension,$mime) {
 288                 $ext= $this->getExtensionsForType($mime);
 289
 290                 if (!$ext) {
 291                         return NULL;  //unknown
 292                 }
 293
 294                 $ext= explode(' ',$ext);
 295
 296                 $extension= strtolower($extension);
 297                 if (in_array($extension,$ext)) {
 298                         return true;
 299                 }
 300
 301                 return false;
 302         }
 303
 304         /** returns true if the mime type is known to represent
 305         * an image format supported by the PHP GD library.
 306         */
 307         function isPHPImageType( $mime ) {
 308                 #as defined by imagegetsize and image_type_to_mime
 309                 static $types = array(
 310                         'image/gif', 'image/jpeg', 'image/png',
 311                         'image/x-bmp', 'image/xbm', 'image/tiff',
 312                         'image/jp2', 'image/jpeg2000', 'image/iff',
 313                         'image/xbm', 'image/x-xbitmap',
 314                         'image/vnd.wap.wbmp', 'image/vnd.xiff',
 315                         'image/x-photoshop',
 316                         'application/x-shockwave-flash',
 317                 );
 318
 319                 return in_array( $mime, $types );
 320         }
 321
 322         /**
 323          * Returns true if the extension represents a type which can
 324          * be reliably detected from its content. Use this to determine
 325          * whether strict content checks should be applied to reject
 326          * invalid uploads; if we can't identify the type we won't
 327          * be able to say if it's invalid.
 328          *
 329          * @todo Be more accurate when using fancy mime detector plugins;
 330          *       right now this is the bare minimum getimagesize() list.
 331          * @return bool
 332          */
 333         function isRecognizableExtension( $extension ) {
 334                 static $types = array(
 335                         'gif', 'jpeg', 'jpg', 'png', 'swf', 'psd',
 336                         'bmp', 'tiff', 'tif', 'jpc', 'jp2',
 337                         'jpx', 'jb2', 'swc', 'iff', 'wbmp',
 338                         'xbm', 'djvu'
 339                 );
 340                 return in_array( strtolower( $extension ), $types );
 341         }
 342
 343
 344         /** mime type detection. This uses detectMimeType to detect the mim type of the file,
 345         * but applies additional checks to determine some well known file formats that may be missed
 346         * or misinterpreter by the default mime detection (namely xml based formats like XHTML or SVG).
 347         *
 348         * @param string $file The file to check
 349         * @param bool $useExt switch for allowing to use the file extension to guess the mime type. true by default.
 350         *
 351         * @return string the mime type of $file
 352         */
 353         function guessMimeType( $file, $useExt=true ) {
 354                 $fname = 'MimeMagic::guessMimeType';
 355                 $mime= $this->detectMimeType($file,$useExt);
 356
 357                 // Read a chunk of the file
 358                 $f = fopen( $file, "rt" );
 359                 if( !$f ) return "unknown/unknown";
 360                 $head = fread( $f, 1024 );
 361                 fclose( $f );
 362
 363                 $sub4 =  substr( $head, 0, 4 );
 364                 if ( $sub4 == "\x01\x00\x09\x00" || $sub4 == "\xd7\xcd\xc6\x9a" ) {
 365                         // WMF kill kill kill
 366                         // Note that WMF may have a bare header, no magic number.
 367                         // The former of the above two checks is theoretically prone to false positives
 368                         $mime = "application/x-msmetafile";
 369                 }
 370
 371                 if (strpos($mime,"text/")===0 || $mime==="application/xml") {
 372
 373                         $xml_type= NULL;
 374                         $script_type= NULL;
 375
 376                         /*
 377                         * look for XML formats (XHTML and SVG)
 378                         */
 379                         if ($mime==="text/sgml" ||
 380                             $mime==="text/plain" ||
 381                             $mime==="text/html" ||
 382                             $mime==="text/xml" ||
 383                             $mime==="application/xml") {
 384
 385                                 if (substr($head,0,5)=="<?xml") $xml_type= "ASCII";
 386                                 elseif (substr($head,0,8)=="\xef\xbb\xbf<?xml") $xml_type= "UTF-8";
 387                                 elseif (substr($head,0,10)=="\xfe\xff\x00<\x00?\x00x\x00m\x00l") $xml_type= "UTF-16BE";
 388                                 elseif (substr($head,0,10)=="\xff\xfe<\x00?\x00x\x00m\x00l\x00") $xml_type= "UTF-16LE";
 389
 390                                 if ($xml_type) {
 391                                         if ($xml_type!=="UTF-8" && $xml_type!=="ASCII") $head= iconv($xml_type,"ASCII//IGNORE",$head);
 392
 393                                         $match= array();
 394                                         $doctype= "";
 395                                         $tag= "";
 396
 397                                         if (preg_match('%<!DOCTYPE\s+[\w-]+\s+PUBLIC\s+["'."'".'"](.*?)["'."'".'"].*>%sim',$head,$match)) $doctype= $match[1];
 398                                         if (preg_match('%<(\w+).*>%sim',$head,$match)) $tag= $match[1];
 399
 400                                         #print "<br>ANALYSING $file ($mime): doctype= $doctype; tag= $tag<br>";
 401
 402                                         if (strpos($doctype,"-//W3C//DTD SVG")===0) $mime= "image/svg";
 403                                         elseif ($tag==="svg") $mime= "image/svg";
 404                                         elseif (strpos($doctype,"-//W3C//DTD XHTML")===0) $mime= "text/html";
 405                                         elseif ($tag==="html") $mime= "text/html";
 406                                 }
 407                         }
 408
 409                         /*
 410                         * look for shell scripts
 411                         */
 412                         if (!$xml_type) {
 413                                 $script_type= NULL;
 414
 415                                 #detect by shebang
 416                                 if (substr($head,0,2)=="#!") $script_type= "ASCII";
 417                                 elseif (substr($head,0,5)=="\xef\xbb\xbf#!") $script_type= "UTF-8";
 418                                 elseif (substr($head,0,7)=="\xfe\xff\x00#\x00!") $script_type= "UTF-16BE";
 419                                 elseif (substr($head,0,7)=="\xff\xfe#\x00!") $script_type= "UTF-16LE";
 420
 421                                 if ($script_type) {
 422                                         if ($script_type!=="UTF-8" && $script_type!=="ASCII") $head= iconv($script_type,"ASCII//IGNORE",$head);
 423
 424                                         $match= array();
 425                                         $prog= "";
 426
 427                                         if (preg_match('%/?([^\s]+/)(w+)%sim',$head,$match)) $script= $match[2];
 428
 429                                         $mime= "application/x-$prog";
 430                                 }
 431                         }
 432
 433                         /*
 434                         * look for PHP
 435                         */
 436                         if( !$xml_type && !$script_type ) {
 437
 438                                 if( ( strpos( $head, '<?php' ) !== false ) ||
 439                                     ( strpos( $head, '<? ' ) !== false ) ||
 440                                     ( strpos( $head, "<?\n" ) !== false ) ||
 441                                     ( strpos( $head, "<?\t" ) !== false ) ||
 442                                     ( strpos( $head, "<?=" ) !== false ) ||
 443
 444                                     ( strpos( $head, "<\x00?\x00p\x00h\x00p" ) !== false ) ||
 445                                     ( strpos( $head, "<\x00?\x00 " ) !== false ) ||
 446                                     ( strpos( $head, "<\x00?\x00\n" ) !== false ) ||
 447                                     ( strpos( $head, "<\x00?\x00\t" ) !== false ) ||
 448                                     ( strpos( $head, "<\x00?\x00=" ) !== false ) ) {
 449
 450                                         $mime= "application/x-php";
 451                                 }
 452                         }
 453
 454                 }
 455
 456                 if (isset($this->mMimeTypeAliases[$mime])) $mime= $this->mMimeTypeAliases[$mime];
 457
 458                 wfDebug("$fname: final mime type of $file: $mime\n");
 459                 return $mime;
 460         }
 461
 462         /** Internal mime type detection, please use guessMimeType() for application code instead.
 463         * Detection is done using an external program, if $wgMimeDetectorCommand is set.
 464         * Otherwise, the fileinfo extension and mime_content_type are tried (in this order), if they are available.
 465         * If the dections fails and $useExt is true, the mime type is guessed from the file extension, using guessTypesForExtension.
 466         * If the mime type is still unknown, getimagesize is used to detect the mime type if the file is an image.
 467         * If no mime type can be determined, this function returns "unknown/unknown".
 468         *
 469         * @param string $file The file to check
 470         * @param bool $useExt switch for allowing to use the file extension to guess the mime type. true by default.
 471         *
 472         * @return string the mime type of $file
 473         * @access private
 474         */
 475         function detectMimeType( $file, $useExt=true ) {
 476                 $fname = 'MimeMagic::detectMimeType';
 477
 478                 global $wgMimeDetectorCommand;
 479
 480                 $m= NULL;
 481                 if ($wgMimeDetectorCommand) {
 482                         $fn= wfEscapeShellArg($file);
 483                         $m= `$wgMimeDetectorCommand $fn`;
 484                 }
 485                 else if (function_exists("finfo_open") && function_exists("finfo_file")) {
 486
 487                         # This required the fileinfo extension by PECL,
 488                         # see http://pecl.php.net/package/fileinfo
 489                         # This must be compiled into PHP
 490                         #
 491                         # finfo is the official replacement for the deprecated
 492                         # mime_content_type function, see below.
 493                         #
 494                         # If you may need to load the fileinfo extension at runtime, set
 495                         # $wgLoadFileinfoExtension in LocalSettings.php
 496
 497                         $mime_magic_resource = finfo_open(FILEINFO_MIME); /* return mime type ala mimetype extension */
 498
 499                         if ($mime_magic_resource) {
 500                                 $m= finfo_file($mime_magic_resource, $file);
 501
 502                                 finfo_close($mime_magic_resource);
 503                         }
 504                         else wfDebug("$fname: finfo_open failed on ".FILEINFO_MIME."!\n");
 505                 }
 506                 else if (function_exists("mime_content_type")) {
 507
 508                         # NOTE: this function is available since PHP 4.3.0, but only if
 509                         # PHP was compiled with --with-mime-magic or, before 4.3.2, with --enable-mime-magic.
 510                         #
 511                         # On Windows, you must set mime_magic.magicfile in php.ini to point to the mime.magic file bundeled with PHP;
 512                         # sometimes, this may even be needed under linus/unix.
 513                         #
 514                         # Also note that this has been DEPRECATED in favor of the fileinfo extension by PECL, see above.
 515                         # see http://www.php.net/manual/en/ref.mime-magic.php for details.
 516
 517                         $m= mime_content_type($file);
 518
 519                         if ( $m == 'text/plain' ) {
 520                                 // mime_content_type sometimes considers DJVU files to be text/plain.
 521                                 $deja = new DjVuImage( $file );
 522                                 if( $deja->isValid() ) {
 523                                         wfDebug("$fname: (re)detected $file as image/vnd.djvu\n");
 524                                         $m = 'image/vnd.djvu';
 525                                 }
 526                         }
 527                 }
 528                 else wfDebug("$fname: no magic mime detector found!\n");
 529
 530                 if ($m) {
 531                         #normalize
 532                         $m= preg_replace('![;, ].*$!','',$m); #strip charset, etc
 533                         $m= trim($m);
 534                         $m= strtolower($m);
 535
 536                         if (strpos($m,'unknown')!==false) $m= NULL;
 537                         else {
 538                                 wfDebug("$fname: magic mime type of $file: $m\n");
 539                                 return $m;
 540                         }
 541                 }
 542
 543                 #if still not known, use getimagesize to find out the type of image
 544                 #TODO: skip things that do not have a well-known image extension? Would that be safe?
 545                 wfSuppressWarnings();
 546                 $gis = getimagesize( $file );
 547                 wfRestoreWarnings();
 548
 549                 $notAnImage= false;
 550
 551                 if ($gis && is_array($gis) && $gis[2]) {
 552                         switch ($gis[2]) {
 553                                 case IMAGETYPE_GIF: $m= "image/gif"; break;
 554                                 case IMAGETYPE_JPEG: $m= "image/jpeg"; break;
 555                                 case IMAGETYPE_PNG: $m= "image/png"; break;
 556                                 case IMAGETYPE_SWF: $m= "application/x-shockwave-flash"; break;
 557                                 case IMAGETYPE_PSD: $m= "application/photoshop"; break;
 558                                 case IMAGETYPE_BMP: $m= "image/bmp"; break;
 559                                 case IMAGETYPE_TIFF_II: $m= "image/tiff"; break;
 560                                 case IMAGETYPE_TIFF_MM: $m= "image/tiff"; break;
 561                                 case IMAGETYPE_JPC: $m= "image"; break;
 562                                 case IMAGETYPE_JP2: $m= "image/jpeg2000"; break;
 563                                 case IMAGETYPE_JPX: $m= "image/jpeg2000"; break;
 564                                 case IMAGETYPE_JB2: $m= "image"; break;
 565                                 case IMAGETYPE_SWC: $m= "application/x-shockwave-flash"; break;
 566                                 case IMAGETYPE_IFF: $m= "image/vnd.xiff"; break;
 567                                 case IMAGETYPE_WBMP: $m= "image/vnd.wap.wbmp"; break;
 568                                 case IMAGETYPE_XBM: $m= "image/x-xbitmap"; break;
 569                         }
 570
 571                         if ($m) {
 572                                 wfDebug("$fname: image mime type of $file: $m\n");
 573                                 return $m;
 574                         }
 575                         else $notAnImage= true;
 576                 } else {
 577                         // Also test DjVu
 578                         $deja = new DjVuImage( $file );
 579                         if( $deja->isValid() ) {
 580                                 wfDebug("$fname: detected $file as image/vnd.djvu\n");
 581                                 return 'image/vnd.djvu';
 582                         }
 583                 }
 584
 585                 #if desired, look at extension as a fallback.
 586                 if ($useExt) {
 587                         $i = strrpos( $file, '.' );
 588                         $e= strtolower( $i ? substr( $file, $i + 1 ) : '' );
 589
 590                         $m= $this->guessTypesForExtension($e);
 591
 592                         #TODO: if $notAnImage is set, do not trust the file extension if
 593                         # the results is one of the image types that should have been recognized
 594                         # by getimagesize
 595
 596                         if ($m) {
 597                                 wfDebug("$fname: extension mime type of $file: $m\n");
 598                                 return $m;
 599                         }
 600                 }
 601
 602                 #unknown type
 603                 wfDebug("$fname: failed to guess mime type for $file!\n");
 604                 return "unknown/unknown";
 605         }
 606
 607         /**
 608         * Determine the media type code for a file, using its mime type, name and possibly
 609         * its contents.
 610         *
 611         * This function relies on the findMediaType(), mapping extensions and mime
 612         * types to media types.
 613         *
 614         * @todo analyse file if need be
 615         * @todo look at multiple extension, separately and together.
 616         *
 617         * @param string $path full path to the image file, in case we have to look at the contents
 618         *        (if null, only the mime type is used to determine the media type code).
 619         * @param string $mime mime type. If null it will be guessed using guessMimeType.
 620         *
 621         * @return (int?string?) a value to be used with the MEDIATYPE_xxx constants.
 622         */
 623         function getMediaType($path=NULL,$mime=NULL) {
 624                 if( !$mime && !$path ) return MEDIATYPE_UNKNOWN;
 625
 626                 #if mime type is unknown, guess it
 627                 if( !$mime ) $mime= $this->guessMimeType($path,false);
 628
 629                 #special code for ogg - detect if it's video (theora),
 630                 #else label it as sound.
 631                 if( $mime=="application/ogg" && file_exists($path) ) {
 632
 633                         // Read a chunk of the file
 634                         $f = fopen( $path, "rt" );
 635                         if( !$f ) return MEDIATYPE_UNKNOWN;
 636                         $head = fread( $f, 256 );
 637                         fclose( $f );
 638
 639                         $head= strtolower( $head );
 640
 641                         #This is an UGLY HACK, file should be parsed correctly
 642                         if( strpos($head,'theora')!==false ) return MEDIATYPE_VIDEO;
 643                         elseif( strpos($head,'vorbis')!==false ) return MEDIATYPE_AUDIO;
 644                         elseif( strpos($head,'flac')!==false ) return MEDIATYPE_AUDIO;
 645                         elseif( strpos($head,'speex')!==false ) return MEDIATYPE_AUDIO;
 646                         else return MEDIATYPE_MULTIMEDIA;
 647                 }
 648
 649                 #check for entry for full mime type
 650                 if( $mime ) {
 651                         $type= $this->findMediaType($mime);
 652                         if( $type!==MEDIATYPE_UNKNOWN ) return $type;
 653                 }
 654
 655                 #check for entry for file extension
 656                 $e= NULL;
 657                 if( $path ) {
 658                         $i = strrpos( $path, '.' );
 659                         $e= strtolower( $i ? substr( $path, $i + 1 ) : '' );
 660
 661                         #TODO: look at multi-extension if this fails, parse from full path
 662
 663                         $type= $this->findMediaType('.'.$e);
 664                         if( $type!==MEDIATYPE_UNKNOWN ) return $type;
 665                 }
 666
 667                 #check major mime type
 668                 if( $mime ) {
 669                         $i= strpos($mime,'/');
 670                         if( $i !== false ) {
 671                                 $major= substr($mime,0,$i);
 672                                 $type= $this->findMediaType($major);
 673                                 if( $type!==MEDIATYPE_UNKNOWN ) return $type;
 674                         }
 675                 }
 676
 677                 if( !$type ) $type= MEDIATYPE_UNKNOWN;
 678
 679                 return $type;
 680         }
 681
 682         /** returns a media code matching the given mime type or file extension.
 683         * File extensions are represented by a string starting with a dot (.) to
 684         * distinguish them from mime types.
 685         *
 686         * This funktion relies on the mapping defined by $this->mMediaTypes
 687         * @access private
 688         */
 689         function findMediaType($extMime) {
 690
 691                 if (strpos($extMime,'.')===0) { #if it's an extension, look up the mime types
 692                         $m= $this->getTypesForExtension(substr($extMime,1));
 693                         if (!$m) return MEDIATYPE_UNKNOWN;
 694
 695                         $m= explode(' ',$m);
 696                 }
 697                 else { #normalize mime type
 698                         if (isset($this->mMimeTypeAliases[$extMime])) {
 699                                 $extMime= $this->mMimeTypeAliases[$extMime];
 700                         }
 701
 702                         $m= array($extMime);
 703                 }
 704
 705                 foreach ($m as $mime) {
 706                         foreach ($this->mMediaTypes as $type => $codes) {
 707                                 if (in_array($mime,$codes,true)) return $type;
 708                         }
 709                 }
 710
 711                 return MEDIATYPE_UNKNOWN;
 712         }
 713 }
 714
 715 ?>