summaryrefslogtreecommitdiff
path: root/includes/MimeMagic.php
blob: 2b240c3b02b45e19002450442450ca1b6d116337 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
<?php
/**
 * Module defining helper functions for detecting and dealing with MIME types.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 */

/**
 * Defines a set of well known MIME types
 * This is used as a fallback to mime.types files.
 * An extensive list of well known MIME types is provided by
 * the file mime.types in the includes directory.
 *
 * This list concatenated with mime.types is used to create a MIME <-> ext
 * map. Each line contains a MIME type followed by a space separated list of
 * extensions. If multiple extensions for a single MIME type exist or if
 * multiple MIME types exist for a single extension then in most cases
 * MediaWiki assumes that the first extension following the MIME type is the
 * canonical extension, and the first time a MIME type appears for a certain
 * extension is considered the canonical MIME type.
 *
 * (Note that appending $wgMimeTypeFile to the end of MM_WELL_KNOWN_MIME_TYPES
 * sucks because you can't redefine canonical types. This could be fixed by
 * appending MM_WELL_KNOWN_MIME_TYPES behind $wgMimeTypeFile, but who knows
 * what will break? In practice this probably isn't a problem anyway -- Bryan)
 */
define( 'MM_WELL_KNOWN_MIME_TYPES', <<<END_STRING
application/ogg ogx ogg ogm ogv oga spx
application/pdf pdf
application/vnd.oasis.opendocument.chart odc
application/vnd.oasis.opendocument.chart-template otc
application/vnd.oasis.opendocument.database odb
application/vnd.oasis.opendocument.formula odf
application/vnd.oasis.opendocument.formula-template otf
application/vnd.oasis.opendocument.graphics odg
application/vnd.oasis.opendocument.graphics-template otg
application/vnd.oasis.opendocument.image odi
application/vnd.oasis.opendocument.image-template oti
application/vnd.oasis.opendocument.presentation odp
application/vnd.oasis.opendocument.presentation-template otp
application/vnd.oasis.opendocument.spreadsheet ods
application/vnd.oasis.opendocument.spreadsheet-template ots
application/vnd.oasis.opendocument.text odt
application/vnd.oasis.opendocument.text-master otm
application/vnd.oasis.opendocument.text-template ott
application/vnd.oasis.opendocument.text-web oth
application/x-javascript js
application/x-shockwave-flash swf
audio/midi mid midi kar
audio/mpeg mpga mpa mp2 mp3
audio/x-aiff aif aiff aifc
audio/x-wav wav
audio/ogg oga spx ogg
image/x-bmp bmp
image/gif gif
image/jpeg jpeg jpg jpe
image/png png
image/svg+xml svg
image/svg svg
image/tiff tiff tif
image/vnd.djvu djvu
image/x.djvu djvu
image/x-djvu djvu
image/x-portable-pixmap ppm
image/x-xcf xcf
text/plain txt
text/html html htm
video/ogg ogv ogm ogg
video/mpeg mpg mpeg
END_STRING
);

/**
 * Defines a set of well known MIME info entries
 * This is used as a fallback to mime.info files.
 * An extensive list of well known MIME types is provided by
 * the file mime.info in the includes directory.
 */
define( 'MM_WELL_KNOWN_MIME_INFO', <<<END_STRING
application/pdf [OFFICE]
application/vnd.oasis.opendocument.chart [OFFICE]
application/vnd.oasis.opendocument.chart-template [OFFICE]
application/vnd.oasis.opendocument.database [OFFICE]
application/vnd.oasis.opendocument.formula [OFFICE]
application/vnd.oasis.opendocument.formula-template [OFFICE]
application/vnd.oasis.opendocument.graphics [OFFICE]
application/vnd.oasis.opendocument.graphics-template [OFFICE]
application/vnd.oasis.opendocument.image [OFFICE]
application/vnd.oasis.opendocument.image-template [OFFICE]
application/vnd.oasis.opendocument.presentation [OFFICE]
application/vnd.oasis.opendocument.presentation-template [OFFICE]
application/vnd.oasis.opendocument.spreadsheet [OFFICE]
application/vnd.oasis.opendocument.spreadsheet-template [OFFICE]
application/vnd.oasis.opendocument.text [OFFICE]
application/vnd.oasis.opendocument.text-template [OFFICE]
application/vnd.oasis.opendocument.text-master [OFFICE]
application/vnd.oasis.opendocument.text-web [OFFICE]
text/javascript application/x-javascript [EXECUTABLE]
application/x-shockwave-flash [MULTIMEDIA]
audio/midi [AUDIO]
audio/x-aiff [AUDIO]
audio/x-wav [AUDIO]
audio/mp3 audio/mpeg [AUDIO]
application/ogg audio/ogg video/ogg [MULTIMEDIA]
image/x-bmp image/x-ms-bmp image/bmp [BITMAP]
image/gif [BITMAP]
image/jpeg [BITMAP]
image/png [BITMAP]
image/svg+xml [DRAWING]
image/tiff [BITMAP]
image/vnd.djvu [BITMAP]
image/x-xcf [BITMAP]
image/x-portable-pixmap [BITMAP]
text/plain [TEXT]
text/html [TEXT]
video/ogg [VIDEO]
video/mpeg [VIDEO]
unknown/unknown application/octet-stream application/x-empty [UNKNOWN]
END_STRING
);

/**
 * Implements functions related to MIME types such as detection and mapping to
 * file extension.
 *
 * Instances of this class are stateless, there only needs to be one global instance
 * of MimeMagic. Please use MimeMagic::singleton() to get that instance.
 */
class MimeMagic {
	/**
	 * @var array Mapping of media types to arrays of MIME types.
	 * This is used by findMediaType and getMediaType, respectively
	 */
	protected $mMediaTypes = null;

	/** @var array Map of MIME type aliases
	 */
	protected $mMimeTypeAliases = null;

	/** @var array Map of MIME types to file extensions (as a space separated list)
	 */
	protected $mMimeToExt = null;

	/** @var array Map of file extensions types to MIME types (as a space separated list)
	 */
	public $mExtToMime = null;

	/** @var IEContentAnalyzer
	 */
	protected $mIEAnalyzer;

	/** @var string Extra MIME types, set for example by media handling extensions
	 */
	private $mExtraTypes = '';

	/** @var string Extra MIME info, set for example by media handling extensions
	 */
	private $mExtraInfo = '';

	/** @var Config */
	private $mConfig;

	/** @var MimeMagic The singleton instance
	 */
	private static $instance = null;

	/** Initializes the MimeMagic object. This is called by MimeMagic::singleton().
	 *
	 * This constructor parses the mime.types and mime.info files and build internal mappings.
	 *
	 * @todo Make this constructor private once everything uses the singleton instance
	 * @param Config $config
	 */
	function __construct( Config $config = null ) {
		if ( !$config ) {
			wfDebug( __METHOD__ . ' called with no Config instance passed to it' );
			$config = ConfigFactory::getDefaultInstance()->makeConfig( 'main' );
		}
		$this->mConfig = $config;

		/**
		 *   --- load mime.types ---
		 */

		global $IP;

		# Allow media handling extensions adding MIME-types and MIME-info
		Hooks::run( 'MimeMagicInit', array( $this ) );

		$types = MM_WELL_KNOWN_MIME_TYPES;

		$mimeTypeFile = $this->mConfig->get( 'MimeTypeFile' );
		if ( $mimeTypeFile == 'includes/mime.types' ) {
			$mimeTypeFile = "$IP/$mimeTypeFile";
		}

		if ( $mimeTypeFile ) {
			if ( is_file( $mimeTypeFile ) && is_readable( $mimeTypeFile ) ) {
				wfDebug( __METHOD__ . ": loading mime types from $mimeTypeFile\n" );
				$types .= "\n";
				$types .= file_get_contents( $mimeTypeFile );
			} else {
				wfDebug( __METHOD__ . ": can't load mime types from $mimeTypeFile\n" );
			}
		} else {
			wfDebug( __METHOD__ . ": no mime types file defined, using built-ins only.\n" );
		}

		$types .= "\n" . $this->mExtraTypes;

		$types = str_replace( array( "\r\n", "\n\r", "\n\n", "\r\r", "\r" ), "\n", $types );
		$types = str_replace( "\t", " ", $types );

		$this->mMimeToExt = array();
		$this->mExtToMime = array();

		$lines = explode( "\n", $types );
		foreach ( $lines as $s ) {
			$s = trim( $s );
			if ( empty( $s ) ) {
				continue;
			}
			if ( strpos( $s, '#' ) === 0 ) {
				continue;
			}

			$s = strtolower( $s );
			$i = strpos( $s, ' ' );

			if ( $i === false ) {
				continue;
			}

			$mime = substr( $s, 0, $i );
			$ext = trim( substr( $s, $i + 1 ) );

			if ( empty( $ext ) ) {
				continue;
			}

			if ( !empty( $this->mMimeToExt[$mime] ) ) {
				$this->mMimeToExt[$mime] .= ' ' . $ext;
			} else {
				$this->mMimeToExt[$mime] = $ext;
			}

			$extensions = explode( ' ', $ext );

			foreach ( $extensions as $e ) {
				$e = trim( $e );
				if ( empty( $e ) ) {
					continue;
				}

				if ( !empty( $this->mExtToMime[$e] ) ) {
					$this->mExtToMime[$e] .= ' ' . $mime;
				} else {
					$this->mExtToMime[$e] = $mime;
				}
			}
		}

		/**
		 *   --- load mime.info ---
		 */

		$mimeInfoFile = $this->mConfig->get( 'MimeInfoFile' );
		if ( $mimeInfoFile == 'includes/mime.info' ) {
			$mimeInfoFile = "$IP/$mimeInfoFile";
		}

		$info = MM_WELL_KNOWN_MIME_INFO;

		if ( $mimeInfoFile ) {
			if ( is_file( $mimeInfoFile ) && is_readable( $mimeInfoFile ) ) {
				wfDebug( __METHOD__ . ": loading mime info from $mimeInfoFile\n" );
				$info .= "\n";
				$info .= file_get_contents( $mimeInfoFile );
			} else {
				wfDebug( __METHOD__ . ": can't load mime info from $mimeInfoFile\n" );
			}
		} else {
			wfDebug( __METHOD__ . ": no mime info file defined, using built-ins only.\n" );
		}

		$info .= "\n" . $this->mExtraInfo;

		$info = str_replace( array( "\r\n", "\n\r", "\n\n", "\r\r", "\r" ), "\n", $info );
		$info = str_replace( "\t", " ", $info );

		$this->mMimeTypeAliases = array();
		$this->mMediaTypes = array();

		$lines = explode( "\n", $info );
		foreach ( $lines as $s ) {
			$s = trim( $s );
			if ( empty( $s ) ) {
				continue;
			}
			if ( strpos( $s, '#' ) === 0 ) {
				continue;
			}

			$s = strtolower( $s );
			$i = strpos( $s, ' ' );

			if ( $i === false ) {
				continue;
			}

			#print "processing MIME INFO line $s<br>";

			$match = array();
			if ( preg_match( '!\[\s*(\w+)\s*\]!', $s, $match ) ) {
				$s = preg_replace( '!\[\s*(\w+)\s*\]!', '', $s );
				$mtype = trim( strtoupper( $match[1] ) );
			} else {
				$mtype = MEDIATYPE_UNKNOWN;
			}

			$m = explode( ' ', $s );

			if ( !isset( $this->mMediaTypes[$mtype] ) ) {
				$this->mMediaTypes[$mtype] = array();
			}

			foreach ( $m as $mime ) {
				$mime = trim( $mime );
				if ( empty( $mime ) ) {
					continue;
				}

				$this->mMediaTypes[$mtype][] = $mime;
			}

			if ( count( $m ) > 1 ) {
				$main = $m[0];
				$mCount = count( $m );
				for ( $i = 1; $i < $mCount; $i += 1 ) {
					$mime = $m[$i];
					$this->mMimeTypeAliases[$mime] = $main;
				}
			}
		}
	}

	/**
	 * Get an instance of this class
	 * @return MimeMagic
	 */
	public static function singleton() {
		if ( self::$instance === null ) {
			self::$instance = new MimeMagic(
				ConfigFactory::getDefaultInstance()->makeConfig( 'main' )
			);
		}
		return self::$instance;
	}

	/**
	 * Adds to the list mapping MIME to file extensions.
	 * As an extension author, you are encouraged to submit patches to
	 * MediaWiki's core to add new MIME types to mime.types.
	 * @param string $types
	 */
	public function addExtraTypes( $types ) {
		$this->mExtraTypes .= "\n" . $types;
	}

	/**
	 * Adds to the list mapping MIME to media type.
	 * As an extension author, you are encouraged to submit patches to
	 * MediaWiki's core to add new MIME info to mime.info.
	 * @param string $info
	 */
	public function addExtraInfo( $info ) {
		$this->mExtraInfo .= "\n" . $info;
	}

	/**
	 * Returns a list of file extensions for a given MIME type as a space
	 * separated string or null if the MIME type was unrecognized. Resolves
	 * MIME type aliases.
	 *
	 * @param string $mime
	 * @return string|null
	 */
	public function getExtensionsForType( $mime ) {
		$mime = strtolower( $mime );

		// Check the mime-to-ext map
		if ( isset( $this->mMimeToExt[$mime] ) ) {
			return $this->mMimeToExt[$mime];
		}

		// Resolve the MIME type to the canonical type
		if ( isset( $this->mMimeTypeAliases[$mime] ) ) {
			$mime = $this->mMimeTypeAliases[$mime];
			if ( isset( $this->mMimeToExt[$mime] ) ) {
				return $this->mMimeToExt[$mime];
			}
		}

		return null;
	}

	/**
	 * Returns a list of MIME types for a given file extension as a space
	 * separated string or null if the extension was unrecognized.
	 *
	 * @param string $ext
	 * @return string|null
	 */
	public function getTypesForExtension( $ext ) {
		$ext = strtolower( $ext );

		$r = isset( $this->mExtToMime[$ext] ) ? $this->mExtToMime[$ext] : null;
		return $r;
	}

	/**
	 * Returns a single MIME type for a given file extension or null if unknown.
	 * This is always the first type from the list returned by getTypesForExtension($ext).
	 *
	 * @param string $ext
	 * @return string|null
	 */
	public function guessTypesForExtension( $ext ) {
		$m = $this->getTypesForExtension( $ext );
		if ( is_null( $m ) ) {
			return null;
		}

		// TODO: Check if this is needed; strtok( $m, ' ' ) should be sufficient
		$m = trim( $m );
		$m = preg_replace( '/\s.*$/', '', $m );

		return $m;
	}

	/**
	 * Tests if the extension matches the given MIME type. Returns true if a
	 * match was found, null if the MIME type is unknown, and false if the
	 * MIME type is known but no matches where found.
	 *
	 * @param string $extension
	 * @param string $mime
	 * @return bool|null
	 */
	public function isMatchingExtension( $extension, $mime ) {
		$ext = $this->getExtensionsForType( $mime );

		if ( !$ext ) {
			return null; // Unknown MIME type
		}

		$ext = explode( ' ', $ext );

		$extension = strtolower( $extension );
		return in_array( $extension, $ext );
	}

	/**
	 * Returns true if the MIME type is known to represent an image format
	 * supported by the PHP GD library.
	 *
	 * @param string $mime
	 *
	 * @return bool
	 */
	public function isPHPImageType( $mime ) {
		// As defined by imagegetsize and image_type_to_mime
		static $types = array(
			'image/gif', 'image/jpeg', 'image/png',
			'image/x-bmp', 'image/xbm', 'image/tiff',
			'image/jp2', 'image/jpeg2000', 'image/iff',
			'image/xbm', 'image/x-xbitmap',
			'image/vnd.wap.wbmp', 'image/vnd.xiff',
			'image/x-photoshop',
			'application/x-shockwave-flash',
		);

		return in_array( $mime, $types );
	}

	/**
	 * Returns true if the extension represents a type which can
	 * be reliably detected from its content. Use this to determine
	 * whether strict content checks should be applied to reject
	 * invalid uploads; if we can't identify the type we won't
	 * be able to say if it's invalid.
	 *
	 * @todo Be more accurate when using fancy MIME detector plugins;
	 *       right now this is the bare minimum getimagesize() list.
	 * @param string $extension
	 * @return bool
	 */
	function isRecognizableExtension( $extension ) {
		static $types = array(
			// Types recognized by getimagesize()
			'gif', 'jpeg', 'jpg', 'png', 'swf', 'psd',
			'bmp', 'tiff', 'tif', 'jpc', 'jp2',
			'jpx', 'jb2', 'swc', 'iff', 'wbmp',
			'xbm',

			// Formats we recognize magic numbers for
			'djvu', 'ogx', 'ogg', 'ogv', 'oga', 'spx',
			'mid', 'pdf', 'wmf', 'xcf', 'webm', 'mkv', 'mka',
			'webp',

			// XML formats we sure hope we recognize reliably
			'svg',
		);
		return in_array( strtolower( $extension ), $types );
	}

	/**
	 * Improves a MIME type using the file extension. Some file formats are very generic,
	 * so their MIME type is not very meaningful. A more useful MIME type can be derived
	 * by looking at the file extension. Typically, this method would be called on the
	 * result of guessMimeType().
	 *
	 * @param string $mime The MIME type, typically guessed from a file's content.
	 * @param string $ext The file extension, as taken from the file name
	 *
	 * @return string The MIME type
	 */
	public function improveTypeFromExtension( $mime, $ext ) {
		if ( $mime === 'unknown/unknown' ) {
			if ( $this->isRecognizableExtension( $ext ) ) {
				wfDebug( __METHOD__ . ': refusing to guess mime type for .' .
					"$ext file, we should have recognized it\n" );
			} else {
				// Not something we can detect, so simply
				// trust the file extension
				$mime = $this->guessTypesForExtension( $ext );
			}
		} elseif ( $mime === 'application/x-opc+zip' ) {
			if ( $this->isMatchingExtension( $ext, $mime ) ) {
				// A known file extension for an OPC file,
				// find the proper MIME type for that file extension
				$mime = $this->guessTypesForExtension( $ext );
			} else {
				wfDebug( __METHOD__ . ": refusing to guess better type for $mime file, " .
					".$ext is not a known OPC extension.\n" );
				$mime = 'application/zip';
			}
		} elseif ( $mime === 'text/plain' && $this->findMediaType( ".$ext" ) === MEDIATYPE_TEXT ) {
			// Textual types are sometimes not recognized properly.
			// If detected as text/plain, and has an extension which is textual
			// improve to the extension's type. For example, csv and json are often
			// misdetected as text/plain.
			$mime = $this->guessTypesForExtension( $ext );
		}

		# Media handling extensions can improve the MIME detected
		Hooks::run( 'MimeMagicImproveFromExtension', array( $this, $ext, &$mime ) );

		if ( isset( $this->mMimeTypeAliases[$mime] ) ) {
			$mime = $this->mMimeTypeAliases[$mime];
		}

		wfDebug( __METHOD__ . ": improved mime type for .$ext: $mime\n" );
		return $mime;
	}

	/**
	 * MIME type detection. This uses detectMimeType to detect the MIME type
	 * of the file, but applies additional checks to determine some well known
	 * file formats that may be missed or misinterpreted by the default MIME
	 * detection (namely XML based formats like XHTML or SVG, as well as ZIP
	 * based formats like OPC/ODF files).
	 *
	 * @param string $file The file to check
	 * @param string|bool $ext The file extension, or true (default) to extract it from the filename.
	 *   Set it to false to ignore the extension. DEPRECATED! Set to false, use
	 *   improveTypeFromExtension($mime, $ext) later to improve MIME type.
	 *
	 * @return string The MIME type of $file
	 */
	public function guessMimeType( $file, $ext = true ) {
		if ( $ext ) { // TODO: make $ext default to false. Or better, remove it.
			wfDebug( __METHOD__ . ": WARNING: use of the \$ext parameter is deprecated. " .
				"Use improveTypeFromExtension(\$mime, \$ext) instead.\n" );
		}

		$mime = $this->doGuessMimeType( $file, $ext );

		if ( !$mime ) {
			wfDebug( __METHOD__ . ": internal type detection failed for $file (.$ext)...\n" );
			$mime = $this->detectMimeType( $file, $ext );
		}

		if ( isset( $this->mMimeTypeAliases[$mime] ) ) {
			$mime = $this->mMimeTypeAliases[$mime];
		}

		wfDebug( __METHOD__ . ": guessed mime type of $file: $mime\n" );
		return $mime;
	}

	/**
	 * Guess the MIME type from the file contents.
	 *
	 * @todo Remove $ext param
	 *
	 * @param string $file
	 * @param mixed $ext
	 * @return bool|string
	 * @throws MWException
	 */
	private function doGuessMimeType( $file, $ext ) {
		// Read a chunk of the file
		MediaWiki\suppressWarnings();
		$f = fopen( $file, 'rb' );
		MediaWiki\restoreWarnings();

		if ( !$f ) {
			return 'unknown/unknown';
		}

		$fsize = filesize( $file );
		if ( $fsize === false ) {
			return 'unknown/unknown';
		}

		$head = fread( $f, 1024 );
		$tailLength = min( 65558, $fsize ); // 65558 = maximum size of a zip EOCDR
		if ( fseek( $f, -1 * $tailLength, SEEK_END ) === -1 ) {
			throw new MWException(
				"Seeking $tailLength bytes from EOF failed in " . __METHOD__ );
		}
		$tail = fread( $f, $tailLength );
		fclose( $f );

		wfDebug( __METHOD__ . ": analyzing head and tail of $file for magic numbers.\n" );

		// Hardcode a few magic number checks...
		$headers = array(
			// Multimedia...
			'MThd'             => 'audio/midi',
			'OggS'             => 'application/ogg',

			// Image formats...
			// Note that WMF may have a bare header, no magic number.
			"\x01\x00\x09\x00" => 'application/x-msmetafile', // Possibly prone to false positives?
			"\xd7\xcd\xc6\x9a" => 'application/x-msmetafile',
			'%PDF'             => 'application/pdf',
			'gimp xcf'         => 'image/x-xcf',

			// Some forbidden fruit...
			'MZ'               => 'application/octet-stream', // DOS/Windows executable
			"\xca\xfe\xba\xbe" => 'application/octet-stream', // Mach-O binary
			"\x7fELF"          => 'application/octet-stream', // ELF binary
		);

		foreach ( $headers as $magic => $candidate ) {
			if ( strncmp( $head, $magic, strlen( $magic ) ) == 0 ) {
				wfDebug( __METHOD__ . ": magic header in $file recognized as $candidate\n" );
				return $candidate;
			}
		}

		/* Look for WebM and Matroska files */
		if ( strncmp( $head, pack( "C4", 0x1a, 0x45, 0xdf, 0xa3 ), 4 ) == 0 ) {
			$doctype = strpos( $head, "\x42\x82" );
			if ( $doctype ) {
				// Next byte is datasize, then data (sizes larger than 1 byte are very stupid muxers)
				$data = substr( $head, $doctype + 3, 8 );
				if ( strncmp( $data, "matroska", 8 ) == 0 ) {
					wfDebug( __METHOD__ . ": recognized file as video/x-matroska\n" );
					return "video/x-matroska";
				} elseif ( strncmp( $data, "webm", 4 ) == 0 ) {
					wfDebug( __METHOD__ . ": recognized file as video/webm\n" );
					return "video/webm";
				}
			}
			wfDebug( __METHOD__ . ": unknown EBML file\n" );
			return "unknown/unknown";
		}

		/* Look for WebP */
		if ( strncmp( $head, "RIFF", 4 ) == 0 && strncmp( substr( $head, 8, 7 ), "WEBPVP8", 7 ) == 0 ) {
			wfDebug( __METHOD__ . ": recognized file as image/webp\n" );
			return "image/webp";
		}

		/**
		 * Look for PHP.  Check for this before HTML/XML...  Warning: this is a
		 * heuristic, and won't match a file with a lot of non-PHP before.  It
		 * will also match text files which could be PHP. :)
		 *
		 * @todo FIXME: For this reason, the check is probably useless -- an attacker
		 * could almost certainly just pad the file with a lot of nonsense to
		 * circumvent the check in any case where it would be a security
		 * problem.  On the other hand, it causes harmful false positives (bug
		 * 16583).  The heuristic has been cut down to exclude three-character
		 * strings like "<? ", but should it be axed completely?
		 */
		if ( ( strpos( $head, '<?php' ) !== false ) ||
			( strpos( $head, "<\x00?\x00p\x00h\x00p" ) !== false ) ||
			( strpos( $head, "<\x00?\x00 " ) !== false ) ||
			( strpos( $head, "<\x00?\x00\n" ) !== false ) ||
			( strpos( $head, "<\x00?\x00\t" ) !== false ) ||
			( strpos( $head, "<\x00?\x00=" ) !== false ) ) {

			wfDebug( __METHOD__ . ": recognized $file as application/x-php\n" );
			return 'application/x-php';
		}

		/**
		 * look for XML formats (XHTML and SVG)
		 */
		$xml = new XmlTypeCheck( $file );
		if ( $xml->wellFormed ) {
			$xmlMimeTypes = $this->mConfig->get( 'XMLMimeTypes' );
			if ( isset( $xmlMimeTypes[$xml->getRootElement()] ) ) {
				return $xmlMimeTypes[$xml->getRootElement()];
			} else {
				return 'application/xml';
			}
		}

		/**
		 * look for shell scripts
		 */
		$script_type = null;

		# detect by shebang
		if ( substr( $head, 0, 2 ) == "#!" ) {
			$script_type = "ASCII";
		} elseif ( substr( $head, 0, 5 ) == "\xef\xbb\xbf#!" ) {
			$script_type = "UTF-8";
		} elseif ( substr( $head, 0, 7 ) == "\xfe\xff\x00#\x00!" ) {
			$script_type = "UTF-16BE";
		} elseif ( substr( $head, 0, 7 ) == "\xff\xfe#\x00!" ) {
			$script_type = "UTF-16LE";
		}

		if ( $script_type ) {
			if ( $script_type !== "UTF-8" && $script_type !== "ASCII" ) {
				// Quick and dirty fold down to ASCII!
				$pack = array( 'UTF-16BE' => 'n*', 'UTF-16LE' => 'v*' );
				$chars = unpack( $pack[$script_type], substr( $head, 2 ) );
				$head = '';
				foreach ( $chars as $codepoint ) {
					if ( $codepoint < 128 ) {
						$head .= chr( $codepoint );
					} else {
						$head .= '?';
					}
				}
			}

			$match = array();

			if ( preg_match( '%/?([^\s]+/)(\w+)%', $head, $match ) ) {
				$mime = "application/x-{$match[2]}";
				wfDebug( __METHOD__ . ": shell script recognized as $mime\n" );
				return $mime;
			}
		}

		// Check for ZIP variants (before getimagesize)
		if ( strpos( $tail, "PK\x05\x06" ) !== false ) {
			wfDebug( __METHOD__ . ": ZIP header present in $file\n" );
			return $this->detectZipType( $head, $tail, $ext );
		}

		MediaWiki\suppressWarnings();
		$gis = getimagesize( $file );
		MediaWiki\restoreWarnings();

		if ( $gis && isset( $gis['mime'] ) ) {
			$mime = $gis['mime'];
			wfDebug( __METHOD__ . ": getimagesize detected $file as $mime\n" );
			return $mime;
		}

		// Also test DjVu
		$deja = new DjVuImage( $file );
		if ( $deja->isValid() ) {
			wfDebug( __METHOD__ . ": detected $file as image/vnd.djvu\n" );
			return 'image/vnd.djvu';
		}

		# Media handling extensions can guess the MIME by content
		# It's intentionally here so that if core is wrong about a type (false positive),
		# people will hopefully nag and submit patches :)
		$mime = false;
		# Some strings by reference for performance - assuming well-behaved hooks
		Hooks::run(
			'MimeMagicGuessFromContent',
			array( $this, &$head, &$tail, $file, &$mime )
		);

		return $mime;
	}

	/**
	 * Detect application-specific file type of a given ZIP file from its
	 * header data.  Currently works for OpenDocument and OpenXML types...
	 * If can't tell, returns 'application/zip'.
	 *
	 * @param string $header Some reasonably-sized chunk of file header
	 * @param string|null $tail The tail of the file
	 * @param string|bool $ext The file extension, or true to extract it from the filename.
	 *   Set it to false (default) to ignore the extension. DEPRECATED! Set to false,
	 *   use improveTypeFromExtension($mime, $ext) later to improve MIME type.
	 *
	 * @return string
	 */
	function detectZipType( $header, $tail = null, $ext = false ) {
		if ( $ext ) { # TODO: remove $ext param
			wfDebug( __METHOD__ . ": WARNING: use of the \$ext parameter is deprecated. " .
				"Use improveTypeFromExtension(\$mime, \$ext) instead.\n" );
		}

		$mime = 'application/zip';
		$opendocTypes = array(
			'chart-template',
			'chart',
			'formula-template',
			'formula',
			'graphics-template',
			'graphics',
			'image-template',
			'image',
			'presentation-template',
			'presentation',
			'spreadsheet-template',
			'spreadsheet',
			'text-template',
			'text-master',
			'text-web',
			'text' );

		// http://lists.oasis-open.org/archives/office/200505/msg00006.html
		$types = '(?:' . implode( '|', $opendocTypes ) . ')';
		$opendocRegex = "/^mimetype(application\/vnd\.oasis\.opendocument\.$types)/";

		$openxmlRegex = "/^\[Content_Types\].xml/";

		if ( preg_match( $opendocRegex, substr( $header, 30 ), $matches ) ) {
			$mime = $matches[1];
			wfDebug( __METHOD__ . ": detected $mime from ZIP archive\n" );
		} elseif ( preg_match( $openxmlRegex, substr( $header, 30 ) ) ) {
			$mime = "application/x-opc+zip";
			# TODO: remove the block below, as soon as improveTypeFromExtension is used everywhere
			if ( $ext !== true && $ext !== false ) {
				/** This is the mode used by getPropsFromPath
				 * These MIME's are stored in the database, where we don't really want
				 * x-opc+zip, because we use it only for internal purposes
				 */
				if ( $this->isMatchingExtension( $ext, $mime ) ) {
					/* A known file extension for an OPC file,
					 * find the proper mime type for that file extension
					 */
					$mime = $this->guessTypesForExtension( $ext );
				} else {
					$mime = "application/zip";
				}
			}
			wfDebug( __METHOD__ . ": detected an Open Packaging Conventions archive: $mime\n" );
		} elseif ( substr( $header, 0, 8 ) == "\xd0\xcf\x11\xe0\xa1\xb1\x1a\xe1" &&
				( $headerpos = strpos( $tail, "PK\x03\x04" ) ) !== false &&
				preg_match( $openxmlRegex, substr( $tail, $headerpos + 30 ) ) ) {
			if ( substr( $header, 512, 4 ) == "\xEC\xA5\xC1\x00" ) {
				$mime = "application/msword";
			}
			switch ( substr( $header, 512, 6 ) ) {
				case "\xEC\xA5\xC1\x00\x0E\x00":
				case "\xEC\xA5\xC1\x00\x1C\x00":
				case "\xEC\xA5\xC1\x00\x43\x00":
					$mime = "application/vnd.ms-powerpoint";
					break;
				case "\xFD\xFF\xFF\xFF\x10\x00":
				case "\xFD\xFF\xFF\xFF\x1F\x00":
				case "\xFD\xFF\xFF\xFF\x22\x00":
				case "\xFD\xFF\xFF\xFF\x23\x00":
				case "\xFD\xFF\xFF\xFF\x28\x00":
				case "\xFD\xFF\xFF\xFF\x29\x00":
				case "\xFD\xFF\xFF\xFF\x10\x02":
				case "\xFD\xFF\xFF\xFF\x1F\x02":
				case "\xFD\xFF\xFF\xFF\x22\x02":
				case "\xFD\xFF\xFF\xFF\x23\x02":
				case "\xFD\xFF\xFF\xFF\x28\x02":
				case "\xFD\xFF\xFF\xFF\x29\x02":
					$mime = "application/vnd.msexcel";
					break;
			}

			wfDebug( __METHOD__ . ": detected a MS Office document with OPC trailer\n" );
		} else {
			wfDebug( __METHOD__ . ": unable to identify type of ZIP archive\n" );
		}
		return $mime;
	}

	/**
	 * Internal MIME type detection. Detection is done using an external
	 * program, if $wgMimeDetectorCommand is set. Otherwise, the fileinfo
	 * extension is tried if it is available. If detection fails and $ext
	 * is not false, the MIME type is guessed from the file extension,
	 * using guessTypesForExtension.
	 *
	 * If the MIME type is still unknown, getimagesize is used to detect the
	 * MIME type if the file is an image. If no MIME type can be determined,
	 * this function returns 'unknown/unknown'.
	 *
	 * @param string $file The file to check
	 * @param string|bool $ext The file extension, or true (default) to extract it from the filename.
	 *   Set it to false to ignore the extension. DEPRECATED! Set to false, use
	 *   improveTypeFromExtension($mime, $ext) later to improve MIME type.
	 *
	 * @return string The MIME type of $file
	 */
	private function detectMimeType( $file, $ext = true ) {
		/** @todo Make $ext default to false. Or better, remove it. */
		if ( $ext ) {
			wfDebug( __METHOD__ . ": WARNING: use of the \$ext parameter is deprecated. "
				. "Use improveTypeFromExtension(\$mime, \$ext) instead.\n" );
		}

		$mimeDetectorCommand = $this->mConfig->get( 'MimeDetectorCommand' );
		$m = null;
		if ( $mimeDetectorCommand ) {
			$args = wfEscapeShellArg( $file );
			$m = wfShellExec( "$mimeDetectorCommand $args" );
		} elseif ( function_exists( "finfo_open" ) && function_exists( "finfo_file" ) ) {
			$mime_magic_resource = finfo_open( FILEINFO_MIME );

			if ( $mime_magic_resource ) {
				$m = finfo_file( $mime_magic_resource, $file );
				finfo_close( $mime_magic_resource );
			} else {
				wfDebug( __METHOD__ . ": finfo_open failed on " . FILEINFO_MIME . "!\n" );
			}
		} else {
			wfDebug( __METHOD__ . ": no magic mime detector found!\n" );
		}

		if ( $m ) {
			# normalize
			$m = preg_replace( '![;, ].*$!', '', $m ); #strip charset, etc
			$m = trim( $m );
			$m = strtolower( $m );

			if ( strpos( $m, 'unknown' ) !== false ) {
				$m = null;
			} else {
				wfDebug( __METHOD__ . ": magic mime type of $file: $m\n" );
				return $m;
			}
		}

		// If desired, look at extension as a fallback.
		if ( $ext === true ) {
			$i = strrpos( $file, '.' );
			$ext = strtolower( $i ? substr( $file, $i + 1 ) : '' );
		}
		if ( $ext ) {
			if ( $this->isRecognizableExtension( $ext ) ) {
				wfDebug( __METHOD__ . ": refusing to guess mime type for .$ext file, "
					. "we should have recognized it\n" );
			} else {
				$m = $this->guessTypesForExtension( $ext );
				if ( $m ) {
					wfDebug( __METHOD__ . ": extension mime type of $file: $m\n" );
					return $m;
				}
			}
		}

		// Unknown type
		wfDebug( __METHOD__ . ": failed to guess mime type for $file!\n" );
		return 'unknown/unknown';
	}

	/**
	 * Determine the media type code for a file, using its MIME type, name and
	 * possibly its contents.
	 *
	 * This function relies on the findMediaType(), mapping extensions and MIME
	 * types to media types.
	 *
	 * @todo analyse file if need be
	 * @todo look at multiple extension, separately and together.
	 *
	 * @param string $path Full path to the image file, in case we have to look at the contents
	 *        (if null, only the MIME type is used to determine the media type code).
	 * @param string $mime MIME type. If null it will be guessed using guessMimeType.
	 *
	 * @return string A value to be used with the MEDIATYPE_xxx constants.
	 */
	function getMediaType( $path = null, $mime = null ) {
		if ( !$mime && !$path ) {
			return MEDIATYPE_UNKNOWN;
		}

		// If MIME type is unknown, guess it
		if ( !$mime ) {
			$mime = $this->guessMimeType( $path, false );
		}

		// Special code for ogg - detect if it's video (theora),
		// else label it as sound.
		if ( $mime == 'application/ogg' && file_exists( $path ) ) {

			// Read a chunk of the file
			$f = fopen( $path, "rt" );
			if ( !$f ) {
				return MEDIATYPE_UNKNOWN;
			}
			$head = fread( $f, 256 );
			fclose( $f );

			$head = str_replace( 'ffmpeg2theora', '', strtolower( $head ) );

			// This is an UGLY HACK, file should be parsed correctly
			if ( strpos( $head, 'theora' ) !== false ) {
				return MEDIATYPE_VIDEO;
			} elseif ( strpos( $head, 'vorbis' ) !== false ) {
				return MEDIATYPE_AUDIO;
			} elseif ( strpos( $head, 'flac' ) !== false ) {
				return MEDIATYPE_AUDIO;
			} elseif ( strpos( $head, 'speex' ) !== false ) {
				return MEDIATYPE_AUDIO;
			} else {
				return MEDIATYPE_MULTIMEDIA;
			}
		}

		// Check for entry for full MIME type
		if ( $mime ) {
			$type = $this->findMediaType( $mime );
			if ( $type !== MEDIATYPE_UNKNOWN ) {
				return $type;
			}
		}

		// Check for entry for file extension
		if ( $path ) {
			$i = strrpos( $path, '.' );
			$e = strtolower( $i ? substr( $path, $i + 1 ) : '' );

			// TODO: look at multi-extension if this fails, parse from full path
			$type = $this->findMediaType( '.' . $e );
			if ( $type !== MEDIATYPE_UNKNOWN ) {
				return $type;
			}
		}

		// Check major MIME type
		if ( $mime ) {
			$i = strpos( $mime, '/' );
			if ( $i !== false ) {
				$major = substr( $mime, 0, $i );
				$type = $this->findMediaType( $major );
				if ( $type !== MEDIATYPE_UNKNOWN ) {
					return $type;
				}
			}
		}

		if ( !$type ) {
			$type = MEDIATYPE_UNKNOWN;
		}

		return $type;
	}

	/**
	 * Returns a media code matching the given MIME type or file extension.
	 * File extensions are represented by a string starting with a dot (.) to
	 * distinguish them from MIME types.
	 *
	 * This function relies on the mapping defined by $this->mMediaTypes
	 * @access private
	 * @param string $extMime
	 * @return int|string
	 */
	function findMediaType( $extMime ) {
		if ( strpos( $extMime, '.' ) === 0 ) {
			// If it's an extension, look up the MIME types
			$m = $this->getTypesForExtension( substr( $extMime, 1 ) );
			if ( !$m ) {
				return MEDIATYPE_UNKNOWN;
			}

			$m = explode( ' ', $m );
		} else {
			// Normalize MIME type
			if ( isset( $this->mMimeTypeAliases[$extMime] ) ) {
				$extMime = $this->mMimeTypeAliases[$extMime];
			}

			$m = array( $extMime );
		}

		foreach ( $m as $mime ) {
			foreach ( $this->mMediaTypes as $type => $codes ) {
				if ( in_array( $mime, $codes, true ) ) {
					return $type;
				}
			}
		}

		return MEDIATYPE_UNKNOWN;
	}

	/**
	 * Get the MIME types that various versions of Internet Explorer would
	 * detect from a chunk of the content.
	 *
	 * @param string $fileName The file name (unused at present)
	 * @param string $chunk The first 256 bytes of the file
	 * @param string $proposed The MIME type proposed by the server
	 * @return array
	 */
	public function getIEMimeTypes( $fileName, $chunk, $proposed ) {
		$ca = $this->getIEContentAnalyzer();
		return $ca->getRealMimesFromData( $fileName, $chunk, $proposed );
	}

	/**
	 * Get a cached instance of IEContentAnalyzer
	 *
	 * @return IEContentAnalyzer
	 */
	protected function getIEContentAnalyzer() {
		if ( is_null( $this->mIEAnalyzer ) ) {
			$this->mIEAnalyzer = new IEContentAnalyzer;
		}
		return $this->mIEAnalyzer;
	}
}