summaryrefslogtreecommitdiff
path: root/includes/HttpFunctions.php
blob: fa2fc12b02506007f5c67109188311bbb006ace8 (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
<?php
/**
 * Various HTTP related functions.
 *
 * 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
 * @ingroup HTTP
 */

/**
 * @defgroup HTTP HTTP
 */

/**
 * Various HTTP related functions
 * @ingroup HTTP
 */
class Http {
	static $httpEngine = false;

	/**
	 * Perform an HTTP request
	 *
	 * @param string $method HTTP method. Usually GET/POST
	 * @param string $url full URL to act on. If protocol-relative, will be expanded to an http:// URL
	 * @param array $options options to pass to MWHttpRequest object.
	 *	Possible keys for the array:
	 *    - timeout             Timeout length in seconds
	 *    - connectTimeout      Timeout for connection, in seconds (curl only)
	 *    - postData            An array of key-value pairs or a url-encoded form data
	 *    - proxy               The proxy to use.
	 *                          Otherwise it will use $wgHTTPProxy (if set)
	 *                          Otherwise it will use the environment variable "http_proxy" (if set)
	 *    - noProxy             Don't use any proxy at all. Takes precedence over proxy value(s).
	 *    - sslVerifyHost       Verify hostname against certificate
	 *    - sslVerifyCert       Verify SSL certificate
	 *    - caInfo              Provide CA information
	 *    - maxRedirects        Maximum number of redirects to follow (defaults to 5)
	 *    - followRedirects     Whether to follow redirects (defaults to false).
	 *		                    Note: this should only be used when the target URL is trusted,
	 *		                    to avoid attacks on intranet services accessible by HTTP.
	 *    - userAgent           A user agent, if you want to override the default
	 *                          MediaWiki/$wgVersion
	 * @return Mixed: (bool)false on failure or a string on success
	 */
	public static function request( $method, $url, $options = array() ) {
		wfDebug( "HTTP: $method: $url\n" );
		wfProfileIn( __METHOD__ . "-$method" );

		$options['method'] = strtoupper( $method );

		if ( !isset( $options['timeout'] ) ) {
			$options['timeout'] = 'default';
		}
		if ( !isset( $options['connectTimeout'] ) ) {
			$options['connectTimeout'] = 'default';
		}

		$req = MWHttpRequest::factory( $url, $options );
		$status = $req->execute();

		$content = false;
		if ( $status->isOK() ) {
			$content = $req->getContent();
		}
		wfProfileOut( __METHOD__ . "-$method" );
		return $content;
	}

	/**
	 * Simple wrapper for Http::request( 'GET' )
	 * @see Http::request()
	 *
	 * @param $url
	 * @param $timeout string
	 * @param $options array
	 * @return string
	 */
	public static function get( $url, $timeout = 'default', $options = array() ) {
		$options['timeout'] = $timeout;
		return Http::request( 'GET', $url, $options );
	}

	/**
	 * Simple wrapper for Http::request( 'POST' )
	 * @see Http::request()
	 *
	 * @param $url
	 * @param $options array
	 * @return string
	 */
	public static function post( $url, $options = array() ) {
		return Http::request( 'POST', $url, $options );
	}

	/**
	 * Check if the URL can be served by localhost
	 *
	 * @param string $url full url to check
	 * @return Boolean
	 */
	public static function isLocalURL( $url ) {
		global $wgCommandLineMode, $wgConf;

		if ( $wgCommandLineMode ) {
			return false;
		}

		// Extract host part
		$matches = array();
		if ( preg_match( '!^http://([\w.-]+)[/:].*$!', $url, $matches ) ) {
			$host = $matches[1];
			// Split up dotwise
			$domainParts = explode( '.', $host );
			// Check if this domain or any superdomain is listed in $wgConf as a local virtual host
			$domainParts = array_reverse( $domainParts );

			$domain = '';
			for ( $i = 0; $i < count( $domainParts ); $i++ ) {
				$domainPart = $domainParts[$i];
				if ( $i == 0 ) {
					$domain = $domainPart;
				} else {
					$domain = $domainPart . '.' . $domain;
				}

				if ( $wgConf->isLocalVHost( $domain ) ) {
					return true;
				}
			}
		}

		return false;
	}

	/**
	 * A standard user-agent we can use for external requests.
	 * @return String
	 */
	public static function userAgent() {
		global $wgVersion;
		return "MediaWiki/$wgVersion";
	}

	/**
	 * Checks that the given URI is a valid one. Hardcoding the
	 * protocols, because we only want protocols that both cURL
	 * and php support.
	 *
	 * file:// should not be allowed here for security purpose (r67684)
	 *
	 * @todo FIXME this is wildly inaccurate and fails to actually check most stuff
	 *
	 * @param $uri Mixed: URI to check for validity
	 * @return Boolean
	 */
	public static function isValidURI( $uri ) {
		return preg_match(
			'/^https?:\/\/[^\/\s]\S*$/D',
			$uri
		);
	}
}

/**
 * This wrapper class will call out to curl (if available) or fallback
 * to regular PHP if necessary for handling internal HTTP requests.
 *
 * Renamed from HttpRequest to MWHttpRequest to avoid conflict with
 * PHP's HTTP extension.
 */
class MWHttpRequest {
	const SUPPORTS_FILE_POSTS = false;

	protected $content;
	protected $timeout = 'default';
	protected $headersOnly = null;
	protected $postData = null;
	protected $proxy = null;
	protected $noProxy = false;
	protected $sslVerifyHost = true;
	protected $sslVerifyCert = true;
	protected $caInfo = null;
	protected $method = "GET";
	protected $reqHeaders = array();
	protected $url;
	protected $parsedUrl;
	protected $callback;
	protected $maxRedirects = 5;
	protected $followRedirects = false;

	/**
	 * @var  CookieJar
	 */
	protected $cookieJar;

	protected $headerList = array();
	protected $respVersion = "0.9";
	protected $respStatus = "200 Ok";
	protected $respHeaders = array();

	public $status;

	/**
	 * @param string $url url to use. If protocol-relative, will be expanded to an http:// URL
	 * @param array $options (optional) extra params to pass (see Http::request())
	 */
	protected function __construct( $url, $options = array() ) {
		global $wgHTTPTimeout, $wgHTTPConnectTimeout;

		$this->url = wfExpandUrl( $url, PROTO_HTTP );
		$this->parsedUrl = wfParseUrl( $this->url );

		if ( !$this->parsedUrl || !Http::isValidURI( $this->url ) ) {
			$this->status = Status::newFatal( 'http-invalid-url' );
		} else {
			$this->status = Status::newGood( 100 ); // continue
		}

		if ( isset( $options['timeout'] ) && $options['timeout'] != 'default' ) {
			$this->timeout = $options['timeout'];
		} else {
			$this->timeout = $wgHTTPTimeout;
		}
		if ( isset( $options['connectTimeout'] ) && $options['connectTimeout'] != 'default' ) {
			$this->connectTimeout = $options['connectTimeout'];
		} else {
			$this->connectTimeout = $wgHTTPConnectTimeout;
		}
		if ( isset( $options['userAgent'] ) ) {
			$this->setUserAgent( $options['userAgent'] );
		}

		$members = array( "postData", "proxy", "noProxy", "sslVerifyHost", "caInfo",
				"method", "followRedirects", "maxRedirects", "sslVerifyCert", "callback" );

		foreach ( $members as $o ) {
			if ( isset( $options[$o] ) ) {
				// ensure that MWHttpRequest::method is always
				// uppercased. Bug 36137
				if ( $o == 'method' ) {
					$options[$o] = strtoupper( $options[$o] );
				}
				$this->$o = $options[$o];
			}
		}

		if ( $this->noProxy ) {
			$this->proxy = ''; // noProxy takes precedence
		}
	}

	/**
	 * Simple function to test if we can make any sort of requests at all, using
	 * cURL or fopen()
	 * @return bool
	 */
	public static function canMakeRequests() {
		return function_exists( 'curl_init' ) || wfIniGetBool( 'allow_url_fopen' );
	}

	/**
	 * Generate a new request object
	 * @param string $url url to use
	 * @param array $options (optional) extra params to pass (see Http::request())
	 * @throws MWException
	 * @return CurlHttpRequest|PhpHttpRequest
	 * @see MWHttpRequest::__construct
	 */
	public static function factory( $url, $options = null ) {
		if ( !Http::$httpEngine ) {
			Http::$httpEngine = function_exists( 'curl_init' ) ? 'curl' : 'php';
		} elseif ( Http::$httpEngine == 'curl' && !function_exists( 'curl_init' ) ) {
			throw new MWException( __METHOD__ . ': curl (http://php.net/curl) is not installed, but' .
				' Http::$httpEngine is set to "curl"' );
		}

		switch ( Http::$httpEngine ) {
			case 'curl':
				return new CurlHttpRequest( $url, $options );
			case 'php':
				if ( !wfIniGetBool( 'allow_url_fopen' ) ) {
					throw new MWException( __METHOD__ . ': allow_url_fopen needs to be enabled for pure PHP' .
						' http requests to work. If possible, curl should be used instead. See http://php.net/curl.' );
				}
				return new PhpHttpRequest( $url, $options );
			default:
				throw new MWException( __METHOD__ . ': The setting of Http::$httpEngine is not valid.' );
		}
	}

	/**
	 * Get the body, or content, of the response to the request
	 *
	 * @return String
	 */
	public function getContent() {
		return $this->content;
	}

	/**
	 * Set the parameters of the request
	 *
	 * @param $args Array
	 * @todo overload the args param
	 */
	public function setData( $args ) {
		$this->postData = $args;
	}

	/**
	 * Take care of setting up the proxy (do nothing if "noProxy" is set)
	 *
	 * @return void
	 */
	public function proxySetup() {
		global $wgHTTPProxy;

		// If there is an explicit proxy set and proxies are not disabled, then use it
		if ( $this->proxy && !$this->noProxy ) {
			return;
		}

		// Otherwise, fallback to $wgHTTPProxy/http_proxy (when set) if this is not a machine
		// local URL and proxies are not disabled
		if ( Http::isLocalURL( $this->url ) || $this->noProxy ) {
			$this->proxy = '';
		} elseif ( $wgHTTPProxy ) {
			$this->proxy = $wgHTTPProxy;
		} elseif ( getenv( "http_proxy" ) ) {
			$this->proxy = getenv( "http_proxy" );
		}
	}

	/**
	 * Set the referrer header
	 */
	public function setReferer( $url ) {
		$this->setHeader( 'Referer', $url );
	}

	/**
	 * Set the user agent
	 * @param $UA string
	 */
	public function setUserAgent( $UA ) {
		$this->setHeader( 'User-Agent', $UA );
	}

	/**
	 * Set an arbitrary header
	 * @param $name
	 * @param $value
	 */
	public function setHeader( $name, $value ) {
		// I feel like I should normalize the case here...
		$this->reqHeaders[$name] = $value;
	}

	/**
	 * Get an array of the headers
	 * @return array
	 */
	public function getHeaderList() {
		$list = array();

		if ( $this->cookieJar ) {
			$this->reqHeaders['Cookie'] =
				$this->cookieJar->serializeToHttpRequest(
					$this->parsedUrl['path'],
					$this->parsedUrl['host']
				);
		}

		foreach ( $this->reqHeaders as $name => $value ) {
			$list[] = "$name: $value";
		}

		return $list;
	}

	/**
	 * Set a read callback to accept data read from the HTTP request.
	 * By default, data is appended to an internal buffer which can be
	 * retrieved through $req->getContent().
	 *
	 * To handle data as it comes in -- especially for large files that
	 * would not fit in memory -- you can instead set your own callback,
	 * in the form function($resource, $buffer) where the first parameter
	 * is the low-level resource being read (implementation specific),
	 * and the second parameter is the data buffer.
	 *
	 * You MUST return the number of bytes handled in the buffer; if fewer
	 * bytes are reported handled than were passed to you, the HTTP fetch
	 * will be aborted.
	 *
	 * @param $callback Callback
	 * @throws MWException
	 */
	public function setCallback( $callback ) {
		if ( !is_callable( $callback ) ) {
			throw new MWException( 'Invalid MwHttpRequest callback' );
		}
		$this->callback = $callback;
	}

	/**
	 * A generic callback to read the body of the response from a remote
	 * server.
	 *
	 * @param $fh handle
	 * @param $content String
	 * @return int
	 */
	public function read( $fh, $content ) {
		$this->content .= $content;
		return strlen( $content );
	}

	/**
	 * Take care of whatever is necessary to perform the URI request.
	 *
	 * @return Status
	 */
	public function execute() {
		global $wgTitle;

		wfProfileIn( __METHOD__ );

		$this->content = "";

		if ( strtoupper( $this->method ) == "HEAD" ) {
			$this->headersOnly = true;
		}

		if ( is_object( $wgTitle ) && !isset( $this->reqHeaders['Referer'] ) ) {
			$this->setReferer( wfExpandUrl( $wgTitle->getFullURL(), PROTO_CURRENT ) );
		}

		$this->proxySetup(); // set up any proxy as needed

		if ( !$this->callback ) {
			$this->setCallback( array( $this, 'read' ) );
		}

		if ( !isset( $this->reqHeaders['User-Agent'] ) ) {
			$this->setUserAgent( Http::userAgent() );
		}

		wfProfileOut( __METHOD__ );
	}

	/**
	 * Parses the headers, including the HTTP status code and any
	 * Set-Cookie headers.  This function expects the headers to be
	 * found in an array in the member variable headerList.
	 */
	protected function parseHeader() {
		wfProfileIn( __METHOD__ );

		$lastname = "";

		foreach ( $this->headerList as $header ) {
			if ( preg_match( "#^HTTP/([0-9.]+) (.*)#", $header, $match ) ) {
				$this->respVersion = $match[1];
				$this->respStatus = $match[2];
			} elseif ( preg_match( "#^[ \t]#", $header ) ) {
				$last = count( $this->respHeaders[$lastname] ) - 1;
				$this->respHeaders[$lastname][$last] .= "\r\n$header";
			} elseif ( preg_match( "#^([^:]*):[\t ]*(.*)#", $header, $match ) ) {
				$this->respHeaders[strtolower( $match[1] )][] = $match[2];
				$lastname = strtolower( $match[1] );
			}
		}

		$this->parseCookies();

		wfProfileOut( __METHOD__ );
	}

	/**
	 * Sets HTTPRequest status member to a fatal value with the error
	 * message if the returned integer value of the status code was
	 * not successful (< 300) or a redirect (>=300 and < 400).  (see
	 * RFC2616, section 10,
	 * http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html for a
	 * list of status codes.)
	 */
	protected function setStatus() {
		if ( !$this->respHeaders ) {
			$this->parseHeader();
		}

		if ( (int)$this->respStatus > 399 ) {
			list( $code, $message ) = explode( " ", $this->respStatus, 2 );
			$this->status->fatal( "http-bad-status", $code, $message );
		}
	}

	/**
	 * Get the integer value of the HTTP status code (e.g. 200 for "200 Ok")
	 * (see RFC2616, section 10, http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html
	 * for a list of status codes.)
	 *
	 * @return Integer
	 */
	public function getStatus() {
		if ( !$this->respHeaders ) {
			$this->parseHeader();
		}

		return (int)$this->respStatus;
	}

	/**
	 * Returns true if the last status code was a redirect.
	 *
	 * @return Boolean
	 */
	public function isRedirect() {
		if ( !$this->respHeaders ) {
			$this->parseHeader();
		}

		$status = (int)$this->respStatus;

		if ( $status >= 300 && $status <= 303 ) {
			return true;
		}

		return false;
	}

	/**
	 * Returns an associative array of response headers after the
	 * request has been executed.  Because some headers
	 * (e.g. Set-Cookie) can appear more than once the, each value of
	 * the associative array is an array of the values given.
	 *
	 * @return Array
	 */
	public function getResponseHeaders() {
		if ( !$this->respHeaders ) {
			$this->parseHeader();
		}

		return $this->respHeaders;
	}

	/**
	 * Returns the value of the given response header.
	 *
	 * @param $header String
	 * @return String
	 */
	public function getResponseHeader( $header ) {
		if ( !$this->respHeaders ) {
			$this->parseHeader();
		}

		if ( isset( $this->respHeaders[strtolower( $header )] ) ) {
			$v = $this->respHeaders[strtolower( $header )];
			return $v[count( $v ) - 1];
		}

		return null;
	}

	/**
	 * Tells the MWHttpRequest object to use this pre-loaded CookieJar.
	 *
	 * @param $jar CookieJar
	 */
	public function setCookieJar( $jar ) {
		$this->cookieJar = $jar;
	}

	/**
	 * Returns the cookie jar in use.
	 *
	 * @return CookieJar
	 */
	public function getCookieJar() {
		if ( !$this->respHeaders ) {
			$this->parseHeader();
		}

		return $this->cookieJar;
	}

	/**
	 * Sets a cookie. Used before a request to set up any individual
	 * cookies. Used internally after a request to parse the
	 * Set-Cookie headers.
	 * @see Cookie::set
	 * @param $name
	 * @param $value null
	 * @param $attr null
	 */
	public function setCookie( $name, $value = null, $attr = null ) {
		if ( !$this->cookieJar ) {
			$this->cookieJar = new CookieJar;
		}

		$this->cookieJar->setCookie( $name, $value, $attr );
	}

	/**
	 * Parse the cookies in the response headers and store them in the cookie jar.
	 */
	protected function parseCookies() {
		wfProfileIn( __METHOD__ );

		if ( !$this->cookieJar ) {
			$this->cookieJar = new CookieJar;
		}

		if ( isset( $this->respHeaders['set-cookie'] ) ) {
			$url = parse_url( $this->getFinalUrl() );
			foreach ( $this->respHeaders['set-cookie'] as $cookie ) {
				$this->cookieJar->parseCookieResponseHeader( $cookie, $url['host'] );
			}
		}

		wfProfileOut( __METHOD__ );
	}

	/**
	 * Returns the final URL after all redirections.
	 *
	 * Relative values of the "Location" header are incorrect as stated in RFC, however they do happen and modern browsers support them.
	 * This function loops backwards through all locations in order to build the proper absolute URI - Marooned at wikia-inc.com
	 *
	 * Note that the multiple Location: headers are an artifact of CURL -- they
	 * shouldn't actually get returned this way. Rewrite this when bug 29232 is
	 * taken care of (high-level redirect handling rewrite).
	 *
	 * @return string
	 */
	public function getFinalUrl() {
		$headers = $this->getResponseHeaders();

		//return full url (fix for incorrect but handled relative location)
		if ( isset( $headers['location'] ) ) {
			$locations = $headers['location'];
			$domain = '';
			$foundRelativeURI = false;
			$countLocations = count( $locations );

			for ( $i = $countLocations - 1; $i >= 0; $i-- ) {
				$url = parse_url( $locations[$i] );

				if ( isset( $url['host'] ) ) {
					$domain = $url['scheme'] . '://' . $url['host'];
					break; //found correct URI (with host)
				} else {
					$foundRelativeURI = true;
				}
			}

			if ( $foundRelativeURI ) {
				if ( $domain ) {
					return $domain . $locations[$countLocations - 1];
				} else {
					$url = parse_url( $this->url );
					if ( isset( $url['host'] ) ) {
						return $url['scheme'] . '://' . $url['host'] . $locations[$countLocations - 1];
					}
				}
			} else {
				return $locations[$countLocations - 1];
			}
		}

		return $this->url;
	}

	/**
	 * Returns true if the backend can follow redirects. Overridden by the
	 * child classes.
	 * @return bool
	 */
	public function canFollowRedirects() {
		return true;
	}
}

/**
 * MWHttpRequest implemented using internal curl compiled into PHP
 */
class CurlHttpRequest extends MWHttpRequest {
	const SUPPORTS_FILE_POSTS = true;

	protected $curlOptions = array();
	protected $headerText = "";

	/**
	 * @param $fh
	 * @param $content
	 * @return int
	 */
	protected function readHeader( $fh, $content ) {
		$this->headerText .= $content;
		return strlen( $content );
	}

	public function execute() {
		wfProfileIn( __METHOD__ );

		parent::execute();

		if ( !$this->status->isOK() ) {
			wfProfileOut( __METHOD__ );
			return $this->status;
		}

		$this->curlOptions[CURLOPT_PROXY] = $this->proxy;
		$this->curlOptions[CURLOPT_TIMEOUT] = $this->timeout;

		// Only supported in curl >= 7.16.2
		if ( defined( 'CURLOPT_CONNECTTIMEOUT_MS' ) ) {
			$this->curlOptions[CURLOPT_CONNECTTIMEOUT_MS] = $this->connectTimeout * 1000;
		}

		$this->curlOptions[CURLOPT_HTTP_VERSION] = CURL_HTTP_VERSION_1_0;
		$this->curlOptions[CURLOPT_WRITEFUNCTION] = $this->callback;
		$this->curlOptions[CURLOPT_HEADERFUNCTION] = array( $this, "readHeader" );
		$this->curlOptions[CURLOPT_MAXREDIRS] = $this->maxRedirects;
		$this->curlOptions[CURLOPT_ENCODING] = ""; # Enable compression

		/* not sure these two are actually necessary */
		if ( isset( $this->reqHeaders['Referer'] ) ) {
			$this->curlOptions[CURLOPT_REFERER] = $this->reqHeaders['Referer'];
		}
		$this->curlOptions[CURLOPT_USERAGENT] = $this->reqHeaders['User-Agent'];

		$this->curlOptions[CURLOPT_SSL_VERIFYHOST] = $this->sslVerifyHost ? 2 : 0;
		$this->curlOptions[CURLOPT_SSL_VERIFYPEER] = $this->sslVerifyCert;

		if ( $this->caInfo ) {
			$this->curlOptions[CURLOPT_CAINFO] = $this->caInfo;
		}

		if ( $this->headersOnly ) {
			$this->curlOptions[CURLOPT_NOBODY] = true;
			$this->curlOptions[CURLOPT_HEADER] = true;
		} elseif ( $this->method == 'POST' ) {
			$this->curlOptions[CURLOPT_POST] = true;
			$this->curlOptions[CURLOPT_POSTFIELDS] = $this->postData;
			// Suppress 'Expect: 100-continue' header, as some servers
			// will reject it with a 417 and Curl won't auto retry
			// with HTTP 1.0 fallback
			$this->reqHeaders['Expect'] = '';
		} else {
			$this->curlOptions[CURLOPT_CUSTOMREQUEST] = $this->method;
		}

		$this->curlOptions[CURLOPT_HTTPHEADER] = $this->getHeaderList();

		$curlHandle = curl_init( $this->url );

		if ( !curl_setopt_array( $curlHandle, $this->curlOptions ) ) {
			wfProfileOut( __METHOD__ );
			throw new MWException( "Error setting curl options." );
		}

		if ( $this->followRedirects && $this->canFollowRedirects() ) {
			wfSuppressWarnings();
			if ( ! curl_setopt( $curlHandle, CURLOPT_FOLLOWLOCATION, true ) ) {
				wfDebug( __METHOD__ . ": Couldn't set CURLOPT_FOLLOWLOCATION. " .
					"Probably safe_mode or open_basedir is set.\n" );
				// Continue the processing. If it were in curl_setopt_array,
				// processing would have halted on its entry
			}
			wfRestoreWarnings();
		}

		$curlRes = curl_exec( $curlHandle );
		if ( curl_errno( $curlHandle ) == CURLE_OPERATION_TIMEOUTED ) {
			$this->status->fatal( 'http-timed-out', $this->url );
		} elseif ( $curlRes === false ) {
			$this->status->fatal( 'http-curl-error', curl_error( $curlHandle ) );
		} else {
			$this->headerList = explode( "\r\n", $this->headerText );
		}

		curl_close( $curlHandle );

		$this->parseHeader();
		$this->setStatus();

		wfProfileOut( __METHOD__ );

		return $this->status;
	}

	/**
	 * @return bool
	 */
	public function canFollowRedirects() {
		if ( strval( ini_get( 'open_basedir' ) ) !== '' || wfIniGetBool( 'safe_mode' ) ) {
			wfDebug( "Cannot follow redirects in safe mode\n" );
			return false;
		}

		if ( !defined( 'CURLOPT_REDIR_PROTOCOLS' ) ) {
			wfDebug( "Cannot follow redirects with libcurl < 7.19.4 due to CVE-2009-0037\n" );
			return false;
		}

		return true;
	}
}

class PhpHttpRequest extends MWHttpRequest {

	/**
	 * @param $url string
	 * @return string
	 */
	protected function urlToTcp( $url ) {
		$parsedUrl = parse_url( $url );

		return 'tcp://' . $parsedUrl['host'] . ':' . $parsedUrl['port'];
	}

	public function execute() {
		wfProfileIn( __METHOD__ );

		parent::execute();

		if ( is_array( $this->postData ) ) {
			$this->postData = wfArrayToCgi( $this->postData );
		}

		if ( $this->parsedUrl['scheme'] != 'http' &&
			 $this->parsedUrl['scheme'] != 'https' ) {
			$this->status->fatal( 'http-invalid-scheme', $this->parsedUrl['scheme'] );
		}

		$this->reqHeaders['Accept'] = "*/*";
		if ( $this->method == 'POST' ) {
			// Required for HTTP 1.0 POSTs
			$this->reqHeaders['Content-Length'] = strlen( $this->postData );
			if ( !isset( $this->reqHeaders['Content-Type'] ) ) {
				$this->reqHeaders['Content-Type'] = "application/x-www-form-urlencoded";
			}
		}

		$options = array();
		if ( $this->proxy ) {
			$options['proxy'] = $this->urlToTCP( $this->proxy );
			$options['request_fulluri'] = true;
		}

		if ( !$this->followRedirects ) {
			$options['max_redirects'] = 0;
		} else {
			$options['max_redirects'] = $this->maxRedirects;
		}

		$options['method'] = $this->method;
		$options['header'] = implode( "\r\n", $this->getHeaderList() );
		// Note that at some future point we may want to support
		// HTTP/1.1, but we'd have to write support for chunking
		// in version of PHP < 5.3.1
		$options['protocol_version'] = "1.0";

		// This is how we tell PHP we want to deal with 404s (for example) ourselves.
		// Only works on 5.2.10+
		$options['ignore_errors'] = true;

		if ( $this->postData ) {
			$options['content'] = $this->postData;
		}

		$options['timeout'] = $this->timeout;

		if ( $this->sslVerifyHost ) {
			$options['CN_match'] = $this->parsedUrl['host'];
		}
		if ( $this->sslVerifyCert ) {
			$options['verify_peer'] = true;
		}

		if ( is_dir( $this->caInfo ) ) {
			$options['capath'] = $this->caInfo;
		} elseif ( is_file( $this->caInfo ) ) {
			$options['cafile'] = $this->caInfo;
		} elseif ( $this->caInfo ) {
			throw new MWException( "Invalid CA info passed: {$this->caInfo}" );
		}

		$scheme = $this->parsedUrl['scheme'];
		$context = stream_context_create( array( "$scheme" => $options ) );

		$this->headerList = array();
		$reqCount = 0;
		$url = $this->url;

		$result = array();

		do {
			$reqCount++;
			wfSuppressWarnings();
			$fh = fopen( $url, "r", false, $context );
			wfRestoreWarnings();

			if ( !$fh ) {
				break;
			}

			$result = stream_get_meta_data( $fh );
			$this->headerList = $result['wrapper_data'];
			$this->parseHeader();

			if ( !$this->followRedirects ) {
				break;
			}

			# Handle manual redirection
			if ( !$this->isRedirect() || $reqCount > $this->maxRedirects ) {
				break;
			}
			# Check security of URL
			$url = $this->getResponseHeader( "Location" );

			if ( !Http::isValidURI( $url ) ) {
				wfDebug( __METHOD__ . ": insecure redirection\n" );
				break;
			}
		} while ( true );

		$this->setStatus();

		if ( $fh === false ) {
			$this->status->fatal( 'http-request-error' );
			wfProfileOut( __METHOD__ );
			return $this->status;
		}

		if ( $result['timed_out'] ) {
			$this->status->fatal( 'http-timed-out', $this->url );
			wfProfileOut( __METHOD__ );
			return $this->status;
		}

		// If everything went OK, or we received some error code
		// get the response body content.
		if ( $this->status->isOK() || (int)$this->respStatus >= 300 ) {
			while ( !feof( $fh ) ) {
				$buf = fread( $fh, 8192 );

				if ( $buf === false ) {
					$this->status->fatal( 'http-read-error' );
					break;
				}

				if ( strlen( $buf ) ) {
					call_user_func( $this->callback, $fh, $buf );
				}
			}
		}
		fclose( $fh );

		wfProfileOut( __METHOD__ );

		return $this->status;
	}
}