tanora /xandra.org/www/system/classes/Kohana/HTTP/Header.php

Language PHP Lines 944
MD5 Hash 69ef4437e377d3f540dce99be1fdc88f Estimated Cost $11,927 (why?)
Repository https://bitbucket.org/ekkl/tanora View Raw File View Project SPDX
  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
<?php defined('SYSPATH') OR die('No direct script access.');
/**
 * The Kohana_HTTP_Header class provides an Object-Orientated interface
 * to HTTP headers. This can parse header arrays returned from the
 * PHP functions `apache_request_headers()` or the `http_parse_headers()`
 * function available within the PECL HTTP library.
 *
 * @package    Kohana
 * @category   HTTP
 * @author     Kohana Team
 * @since      3.1.0
 * @copyright  (c) 2008-2012 Kohana Team
 * @license    http://kohanaphp.com/license
 */
class Kohana_HTTP_Header extends ArrayObject {

	// Default Accept-* quality value if none supplied
	const DEFAULT_QUALITY = 1;

	/**
	 * Parses an Accept(-*) header and detects the quality
	 *
	 * @param   array   $parts  accept header parts
	 * @return  array
	 * @since   3.2.0
	 */
	public static function accept_quality(array $parts)
	{
		$parsed = array();

		// Resource light iteration
		$parts_keys = array_keys($parts);
		foreach ($parts_keys as $key)
		{
			$value = trim(str_replace(array("\r", "\n"), '', $parts[$key]));

			$pattern = '~\b(\;\s*+)?q\s*+=\s*+([.0-9]+)~';

			// If there is no quality directive, return default
			if ( ! preg_match($pattern, $value, $quality))
			{
				$parsed[$value] = (float) HTTP_Header::DEFAULT_QUALITY;
			}
			else
			{
				$quality = $quality[2];

				if ($quality[0] === '.')
				{
					$quality = '0'.$quality;
				}

				// Remove the quality value from the string and apply quality
				$parsed[trim(preg_replace($pattern, '', $value, 1), '; ')] = (float) $quality;
			}
		}

		return $parsed;
	}

	/**
	 * Parses the accept header to provide the correct quality values
	 * for each supplied accept type.
	 *
	 * @link    http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.1
	 * @param   string  $accepts    accept content header string to parse
	 * @return  array
	 * @since   3.2.0
	 */
	public static function parse_accept_header($accepts = NULL)
	{
		$accepts = explode(',', (string) $accepts);

		// If there is no accept, lets accept everything
		if ($accepts === NULL)
			return array('*' => array('*' => (float) HTTP_Header::DEFAULT_QUALITY));

		// Parse the accept header qualities
		$accepts = HTTP_Header::accept_quality($accepts);

		$parsed_accept = array();

		// This method of iteration uses less resource
		$keys = array_keys($accepts);
		foreach ($keys as $key)
		{
			// Extract the parts
			$parts = explode('/', $key, 2);

			// Invalid content type- bail
			if ( ! isset($parts[1]))
				continue;

			// Set the parsed output
			$parsed_accept[$parts[0]][$parts[1]] = $accepts[$key];
		}

		return $parsed_accept;
	}

	/**
	 * Parses the `Accept-Charset:` HTTP header and returns an array containing
	 * the charset and associated quality.
	 *
	 * @link    http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.2
	 * @param   string  $charset    charset string to parse
	 * @return  array
	 * @since   3.2.0
	 */
	public static function parse_charset_header($charset = NULL)
	{
		if ($charset === NULL)
		{
			return array('*' => (float) HTTP_Header::DEFAULT_QUALITY);
		}

		return HTTP_Header::accept_quality(explode(',', (string) $charset));
	}

	/**
	 * Parses the `Accept-Encoding:` HTTP header and returns an array containing
	 * the charsets and associated quality.
	 *
	 * @link    http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.3
	 * @param   string  $encoding   charset string to parse
	 * @return  array
	 * @since   3.2.0
	 */
	public static function parse_encoding_header($encoding = NULL)
	{
		// Accept everything
		if ($encoding === NULL)
		{
			return array('*' => (float) HTTP_Header::DEFAULT_QUALITY);
		}
		elseif ($encoding === '')
		{
			return array('identity' => (float) HTTP_Header::DEFAULT_QUALITY);
		}
		else
		{
			return HTTP_Header::accept_quality(explode(',', (string) $encoding));
		}
	}

	/**
	 * Parses the `Accept-Language:` HTTP header and returns an array containing
	 * the languages and associated quality.
	 *
	 * @link    http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.4
	 * @param   string  $language   charset string to parse
	 * @return  array
	 * @since   3.2.0
	 */
	public static function parse_language_header($language = NULL)
	{
		if ($language === NULL)
		{
			return array('*' => array('*' => (float) HTTP_Header::DEFAULT_QUALITY));
		}

		$language = HTTP_Header::accept_quality(explode(',', (string) $language));

		$parsed_language = array();

		$keys = array_keys($language);
		foreach ($keys as $key)
		{
			// Extract the parts
			$parts = explode('-', $key, 2);

			// Invalid content type- bail
			if ( ! isset($parts[1]))
			{
				$parsed_language[$parts[0]]['*'] = $language[$key];
			}
			else
			{
				// Set the parsed output
				$parsed_language[$parts[0]][$parts[1]] = $language[$key];
			}
		}

		return $parsed_language;
	}

	/**
	 * Generates a Cache-Control HTTP header based on the supplied array.
	 *
	 *     // Set the cache control headers you want to use
	 *     $cache_control = array(
	 *         'max-age'          => 3600,
	 *         'must-revalidate',
	 *         'public'
	 *     );
	 *
	 *     // Create the cache control header, creates :
	 *     // cache-control: max-age=3600, must-revalidate, public
	 *     $response->headers('Cache-Control', HTTP_Header::create_cache_control($cache_control);
	 *
	 * @link    http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13
	 * @param   array   $cache_control  Cache-Control to render to string
	 * @return  string
	 */
	public static function create_cache_control(array $cache_control)
	{
		$parts = array();

		foreach ($cache_control as $key => $value)
		{
			$parts[] = (is_int($key)) ? $value : ($key.'='.$value);
		}

		return implode(', ', $parts);
	}

	/**
	 * Parses the Cache-Control header and returning an array representation of the Cache-Control
	 * header.
	 *
	 *     // Create the cache control header
	 *     $response->headers('cache-control', 'max-age=3600, must-revalidate, public');
	 *
	 *     // Parse the cache control header
	 *     if ($cache_control = HTTP_Header::parse_cache_control($response->headers('cache-control')))
	 *     {
	 *          // Cache-Control header was found
	 *          $maxage = $cache_control['max-age'];
	 *     }
	 *
	 * @param   array   $cache_control Array of headers
	 * @return  mixed
	 */
	public static function parse_cache_control($cache_control)
	{
		$directives = explode(',', strtolower($cache_control));

		if ($directives === FALSE)
			return FALSE;

		$output = array();

		foreach ($directives as $directive)
		{
			if (strpos($directive, '=') !== FALSE)
			{
				list($key, $value) = explode('=', trim($directive), 2);

				$output[$key] = ctype_digit($value) ? (int) $value : $value;
			}
			else
			{
				$output[] = trim($directive);
			}
		}

		return $output;
	}

	/**
	 * @var     array    Accept: (content) types
	 */
	protected $_accept_content;

	/**
	 * @var     array    Accept-Charset: parsed header
	 */
	protected $_accept_charset;

	/**
	 * @var     array    Accept-Encoding: parsed header
	 */
	protected $_accept_encoding;

	/**
	 * @var     array    Accept-Language: parsed header
	 */
	protected $_accept_language;

	/**
	 * Constructor method for [Kohana_HTTP_Header]. Uses the standard constructor
	 * of the parent `ArrayObject` class.
	 *
	 *     $header_object = new HTTP_Header(array('x-powered-by' => 'Kohana 3.1.x', 'expires' => '...'));
	 *
	 * @param   mixed   $input          Input array
	 * @param   int     $flags          Flags
	 * @param   string  $iterator_class The iterator class to use
	 */
	public function __construct(array $input = array(), $flags = NULL, $iterator_class = 'ArrayIterator')
	{
		/**
		 * @link http://www.w3.org/Protocols/rfc2616/rfc2616.html
		 *
		 * HTTP header declarations should be treated as case-insensitive
		 */
		$input = array_change_key_case( (array) $input, CASE_LOWER);

		parent::__construct($input, $flags, $iterator_class);
	}

	/**
	 * Returns the header object as a string, including
	 * the terminating new line
	 *
	 *     // Return the header as a string
	 *     echo (string) $request->headers();
	 *
	 * @return  string
	 */
	public function __toString()
	{
		$header = '';

		foreach ($this as $key => $value)
		{
			// Put the keys back the Case-Convention expected
			$key = Text::ucfirst($key);

			if (is_array($value))
			{
				$header .= $key.': '.(implode(', ', $value))."\r\n";
			}
			else
			{
				$header .= $key.': '.$value."\r\n";
			}
		}

		return $header."\r\n";
	}

	/**
	 * Overloads `ArrayObject::offsetSet()` to enable handling of header
	 * with multiple instances of the same directive. If the `$replace` flag
	 * is `FALSE`, the header will be appended rather than replacing the
	 * original setting.
	 *
	 * @param   mixed   $index      index to set `$newval` to
	 * @param   mixed   $newval     new value to set
	 * @param   boolean $replace    replace existing value
	 * @return  void
	 * @since   3.2.0
	 */
	public function offsetSet($index, $newval, $replace = TRUE)
	{
		// Ensure the index is lowercase
		$index = strtolower($index);

		if ($replace OR ! $this->offsetExists($index))
		{
			return parent::offsetSet($index, $newval);
		}

		$current_value = $this->offsetGet($index);

		if (is_array($current_value))
		{
			$current_value[] = $newval;
		}
		else
		{
			$current_value = array($current_value, $newval);
		}

		return parent::offsetSet($index, $current_value);
	}

	/**
	 * Overloads the `ArrayObject::offsetExists()` method to ensure keys
	 * are lowercase.
	 *
	 * @param   string  $index
	 * @return  boolean
	 * @since   3.2.0
	 */
	public function offsetExists($index)
	{
		return parent::offsetExists(strtolower($index));
	}

	/**
	 * Overloads the `ArrayObject::offsetUnset()` method to ensure keys
	 * are lowercase.
	 *
	 * @param   string  $index
	 * @return  void
	 * @since   3.2.0
	 */
	public function offsetUnset($index)
	{
		return parent::offsetUnset(strtolower($index));
	}

	/**
	 * Overload the `ArrayObject::offsetGet()` method to ensure that all
	 * keys passed to it are formatted correctly for this object.
	 *
	 * @param   string  $index  index to retrieve
	 * @return  mixed
	 * @since   3.2.0
	 */
	public function offsetGet($index)
	{
		return parent::offsetGet(strtolower($index));
	}

	/**
	 * Overloads the `ArrayObject::exchangeArray()` method to ensure that
	 * all keys are changed to lowercase.
	 *
	 * @param   mixed   $input
	 * @return  array
	 * @since   3.2.0
	 */
	public function exchangeArray($input)
	{
		/**
		 * @link http://www.w3.org/Protocols/rfc2616/rfc2616.html
		 *
		 * HTTP header declarations should be treated as case-insensitive
		 */
		$input = array_change_key_case( (array) $input, CASE_LOWER);

		return parent::exchangeArray($input);
	}

	/**
	 * Parses a HTTP Message header line and applies it to this HTTP_Header
	 *
	 *     $header = $response->headers();
	 *     $header->parse_header_string(NULL, 'content-type: application/json');
	 *
	 * @param   resource    $resource       the resource (required by Curl API)
	 * @param   string      $header_line    the line from the header to parse
	 * @return  int
	 * @since   3.2.0
	 */
	public function parse_header_string($resource, $header_line)
	{
		$headers = array();

		if (preg_match_all('/(\w[^\s:]*):[ ]*([^\r\n]*(?:\r\n[ \t][^\r\n]*)*)/', $header_line, $matches))
		{
			foreach ($matches[0] as $key => $value)
			{
				$this->offsetSet($matches[1][$key], $matches[2][$key], FALSE);
			}
		}

		return strlen($header_line);
	}

	/**
	 * Returns the accept quality of a submitted mime type based on the
	 * request `Accept:` header. If the `$explicit` argument is `TRUE`,
	 * only precise matches will be returned, excluding all wildcard (`*`)
	 * directives.
	 *
	 *     // Accept: application/xml; application/json; q=.5; text/html; q=.2, text/*
	 *     // Accept quality for application/json
	 *
	 *     // $quality = 0.5
	 *     $quality = $request->headers()->accepts_at_quality('application/json');
	 *
	 *     // $quality_explicit = FALSE
	 *     $quality_explicit = $request->headers()->accepts_at_quality('text/plain', TRUE);
	 *
	 * @param   string  $type
	 * @param   boolean $explicit   explicit check, excludes `*`
	 * @return  mixed
	 * @since   3.2.0
	 */
	public function accepts_at_quality($type, $explicit = FALSE)
	{
		// Parse Accept header if required
		if ($this->_accept_content === NULL)
		{
			if ($this->offsetExists('Accept'))
			{
				$accept = $this->offsetGet('Accept');
			}
			else
			{
				$accept = '*/*';
			}

			$this->_accept_content = HTTP_Header::parse_accept_header($accept);
		}

		// If not a real mime, try and find it in config
		if (strpos($type, '/') === FALSE)
		{
			$mime = Kohana::$config->load('mimes.'.$type);

			if ($mime === NULL)
				return FALSE;

			$quality = FALSE;

			foreach ($mime as $_type)
			{
				$quality_check = $this->accepts_at_quality($_type, $explicit);
				$quality = ($quality_check > $quality) ? $quality_check : $quality;
			}

			return $quality;
		}

		$parts = explode('/', $type, 2);

		if (isset($this->_accept_content[$parts[0]][$parts[1]]))
		{
			return $this->_accept_content[$parts[0]][$parts[1]];
		}
		elseif ($explicit === TRUE)
		{
			return FALSE;
		}
		else
		{
			if (isset($this->_accept_content[$parts[0]]['*']))
			{
				return $this->_accept_content[$parts[0]]['*'];
			}
			elseif (isset($this->_accept_content['*']['*']))
			{
				return $this->_accept_content['*']['*'];
			}
			else
			{
				return FALSE;
			}
		}
	}

	/**
	 * Returns the preferred response content type based on the accept header
	 * quality settings. If items have the same quality value, the first item
	 * found in the array supplied as `$types` will be returned.
	 *
	 *     // Get the preferred acceptable content type
	 *     // Accept: text/html, application/json; q=.8, text/*
	 *     $result = $header->preferred_accept(array(
	 *         'text/html'
	 *         'text/rtf',
	 *         'application/json'
	 *     )); // $result = 'application/json'
	 *
	 *     $result = $header->preferred_accept(array(
	 *         'text/rtf',
	 *         'application/xml'
	 *     ), TRUE); // $result = FALSE (none matched explicitly)
	 *
	 *
	 * @param   array   $types      the content types to examine
	 * @param   boolean $explicit   only allow explicit references, no wildcards
	 * @return  string  name of the preferred content type
	 * @since   3.2.0
	 */
	public function preferred_accept(array $types, $explicit = FALSE)
	{
		$preferred = FALSE;
		$ceiling = 0;

		foreach ($types as $type)
		{
			$quality = $this->accepts_at_quality($type, $explicit);

			if ($quality > $ceiling)
			{
				$preferred = $type;
				$ceiling = $quality;
			}
		}

		return $preferred;
	}

	/**
	 * Returns the quality of the supplied `$charset` argument. This method
	 * will automatically parse the `Accept-Charset` header if present and
	 * return the associated resolved quality value.
	 *
	 *      // Accept-Charset: utf-8, utf-16; q=.8, iso-8859-1; q=.5
	 *      $quality = $header->accepts_charset_at_quality('utf-8');
	 *            // $quality = (float) 1
	 *
	 * @param   string  $charset    charset to examine
	 * @return  float   the quality of the charset
	 * @since   3.2.0
	 */
	public function accepts_charset_at_quality($charset)
	{
		if ($this->_accept_charset === NULL)
		{
			if ($this->offsetExists('Accept-Charset'))
			{
				$charset_header = strtolower($this->offsetGet('Accept-Charset'));
				$this->_accept_charset = HTTP_Header::parse_charset_header($charset_header);
			}
			else
			{
				$this->_accept_charset = HTTP_Header::parse_charset_header(NULL);
			}
		}

		$charset = strtolower($charset);

		if (isset($this->_accept_charset[$charset]))
		{
			return $this->_accept_charset[$charset];
		}
		elseif (isset($this->_accept_charset['*']))
		{
			return $this->_accept_charset['*'];
		}
		elseif ($charset === 'iso-8859-1')
		{
			return (float) 1;
		}

		return (float) 0;
	}

	/**
	 * Returns the preferred charset from the supplied array `$charsets` based
	 * on the `Accept-Charset` header directive.
	 *
	 *      // Accept-Charset: utf-8, utf-16; q=.8, iso-8859-1; q=.5
	 *      $charset = $header->preferred_charset(array(
	 *          'utf-10', 'ascii', 'utf-16', 'utf-8'
	 *      )); // $charset = 'utf-8'
	 *
	 * @param   array   $charsets   charsets to test
	 * @return  mixed   preferred charset or `FALSE`
	 * @since   3.2.0
	 */
	public function preferred_charset(array $charsets)
	{
		$preferred = FALSE;
		$ceiling = 0;

		foreach ($charsets as $charset)
		{
			$quality = $this->accepts_charset_at_quality($charset);

			if ($quality > $ceiling)
			{
				$preferred = $charset;
				$ceiling = $quality;
			}
		}

		return $preferred;
	}

	/**
	 * Returns the quality of the `$encoding` type passed to it. Encoding
	 * is usually compression such as `gzip`, but could be some other
	 * message encoding algorithm. This method allows explicit checks to be
	 * done ignoring wildcards.
	 *
	 *      // Accept-Encoding: compress, gzip, *; q=.5
	 *      $encoding = $header->accepts_encoding_at_quality('gzip');
	 *      // $encoding = (float) 1.0s
	 *
	 * @param   string  $encoding   encoding type to interrogate
	 * @param   boolean $explicit   explicit check, ignoring wildcards and `identity`
	 * @return  float
	 * @since   3.2.0
	 */
	public function accepts_encoding_at_quality($encoding, $explicit = FALSE)
	{
		if ($this->_accept_encoding === NULL)
		{
			if ($this->offsetExists('Accept-Encoding'))
			{
				$encoding_header = $this->offsetGet('Accept-Encoding');
			}
			else
			{
				$encoding_header = NULL;
			}

			$this->_accept_encoding = HTTP_Header::parse_encoding_header($encoding_header);
		}

		// Normalize the encoding
		$encoding = strtolower($encoding);

		if (isset($this->_accept_encoding[$encoding]))
		{
			return $this->_accept_encoding[$encoding];
		}

		if ($explicit === FALSE)
		{
			if (isset($this->_accept_encoding['*']))
			{
				return $this->_accept_encoding['*'];
			}
			elseif ($encoding === 'identity')
			{
				return (float) HTTP_Header::DEFAULT_QUALITY;
			}
		}

		return (float) 0;
	}

	/**
	 * Returns the preferred message encoding type based on quality, and can
	 * optionally ignore wildcard references. If two or more encodings have the
	 * same quality, the first listed in `$encodings` will be returned.
	 *
	 *     // Accept-Encoding: compress, gzip, *; q.5
	 *     $encoding = $header->preferred_encoding(array(
	 *          'gzip', 'bzip', 'blowfish'
	 *     ));
	 *     // $encoding = 'gzip';
	 *
	 * @param   array   $encodings  encodings to test against
	 * @param   boolean $explicit   explicit check, if `TRUE` wildcards are excluded
	 * @return  mixed
	 * @since   3.2.0
	 */
	public function preferred_encoding(array $encodings, $explicit = FALSE)
	{
		$ceiling = 0;
		$preferred = FALSE;

		foreach ($encodings as $encoding)
		{
			$quality = $this->accepts_encoding_at_quality($encoding, $explicit);

			if ($quality > $ceiling)
			{
				$ceiling = $quality;
				$preferred = $encoding;
			}
		}

		return $preferred;
	}

	/**
	 * Returns the quality of `$language` supplied, optionally ignoring
	 * wildcards if `$explicit` is set to a non-`FALSE` value. If the quality
	 * is not found, `0.0` is returned.
	 *
	 *     // Accept-Language: en-us, en-gb; q=.7, en; q=.5
	 *     $lang = $header->accepts_language_at_quality('en-gb');
	 *     // $lang = (float) 0.7
	 *
	 *     $lang2 = $header->accepts_language_at_quality('en-au');
	 *     // $lang2 = (float) 0.5
	 *
	 *     $lang3 = $header->accepts_language_at_quality('en-au', TRUE);
	 *     // $lang3 = (float) 0.0
	 *
	 * @param   string  $language   language to interrogate
	 * @param   boolean $explicit   explicit interrogation, `TRUE` ignores wildcards
	 * @return  float
	 * @since   3.2.0
	 */
	public function accepts_language_at_quality($language, $explicit = FALSE)
	{
		if ($this->_accept_language === NULL)
		{
			if ($this->offsetExists('Accept-Language'))
			{
				$language_header = strtolower($this->offsetGet('Accept-Language'));
			}
			else
			{
				$language_header = NULL;
			}

			$this->_accept_language = HTTP_Header::parse_language_header($language_header);
		}

		// Normalize the language
		$language_parts = explode('-', strtolower($language), 2);

		if (isset($this->_accept_language[$language_parts[0]]))
		{
			if (isset($language_parts[1]))
			{
				if (isset($this->_accept_language[$language_parts[0]][$language_parts[1]]))
				{
					return $this->_accept_language[$language_parts[0]][$language_parts[1]];
				}
				elseif ($explicit === FALSE AND isset($this->_accept_language[$language_parts[0]]['*']))
				{
					return $this->_accept_language[$language_parts[0]]['*'];
				}
			}
			elseif (isset($this->_accept_language[$language_parts[0]]['*']))
			{
				return $this->_accept_language[$language_parts[0]]['*'];
			}
		}

		if ($explicit === FALSE AND isset($this->_accept_language['*']))
		{
			return $this->_accept_language['*'];
		}

		return (float) 0;
	}

	/**
	 * Returns the preferred language from the supplied array `$languages` based
	 * on the `Accept-Language` header directive.
	 *
	 *      // Accept-Language: en-us, en-gb; q=.7, en; q=.5
	 *      $lang = $header->preferred_language(array(
	 *          'en-gb', 'en-au', 'fr', 'es'
	 *      )); // $lang = 'en-gb'
	 *
	 * @param   array   $languages
	 * @param   boolean $explicit
	 * @return  mixed
	 * @since   3.2.0
	 */
	public function preferred_language(array $languages, $explicit = FALSE)
	{
		$ceiling = 0;
		$preferred = FALSE;

		foreach ($languages as $language)
		{
			$quality = $this->accepts_language_at_quality($language, $explicit);

			if ($quality > $ceiling)
			{
				$ceiling = $quality;
				$preferred = $language;
			}
		}

		return $preferred;
	}

	/**
	 * Sends headers to the php processor, or supplied `$callback` argument.
	 * This method formats the headers correctly for output, re-instating their
	 * capitalization for transmission.
	 *
	 * [!!] if you supply a custom header handler via `$callback`, it is
	 *  recommended that `$response` is returned
	 *
	 * @param   HTTP_Response   $response   header to send
	 * @param   boolean         $replace    replace existing value
	 * @param   callback        $callback   optional callback to replace PHP header function
	 * @return  mixed
	 * @since   3.2.0
	 */
	public function send_headers(HTTP_Response $response = NULL, $replace = FALSE, $callback = NULL)
	{
		$protocol = $response->protocol();
		$status = $response->status();

		// Create the response header
		$processed_headers = array($protocol.' '.$status.' '.Response::$messages[$status]);

		// Get the headers array
		$headers = $response->headers()->getArrayCopy();

		foreach ($headers as $header => $value)
		{
			if (is_array($value))
			{
				$value = implode(', ', $value);
			}

			$processed_headers[] = Text::ucfirst($header).': '.$value;
		}

		if ( ! isset($headers['content-type']))
		{
			$processed_headers[] = 'Content-Type: '.Kohana::$content_type.'; charset='.Kohana::$charset;
		}

		if (Kohana::$expose AND ! isset($headers['x-powered-by']))
		{
			$processed_headers[] = 'X-Powered-By: '.Kohana::version();
		}

		// Get the cookies and apply
		if ($cookies = $response->cookie())
		{
			$processed_headers['Set-Cookie'] = $cookies;
		}

		if (is_callable($callback))
		{
			// Use the callback method to set header
			return call_user_func($callback, $response, $processed_headers, $replace);
		}
		else
		{
			$this->_send_headers_to_php($processed_headers, $replace);
			return $response;
		}
	}

	/**
	 * Sends the supplied headers to the PHP output buffer. If cookies
	 * are included in the message they will be handled appropriately.
	 *
	 * @param   array   $headers    headers to send to php
	 * @param   boolean $replace    replace existing headers
	 * @return  self
	 * @since   3.2.0
	 */
	protected function _send_headers_to_php(array $headers, $replace)
	{
		// If the headers have been sent, get out
		if (headers_sent())
			return $this;

		foreach ($headers as $key => $line)
		{
			if ($key == 'Set-Cookie' AND is_array($line))
			{
				// Send cookies
				foreach ($line as $name => $value)
				{
					Cookie::set($name, $value['value'], $value['expiration']);
				}

				continue;
			}

			header($line, $replace);
		}

		return $this;
	}

}
Back to Top