CodeIgniter.php 引入的第九个核心文件($IN)。为了安全性,对输入数据进行预处理,提供了一些辅助方法来获取输入数据并处理。

文档地址

string strip_tags ( string $str [, string $allowable_tags ] )

该函数尝试返回给定的字符串 str 去除空字符、HTML 和 PHP 标记后的结果。它使用与函数 fgetss() 一样的机制去除标记。

mixed filter_var ( mixed $variable [, int $filter = FILTER_DEFAULT [, mixed $options ]] )

使用特定的过滤器过滤一个变量

Magic Quotes 、mysql_real_escape_string、stripslashes、addslashes

StackOverFlow

数组操作

待学习:array notation

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
<?php
/**
* CodeIgniter
*
* An open source application development framework for PHP
*
* This content is released under the MIT License (MIT)
*
* Copyright (c) 2014 - 2015, British Columbia Institute of Technology
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*
* @package CodeIgniter
* @author EllisLab Dev Team
* @copyright Copyright (c) 2008 - 2014, EllisLab, Inc. (http://ellislab.com/)
* @copyright Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/)
* @license http://opensource.org/licenses/MIT MIT License
* @link http://codeigniter.com
* @since Version 1.0.0
* @filesource
*/
defined('BASEPATH') OR exit('No direct script access allowed');

/**
* Input Class
*
* Pre-processes global input data for security
*
* @package CodeIgniter
* @subpackage Libraries
* @category Input
* @author EllisLab Dev Team
* @link http://codeigniter.com/user_guide/libraries/input.html
*/
class CI_Input {

/**
* IP address of the current user
*
* @var string
*/
protected $ip_address = FALSE;

/**
* Allow GET array flag
*
* If set to FALSE, then $_GET will be set to an empty array.
*
* @var bool
*/
protected $_allow_get_array = TRUE;

/**
* Standardize new lines flag
*
* If set to TRUE, then newlines are standardized.
*
* @var bool
*/
protected $_standardize_newlines;

/**
* Enable XSS flag
*
* Determines whether the XSS filter is always active when
* GET, POST or COOKIE data is encountered.
* Set automatically based on config setting.
*
* @var bool
*/
protected $_enable_xss = FALSE;

/**
* Enable CSRF flag
*
* Enables a CSRF cookie token to be set.
* Set automatically based on config setting.
*
* @var bool
*/
protected $_enable_csrf = FALSE;

/**
* List of all HTTP request headers
*
* @var array
*/
protected $headers = array();

/**
* Raw input stream data
*
* Holds a cache of php://input contents
*
* @var string
*/
protected $_raw_input_stream;

/**
* Parsed input stream data
*
* Parsed from php://input at runtime
*
* @see CI_Input::input_stream()
* @var array
*/
protected $_input_stream;

protected $security;
protected $uni;

// --------------------------------------------------------------------

/**
* Class constructor
*
* Determines whether to globally enable the XSS processing
* and whether to allow the $_GET array.
*
* @return void
*/
public function __construct()
{
$this->_allow_get_array = (config_item('allow_get_array') === TRUE);
$this->_enable_xss = (config_item('global_xss_filtering') === TRUE);
$this->_enable_csrf = (config_item('csrf_protection') === TRUE);
$this->_standardize_newlines = (bool) config_item('standardize_newlines');

$this->security =& load_class('Security', 'core');

// Do we need the UTF-8 class?
if (UTF8_ENABLED === TRUE)
{
$this->uni =& load_class('Utf8', 'core');
}

// Sanitize global arrays 净化
$this->_sanitize_globals();

// CSRF Protection check
if ($this->_enable_csrf === TRUE && ! is_cli())
{
$this->security->csrf_verify();
}

log_message('info', 'Input Class Initialized');
}

// --------------------------------------------------------------------

/**
* Fetch from array
* 核心参数:获取指定数组中的参数
*
* Internal method used to retrieve(取得) values from global arrays.
*
* @param array &$array $_GET, $_POST, $_COOKIE, $_SERVER, etc.
* @param mixed $index Index for item to be fetched from $array
* @param bool $xss_clean Whether to apply XSS filtering
* @return mixed
*/
protected function _fetch_from_array(&$array, $index = NULL, $xss_clean = NULL)
{
is_bool($xss_clean) OR $xss_clean = $this->_enable_xss;

// If $index is NULL, it means that the whole $array is requested
// 没有指定 index 则返回所有
isset($index) OR $index = array_keys($array);

// allow fetching multiple keys at once
if (is_array($index))
{
$output = array();
foreach ($index as $key)
{
$output[$key] = $this->_fetch_from_array($array, $key, $xss_clean);
}

return $output;
}

if (isset($array[$index]))
{
$value = $array[$index];
}
elseif (($count = preg_match_all('/(?:^[^\[]+)|\[[^]]*\]/', $index, $matches)) > 1) // Does the index contain array notation
{
$value = $array;
for ($i = 0; $i < $count; $i++)
{
$key = trim($matches[0][$i], '[]');
if ($key === '') // Empty notation will return the value as array
{
break;
}

if (isset($value[$key]))
{
$value = $value[$key];
}
else
{
return NULL;
}
}
}
else
{
return NULL;
}

return ($xss_clean === TRUE)
? $this->security->xss_clean($value)
: $value;
}

// --------------------------------------------------------------------

/**
* Fetch an item from the GET array
*
* @param mixed $index Index for item to be fetched from $_GET
* @param bool $xss_clean Whether to apply XSS filtering
* @return mixed
*/
public function get($index = NULL, $xss_clean = NULL)
{
return $this->_fetch_from_array($_GET, $index, $xss_clean);
}

// --------------------------------------------------------------------

/**
* Fetch an item from the POST array
*
* @param mixed $index Index for item to be fetched from $_POST
* @param bool $xss_clean Whether to apply XSS filtering
* @return mixed
*/
public function post($index = NULL, $xss_clean = NULL)
{
return $this->_fetch_from_array($_POST, $index, $xss_clean);
}

// --------------------------------------------------------------------

/**
* Fetch an item from POST data with fallback to GET
*
* @param string $index Index for item to be fetched from $_POST or $_GET
* @param bool $xss_clean Whether to apply XSS filtering
* @return mixed
*/
public function post_get($index, $xss_clean = NULL)
{
return isset($_POST[$index])
? $this->post($index, $xss_clean)
: $this->get($index, $xss_clean);
}

// --------------------------------------------------------------------

/**
* Fetch an item from GET data with fallback to POST
*
* @param string $index Index for item to be fetched from $_GET or $_POST
* @param bool $xss_clean Whether to apply XSS filtering
* @return mixed
*/
public function get_post($index, $xss_clean = NULL)
{
return isset($_GET[$index])
? $this->get($index, $xss_clean)
: $this->post($index, $xss_clean);
}

// --------------------------------------------------------------------

/**
* Fetch an item from the COOKIE array
*
* @param mixed $index Index for item to be fetched from $_COOKIE
* @param bool $xss_clean Whether to apply XSS filtering
* @return mixed
*/
public function cookie($index = NULL, $xss_clean = NULL)
{
return $this->_fetch_from_array($_COOKIE, $index, $xss_clean);
}

// --------------------------------------------------------------------

/**
* Fetch an item from the SERVER array
*
* @param mixed $index Index for item to be fetched from $_SERVER
* @param bool $xss_clean Whether to apply XSS filtering
* @return mixed
*/
public function server($index, $xss_clean = NULL)
{
return $this->_fetch_from_array($_SERVER, $index, $xss_clean);
}

// ------------------------------------------------------------------------

/**
* Fetch an item from the php://input stream
*
* Useful when you need to access PUT, DELETE or PATCH request data.
*
* @param string $index Index for item to be fetched
* @param bool $xss_clean Whether to apply XSS filtering
* @return mixed
*/
public function input_stream($index = NULL, $xss_clean = NULL)
{
// Prior to PHP 5.6, the input stream can only be read once,
// so we'll need to check if we have already done that first.
if ( ! is_array($this->_input_stream))
{
// $this->raw_input_stream will trigger __get().
parse_str($this->raw_input_stream, $this->_input_stream);
is_array($this->_input_stream) OR $this->_input_stream = array();
}

return $this->_fetch_from_array($this->_input_stream, $index, $xss_clean);
}

// ------------------------------------------------------------------------

/**
* Set cookie
*
* Accepts an arbitrary number of parameters (up to 7) or an associative
* array in the first parameter containing all the values.
*
* @param string|mixed[] $name Cookie name or an array containing parameters
* @param string $value Cookie value
* @param int $expire Cookie expiration time in seconds
* @param string $domain Cookie domain (e.g.: '.yourdomain.com')
* @param string $path Cookie path (default: '/')
* @param string $prefix Cookie name prefix
* @param bool $secure Whether to only transfer cookies via SSL
* @param bool $httponly Whether to only makes the cookie accessible via HTTP (no javascript)
* @return void
*/
public function set_cookie($name, $value = '', $expire = '', $domain = '', $path = '/', $prefix = '', $secure = FALSE, $httponly = FALSE)
{
if (is_array($name))
{
// always leave 'name' in last place, as the loop will break otherwise, due to $$item
foreach (array('value', 'expire', 'domain', 'path', 'prefix', 'secure', 'httponly', 'name') as $item)
{
if (isset($name[$item]))
{
$$item = $name[$item];
}
}
}

if ($prefix === '' && config_item('cookie_prefix') !== '')
{
$prefix = config_item('cookie_prefix');
}

if ($domain == '' && config_item('cookie_domain') != '')
{
$domain = config_item('cookie_domain');
}

if ($path === '/' && config_item('cookie_path') !== '/')
{
$path = config_item('cookie_path');
}

if ($secure === FALSE && config_item('cookie_secure') === TRUE)
{
$secure = config_item('cookie_secure');
}

if ($httponly === FALSE && config_item('cookie_httponly') !== FALSE)
{
$httponly = config_item('cookie_httponly');
}

if ( ! is_numeric($expire))
{
$expire = time() - 86500;
}
else
{
$expire = ($expire > 0) ? time() + $expire : 0;
}

setcookie($prefix.$name, $value, $expire, $path, $domain, $secure, $httponly);
}

// --------------------------------------------------------------------

/**
* Fetch the IP Address
*
* Determines and validates the visitor's IP address.
*
* @return string IP address
*/
public function ip_address()
{
if ($this->ip_address !== FALSE)
{
return $this->ip_address;
}

$proxy_ips = config_item('proxy_ips');
if ( ! empty($proxy_ips) && ! is_array($proxy_ips))
{
$proxy_ips = explode(',', str_replace(' ', '', $proxy_ips));
}

$this->ip_address = $this->server('REMOTE_ADDR');

if ($proxy_ips)
{
foreach (array('HTTP_X_FORWARDED_FOR', 'HTTP_CLIENT_IP', 'HTTP_X_CLIENT_IP', 'HTTP_X_CLUSTER_CLIENT_IP') as $header)
{
if (($spoof = $this->server($header)) !== NULL)
{
// Some proxies typically list the whole chain of IP
// addresses through which the client has reached us.
// e.g. client_ip, proxy_ip1, proxy_ip2, etc.
sscanf($spoof, '%[^,]', $spoof);

if ( ! $this->valid_ip($spoof))
{
$spoof = NULL;
}
else
{
break;
}
}
}

if ($spoof)
{
for ($i = 0, $c = count($proxy_ips); $i < $c; $i++)
{
// Check if we have an IP address or a subnet
if (strpos($proxy_ips[$i], '/') === FALSE)
{
// An IP address (and not a subnet) is specified.
// We can compare right away.
if ($proxy_ips[$i] === $this->ip_address)
{
$this->ip_address = $spoof;
break;
}

continue;
}

// We have a subnet ... now the heavy lifting begins
isset($separator) OR $separator = $this->valid_ip($this->ip_address, 'ipv6') ? ':' : '.';

// If the proxy entry doesn't match the IP protocol - skip it
if (strpos($proxy_ips[$i], $separator) === FALSE)
{
continue;
}

// Convert the REMOTE_ADDR IP address to binary, if needed
if ( ! isset($ip, $sprintf))
{
if ($separator === ':')
{
// Make sure we're have the "full" IPv6 format
$ip = explode(':',
str_replace('::',
str_repeat(':', 9 - substr_count($this->ip_address, ':')),
$this->ip_address
)
);

for ($j = 0; $j < 8; $j++)
{
$ip[$j] = intval($ip[$j], 16);
}

$sprintf = '%016b%016b%016b%016b%016b%016b%016b%016b';
}
else
{
$ip = explode('.', $this->ip_address);
$sprintf = '%08b%08b%08b%08b';
}

$ip = vsprintf($sprintf, $ip);
}

// Split the netmask length off the network address
sscanf($proxy_ips[$i], '%[^/]/%d', $netaddr, $masklen);

// Again, an IPv6 address is most likely in a compressed form
if ($separator === ':')
{
$netaddr = explode(':', str_replace('::', str_repeat(':', 9 - substr_count($netaddr, ':')), $netaddr));
for ($i = 0; $i < 8; $i++)
{
$netaddr[$i] = intval($netaddr[$i], 16);
}
}
else
{
$netaddr = explode('.', $netaddr);
}

// Convert to binary and finally compare
if (strncmp($ip, vsprintf($sprintf, $netaddr), $masklen) === 0)
{
$this->ip_address = $spoof;
break;
}
}
}
}

if ( ! $this->valid_ip($this->ip_address))
{
return $this->ip_address = '0.0.0.0';
}

return $this->ip_address;
}

// --------------------------------------------------------------------

/**
* Validate IP Address
* 校验IP有效性
*
* @param string $ip IP address
* @param string $which IP protocol: 'ipv4' or 'ipv6'
* @return bool
*/
public function valid_ip($ip, $which = '')
{
switch (strtolower($which))
{
case 'ipv4':
$which = FILTER_FLAG_IPV4;
break;
case 'ipv6':
$which = FILTER_FLAG_IPV6;
break;
default:
$which = NULL;
break;
}

return (bool) filter_var($ip, FILTER_VALIDATE_IP, $which);
}

// --------------------------------------------------------------------

/**
* Fetch User Agent string
*
* 获取 UA
*
* @return string|null User Agent string or NULL if it doesn't exist
*/
public function user_agent($xss_clean = NULL)
{
return $this->_fetch_from_array($_SERVER, 'HTTP_USER_AGENT', $xss_clean);
}

// --------------------------------------------------------------------

/**
* Sanitize Globals
* 净化全局变量
*
* Internal method serving for the following purposes:
*
* - Unsets $_GET data, if query strings are not enabled
* - Cleans POST, COOKIE and SERVER data
* - Standardizes newline characters to PHP_EOL (换行符)
*
* @return void
*/
protected function _sanitize_globals()
{
// Is $_GET data allowed? If not we'll set the $_GET to an empty array
if ($this->_allow_get_array === FALSE)
{
$_GET = array();
}
elseif (is_array($_GET))
{
foreach ($_GET as $key => $val)
{
$_GET[$this->_clean_input_keys($key)] = $this->_clean_input_data($val);
}
}

// Clean $_POST Data
if (is_array($_POST))
{
foreach ($_POST as $key => $val)
{
$_POST[$this->_clean_input_keys($key)] = $this->_clean_input_data($val);
}
}

// Clean $_COOKIE Data
if (is_array($_COOKIE))
{
// 去除无用但会触发检测报警的参数
// Also get rid of specially treated cookies that might be set by a server
// or silly application, that are of no use to a CI application anyway
// but that when present will trip our 'Disallowed Key Characters' alarm
// http://www.ietf.org/rfc/rfc2109.txt
// note that the key names below are single quoted strings, and are not PHP variables
unset(
$_COOKIE['$Version'],
$_COOKIE['$Path'],
$_COOKIE['$Domain']
);

foreach ($_COOKIE as $key => $val)
{
if (($cookie_key = $this->_clean_input_keys($key)) !== FALSE)
{
$_COOKIE[$cookie_key] = $this->_clean_input_data($val);
}
else
{
unset($_COOKIE[$key]);
}
}
}

// Sanitize PHP_SELF
$_SERVER['PHP_SELF'] = strip_tags($_SERVER['PHP_SELF']);

log_message('debug', 'Global POST, GET and COOKIE data sanitized');
}

// --------------------------------------------------------------------

/**
* Clean Input Data
*
* Internal method that aids in escaping data and
* standardizing newline characters to PHP_EOL.
*
* @param string|string[] $str Input string(s)
* @return string
*/
protected function _clean_input_data($str)
{
if (is_array($str))
{
$new_array = array();
foreach (array_keys($str) as $key)
{
$new_array[$this->_clean_input_keys($key)] = $this->_clean_input_data($str[$key]);
}
return $new_array;
}

/* We strip slashes if magic quotes is on to keep things consistent
*
* 当 magic_quotes 为 on,所有的 ' (单引号)、" (双引号)、\(反斜杠)和 NUL's 被一个反斜杠自动转义。

NOTE: In PHP 5.4 get_magic_quotes_gpc() will always return 0 and
it will probably not exist in future versions at all.
*/
if ( ! is_php('5.4') && get_magic_quotes_gpc())
{
$str = stripslashes($str);
}

// Clean UTF-8 if supported
if (UTF8_ENABLED === TRUE)
{
$str = $this->uni->clean_string($str);
}

// Remove control characters
$str = remove_invisible_characters($str, FALSE);

// Standardize newlines if needed
if ($this->_standardize_newlines === TRUE)
{
return preg_replace('/(?:\r\n|[\r\n])/', PHP_EOL, $str);
}

return $str;
}

// --------------------------------------------------------------------

/**
* Clean Keys
*
* Internal method that helps to prevent malicious users
* from trying to exploit keys we make sure that keys are
* only named with alpha-numeric text and a few other items.
*
* @param string $str Input string
* @param bool $fatal Whether to terminate script exection
* or to return FALSE if an invalid (出现问题时是否退出)
* key is encountered
* @return string|bool
*/
protected function _clean_input_keys($str, $fatal = TRUE)
{
if ( ! preg_match('/^[a-z0-9:_\/|-]+$/i', $str))
{
if ($fatal === TRUE)
{
return FALSE;
}
else
{
set_status_header(503);
echo 'Disallowed Key Characters.';
exit(7); // EXIT_USER_INPUT
}
}

// Clean UTF-8 if supported
if (UTF8_ENABLED === TRUE)
{
return $this->uni->clean_string($str);
}

return $str;
}

// --------------------------------------------------------------------

/**
* Request Headers
* 返回 HTTP 请求头数组
*
* @param bool $xss_clean Whether to apply XSS filtering
* @return array
*/
public function request_headers($xss_clean = FALSE)
{
// If header is already defined, return it immediately
if ( ! empty($this->headers))
{
return $this->headers;
}

// In Apache, you can simply call apache_request_headers()
if (function_exists('apache_request_headers'))
{
return $this->headers = apache_request_headers();
}

$this->headers['Content-Type'] = isset($_SERVER['CONTENT_TYPE']) ? $_SERVER['CONTENT_TYPE'] : @getenv('CONTENT_TYPE');

foreach ($_SERVER as $key => $val)
{
if (sscanf($key, 'HTTP_%s', $header) === 1)
{
// take SOME_HEADER and turn it into Some-Header
$header = str_replace('_', ' ', strtolower($header));
$header = str_replace(' ', '-', ucwords($header));

$this->headers[$header] = $this->_fetch_from_array($_SERVER, $key, $xss_clean);
}
}

return $this->headers;
}

// --------------------------------------------------------------------

/**
* Get Request Header
*
* Returns the value of a single member of the headers class member
*
* @param string $index Header name
* @param bool $xss_clean Whether to apply XSS filtering
* @return string|null The requested header on success or NULL on failure
*/
public function get_request_header($index, $xss_clean = FALSE)
{
static $headers;

if ( ! isset($headers))
{
empty($this->headers) && $this->request_headers();
foreach ($this->headers as $key => $value)
{
$headers[strtolower($key)] = $value;
}
}

$index = strtolower($index);

if ( ! isset($headers[$index]))
{
return NULL;
}

return ($xss_clean === TRUE)
? $this->security->xss_clean($headers[$index])
: $headers[$index];
}

// --------------------------------------------------------------------

/**
* Is AJAX request?
*
* Test to see if a request contains the HTTP_X_REQUESTED_WITH header.
*
* @return bool
*/
public function is_ajax_request()
{
return ( ! empty($_SERVER['HTTP_X_REQUESTED_WITH']) && strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) === 'xmlhttprequest');
}

// --------------------------------------------------------------------

/**
* Is CLI request?
*
* Test to see if a request was made from the command line.
*
* @deprecated 3.0.0 Use is_cli() instead
* @return bool
*/
public function is_cli_request()
{
return is_cli();
}

// --------------------------------------------------------------------

/**
* Get Request Method
*
* Return the request method
*
* @param bool $upper Whether to return in upper or lower case
* (default: FALSE)
* @return string
*/
public function method($upper = FALSE)
{
return ($upper)
? strtoupper($this->server('REQUEST_METHOD'))
: strtolower($this->server('REQUEST_METHOD'));
}

// ------------------------------------------------------------------------

/**
* Magic __get()
*
* Allows read access to protected properties
*
* @param string $name
* @return mixed
*/
public function __get($name)
{
if ($name === 'raw_input_stream')
{
isset($this->_raw_input_stream) OR $this->_raw_input_stream = file_get_contents('php://input');
return $this->_raw_input_stream;
}
elseif ($name === 'ip_address')
{
return $this->ip_address;
}
}

}