Merge branch 'refs/heads/develop' into feature/form_error_msgs

Conflicts:
	system/language/english/form_validation_lang.php
	user_guide_src/source/libraries/form_validation.rst

Signed-off-by: Eric Roberts <eric@cryode.com>

1 files changed, 387 insertions, 208 deletions

diff --git a/system/core/Input.php b/system/core/Input.php
index 6e6885992..a3ad14e24 100755..100644
--- a/system/core/Input.php
+++ b/system/core/Input.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * Input Class
@@ -41,53 +42,80 @@ class CI_Input {
 	/**
 	 * IP address of the current user
 	 *
-	 * @var string
+	 * @var	string
 	 */
-	public $ip_address				= FALSE;
+	public $ip_address = FALSE;
+
 	/**
-	 * user agent (web browser) being used by the current user
+	 * User agent strin
 	 *
-	 * @var string
+	 * @var	string
 	 */
-	public $user_agent				= FALSE;
+	public $user_agent = FALSE;
+
 	/**
-	 * If FALSE, then $_GET will be set to an empty array
+	 * Allow GET array flag
+	 *
+	 * If set to FALSE, then $_GET will be set to an empty array.
 	 *
-	 * @var bool
+	 * @var	bool
 	 */
-	protected $_allow_get_array		= TRUE;
+	protected $_allow_get_array = TRUE;
+
 	/**
-	 * If TRUE, then newlines are standardized
+	 * Standartize new lines flag
+	 *
+	 * If set to TRUE, then newlines are standardized.
 	 *
-	 * @var bool
+	 * @var	bool
 	 */
-	protected $_standardize_newlines	= TRUE;
+	protected $_standardize_newlines = TRUE;
+
 	/**
-	 * Determines whether the XSS filter is always active when GET, POST or COOKIE data is encountered
-	 * Set automatically based on config setting
+	 * 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
+	 * @var	bool
 	 */
-	protected $_enable_xss			= FALSE;
+	protected $_enable_xss = FALSE;
+
 	/**
+	 * Enable CSRF flag
+	 *
 	 * Enables a CSRF cookie token to be set.
-	 * Set automatically based on config setting
+	 * Set automatically based on config setting.
 	 *
-	 * @var bool
+	 * @var	bool
 	 */
-	protected $_enable_csrf			= FALSE;
+	protected $_enable_csrf = FALSE;
+
 	/**
 	 * List of all HTTP request headers
 	 *
 	 * @var array
 	 */
-	protected $headers			= array();
+	protected $headers = array();
 
 	/**
-	 * Constructor
+	 * Input stream data
 	 *
-	 * Sets whether to globally enable the XSS processing
-	 * and whether to allow the $_GET array
+	 * Parsed from php://input at runtime
+	 *
+	 * @see	CI_Input::input_stream()
+	 * @var	array
+	 */
+	protected $_input_stream = NULL;
+
+	/**
+	 * Class constructor
+	 *
+	 * Determines whether to globally enable the XSS processing
+	 * and whether to allow the $_GET array.
+	 *
+	 * @return	void
 	 */
 	public function __construct()
 	{
@@ -116,18 +144,18 @@ class CI_Input {
 	/**
 	 * Fetch from array
 	 *
-	 * This is a helper function to retrieve values from global arrays
+	 * Internal method used to retrieve values from global arrays.
 	 *
-	 * @param	array
-	 * @param	string
-	 * @param	bool
-	 * @return	string
+	 * @param	array	&$array		$_GET, $_POST, $_COOKIE, $_SERVER, etc.
+	 * @param	string	$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 = '', $xss_clean = FALSE)
 	{
 		if ( ! isset($array[$index]))
 		{
-			return FALSE;
+			return NULL;
 		}
 
 		if ($xss_clean === TRUE)
@@ -141,17 +169,22 @@ class CI_Input {
 	// --------------------------------------------------------------------
 
 	/**
-	* Fetch an item from the GET array
-	*
-	* @param	string
-	* @param	bool
-	* @return	string
-	*/
+	 * Fetch an item from the GET array
+	 *
+	 * @param	string	$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, $xss_clean = FALSE)
 	{
 		// Check if a field has been provided
-		if ($index === NULL && ! empty($_GET))
+		if ($index === NULL)
 		{
+			if (empty($_GET))
+			{
+				return array();
+			}
+
 			$get = array();
 
 			// loop through the full _GET array
@@ -168,17 +201,22 @@ class CI_Input {
 	// --------------------------------------------------------------------
 
 	/**
-	* Fetch an item from the POST array
-	*
-	* @param	string
-	* @param	bool
-	* @return	string
-	*/
+	 * Fetch an item from the POST array
+	 *
+	 * @param	string	$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, $xss_clean = FALSE)
 	{
 		// Check if a field has been provided
-		if ($index === NULL && ! empty($_POST))
+		if ($index === NULL)
 		{
+			if (empty($_POST))
+			{
+				return array();
+			}
+
 			$post = array();
 
 			// Loop through the full _POST array and return it
@@ -192,16 +230,15 @@ class CI_Input {
 		return $this->_fetch_from_array($_POST, $index, $xss_clean);
 	}
 
-
 	// --------------------------------------------------------------------
 
 	/**
-	* Fetch an item from either the GET array or the POST
-	*
-	* @param	string	The index key
-	* @param	bool	XSS cleaning
-	* @return	string
-	*/
+	 * 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	$xss_clean	Whether to apply XSS filtering
+	 * @return	mixed
+	 */
 	public function get_post($index = '', $xss_clean = FALSE)
 	{
 		return isset($_POST[$index])
@@ -212,35 +249,80 @@ class CI_Input {
 	// --------------------------------------------------------------------
 
 	/**
-	* Fetch an item from the COOKIE array
-	*
-	* @param	string
-	* @param	bool
-	* @return	string
-	*/
+	 * Fetch an item from the COOKIE array
+	 *
+	 * @param	string	$index		Index for item to be fetched from $_COOKIE
+	 * @param	bool	$xss_clean	Whether to apply XSS filtering
+	 * @return	mixed
+	 */
 	public function cookie($index = '', $xss_clean = FALSE)
 	{
 		return $this->_fetch_from_array($_COOKIE, $index, $xss_clean);
 	}
 
+	// --------------------------------------------------------------------
+
+	/**
+	 * Fetch an item from the SERVER array
+	 *
+	 * @param	string	$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 = FALSE)
+	{
+		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 = '', $xss_clean = FALSE)
+	{
+		// The input stream can only be read once, so we'll need to check
+		// if we have already done that first.
+		if (is_array($this->_input_stream))
+		{
+			return $this->_fetch_from_array($this->_input_stream, $index, $xss_clean);
+		}
+
+		// Parse the input stream in our cache var
+		parse_str(file_get_contents('php://input'), $this->_input_stream);
+		if ( ! is_array($this->_input_stream))
+		{
+			$this->_input_stream = array();
+			return NULL;
+		}
+
+		return $this->_fetch_from_array($this->_input_stream, $index, $xss_clean);
+	}
+
 	// ------------------------------------------------------------------------
 
 	/**
-	* Set cookie
-	*
-	* Accepts seven parameters, or you can submit an associative
-	* array in the first parameter containing all the values.
-	*
-	* @param	mixed
-	* @param	string	the value of the cookie
-	* @param	string	the number of seconds until expiration
-	* @param	string	the cookie domain.  Usually:  .yourdomain.com
-	* @param	string	the cookie path
-	* @param	string	the cookie prefix
-	* @param	bool	true makes the cookie secure
-	* @param	bool	true makes the cookie accessible via http(s) only (no javascript)
-	* @return	void
-	*/
+	 * 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))
@@ -255,23 +337,27 @@ class CI_Input {
 			}
 		}
 
-		if ($prefix == '' && config_item('cookie_prefix') != '')
+		if ($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') !== '/')
+
+		if ($path === '/' && config_item('cookie_path') !== '/')
 		{
 			$path = config_item('cookie_path');
 		}
-		if ($secure == FALSE && config_item('cookie_secure') != FALSE)
+
+		if ($secure === FALSE && config_item('cookie_secure') !== FALSE)
 		{
 			$secure = config_item('cookie_secure');
 		}
-		if ($httponly == FALSE && config_item('cookie_httponly') != FALSE)
+
+		if ($httponly === FALSE && config_item('cookie_httponly') !== FALSE)
 		{
 			$httponly = config_item('cookie_httponly');
 		}
@@ -291,24 +377,12 @@ class CI_Input {
 	// --------------------------------------------------------------------
 
 	/**
-	* Fetch an item from the SERVER array
-	*
-	* @param	string
-	* @param	bool
-	* @return	string
-	*/
-	public function server($index = '', $xss_clean = FALSE)
-	{
-		return $this->_fetch_from_array($_SERVER, $index, $xss_clean);
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
-	* Fetch the IP Address
-	*
-	* @return	string
-	*/
+	 * Fetch the IP Address
+	 *
+	 * Determines and validates the visitor's IP address.
+	 *
+	 * @return	string	IP address
+	 */
 	public function ip_address()
 	{
 		if ($this->ip_address !== FALSE)
@@ -316,39 +390,117 @@ class CI_Input {
 			return $this->ip_address;
 		}
 
-		if (config_item('proxy_ips') != '' && $this->server('HTTP_X_FORWARDED_FOR') && $this->server('REMOTE_ADDR'))
+		$proxy_ips = config_item('proxy_ips');
+		if ( ! empty($proxy_ips) && ! is_array($proxy_ips))
 		{
-			$proxies = preg_split('/[\s,]/', config_item('proxy_ips'), -1, PREG_SPLIT_NO_EMPTY);
-			$proxies = is_array($proxies) ? $proxies : array($proxies);
-
-			$this->ip_address = in_array($_SERVER['REMOTE_ADDR'], $proxies) ? $_SERVER['HTTP_X_FORWARDED_FOR'] : $_SERVER['REMOTE_ADDR'];
-		}
-		elseif ( ! $this->server('HTTP_CLIENT_IP') && $this->server('REMOTE_ADDR'))
-		{
-			$this->ip_address = $_SERVER['REMOTE_ADDR'];
-		}
-		elseif ($this->server('REMOTE_ADDR') && $this->server('HTTP_CLIENT_IP'))
-		{
-			$this->ip_address = $_SERVER['HTTP_CLIENT_IP'];
-		}
-		elseif ($this->server('HTTP_CLIENT_IP'))
-		{
-			$this->ip_address = $_SERVER['HTTP_CLIENT_IP'];
-		}
-		elseif ($this->server('HTTP_X_FORWARDED_FOR'))
-		{
-			$this->ip_address = $_SERVER['HTTP_X_FORWARDED_FOR'];
+			$proxy_ips = explode(',', str_replace(' ', '', $proxy_ips));
 		}
 
-		if ($this->ip_address === FALSE)
-		{
-			return $this->ip_address = '0.0.0.0';
-		}
+		$this->ip_address = $this->server('REMOTE_ADDR');
 
-		if (strpos($this->ip_address, ',') !== FALSE)
+		if ($proxy_ips)
 		{
-			$x = explode(',', $this->ip_address);
-			$this->ip_address = trim(end($x));
+			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, ':')),
+									$this->ip_address
+								)
+							);
+
+							for ($i = 0; $i < 8; $i++)
+							{
+								$ip[$i] = intval($ip[$i], 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))
@@ -362,25 +514,37 @@ class CI_Input {
 	// --------------------------------------------------------------------
 
 	/**
-	* Validate IP Address
-	*
-	* Updated version suggested by Geert De Deckere
-	*
-	* @param	string
-	* @return	bool
-	*/
-	public function valid_ip($ip)
+	 * Validate IP Address
+	 *
+	 * @param	string	$ip	IP address
+	 * @param	string	$which	IP protocol: 'ipv4' or 'ipv6'
+	 * @return	bool
+	 */
+	public function valid_ip($ip, $which = '')
 	{
-		return (bool) filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4);
+		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);
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	* User Agent
-	*
-	* @return	string
-	*/
+	 * Fetch User Agent string
+	 *
+	 * @return	string|null	User Agent string or NULL if it doesn't exist
+	 */
 	public function user_agent()
 	{
 		if ($this->user_agent !== FALSE)
@@ -388,58 +552,75 @@ class CI_Input {
 			return $this->user_agent;
 		}
 
-		return $this->user_agent = isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : FALSE;
+		return $this->user_agent = isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : NULL;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	* Sanitize Globals
-	*
-	* This function does the following:
-	*
-	* - Unsets $_GET data (if query strings are not enabled)
-	* - Unsets all globals if register_globals is enabled
-	* - Standardizes newline characters to \n
-	*
-	* @return	void
-	*/
+	 * Sanitize Globals
+	 *
+	 * Internal method serving for the following purposes:
+	 *
+	 *	- Unsets $_GET data (if query strings are not enabled)
+	 *	- Unsets all globals if register_globals is enabled
+	 *	- Cleans POST, COOKIE and SERVER data
+	 * 	- Standardizes newline characters to PHP_EOL
+	 *
+	 * @return	void
+	 */
 	protected function _sanitize_globals()
 	{
 		// It would be "wrong" to unset any of these GLOBALS.
-		$protected = array('_SERVER', '_GET', '_POST', '_FILES', '_REQUEST',
-					'_SESSION', '_ENV', 'GLOBALS', 'HTTP_RAW_POST_DATA',
-					'system_folder', 'application_folder', 'BM', 'EXT',
-					'CFG', 'URI', 'RTR', 'OUT', 'IN'
-				);
-
-		// Unset globals for securiy.
+		$protected = array(
+			'_SERVER',
+			'_GET',
+			'_POST',
+			'_FILES',
+			'_REQUEST',
+			'_SESSION',
+			'_ENV',
+			'GLOBALS',
+			'HTTP_RAW_POST_DATA',
+			'system_folder',
+			'application_folder',
+			'BM',
+			'EXT',
+			'CFG',
+			'URI',
+			'RTR',
+			'OUT',
+			'IN'
+		);
+
+		// Unset globals for security.
 		// This is effectively the same as register_globals = off
-		foreach (array($_GET, $_POST, $_COOKIE) as $global)
+		// PHP 5.4 no longer has the register_globals functionality.
+		if ( ! is_php('5.4'))
 		{
-			if ( ! is_array($global))
+			foreach (array($_GET, $_POST, $_COOKIE) as $global)
 			{
-				if ( ! in_array($global, $protected))
+				if (is_array($global))
 				{
-					global $$global;
-					$$global = NULL;
-				}
-			}
-			else
-			{
-				foreach ($global as $key => $val)
-				{
-					if ( ! in_array($key, $protected))
+					foreach ($global as $key => $val)
 					{
-						global $$key;
-						$$key = NULL;
+						if ( ! in_array($key, $protected))
+						{
+							global $$key;
+							$$key = NULL;
+						}
 					}
 				}
+				elseif ( ! in_array($global, $protected))
+				{
+					global $$global;
+					$$global = NULL;
+				}
 			}
 		}
 
 		// Is $_GET data allowed? If not we'll set the $_GET to an empty array
-		if ($this->_allow_get_array == FALSE)
+		if ($this->_allow_get_array === FALSE)
 		{
 			$_GET = array();
 		}
@@ -482,7 +663,7 @@ class CI_Input {
 		$_SERVER['PHP_SELF'] = strip_tags($_SERVER['PHP_SELF']);
 
 		// CSRF Protection check
-		if ($this->_enable_csrf == TRUE)
+		if ($this->_enable_csrf === TRUE && ! $this->is_cli_request())
 		{
 			$this->security->csrf_verify();
 		}
@@ -493,22 +674,22 @@ class CI_Input {
 	// --------------------------------------------------------------------
 
 	/**
-	* Clean Input Data
-	*
-	* This is a helper function. It escapes data and
-	* standardizes newline characters to \n
-	*
-	* @param	string
-	* @return	string
-	*/
+	 * 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))
 		{
 			$new_array = array();
-			foreach ($str as $key => $val)
+			foreach (array_keys($str) as $key)
 			{
-				$new_array[$this->_clean_input_keys($key)] = $this->_clean_input_data($val);
+				$new_array[$this->_clean_input_keys($key)] = $this->_clean_input_data($str[$key]);
 			}
 			return $new_array;
 		}
@@ -539,7 +720,7 @@ class CI_Input {
 		}
 
 		// Standardize newlines if needed
-		if ($this->_standardize_newlines == TRUE && strpos($str, "\r") !== FALSE)
+		if ($this->_standardize_newlines === TRUE && strpos($str, "\r") !== FALSE)
 		{
 			return str_replace(array("\r\n", "\r", "\r\n\n"), PHP_EOL, $str);
 		}
@@ -550,18 +731,18 @@ class CI_Input {
 	// --------------------------------------------------------------------
 
 	/**
-	* Clean Keys
-	*
-	* This is a helper function. 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
-	* @return	string
-	*/
+	 * 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	$str	Input string
+	 * @return	string
+	 */
 	protected function _clean_input_keys($str)
 	{
-		if ( ! preg_match('/^[a-z0-9:_\/-]+$/i', $str))
+		if ( ! preg_match('/^[a-z0-9:_\/|-]+$/i', $str))
 		{
 			set_status_header(503);
 			exit('Disallowed Key Characters.');
@@ -581,15 +762,12 @@ class CI_Input {
 	/**
 	 * Request Headers
 	 *
-	 * In Apache, you can simply call apache_request_headers(), however for
-	 * people running other webservers the function is undefined.
-	 *
-	 * @param	bool XSS cleaning
+	 * @param	bool	$xss_clean	Whether to apply XSS filtering
 	 * @return	array
 	 */
 	public function request_headers($xss_clean = FALSE)
 	{
-		// Look at Apache go!
+		// In Apache, you can simply call apache_request_headers()
 		if (function_exists('apache_request_headers'))
 		{
 			$headers = apache_request_headers();
@@ -600,9 +778,9 @@ class CI_Input {
 
 			foreach ($_SERVER as $key => $val)
 			{
-				if (strpos($key, 'HTTP_') === 0)
+				if (sscanf($key, 'HTTP_%s', $header) === 1)
 				{
-					$headers[substr($key, 5)] = $this->_fetch_from_array($_SERVER, $key, $xss_clean);
+					$headers[$header] = $this->_fetch_from_array($_SERVER, $key, $xss_clean);
 				}
 			}
 		}
@@ -626,9 +804,9 @@ class CI_Input {
 	 *
 	 * Returns the value of a single member of the headers class member
 	 *
-	 * @param	string	array key for $this->headers
-	 * @param	bool	XSS Clean or not
-	 * @return	mixed	FALSE on failure, string on success
+	 * @param	string		$index		Header name
+	 * @param	bool		$xss_clean	Whether to apply XSS filtering
+	 * @return	string|bool	The requested header on success or FALSE on failure
 	 */
 	public function get_request_header($index, $xss_clean = FALSE)
 	{
@@ -639,7 +817,7 @@ class CI_Input {
 
 		if ( ! isset($this->headers[$index]))
 		{
-			return FALSE;
+			return NULL;
 		}
 
 		return ($xss_clean === TRUE)
@@ -650,9 +828,9 @@ class CI_Input {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Is ajax Request?
+	 * Is AJAX request?
 	 *
-	 * Test to see if a request contains the HTTP_X_REQUESTED_WITH header
+	 * Test to see if a request contains the HTTP_X_REQUESTED_WITH header.
 	 *
 	 * @return 	bool
 	 */
@@ -664,9 +842,9 @@ class CI_Input {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Is cli Request?
+	 * Is CLI request?
 	 *
-	 * Test to see if a request was made from the command line
+	 * Test to see if a request was made from the command line.
 	 *
 	 * @return 	bool
 	 */
@@ -680,10 +858,11 @@ class CI_Input {
 	/**
 	 * Get Request Method
 	 *
-	 * Return the Request Method
+	 * Return the request method
 	 *
-	 * @param	bool	uppercase or lowercase
-	 * @return 	bool
+	 * @param	bool	$upper	Whether to return in upper or lower case
+	 *				(default: FALSE)
+	 * @return 	string
 	 */
 	public function method($upper = FALSE)
 	{
@@ -695,4 +874,4 @@ class CI_Input {
 }
 
 /* End of file Input.php */
-/* Location: ./system/core/Input.php */
+/* Location: ./system/core/Input.php */
\ No newline at end of file