<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2019, 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. (https://ellislab.com/)
 * @copyright	Copyright (c) 2014 - 2019, British Columbia Institute of Technology (https://bcit.ca/)
 * @license	https://opensource.org/licenses/MIT	MIT License
 * @link	https://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		https://codeigniter.com/userguide3/libraries/input.html
 */
class CI_Input {

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

	/**
	 * CI_Security instance
	 *
	 * Used for the optional $xss_filter parameter that most
	 * getter methods have here.
	 *
	 * @var	CI_Security
	 */
	protected $security;

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

	/**
	 * Class constructor
	 *
	 * Determines whether to globally enable the XSS processing
	 * and whether to allow the $_GET array.
	 *
	 * @return	void
	 */
	public function __construct(CI_Security &$security)
	{
		$this->security = $security;
		log_message('info', 'Input Class Initialized');
	}

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

	/**
	 * Fetch from array
	 *
	 * Internal method used to retrieve 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 = FALSE)
	{
		// If $index is NULL, it means that the whole $array is requested
		isset($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 = FALSE)
	{
		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 = FALSE)
	{
		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 = FALSE)
	{
		$output = $this->post($index, $xss_clean);
		return isset($output) ? $output : $this->get($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 = FALSE)
	{
		$output = $this->get($index, $xss_clean);
		return isset($output) ? $output : $this->post($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 = FALSE)
	{
		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 = 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 = NULL, $xss_clean = FALSE)
	{
		// Prior to PHP 5.6, the input stream can only be read once,
		// so we'll need to check if we have already done that first.
		if ( ! is_array($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)
	 * @param	string		$samesite	SameSite attribute
	 * @return	void
	 */
	public function set_cookie($name, $value = '', $expire = 0, $domain = '', $path = '/', $prefix = '', $secure = NULL, $httponly = NULL, $samesite = NULL)
	{
		if (is_array($name))
		{
			// always leave 'name' in last place, as the loop will break otherwise, due to $$item
			foreach (array('value', 'expire', 'domain', 'path', 'prefix', 'secure', 'httponly', 'name', 'samesite') as $item)
			{
				if (isset($name[$item]))
				{
					$$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');
		}

		$secure = ($secure === NULL && config_item('cookie_secure') !== NULL)
			? (bool) config_item('cookie_secure')
			: (bool) $secure;

		$httponly = ($httponly === NULL && config_item('cookie_httponly') !== NULL)
			? (bool) config_item('cookie_httponly')
			: (bool) $httponly;

		if ( ! is_numeric($expire) OR $expire < 0)
		{
			$expire = 1;
		}
		else
		{
			$expire = ($expire > 0) ? time() + $expire : 0;
		}

		isset($samesite) OR $samesite = config_item('cookie_samesite');
		if (isset($samesite))
		{
			$samesite = ucfirst(strtolower($samesite));
			in_array($samesite, array('Lax', 'Strict', 'None'), TRUE) OR $samesite = 'Lax';
		}
		else
		{
			$samesite = 'Lax';
		}

		if ($samesite === 'None' && ! $secure)
		{
			log_message('error', $name.' cookie sent with SameSite=None, but without Secure attribute.');
		}

		$cookie_header = 'Set-Cookie: '.$prefix.$name.'='.rawurlencode($value);
		$cookie_header .= ($expire === 0 ? '' : '; expires='.gmdate('D, d-M-Y H:i:s T', $expire));
		$cookie_header .= '; path='.$path.($domain !== '' ? '; domain='.$domain : '');
		$cookie_header .= ($secure ? '; secure' : '').($httponly ? '; HttpOnly' : '').'; SameSite='.$samesite;
		header($cookie_header);
	}

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

	/**
	 * 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, ':')), $netaddr));
						for ($j = 0; $j < 8; $j++)
						{
							$netaddr[$j] = intval($netaddr[$j], 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
	 *
	 * @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
	 *
	 * @return	string|null	User Agent string or NULL if it doesn't exist
	 */
	public function user_agent($xss_clean = FALSE)
	{
		return $this->_fetch_from_array($_SERVER, 'HTTP_USER_AGENT', $xss_clean);
	}

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

	/**
	 * Request Headers
	 *
	 * @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 $this->_fetch_from_array($this->headers, NULL, $xss_clean);
		}

		// In Apache, you can simply call apache_request_headers()
		if (function_exists('apache_request_headers'))
		{
			$this->headers = apache_request_headers();
		}
		else
		{
			isset($_SERVER['CONTENT_TYPE']) && $this->headers['Content-Type'] = $_SERVER['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] = $_SERVER[$key];
				}
			}
		}

		return $this->_fetch_from_array($this->headers, NULL, $xss_clean);
	}

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

	/**
	 * 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');
	}

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

	/**
	 * 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;
		}
	}

}