cakephp/lib/Cake/Network/CakeRequest.php

<?php
/**
 * CakeRequest
 *
 * PHP 5
 *
 * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
 * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 *
 * Licensed under The MIT License
 * For full copyright and license information, please see the LICENSE.txt
 * Redistributions of files must retain the above copyright notice.
 *
 * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 * @link          http://cakephp.org CakePHP(tm) Project
 * @since         CakePHP(tm) v 2.0
 * @license       MIT License (http://www.opensource.org/licenses/mit-license.php)
 */
App::uses('Hash', 'Utility');

/**
 * A class that helps wrap Request information and particulars about a single request.
 * Provides methods commonly used to introspect on the request headers and request body.
 *
 * Has both an Array and Object interface. You can access framework parameters using indexes:
 *
 * `$request['controller']` or `$request->controller`.
 *
 * @package       Cake.Network
 */
class CakeRequest implements ArrayAccess {

/**
 * Array of parameters parsed from the url.
 *
 * @var array
 */
	public $params = array(
		'plugin' => null,
		'controller' => null,
		'action' => null,
		'named' => array(),
		'pass' => array(),
	);

/**
 * Array of POST data. Will contain form data as well as uploaded files.
 * Inputs prefixed with 'data' will have the data prefix removed. If there is
 * overlap between an input prefixed with data and one without, the 'data' prefixed
 * value will take precedence.
 *
 * @var array
 */
	public $data = array();

/**
 * Array of querystring arguments
 *
 * @var array
 */
	public $query = array();

/**
 * The url string used for the request.
 *
 * @var string
 */
	public $url;

/**
 * Base url path.
 *
 * @var string
 */
	public $base = false;

/**
 * webroot path segment for the request.
 *
 * @var string
 */
	public $webroot = '/';

/**
 * The full address to the current request
 *
 * @var string
 */
	public $here = null;

/**
 * The built in detectors used with `is()` can be modified with `addDetector()`.
 *
 * There are several ways to specify a detector, see CakeRequest::addDetector() for the
 * various formats and ways to define detectors.
 *
 * @var array
 */
	protected $_detectors = array(
		'get' => array('env' => 'REQUEST_METHOD', 'value' => 'GET'),
		'post' => array('env' => 'REQUEST_METHOD', 'value' => 'POST'),
		'put' => array('env' => 'REQUEST_METHOD', 'value' => 'PUT'),
		'delete' => array('env' => 'REQUEST_METHOD', 'value' => 'DELETE'),
		'head' => array('env' => 'REQUEST_METHOD', 'value' => 'HEAD'),
		'options' => array('env' => 'REQUEST_METHOD', 'value' => 'OPTIONS'),
		'ssl' => array('env' => 'HTTPS', 'value' => 1),
		'ajax' => array('env' => 'HTTP_X_REQUESTED_WITH', 'value' => 'XMLHttpRequest'),
		'flash' => array('env' => 'HTTP_USER_AGENT', 'pattern' => '/^(Shockwave|Adobe) Flash/'),
		'mobile' => array('env' => 'HTTP_USER_AGENT', 'options' => array(
			'Android', 'AvantGo', 'BlackBerry', 'DoCoMo', 'Fennec', 'iPod', 'iPhone', 'iPad',
			'J2ME', 'MIDP', 'NetFront', 'Nokia', 'Opera Mini', 'Opera Mobi', 'PalmOS', 'PalmSource',
			'portalmmm', 'Plucker', 'ReqwirelessWeb', 'SonyEricsson', 'Symbian', 'UP\\.Browser',
			'webOS', 'Windows CE', 'Windows Phone OS', 'Xiino'
		)),
		'requested' => array('param' => 'requested', 'value' => 1)
	);

/**
 * Copy of php://input. Since this stream can only be read once in most SAPI's
 * keep a copy of it so users don't need to know about that detail.
 *
 * @var string
 */
	protected $_input = '';

/**
 * Constructor
 *
 * @param string $url Trimmed url string to use. Should not contain the application base path.
 * @param boolean $parseEnvironment Set to false to not auto parse the environment. ie. GET, POST and FILES.
 */
	public function __construct($url = null, $parseEnvironment = true) {
		$this->_base();
		if (empty($url)) {
			$url = $this->_url();
		}
		if ($url[0] === '/') {
			$url = substr($url, 1);
		}
		$this->url = $url;

		if ($parseEnvironment) {
			$this->_processPost();
			$this->_processGet();
			$this->_processFiles();
		}
		$this->here = $this->base . '/' . $this->url;
	}

/**
 * process the post data and set what is there into the object.
 * processed data is available at `$this->data`
 *
 * Will merge POST vars prefixed with `data`, and ones without
 * into a single array. Variables prefixed with `data` will overwrite those without.
 *
 * If you have mixed POST values be careful not to make any top level keys numeric
 * containing arrays. Hash::merge() is used to merge data, and it has possibly
 * unexpected behavior in this situation.
 *
 * @return void
 */
	protected function _processPost() {
		if ($_POST) {
			$this->data = $_POST;
		} elseif (
			($this->is('put') || $this->is('delete')) &&
			strpos(env('CONTENT_TYPE'), 'application/x-www-form-urlencoded') === 0
		) {
				$data = $this->_readInput();
				parse_str($data, $this->data);
		}
		if (ini_get('magic_quotes_gpc') === '1') {
			$this->data = stripslashes_deep($this->data);
		}
		if (env('HTTP_X_HTTP_METHOD_OVERRIDE')) {
			$this->data['_method'] = env('HTTP_X_HTTP_METHOD_OVERRIDE');
		}
		$isArray = is_array($this->data);
		if ($isArray && isset($this->data['_method'])) {
			if (!empty($_SERVER)) {
				$_SERVER['REQUEST_METHOD'] = $this->data['_method'];
			} else {
				$_ENV['REQUEST_METHOD'] = $this->data['_method'];
			}
			unset($this->data['_method']);
		}
		if ($isArray && isset($this->data['data'])) {
			$data = $this->data['data'];
			if (count($this->data) <= 1) {
				$this->data = $data;
			} else {
				unset($this->data['data']);
				$this->data = Hash::merge($this->data, $data);
			}
		}
	}

/**
 * Process the GET parameters and move things into the object.
 *
 * @return void
 */
	protected function _processGet() {
		if (ini_get('magic_quotes_gpc') === '1') {
			$query = stripslashes_deep($_GET);
		} else {
			$query = $_GET;
		}

		unset($query['/' . str_replace('.', '_', urldecode($this->url))]);
		if (strpos($this->url, '?') !== false) {
			list(, $querystr) = explode('?', $this->url);
			parse_str($querystr, $queryArgs);
			$query += $queryArgs;
		}
		if (isset($this->params['url'])) {
			$query = array_merge($this->params['url'], $query);
		}
		$this->query = $query;
	}

/**
 * Get the request uri. Looks in PATH_INFO first, as this is the exact value we need prepared
 * by PHP. Following that, REQUEST_URI, PHP_SELF, HTTP_X_REWRITE_URL and argv are checked in that order.
 * Each of these server variables have the base path, and query strings stripped off
 *
 * @return string URI The CakePHP request path that is being accessed.
 */
	protected function _url() {
		if (!empty($_SERVER['PATH_INFO'])) {
			return $_SERVER['PATH_INFO'];
		} elseif (isset($_SERVER['REQUEST_URI']) && strpos($_SERVER['REQUEST_URI'], '://') === false) {
			$uri = $_SERVER['REQUEST_URI'];
		} elseif (isset($_SERVER['REQUEST_URI'])) {
			$qPosition = strpos($_SERVER['REQUEST_URI'], '?');
			if ($qPosition !== false && strpos($_SERVER['REQUEST_URI'], '://') > $qPosition) {
				$uri = $_SERVER['REQUEST_URI'];
			} else {
				$uri = substr($_SERVER['REQUEST_URI'], strlen(FULL_BASE_URL));
			}
		} elseif (isset($_SERVER['PHP_SELF']) && isset($_SERVER['SCRIPT_NAME'])) {
			$uri = str_replace($_SERVER['SCRIPT_NAME'], '', $_SERVER['PHP_SELF']);
		} elseif (isset($_SERVER['HTTP_X_REWRITE_URL'])) {
			$uri = $_SERVER['HTTP_X_REWRITE_URL'];
		} elseif ($var = env('argv')) {
			$uri = $var[0];
		}

		$base = $this->base;

		if (strlen($base) > 0 && strpos($uri, $base) === 0) {
			$uri = substr($uri, strlen($base));
		}
		if (strpos($uri, '?') !== false) {
			list($uri) = explode('?', $uri, 2);
		}
		if (empty($uri) || $uri === '/' || $uri === '//' || $uri === '/index.php') {
			return '/';
		}
		return $uri;
	}

/**
 * Returns a base URL and sets the proper webroot
 *
 * @return string Base URL
 */
	protected function _base() {
		$dir = $webroot = null;
		$config = Configure::read('App');
		extract($config);

		if (!isset($base)) {
			$base = $this->base;
		}
		if ($base !== false) {
			$this->webroot = $base . '/';
			return $this->base = $base;
		}

		if (!$baseUrl) {
			$base = dirname(env('PHP_SELF'));

			if ($webroot === 'webroot' && $webroot === basename($base)) {
				$base = dirname($base);
			}
			if ($dir === 'app' && $dir === basename($base)) {
				$base = dirname($base);
			}

			if ($base === DS || $base === '.') {
				$base = '';
			}

			$this->webroot = $base . '/';
			return $this->base = $base;
		}

		$file = '/' . basename($baseUrl);
		$base = dirname($baseUrl);

		if ($base === DS || $base === '.') {
			$base = '';
		}
		$this->webroot = $base . '/';

		$docRoot = env('DOCUMENT_ROOT');
		$docRootContainsWebroot = strpos($docRoot, $dir . DS . $webroot);

		if (!empty($base) || !$docRootContainsWebroot) {
			if (strpos($this->webroot, '/' . $dir . '/') === false) {
				$this->webroot .= $dir . '/';
			}
			if (strpos($this->webroot, '/' . $webroot . '/') === false) {
				$this->webroot .= $webroot . '/';
			}
		}
		return $this->base = $base . $file;
	}

/**
 * Process $_FILES and move things into the object.
 *
 * @return void
 */
	protected function _processFiles() {
		if (isset($_FILES) && is_array($_FILES)) {
			foreach ($_FILES as $name => $data) {
				if ($name !== 'data') {
					$this->params['form'][$name] = $data;
				}
			}
		}

		if (isset($_FILES['data'])) {
			foreach ($_FILES['data'] as $key => $data) {
				$this->_processFileData('', $data, $key);
			}
		}
	}

/**
 * Recursively walks the FILES array restructuring the data
 * into something sane and useable.
 *
 * @param string $path The dot separated path to insert $data into.
 * @param array $data The data to traverse/insert.
 * @param string $field The terminal field name, which is the top level key in $_FILES.
 * @return void
 */
	protected function _processFileData($path, $data, $field) {
		foreach ($data as $key => $fields) {
			$newPath = $key;
			if (!empty($path)) {
				$newPath = $path . '.' . $key;
			}
			if (is_array($fields)) {
				$this->_processFileData($newPath, $fields, $field);
			} else {
				$newPath .= '.' . $field;
				$this->data = Hash::insert($this->data, $newPath, $fields);
			}
		}
	}

/**
 * Get the IP the client is using, or says they are using.
 *
 * @param boolean $safe Use safe = false when you think the user might manipulate their HTTP_CLIENT_IP
 *   header. Setting $safe = false will will also look at HTTP_X_FORWARDED_FOR
 * @return string The client IP.
 */
	public function clientIp($safe = true) {
		if (!$safe && env('HTTP_X_FORWARDED_FOR')) {
			$ipaddr = preg_replace('/(?:,.*)/', '', env('HTTP_X_FORWARDED_FOR'));
		} else {
			if (env('HTTP_CLIENT_IP')) {
				$ipaddr = env('HTTP_CLIENT_IP');
			} else {
				$ipaddr = env('REMOTE_ADDR');
			}
		}

		if (env('HTTP_CLIENTADDRESS')) {
			$tmpipaddr = env('HTTP_CLIENTADDRESS');

			if (!empty($tmpipaddr)) {
				$ipaddr = preg_replace('/(?:,.*)/', '', $tmpipaddr);
			}
		}
		return trim($ipaddr);
	}

/**
 * Returns the referer that referred this request.
 *
 * @param boolean $local Attempt to return a local address. Local addresses do not contain hostnames.
 * @return string The referring address for this request.
 */
	public function referer($local = false) {
		$ref = env('HTTP_REFERER');
		$forwarded = env('HTTP_X_FORWARDED_HOST');
		if ($forwarded) {
			$ref = $forwarded;
		}

		$base = '';
		if (defined('FULL_BASE_URL')) {
			$base = FULL_BASE_URL . $this->webroot;
		}
		if (!empty($ref) && !empty($base)) {
			if ($local && strpos($ref, $base) === 0) {
				$ref = substr($ref, strlen($base));
				if ($ref[0] !== '/') {
					$ref = '/' . $ref;
				}
				return $ref;
			} elseif (!$local) {
				return $ref;
			}
		}
		return '/';
	}

/**
 * Missing method handler, handles wrapping older style isAjax() type methods
 *
 * @param string $name The method called
 * @param array $params Array of parameters for the method call
 * @return mixed
 * @throws CakeException when an invalid method is called.
 */
	public function __call($name, $params) {
		if (strpos($name, 'is') === 0) {
			$type = strtolower(substr($name, 2));
			return $this->is($type);
		}
		throw new CakeException(__d('cake_dev', 'Method %s does not exist', $name));
	}

/**
 * Magic get method allows access to parsed routing parameters directly on the object.
 *
 * Allows access to `$this->params['controller']` via `$this->controller`
 *
 * @param string $name The property being accessed.
 * @return mixed Either the value of the parameter or null.
 */
	public function __get($name) {
		if (isset($this->params[$name])) {
			return $this->params[$name];
		}
		return null;
	}

/**
 * Magic isset method allows isset/empty checks
 * on routing parameters.
 *
 * @param string $name The property being accessed.
 * @return bool Existence
 */
	public function __isset($name) {
		return isset($this->params[$name]);
	}

/**
 * Check whether or not a Request is a certain type.
 *
 * Uses the built in detection rules as well as additional rules
 * defined with CakeRequest::addDetector(). Any detector can be called
 * as `is($type)` or `is$Type()`.
 *
 * @param string|array $type The type of request you want to check. If an array
 *   this method will return true if the request matches any type.
 * @return boolean Whether or not the request is the type you are checking.
 */
	public function is($type) {
		if (is_array($type)) {
			$result = array_map(array($this, 'is'), $type);
			return count(array_filter($result)) > 0;
		}
		$type = strtolower($type);
		if (!isset($this->_detectors[$type])) {
			return false;
		}
		$detect = $this->_detectors[$type];
		if (isset($detect['env'])) {
			if (isset($detect['value'])) {
				return env($detect['env']) == $detect['value'];
			}
			if (isset($detect['pattern'])) {
				return (bool)preg_match($detect['pattern'], env($detect['env']));
			}
			if (isset($detect['options'])) {
				$pattern = '/' . implode('|', $detect['options']) . '/i';
				return (bool)preg_match($pattern, env($detect['env']));
			}
		}
		if (isset($detect['param'])) {
			$key = $detect['param'];
			$value = $detect['value'];
			return isset($this->params[$key]) ? $this->params[$key] == $value : false;
		}
		if (isset($detect['callback']) && is_callable($detect['callback'])) {
			return call_user_func($detect['callback'], $this);
		}
		return false;
	}

/**
 * Add a new detector to the list of detectors that a request can use.
 * There are several different formats and types of detectors that can be set.
 *
 * ### Environment value comparison
 *
 * An environment value comparison, compares a value fetched from `env()` to a known value
 * the environment value is equality checked against the provided value.
 *
 * e.g `addDetector('post', array('env' => 'REQUEST_METHOD', 'value' => 'POST'))`
 *
 * ### Pattern value comparison
 *
 * Pattern value comparison allows you to compare a value fetched from `env()` to a regular expression.
 *
 * e.g `addDetector('iphone', array('env' => 'HTTP_USER_AGENT', 'pattern' => '/iPhone/i'));`
 *
 * ### Option based comparison
 *
 * Option based comparisons use a list of options to create a regular expression. Subsequent calls
 * to add an already defined options detector will merge the options.
 *
 * e.g `addDetector('mobile', array('env' => 'HTTP_USER_AGENT', 'options' => array('Fennec')));`
 *
 * ### Callback detectors
 *
 * Callback detectors allow you to provide a 'callback' type to handle the check. The callback will
 * receive the request object as its only parameter.
 *
 * e.g `addDetector('custom', array('callback' => array('SomeClass', 'somemethod')));`
 *
 * ### Request parameter detectors
 *
 * Allows for custom detectors on the request parameters.
 *
 * e.g `addDetector('post', array('param' => 'requested', 'value' => 1)`
 *
 * @param string $name The name of the detector.
 * @param array $options  The options for the detector definition. See above.
 * @return void
 */
	public function addDetector($name, $options) {
		$name = strtolower($name);
		if (isset($this->_detectors[$name]) && isset($options['options'])) {
			$options = Hash::merge($this->_detectors[$name], $options);
		}
		$this->_detectors[$name] = $options;
	}

/**
 * Add parameters to the request's parsed parameter set. This will overwrite any existing parameters.
 * This modifies the parameters available through `$request->params`.
 *
 * @param array $params Array of parameters to merge in
 * @return The current object, you can chain this method.
 */
	public function addParams($params) {
		$this->params = array_merge($this->params, (array)$params);
		return $this;
	}

/**
 * Add paths to the requests' paths vars. This will overwrite any existing paths.
 * Provides an easy way to modify, here, webroot and base.
 *
 * @param array $paths Array of paths to merge in
 * @return CakeRequest the current object, you can chain this method.
 */
	public function addPaths($paths) {
		foreach (array('webroot', 'here', 'base') as $element) {
			if (isset($paths[$element])) {
				$this->{$element} = $paths[$element];
			}
		}
		return $this;
	}

/**
 * Get the value of the current requests url. Will include named parameters and querystring arguments.
 *
 * @param boolean $base Include the base path, set to false to trim the base path off.
 * @return string the current request url including query string args.
 */
	public function here($base = true) {
		$url = $this->here;
		if (!empty($this->query)) {
			$url .= '?' . http_build_query($this->query, null, '&');
		}
		if (!$base) {
			$url = preg_replace('/^' . preg_quote($this->base, '/') . '/', '', $url, 1);
		}
		return $url;
	}

/**
 * Read an HTTP header from the Request information.
 *
 * @param string $name Name of the header you want.
 * @return mixed Either false on no header being set or the value of the header.
 */
	public static function header($name) {
		$name = 'HTTP_' . strtoupper(str_replace('-', '_', $name));
		if (!empty($_SERVER[$name])) {
			return $_SERVER[$name];
		}
		return false;
	}

/**
 * Get the HTTP method used for this request.
 * There are a few ways to specify a method.
 *
 * - If your client supports it you can use native HTTP methods.
 * - You can set the HTTP-X-Method-Override header.
 * - You can submit an input with the name `_method`
 *
 * Any of these 3 approaches can be used to set the HTTP method used
 * by CakePHP internally, and will effect the result of this method.
 *
 * @return string The name of the HTTP method used.
 */
	public function method() {
		return env('REQUEST_METHOD');
	}

/**
 * Get the host that the request was handled on.
 *
 * @return string
 */
	public function host() {
		return env('HTTP_HOST');
	}

/**
 * Get the domain name and include $tldLength segments of the tld.
 *
 * @param integer $tldLength Number of segments your tld contains. For example: `example.com` contains 1 tld.
 *   While `example.co.uk` contains 2.
 * @return string Domain name without subdomains.
 */
	public function domain($tldLength = 1) {
		$segments = explode('.', $this->host());
		$domain = array_slice($segments, -1 * ($tldLength + 1));
		return implode('.', $domain);
	}

/**
 * Get the subdomains for a host.
 *
 * @param integer $tldLength Number of segments your tld contains. For example: `example.com` contains 1 tld.
 *   While `example.co.uk` contains 2.
 * @return array of subdomains.
 */
	public function subdomains($tldLength = 1) {
		$segments = explode('.', $this->host());
		return array_slice($segments, 0, -1 * ($tldLength + 1));
	}

/**
 * Find out which content types the client accepts or check if they accept a
 * particular type of content.
 *
 * #### Get all types:
 *
 * `$this->request->accepts();`
 *
 * #### Check for a single type:
 *
 * `$this->request->accepts('application/json');`
 *
 * This method will order the returned content types by the preference values indicated
 * by the client.
 *
 * @param string $type The content type to check for. Leave null to get all types a client accepts.
 * @return mixed Either an array of all the types the client accepts or a boolean if they accept the
 *   provided type.
 */
	public function accepts($type = null) {
		$raw = $this->parseAccept();
		$accept = array();
		foreach ($raw as $types) {
			$accept = array_merge($accept, $types);
		}
		if ($type === null) {
			return $accept;
		}
		return in_array($type, $accept);
	}

/**
 * Parse the HTTP_ACCEPT header and return a sorted array with content types
 * as the keys, and pref values as the values.
 *
 * Generally you want to use CakeRequest::accept() to get a simple list
 * of the accepted content types.
 *
 * @return array An array of prefValue => array(content/types)
 */
	public function parseAccept() {
		return $this->_parseAcceptWithQualifier($this->header('accept'));
	}

/**
 * Get the languages accepted by the client, or check if a specific language is accepted.
 *
 * Get the list of accepted languages:
 *
 * {{{ CakeRequest::acceptLanguage(); }}}
 *
 * Check if a specific language is accepted:
 *
 * {{{ CakeRequest::acceptLanguage('es-es'); }}}
 *
 * @param string $language The language to test.
 * @return If a $language is provided, a boolean. Otherwise the array of accepted languages.
 */
	public static function acceptLanguage($language = null) {
		$raw = self::_parseAcceptWithQualifier(self::header('Accept-Language'));
		$accept = array();
		foreach ($raw as $languages) {
			foreach ($languages as &$lang) {
				if (strpos($lang, '_')) {
					$lang = str_replace('_', '-', $lang);
				}
				$lang = strtolower($lang);
			}
			$accept = array_merge($accept, $languages);
		}
		if ($language === null) {
			return $accept;
		}
		return in_array(strtolower($language), $accept);
	}

/**
 * Parse Accept* headers with qualifier options
 *
 * @param string $header
 * @return array
 */
	protected static function _parseAcceptWithQualifier($header) {
		$accept = array();
		$header = explode(',', $header);
		foreach (array_filter($header) as $value) {
			$prefPos = strpos($value, ';');
			if ($prefPos !== false) {
				$prefValue = substr($value, strpos($value, '=') + 1);
				$value = trim(substr($value, 0, $prefPos));
			} else {
				$prefValue = '1.0';
				$value = trim($value);
			}
			if (!isset($accept[$prefValue])) {
				$accept[$prefValue] = array();
			}
			if ($prefValue) {
				$accept[$prefValue][] = $value;
			}
		}
		krsort($accept);
		return $accept;
	}

/**
 * Provides a read accessor for `$this->query`. Allows you
 * to use a syntax similar to `CakeSession` for reading url query data.
 *
 * @param string $name Query string variable name
 * @return mixed The value being read
 */
	public function query($name) {
		return Hash::get($this->query, $name);
	}

/**
 * Provides a read/write accessor for `$this->data`. Allows you
 * to use a syntax similar to `CakeSession` for reading post data.
 *
 * ## Reading values.
 *
 * `$request->data('Post.title');`
 *
 * When reading values you will get `null` for keys/values that do not exist.
 *
 * ## Writing values
 *
 * `$request->data('Post.title', 'New post!');`
 *
 * You can write to any value, even paths/keys that do not exist, and the arrays
 * will be created for you.
 *
 * @param string $name,... Dot separated name of the value to read/write
 * @return mixed Either the value being read, or this so you can chain consecutive writes.
 */
	public function data($name) {
		$args = func_get_args();
		if (count($args) == 2) {
			$this->data = Hash::insert($this->data, $name, $args[1]);
			return $this;
		}
		return Hash::get($this->data, $name);
	}

/**
 * Safely access the values in $this->params.
 *
 * @param string $name The name of the parameter to get.
 * @return mixed The value of the provided parameter. Will
 *   return false if the parameter doesn't exist or is falsey.
 */
	public function param($name) {
		if (!isset($this->params[$name])) {
			return false;
		}
		return $this->params[$name];
	}

/**
 * Read data from `php://input`. Useful when interacting with XML or JSON
 * request body content.
 *
 * Getting input with a decoding function:
 *
 * `$this->request->input('json_decode');`
 *
 * Getting input using a decoding function, and additional params:
 *
 * `$this->request->input('Xml::build', array('return' => 'DOMDocument'));`
 *
 * Any additional parameters are applied to the callback in the order they are given.
 *
 * @param string $callback A decoding callback that will convert the string data to another
 *     representation. Leave empty to access the raw input data. You can also
 *     supply additional parameters for the decoding callback using var args, see above.
 * @return The decoded/processed request data.
 */
	public function input($callback = null) {
		$input = $this->_readInput();
		$args = func_get_args();
		if (!empty($args)) {
			$callback = array_shift($args);
			array_unshift($args, $input);
			return call_user_func_array($callback, $args);
		}
		return $input;
	}

/**
 * Only allow certain HTTP request methods, if the request method does not match
 * a 405 error will be shown and the required "Allow" response header will be set.
 *
 * Example:
 *
 * $this->request->onlyAllow('post', 'delete');
 * or
 * $this->request->onlyAllow(array('post', 'delete'));
 *
 * If the request would be GET, response header "Allow: POST, DELETE" will be set
 * and a 405 error will be returned
 *
 * @param string|array $methods Allowed HTTP request methods
 * @return boolean true
 * @throws MethodNotAllowedException
 */
	public function onlyAllow($methods) {
		if (!is_array($methods)) {
			$methods = func_get_args();
		}
		foreach ($methods as $method) {
			if ($this->is($method)) {
				return true;
			}
		}
		$allowed = strtoupper(implode(', ', $methods));
		$e = new MethodNotAllowedException();
		$e->responseHeader('Allow', $allowed);
		throw $e;
	}

/**
 * Read data from php://input, mocked in tests.
 *
 * @return string contents of php://input
 */
	protected function _readInput() {
		if (empty($this->_input)) {
			$fh = fopen('php://input', 'r');
			$content = stream_get_contents($fh);
			fclose($fh);
			$this->_input = $content;
		}
		return $this->_input;
	}

/**
 * Array access read implementation
 *
 * @param string $name Name of the key being accessed.
 * @return mixed
 */
	public function offsetGet($name) {
		if (isset($this->params[$name])) {
			return $this->params[$name];
		}
		if ($name === 'url') {
			return $this->query;
		}
		if ($name === 'data') {
			return $this->data;
		}
		return null;
	}

/**
 * Array access write implementation
 *
 * @param string $name Name of the key being written
 * @param mixed $value The value being written.
 * @return void
 */
	public function offsetSet($name, $value) {
		$this->params[$name] = $value;
	}

/**
 * Array access isset() implementation
 *
 * @param string $name thing to check.
 * @return boolean
 */
	public function offsetExists($name) {
		return isset($this->params[$name]);
	}

/**
 * Array access unset() implementation
 *
 * @param string $name Name to unset.
 * @return void
 */
	public function offsetUnset($name) {
		unset($this->params[$name]);
	}

}