yii2/framework/web/Request.php

<?php
/**
 * Request class file.
 *
 * @link http://www.yiiframework.com/
 * @copyright Copyright &copy; 2008-2012 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\web;

use \yii\base\BadConfigException;

/**
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 */
class Request extends \yii\base\Request
{
	/**
	 * @var boolean whether cookies should be validated to ensure they are not tampered. Defaults to false.
	 */
	public $enableCookieValidation = false;
	/**
	 * @var boolean whether to enable CSRF (Cross-Site Request Forgery) validation. Defaults to false.
	 * By setting this property to true, forms submitted to an Yii Web application must be originated
	 * from the same application. If not, a 400 HTTP exception will be raised.
	 * Note, this feature requires that the user client accepts cookie.
	 * You also need to use {@link CHtml::form} or {@link CHtml::statefulForm} to generate
	 * the needed HTML forms in your pages.
	 * @see http://seclab.stanford.edu/websec/csrf/csrf.pdf
	 */
	public $enableCsrfValidation = false;
	/**
	 * @var string|boolean the name of the POST parameter that is used to indicate if a request is a PUT or DELETE
	 * request tunneled through POST. If false, it means disabling REST request tunneled through POST.
	 * Default to '_method'.
	 * @see getRequestMethod
	 * @see getRestParams
	 */
	public $restPostVar = '_method';
	/**
	 * @var string the name of the token used to prevent CSRF. Defaults to 'YII_CSRF_TOKEN'.
	 * This property is effective only when {@link enableCsrfValidation} is true.
	 */
	public $csrfTokenName = 'YII_CSRF_TOKEN';
	/**
	 * @var array the property values (in name-value pairs) used to initialize the CSRF cookie.
	 * Any property of {@link CHttpCookie} may be initialized.
	 * This property is effective only when {@link enableCsrfValidation} is true.
	 */
	public $csrfCookie;

	private $_cookies;

	/**
	 * Initializes the application component.
	 * This method overrides the parent implementation by preprocessing
	 * the user request data.
	 */
	public function init()
	{
		parent::init();
		$this->normalizeRequest();
	}

	/**
	 * Normalizes the request data.
	 * This method strips off slashes in request data if get_magic_quotes_gpc() returns true.
	 * It also performs CSRF validation if {@link enableCsrfValidation} is true.
	 */
	protected function normalizeRequest()
	{
		if (get_magic_quotes_gpc()) {
			if (isset($_GET)) {
				$_GET = $this->stripSlashes($_GET);
			}
			if (isset($_POST)) {
				$_POST = $this->stripSlashes($_POST);
			}
			if (isset($_REQUEST)) {
				$_REQUEST = $this->stripSlashes($_REQUEST);
			}
			if (isset($_COOKIE)) {
				$_COOKIE = $this->stripSlashes($_COOKIE);
			}
		}

		if ($this->enableCsrfValidation) {
			\Yii::$application->on('beginRequest', array($this, 'validateCsrfToken'));
		}
	}

	/**
	 * Strips slashes from input data.
	 * This method is applied when magic quotes is enabled.
	 * @param mixed $data input data to be processed
	 * @return mixed processed data
	 */
	public function stripSlashes($data)
	{
		return is_array($data) ? array_map(array($this, 'stripSlashes'), $data) : stripslashes($data);
	}

	/**
	 * Returns the method of the current request (e.g. GET, POST, HEAD, PUT, DELETE).
	 * @return string request method, such as GET, POST, HEAD, PUT, DELETE.
	 * The value returned is turned into upper case.
	 */
	public function getRequestMethod()
	{
		if ($this->restPostVar !== false && isset($_POST[$this->restPostVar])) {
			return strtoupper($_POST[$this->restPostVar]);
		} else {
			return isset($_SERVER['REQUEST_METHOD']) ? strtoupper($_SERVER['REQUEST_METHOD']) : 'GET';
		}
	}


	/**
	 * Returns whether this is a POST request.
	 * @return boolean whether this is a POST request.
	 */
	public function getIsPostRequest()
	{
		return isset($_SERVER['REQUEST_METHOD']) && !strcasecmp($_SERVER['REQUEST_METHOD'], 'POST');
	}

	/**
	 * Returns whether this is a DELETE request.
	 * @return boolean whether this is a DELETE request.
	 */
	public function getIsDeleteRequest()
	{
		return $this->getRequestMethod() === 'DELETE';
	}

	/**
	 * Returns whether this is a PUT request.
	 * @return boolean whether this is a PUT request.
	 */
	public function getIsPutRequest()
	{
		return $this->getRequestMethod() === 'PUT';
	}

	/**
	 * Returns whether this is an AJAX (XMLHttpRequest) request.
	 * @return boolean whether this is an AJAX (XMLHttpRequest) request.
	 */
	public function getIsAjaxRequest()
	{
		return isset($_SERVER['HTTP_X_REQUESTED_WITH']) && $_SERVER['HTTP_X_REQUESTED_WITH'] === 'XMLHttpRequest';
	}

	/**
	 * Returns whether this is an Adobe Flash or Adobe Flex request.
	 * @return boolean whether this is an Adobe Flash or Adobe Flex request.
	 */
	public function getIsFlashRequest()
	{
		return isset($_SERVER['HTTP_USER_AGENT']) &&
			(stripos($_SERVER['HTTP_USER_AGENT'], 'Shockwave') !== false || stripos($_SERVER['HTTP_USER_AGENT'], 'Flash') !== false);
	}

	private $_restParams;

	/**
	 * Returns the request parameters for the RESTful request.
	 * @return array the RESTful request parameters
	 * @see getRequestMethod
	 */
	public function getRestParams()
	{
		if ($this->_restParams === null) {
			if ($this->restPostVar !== false && isset($_POST[$this->restPostVar])) {
				$this->_restParams = $_POST;
			} else {
				$this->_restParams = array();
				if (function_exists('mb_parse_str')) {
					mb_parse_str(file_get_contents('php://input'), $this->_restParams);
				} else {
					parse_str(file_get_contents('php://input'), $this->_restParams);
				}
			}
		}
		return $this->_restParams;
	}

	/**
	 * Sets the RESTful parameters.
	 * @param array $values the RESTful parameters (name-value pairs)
	 */
	public function setRestParams($values)
	{
		$this->_restParams = $values;
	}

	/**
	 * Returns the named GET or POST parameter value.
	 * If the GET or POST parameter does not exist, the second parameter to this method will be returned.
	 * If both GET and POST contains such a named parameter, the GET parameter takes precedence.
	 * @param string $name the GET parameter name
	 * @param mixed $defaultValue the default parameter value if the GET parameter does not exist.
	 * @return mixed the GET parameter value
	 * @see getQuery
	 * @see getPost
	 */
	public function getParam($name, $defaultValue = null)
	{
		return isset($_GET[$name]) ? $_GET[$name] : (isset($_POST[$name]) ? $_POST[$name] : $defaultValue);
	}

	/**
	 * Returns the named RESTful parameter value.
	 * @param string $name the parameter name
	 * @param mixed $defaultValue the default parameter value if the parameter does not exist.
	 * @return mixed the parameter value
	 */
	public function getRestParam($name, $defaultValue = null)
	{
		$params = $this->getRestParams();
		return isset($params[$name]) ? $params[$name] : $defaultValue;
	}

	/**
	 * Returns the named GET parameter value.
	 * If the GET parameter does not exist, the second parameter to this method will be returned.
	 * @param string $name the GET parameter name
	 * @param mixed $defaultValue the default parameter value if the GET parameter does not exist.
	 * @return mixed the GET parameter value
	 * @see getPost
	 * @see getParam
	 */
	public function getQuery($name, $defaultValue = null)
	{
		return isset($_GET[$name]) ? $_GET[$name] : $defaultValue;
	}

	/**
	 * Returns the named POST parameter value.
	 * If the POST parameter does not exist, the second parameter to this method will be returned.
	 * @param string $name the POST parameter name
	 * @param mixed $defaultValue the default parameter value if the POST parameter does not exist.
	 * @return mixed the POST parameter value
	 * @see getParam
	 * @see getQuery
	 */
	public function getPost($name, $defaultValue = null)
	{
		return isset($_POST[$name]) ? $_POST[$name] : $defaultValue;
	}

	/**
	 * Returns the named DELETE parameter value.
	 * @param string $name the DELETE parameter name
	 * @param mixed $defaultValue the default parameter value if the DELETE parameter does not exist.
	 * @return mixed the DELETE parameter value
	 */
	public function getDelete($name, $defaultValue = null)
	{
		return $this->getIsDeleteRequest() ? $this->getRestParam($name, $defaultValue) : null;
	}

	/**
	 * Returns the named PUT parameter value.
	 * @param string $name the PUT parameter name
	 * @param mixed $defaultValue the default parameter value if the PUT parameter does not exist.
	 * @return mixed the PUT parameter value
	 */
	public function getPut($name, $defaultValue = null)
	{
		return $this->getIsPutRequest() ? $this->getRestParam($name, $defaultValue) : null;
	}

	/**
	 * Returns the currently requested URL.
	 * This is the same as [[requestUri]].
	 * @return string part of the request URL after the host info.
	 */
	public function getUrl()
	{
		return $this->getRequestUri();
	}

	private $_hostInfo;

	/**
	 * Returns the schema and host part of the current request URL.
	 * The returned URL does not have an ending slash.
	 * By default this is determined based on the user request information.
	 * You may explicitly specify it by setting the [[setHostInfo()|hostInfo]] property.
	 * @return string schema and hostname part (with port number if needed) of the request URL (e.g. `http://www.yiiframework.com`)
	 * @see setHostInfo
	 */
	public function getHostInfo()
	{
		if ($this->_hostInfo === null) {
			$secure = $this->getIsSecureConnection();
			$http = $secure ? 'https' : 'http';
			if (isset($_SERVER['HTTP_HOST'])) {
				$this->_hostInfo = $http . '://' . $_SERVER['HTTP_HOST'];
			} else {
				$this->_hostInfo = $http . '://' . $_SERVER['SERVER_NAME'];
				$port = $secure ? $this->getSecurePort() : $this->getPort();
				if (($port !== 80 && !$secure) || ($port !== 443 && $secure)) {
					$this->_hostInfo .= ':' . $port;
				}
			}
		}

		return $this->_hostInfo;
	}

	/**
	 * Sets the schema and host part of the application URL.
	 * This setter is provided in case the schema and hostname cannot be determined
	 * on certain Web servers.
	 * @param string $value the schema and host part of the application URL. The trailing slashes will be removed.
	 */
	public function setHostInfo($value)
	{
		$this->_hostInfo = rtrim($value, '/');
	}

	private $_baseUrl;

	/**
	 * Returns the relative URL for the application.
	 * This is similar to [[scriptUrl]] except that it does not include the script file name,
	 * and the ending slashes are removed.
	 * @return string the relative URL for the application
	 * @see setScriptUrl
	 */
	public function getBaseUrl()
	{
		if ($this->_baseUrl === null) {
			$this->_baseUrl = rtrim(dirname($this->getScriptUrl()), '\\/');
		}
		return $this->_baseUrl;
	}

	/**
	 * Sets the relative URL for the application.
	 * By default the URL is determined based on the entry script URL.
	 * This setter is provided in case you want to change this behavior.
	 * @param string $value the relative URL for the application
	 */
	public function setBaseUrl($value)
	{
		$this->_baseUrl = $value;
	}

	private $_scriptUrl;

	/**
	 * Returns the relative URL of the entry script.
	 * The implementation of this method referenced Zend_Controller_Request_Http in Zend Framework.
	 * @return string the relative URL of the entry script.
	 * @throws BadConfigException if unable to determine the entry script URL
	 */
	public function getScriptUrl()
	{
		if ($this->_scriptUrl === null) {
			$scriptName = basename($_SERVER['SCRIPT_FILENAME']);
			if (basename($_SERVER['SCRIPT_NAME']) === $scriptName) {
				$this->_scriptUrl = $_SERVER['SCRIPT_NAME'];
			} elseif (basename($_SERVER['PHP_SELF']) === $scriptName) {
				$this->_scriptUrl = $_SERVER['PHP_SELF'];
			} elseif (isset($_SERVER['ORIG_SCRIPT_NAME']) && basename($_SERVER['ORIG_SCRIPT_NAME']) === $scriptName) {
				$this->_scriptUrl = $_SERVER['ORIG_SCRIPT_NAME'];
			} elseif (($pos = strpos($_SERVER['PHP_SELF'], '/' . $scriptName)) !== false) {
				$this->_scriptUrl = substr($_SERVER['SCRIPT_NAME'], 0, $pos) . '/' . $scriptName;
			} elseif (isset($_SERVER['DOCUMENT_ROOT']) && strpos($_SERVER['SCRIPT_FILENAME'], $_SERVER['DOCUMENT_ROOT']) === 0) {
				$this->_scriptUrl = str_replace('\\', '/', str_replace($_SERVER['DOCUMENT_ROOT'], '', $_SERVER['SCRIPT_FILENAME']));
			} else {
				throw new BadConfigException('Unable to determine the entry script URL.');
			}
		}
		return $this->_scriptUrl;
	}

	/**
	 * Sets the relative URL for the application entry script.
	 * This setter is provided in case the entry script URL cannot be determined
	 * on certain Web servers.
	 * @param string $value the relative URL for the application entry script.
	 */
	public function setScriptUrl($value)
	{
		$this->_scriptUrl = '/' . trim($value, '/');
	}

	private $_pathInfo;

	/**
	 * Returns the path info of the currently requested URL.
	 * A path info refers to the part that is after the entry script and before the question mark (query string).
	 * The starting and ending slashes are both removed.
	 * @return string part of the request URL that is after the entry script and before the question mark.
	 * Note, the returned path info is decoded.
	 * @throws BadConfigException if the path info cannot be determined due to unexpected server configuration
	 */
	public function getPathInfo()
	{
		if ($this->_pathInfo === null) {
			$this->_pathInfo = $this->resolvePathInfo();
		}
		return $this->_pathInfo;
	}

	/**
	 * Resolves the path info part of the currently requested URL.
	 * A path info refers to the part that is after the entry script and before the question mark (query string).
	 * The starting and ending slashes are both removed.
	 * @return string part of the request URL that is after the entry script and before the question mark.
	 * Note, the returned path info is decoded.
	 * @throws BadConfigException if the path info cannot be determined due to unexpected server configuration
	 */
	protected function resolvePathInfo()
	{
		$pathInfo = $this->getRequestUri();

		if (($pos = strpos($pathInfo, '?')) !== false) {
			$pathInfo = substr($pathInfo, 0, $pos);
		}

		$pathInfo = $this->decodeUrl($pathInfo);

		$scriptUrl = $this->getScriptUrl();
		$baseUrl = $this->getBaseUrl();
		if (strpos($pathInfo, $scriptUrl) === 0) {
			$pathInfo = substr($pathInfo, strlen($scriptUrl));
		} elseif ($baseUrl === '' || strpos($pathInfo, $baseUrl) === 0) {
			$pathInfo = substr($pathInfo, strlen($baseUrl));
		} elseif (strpos($_SERVER['PHP_SELF'], $scriptUrl) === 0) {
			$pathInfo = substr($_SERVER['PHP_SELF'], strlen($scriptUrl));
		} else {
			return false;
		}

		return trim($pathInfo, '/');
	}

	/**
	 * Decodes the given URL.
	 * This method is an improved variant of the native urldecode() function. It will properly encode
	 * UTF-8 characters which may be returned by urldecode().
	 * @param string $url encoded URL
	 * @return string decoded URL
	 */
	public function decodeUrl($url)
	{
		$url = urldecode($url);

		// is it UTF-8?
		// http://w3.org/International/questions/qa-forms-utf-8.html
		if (preg_match('%^(?:
				[\x09\x0A\x0D\x20-\x7E]              # ASCII
				| [\xC2-\xDF][\x80-\xBF]             # non-overlong 2-byte
				| \xE0[\xA0-\xBF][\x80-\xBF]         # excluding overlongs
				| [\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}  # straight 3-byte
				| \xED[\x80-\x9F][\x80-\xBF]         # excluding surrogates
				| \xF0[\x90-\xBF][\x80-\xBF]{2}      # planes 1-3
				| [\xF1-\xF3][\x80-\xBF]{3}          # planes 4-15
				| \xF4[\x80-\x8F][\x80-\xBF]{2}      # plane 16
				)*$%xs', $url)) {
			return $url;
		} else {
			return utf8_encode($url);
		}
	}

	private $_requestUri;

	/**
	 * Returns the request URI portion for the currently requested URL.
	 * This refers to the portion that is after the [[hostInfo]] part. It includes the [[queryString]] part if any.
	 * The implementation of this method referenced Zend_Controller_Request_Http in Zend Framework.
	 * @return string the request URI portion for the currently requested URL.
	 * Note that the URI returned is URL-encoded.
	 * @throws BadConfigException if the request URI cannot be determined due to unusual server configuration
	 */
	public function getRequestUri()
	{
		if ($this->_requestUri === null) {
			$this->_requestUri = $this->resolveRequestUri();
		}

		return $this->_requestUri;
	}

	/**
	 * Resolves the request URI portion for the currently requested URL.
	 * This refers to the portion that is after the [[hostInfo]] part. It includes the [[queryString]] part if any.
	 * The implementation of this method referenced Zend_Controller_Request_Http in Zend Framework.
	 * @return string|boolean the request URI portion for the currently requested URL.
	 * Note that the URI returned is URL-encoded.
	 * @throws BadConfigException if the request URI cannot be determined due to unusual server configuration
	 */
	protected function resolveRequestUri()
	{
		if (isset($_SERVER['HTTP_X_REWRITE_URL'])) { // IIS
			$requestUri = $_SERVER['HTTP_X_REWRITE_URL'];
		} elseif (isset($_SERVER['REQUEST_URI'])) {
			$requestUri = $_SERVER['REQUEST_URI'];
			if (!empty($_SERVER['HTTP_HOST'])) {
				if (strpos($requestUri, $_SERVER['HTTP_HOST']) !== false) {
					$requestUri = preg_replace('/^\w+:\/\/[^\/]+/', '', $requestUri);
				}
			} else {
				$requestUri = preg_replace('/^(http|https):\/\/[^\/]+/i', '', $requestUri);
			}
		} elseif (isset($_SERVER['ORIG_PATH_INFO'])) { // IIS 5.0 CGI
			$requestUri = $_SERVER['ORIG_PATH_INFO'];
			if (!empty($_SERVER['QUERY_STRING'])) {
				$requestUri .= '?' . $_SERVER['QUERY_STRING'];
			}
		} else {
			throw new BadConfigException('Unable to determine the request URI.');
		}
		return $requestUri;
	}

	/**
	 * Returns part of the request URL that is after the question mark.
	 * @return string part of the request URL that is after the question mark
	 */
	public function getQueryString()
	{
		return isset($_SERVER['QUERY_STRING']) ? $_SERVER['QUERY_STRING'] : '';
	}

	/**
	 * Return if the request is sent via secure channel (https).
	 * @return boolean if the request is sent via secure channel (https)
	 */
	public function getIsSecureConnection()
	{
		return !empty($_SERVER['HTTPS']) && strcasecmp($_SERVER['HTTPS'], 'off');
	}

	/**
	 * Returns the server name.
	 * @return string server name
	 */
	public function getServerName()
	{
		return $_SERVER['SERVER_NAME'];
	}

	/**
	 * Returns the server port number.
	 * @return integer server port number
	 */
	public function getServerPort()
	{
		return (int)$_SERVER['SERVER_PORT'];
	}

	/**
	 * Returns the URL referrer, null if not present
	 * @return string URL referrer, null if not present
	 */
	public function getReferrer()
	{
		return isset($_SERVER['HTTP_REFERER']) ? $_SERVER['HTTP_REFERER'] : null;
	}

	/**
	 * Returns the user agent, null if not present.
	 * @return string user agent, null if not present
	 */
	public function getUserAgent()
	{
		return isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : null;
	}

	/**
	 * Returns the user IP address.
	 * @return string user IP address
	 */
	public function getUserHostAddress()
	{
		return isset($_SERVER['REMOTE_ADDR']) ? $_SERVER['REMOTE_ADDR'] : '127.0.0.1';
	}

	/**
	 * Returns the user host name, null if it cannot be determined.
	 * @return string user host name, null if cannot be determined
	 */
	public function getUserHost()
	{
		return isset($_SERVER['REMOTE_HOST']) ? $_SERVER['REMOTE_HOST'] : null;
	}

	private $_scriptFile;

	/**
	 * Returns entry script file path.
	 * @return string entry script file path (processed w/ realpath())
	 * @throws BadConfigException if the entry script file path cannot be determined automatically.
	 */
	public function getScriptFile()
	{
		if ($this->_scriptFile === null) {
			$this->setScriptFile($_SERVER['SCRIPT_FILENAME']);
		}
		return $this->_scriptFile;
	}

	/**
	 * Sets the entry script file path.
	 * The entry script file path can normally be determined based on the `SCRIPT_FILENAME` SERVER variable.
	 * However, in some server configuration, this may not be correct or feasible.
	 * This setter is provided so that the entry script file path can be manually specified.
	 * @param string $value the entry script file path
	 * @throws BadConfigException if the provided entry script file path is invalid.
	 */
	public function setScriptFile($value)
	{
		$this->_scriptFile = realpath($value);
		if ($this->_scriptFile === false || !is_file($this->_scriptFile)) {
			throw new BadConfigException('Unable to determine the entry script file path.');
		}
	}

	/**
	 * Returns information about the capabilities of user browser.
	 * @param string $userAgent the user agent to be analyzed. Defaults to null, meaning using the
	 * current User-Agent HTTP header information.
	 * @return array user browser capabilities.
	 * @see http://www.php.net/manual/en/function.get-browser.php
	 */
	public function getBrowser($userAgent = null)
	{
		return get_browser($userAgent, true);
	}

	/**
	 * Returns user browser accept types, null if not present.
	 * @return string user browser accept types, null if not present
	 */
	public function getAcceptTypes()
	{
		return isset($_SERVER['HTTP_ACCEPT']) ? $_SERVER['HTTP_ACCEPT'] : null;
	}

	private $_port;

	/**
	 * Returns the port to use for insecure requests.
	 * Defaults to 80, or the port specified by the server if the current
	 * request is insecure.
	 * @return integer port number for insecure requests.
	 * @see setPort
	 */
	public function getPort()
	{
		if ($this->_port === null) {
			$this->_port = !$this->getIsSecureConnection() && isset($_SERVER['SERVER_PORT']) ? (int)$_SERVER['SERVER_PORT'] : 80;
		}
		return $this->_port;
	}

	/**
	 * Sets the port to use for insecure requests.
	 * This setter is provided in case a custom port is necessary for certain
	 * server configurations.
	 * @param integer $value port number.
	 */
	public function setPort($value)
	{
		if ($value != $this->_port) {
			$this->_port = (int)$value;
			$this->_hostInfo = null;
		}
	}

	private $_securePort;

	/**
	 * Returns the port to use for secure requests.
	 * Defaults to 443, or the port specified by the server if the current
	 * request is secure.
	 * @return integer port number for secure requests.
	 * @see setSecurePort
	 */
	public function getSecurePort()
	{
		if ($this->_securePort === null) {
			$this->_securePort = $this->getIsSecureConnection() && isset($_SERVER['SERVER_PORT']) ? (int)$_SERVER['SERVER_PORT'] : 443;
		}
		return $this->_securePort;
	}

	/**
	 * Sets the port to use for secure requests.
	 * This setter is provided in case a custom port is necessary for certain
	 * server configurations.
	 * @param integer $value port number.
	 */
	public function setSecurePort($value)
	{
		if ($value != $this->_securePort) {
			$this->_securePort = (int)$value;
			$this->_hostInfo = null;
		}
	}

	private $_preferredLanguages;

	/**
	 * Returns the user preferred languages.
	 * The languages returned are ordered by user's preference, starting with the language that the user
	 * prefers the most.
	 * @return string the user preferred languages. An empty array may be returned if the user has no preference.
	 */
	public function getPreferredLanguages()
	{
		if ($this->_preferredLanguages === null) {
			if (isset($_SERVER['HTTP_ACCEPT_LANGUAGE']) && ($n = preg_match_all('/([\w\-_]+)\s*(;\s*q\s*=\s*(\d*\.\d*))?/', $_SERVER['HTTP_ACCEPT_LANGUAGE'], $matches)) > 0) {
				$languages = array();
				for ($i = 0; $i < $n; ++$i) {
					$languages[$matches[1][$i]] = empty($matches[3][$i]) ? 1.0 : floatval($matches[3][$i]);
				}
				arsort($languages);
				$this->_preferredLanguages = array_keys($languages);
			} else {
				$this->_preferredLanguages = array();
			}
		}
		return $this->_preferredLanguages;
	}

	/**
	 * Returns the language most preferred by the user.
	 * @return string|boolean the language most preferred by the user. If the user has no preference, false
	 * will be returned.
	 */
	public function getPreferredLanguage()
	{
		$languages = $this->getPreferredLanguages();
		return isset($languages[0]) ? $languages[0] : false;
	}


	/**
	 * Returns the cookie collection.
	 * The result can be used like an associative array. Adding {@link CHttpCookie} objects
	 * to the collection will send the cookies to the client; and removing the objects
	 * from the collection will delete those cookies on the client.
	 * @return CCookieCollection the cookie collection.
	 */
	public function getCookies()
	{
		if ($this->_cookies !== null) {
			return $this->_cookies;
		} else {
			return $this->_cookies = new CCookieCollection($this);
		}
	}

	private $_csrfToken;

	/**
	 * Returns the random token used to perform CSRF validation.
	 * The token will be read from cookie first. If not found, a new token
	 * will be generated.
	 * @return string the random token for CSRF validation.
	 * @see enableCsrfValidation
	 */
	public function getCsrfToken()
	{
		if ($this->_csrfToken === null) {
			$cookie = $this->getCookies()->itemAt($this->csrfTokenName);
			if (!$cookie || ($this->_csrfToken = $cookie->value) == null) {
				$cookie = $this->createCsrfCookie();
				$this->_csrfToken = $cookie->value;
				$this->getCookies()->add($cookie->name, $cookie);
			}
		}

		return $this->_csrfToken;
	}

	/**
	 * Creates a cookie with a randomly generated CSRF token.
	 * Initial values specified in {@link csrfCookie} will be applied
	 * to the generated cookie.
	 * @return CHttpCookie the generated cookie
	 * @see enableCsrfValidation
	 */
	protected function createCsrfCookie()
	{
		$cookie = new CHttpCookie($this->csrfTokenName, sha1(uniqid(mt_rand(), true)));
		if (is_array($this->csrfCookie)) {
			foreach ($this->csrfCookie as $name => $value) {
				$cookie->$name = $value;
			}
		}
		return $cookie;
	}

	/**
	 * Performs the CSRF validation.
	 * This is the event handler responding to {@link CApplication::onBeginRequest}.
	 * The default implementation will compare the CSRF token obtained
	 * from a cookie and from a POST field. If they are different, a CSRF attack is detected.
	 * @param CEvent $event event parameter
	 * @throws CHttpException if the validation fails
	 */
	public function validateCsrfToken($event)
	{
		if ($this->getIsPostRequest()) {
			// only validate POST requests
			$cookies = $this->getCookies();
			if ($cookies->contains($this->csrfTokenName) && isset($_POST[$this->csrfTokenName])) {
				$tokenFromCookie = $cookies->itemAt($this->csrfTokenName)->value;
				$tokenFromPost = $_POST[$this->csrfTokenName];
				$valid = $tokenFromCookie === $tokenFromPost;
			} else {
				$valid = false;
			}
			if (!$valid) {
				throw new CHttpException(400, Yii::t('yii', 'The CSRF token could not be verified.'));
			}
		}
	}
}