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<?php

/**

 * Session class for CakePHP.

 *

 * CakePHP abstracts the handling of sessions.

 * There are several convenient methods to access session information.

 * This class is the implementation of those methods.

 * They are mostly used by the Session Component.

 *

 * 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

 * @package       Cake.Model.Datasource

 * @since         CakePHP(tm) v .0.10.0.1222

 * @license       http://www.opensource.org/licenses/mit-license.php MIT License

 */

App::uses('Hash', 'Utility');

App::uses('Security', 'Utility');

/**

 * Session class for CakePHP.

 *

 * CakePHP abstracts the handling of sessions. There are several convenient methods to access session information.

 * This class is the implementation of those methods. They are mostly used by the Session Component.

 *

 * @package       Cake.Model.Datasource

 */

class CakeSession {

/**

 * True if the Session is still valid

 *

 * @var bool

 */

	public static $valid = false;

/**

 * Error messages for this session

 *

 * @var array

 */

	public static $error = false;

/**

 * User agent string

 *

 * @var string

 */

	protected static $_userAgent = '';

/**

 * Path to where the session is active.

 *

 * @var string

 */

	public static $path = '/';

/**

 * Error number of last occurred error

 *

 * @var int

 */

	public static $lastError = null;

/**

 * Start time for this session.

 *

 * @var int

 */

	public static $time = false;

/**

 * Cookie lifetime

 *

 * @var int

 */

	public static $cookieLifeTime;

/**

 * Time when this session becomes invalid.

 *

 * @var int

 */

	public static $sessionTime = false;

/**

 * Current Session id

 *

 * @var string

 */

	public static $id = null;

/**

 * Hostname

 *

 * @var string

 */

	public static $host = null;

/**

 * Session timeout multiplier factor

 *

 * @var int

 */

	public static $timeout = null;

/**

 * Number of requests that can occur during a session time without the session being renewed.

 * This feature is only used when config value `Session.autoRegenerate` is set to true.

 *

 * @var int

 * @see CakeSession::_checkValid()

 */

	public static $requestCountdown = 10;

/**

 * Whether or not the init function in this class was already called

 *

 * @var bool

 */

	protected static $_initialized = false;

/**

 * Session cookie name

 *

 * @var string

 */

	protected static $_cookieName = null;

/**

 * Pseudo constructor.

 *

 * @param string $base The base path for the Session

 * @return void

 */

	public static function init($base = null) {

		self::$time = time();

		if (env('HTTP_USER_AGENT')) {

			self::$_userAgent = md5(env('HTTP_USER_AGENT') . Configure::read('Security.salt'));

		}

		self::_setPath($base);

		self::_setHost(env('HTTP_HOST'));

		if (!self::$_initialized) {

			register_shutdown_function('session_write_close');

		}

		self::$_initialized = true;

	}

/**

 * Setup the Path variable

 *

 * @param string $base base path

 * @return void

 */

	protected static function _setPath($base = null) {

		if (empty($base)) {

			self::$path = '/';

			return;

		}

		if (strpos($base, 'index.php') !== false) {

			$base = str_replace('index.php', '', $base);

		}

		if (strpos($base, '?') !== false) {

			$base = str_replace('?', '', $base);

		}

		self::$path = $base;

	}

/**

 * Set the host name

 *

 * @param string $host Hostname

 * @return void

 */

	protected static function _setHost($host) {

		self::$host = $host;

		if (strpos(self::$host, ':') !== false) {

			self::$host = substr(self::$host, 0, strpos(self::$host, ':'));

		}

	}

/**

 * Starts the Session.

 *

 * @return bool True if session was started

 */

	public static function start() {

		if (self::started()) {

			return true;

		}

		$id = self::id();

		self::_startSession();

		if (!$id && self::started()) {

			self::_checkValid();

		}

		self::$error = false;

		self::$valid = true;

		return self::started();

	}

/**

 * Determine if Session has been started.

 *

 * @return bool True if session has been started.

 */

	public static function started() {

		return isset($_SESSION) && session_id();

	}

/**

 * Returns true if given variable is set in session.

 *

 * @param string $name Variable name to check for

 * @return bool True if variable is there

 */

	public static function check($name = null) {

		if (empty($name) || !self::_hasSession() || !self::start()) {

			return false;

		}

		return Hash::get($_SESSION, $name) !== null;

	}

/**

 * Returns the session id.

 * Calling this method will not auto start the session. You might have to manually

 * assert a started session.

 *

 * Passing an id into it, you can also replace the session id if the session

 * has not already been started.

 * Note that depending on the session handler, not all characters are allowed

 * within the session id. For example, the file session handler only allows

 * characters in the range a-z A-Z 0-9 , (comma) and - (minus).

 *

 * @param string $id Id to replace the current session id

 * @return string Session id

 */

	public static function id($id = null) {

		if ($id) {

			self::$id = $id;

			session_id(self::$id);

		}

		if (self::started()) {

			return session_id();

		}

		return self::$id;

	}

/**

 * Removes a variable from session.

 *

 * @param string $name Session variable to remove

 * @return bool Success

 */

	public static function delete($name) {

		if (self::check($name)) {

			self::_overwrite($_SESSION, Hash::remove($_SESSION, $name));

			return !self::check($name);

		}

		return false;

	}

/**

 * Used to write new data to _SESSION, since PHP doesn't like us setting the _SESSION var itself.

 *

 * @param array &$old Set of old variables => values

 * @param array $new New set of variable => value

 * @return void

 */

	protected static function _overwrite(&$old, $new) {

		if (!empty($old)) {

			foreach ($old as $key => $var) {

				if (!isset($new[$key])) {

					unset($old[$key]);

				}

			}

		}

		foreach ($new as $key => $var) {

			$old[$key] = $var;

		}

	}

/**

 * Return error description for given error number.

 *

 * @param int $errorNumber Error to set

 * @return string Error as string

 */

	protected static function _error($errorNumber) {

		if (!is_array(self::$error) || !array_key_exists($errorNumber, self::$error)) {

			return false;

		}

		return self::$error[$errorNumber];

	}

/**

 * Returns last occurred error as a string, if any.

 *

 * @return mixed Error description as a string, or false.

 */

	public static function error() {

		if (self::$lastError) {

			return self::_error(self::$lastError);

		}

		return false;

	}

/**

 * Returns true if session is valid.

 *

 * @return bool Success

 */

	public static function valid() {

		if (self::start() && self::read('Config')) {

			if (self::_validAgentAndTime() && self::$error === false) {

				self::$valid = true;

			} else {

				self::$valid = false;

				self::_setError(1, 'Session Highjacking Attempted !!!');

			}

		}

		return self::$valid;

	}

/**

 * Tests that the user agent is valid and that the session hasn't 'timed out'.

 * Since timeouts are implemented in CakeSession it checks the current self::$time

 * against the time the session is set to expire. The User agent is only checked

 * if Session.checkAgent == true.

 *

 * @return bool

 */

	protected static function _validAgentAndTime() {

		$config = self::read('Config');

		$validAgent = (

			Configure::read('Session.checkAgent') === false ||

			self::$_userAgent == $config['userAgent']

		);

		return ($validAgent && self::$time <= $config['time']);

	}

/**

 * Get / Set the user agent

 *

 * @param string $userAgent Set the user agent

 * @return string Current user agent

 */

	public static function userAgent($userAgent = null) {

		if ($userAgent) {

			self::$_userAgent = $userAgent;

		}

		if (empty(self::$_userAgent)) {

			CakeSession::init(self::$path);

		}

		return self::$_userAgent;

	}

/**

 * Returns given session variable, or all of them, if no parameters given.

 *

 * @param string|array $name The name of the session variable (or a path as sent to Set.extract)

 * @return mixed The value of the session variable, null if session not available,

 *   session not started, or provided name not found in the session.

 */

	public static function read($name = null) {

		if (empty($name) && $name !== null) {

			return false;

		}

		if (!self::_hasSession() || !self::start()) {

			return null;

		}

		if ($name === null) {

			return self::_returnSessionVars();

		}

		$result = Hash::get($_SESSION, $name);

		if (isset($result)) {

			return $result;

		}

		return null;

	}

/**

 * Returns all session variables.

 *

 * @return mixed Full $_SESSION array, or false on error.

 */

	protected static function _returnSessionVars() {

		if (!empty($_SESSION)) {

			return $_SESSION;

		}

		self::_setError(2, 'No Session vars set');

		return false;

	}

/**

 * Writes value to given session variable name.

 *

 * @param string|array $name Name of variable

 * @param string $value Value to write

 * @return bool True if the write was successful, false if the write failed

 */

	public static function write($name, $value = null) {

		if (empty($name) || !self::start()) {

			return false;

		}

		$write = $name;

		if (!is_array($name)) {

			$write = array($name => $value);

		}

		foreach ($write as $key => $val) {

			self::_overwrite($_SESSION, Hash::insert($_SESSION, $key, $val));

			if (Hash::get($_SESSION, $key) !== $val) {

				return false;

			}

		}

		return true;

	}

/**

 * Helper method to destroy invalid sessions.

 *

 * @return void

 */

	public static function destroy() {

		if (!self::started()) {

			self::_startSession();

		}

		session_destroy();

		$_SESSION = null;

		self::$id = null;

		self::$_cookieName = null;

	}

/**

 * Clears the session, the session id, and renews the session.

 *

 * @return void

 */

	public static function clear() {

		$_SESSION = null;

		self::$id = null;

		self::renew();

	}

/**

 * Helper method to initialize a session, based on CakePHP core settings.

 *

 * Sessions can be configured with a few shortcut names as well as have any number of ini settings declared.

 *

 * @return void

 * @throws CakeSessionException Throws exceptions when ini_set() fails.

 */

	protected static function _configureSession() {

		$sessionConfig = Configure::read('Session');

		if (isset($sessionConfig['defaults'])) {

			$defaults = self::_defaultConfig($sessionConfig['defaults']);

			if ($defaults) {

				$sessionConfig = Hash::merge($defaults, $sessionConfig);

			}

		}

		if (!isset($sessionConfig['ini']['session.cookie_secure']) && env('HTTPS')) {

			$sessionConfig['ini']['session.cookie_secure'] = 1;

		}

		if (isset($sessionConfig['timeout']) && !isset($sessionConfig['cookieTimeout'])) {

			$sessionConfig['cookieTimeout'] = $sessionConfig['timeout'];

		}

		if (!isset($sessionConfig['ini']['session.cookie_lifetime'])) {

			$sessionConfig['ini']['session.cookie_lifetime'] = $sessionConfig['cookieTimeout'] * 60;

		}

		if (!isset($sessionConfig['ini']['session.name'])) {

			$sessionConfig['ini']['session.name'] = $sessionConfig['cookie'];

		}

		self::$_cookieName = $sessionConfig['ini']['session.name'];

		if (!empty($sessionConfig['handler'])) {

			$sessionConfig['ini']['session.save_handler'] = 'user';

		}

		if (!isset($sessionConfig['ini']['session.gc_maxlifetime'])) {

			$sessionConfig['ini']['session.gc_maxlifetime'] = $sessionConfig['timeout'] * 60;

		}

		if (!isset($sessionConfig['ini']['session.cookie_httponly'])) {

			$sessionConfig['ini']['session.cookie_httponly'] = 1;

		}

		if (empty($_SESSION)) {

			if (!empty($sessionConfig['ini']) && is_array($sessionConfig['ini'])) {

				foreach ($sessionConfig['ini'] as $setting => $value) {

					if (ini_set($setting, $value) === false) {

						throw new CakeSessionException(__d('cake_dev', 'Unable to configure the session, setting %s failed.', $setting));

					}

				}

			}

		}

		if (!empty($sessionConfig['handler']) && !isset($sessionConfig['handler']['engine'])) {

			call_user_func_array('session_set_save_handler', $sessionConfig['handler']);

		}

		if (!empty($sessionConfig['handler']['engine'])) {

			$handler = self::_getHandler($sessionConfig['handler']['engine']);

			session_set_save_handler(

				array($handler, 'open'),

				array($handler, 'close'),

				array($handler, 'read'),

				array($handler, 'write'),

				array($handler, 'destroy'),

				array($handler, 'gc')

			);

		}

		Configure::write('Session', $sessionConfig);

		self::$sessionTime = self::$time + ($sessionConfig['timeout'] * 60);

	}

/**

 * Get session cookie name.

 *

 * @return string

 */

	protected static function _cookieName() {

		if (self::$_cookieName !== null) {

			return self::$_cookieName;

		}

		self::init();

		self::_configureSession();

		return self::$_cookieName = session_name();

	}

/**

 * Returns whether a session exists

 *

 * @return bool

 */

	protected static function _hasSession() {

		return self::started() || isset($_COOKIE[self::_cookieName()]);

	}

/**

 * Find the handler class and make sure it implements the correct interface.

 *

 * @param string $handler Handler name.

 * @return void

 * @throws CakeSessionException

 */

	protected static function _getHandler($handler) {

		list($plugin, $class) = pluginSplit($handler, true);

		App::uses($class, $plugin . 'Model/Datasource/Session');

		if (!class_exists($class)) {

			throw new CakeSessionException(__d('cake_dev', 'Could not load %s to handle the session.', $class));

		}

		$handler = new $class();

		if ($handler instanceof CakeSessionHandlerInterface) {

			return $handler;

		}

		throw new CakeSessionException(__d('cake_dev', 'Chosen SessionHandler does not implement CakeSessionHandlerInterface it cannot be used with an engine key.'));

	}

/**

 * Get one of the prebaked default session configurations.

 *

 * @param string $name Config name.

 * @return bool|array

 */

	protected static function _defaultConfig($name) {

		$defaults = array(

			'php' => array(

				'cookie' => 'CAKEPHP',

				'timeout' => 240,

				'ini' => array(

					'session.use_trans_sid' => 0,

					'session.cookie_path' => self::$path

				)

			),

			'cake' => array(

				'cookie' => 'CAKEPHP',

				'timeout' => 240,

				'ini' => array(

					'session.use_trans_sid' => 0,

					'url_rewriter.tags' => '',

					'session.serialize_handler' => 'php',

					'session.use_cookies' => 1,

					'session.cookie_path' => self::$path,

					'session.save_path' => TMP . 'sessions',

					'session.save_handler' => 'files'

				)

			),

			'cache' => array(

				'cookie' => 'CAKEPHP',

				'timeout' => 240,

				'ini' => array(

					'session.use_trans_sid' => 0,

					'url_rewriter.tags' => '',

					'session.use_cookies' => 1,

					'session.cookie_path' => self::$path,

					'session.save_handler' => 'user',

				),

				'handler' => array(

					'engine' => 'CacheSession',

					'config' => 'default'

				)

			),

			'database' => array(

				'cookie' => 'CAKEPHP',

				'timeout' => 240,

				'ini' => array(

					'session.use_trans_sid' => 0,

					'url_rewriter.tags' => '',

					'session.use_cookies' => 1,

					'session.cookie_path' => self::$path,

					'session.save_handler' => 'user',

					'session.serialize_handler' => 'php',

				),

				'handler' => array(

					'engine' => 'DatabaseSession',

					'model' => 'Session'

				)

			)

		);

		if (isset($defaults[$name])) {

			return $defaults[$name];

		}

		return false;

	}

/**

 * Helper method to start a session

 *

 * @return bool Success

 */

	protected static function _startSession() {

		self::init();

		session_write_close();

		self::_configureSession();

		if (headers_sent()) {

			if (empty($_SESSION)) {

				$_SESSION = array();

			}

		} else {

			// For IE<=8

			session_cache_limiter("must-revalidate");

			session_start();

		}

		return true;

	}

/**

 * Helper method to create a new session.

 *

 * @return void

 */

	protected static function _checkValid() {

		$config = self::read('Config');

		if ($config) {

			$sessionConfig = Configure::read('Session');

			if (self::valid()) {

				self::write('Config.time', self::$sessionTime);

				if (isset($sessionConfig['autoRegenerate']) && $sessionConfig['autoRegenerate'] === true) {

					$check = $config['countdown'];

					$check -= 1;

					self::write('Config.countdown', $check);

					if ($check < 1) {

						self::renew();

						self::write('Config.countdown', self::$requestCountdown);

					}

				}

			} else {

				$_SESSION = array();

				self::destroy();

				self::_setError(1, 'Session Highjacking Attempted !!!');

				self::_startSession();

				self::_writeConfig();

			}

		} else {

			self::_writeConfig();

		}

	}

/**

 * Writes configuration variables to the session

 *

 * @return void

 */

	protected static function _writeConfig() {

		self::write('Config.userAgent', self::$_userAgent);

		self::write('Config.time', self::$sessionTime);

		self::write('Config.countdown', self::$requestCountdown);

	}

/**

 * Restarts this session.

 *

 * @return void

 */

	public static function renew() {

		if (!session_id()) {

			return;

		}

		if (isset($_COOKIE[session_name()])) {

			setcookie(Configure::read('Session.cookie'), '', time() - 42000, self::$path);

		}

		session_regenerate_id(true);

	}

/**

 * Helper method to set an internal error message.

 *

 * @param int $errorNumber Number of the error

 * @param string $errorMessage Description of the error

 * @return void

 */

	protected static function _setError($errorNumber, $errorMessage) {

		if (self::$error === false) {

			self::$error = array();

		}

		self::$error[$errorNumber] = $errorMessage;

		self::$lastError = $errorNumber;

	}

}