source: Dev/branches/cakephp/cake/libs/view/helpers/session.php @ 126

<?php
/**
 * Session Helper provides access to the Session in the Views.
 *
 * PHP versions 4 and 5
 *
 * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
 * Copyright 2005-2011, Cake Software Foundation, Inc. (http://cakefoundation.org)
 *
 * Licensed under The MIT License
 * Redistributions of files must retain the above copyright notice.
 *
 * @copyright     Copyright 2005-2011, Cake Software Foundation, Inc. (http://cakefoundation.org)
 * @link          http://cakephp.org CakePHP(tm) Project
 * @package       cake
 * @subpackage    cake.cake.libs.view.helpers
 * @since         CakePHP(tm) v 1.1.7.3328
 * @license       MIT License (http://www.opensource.org/licenses/mit-license.php)
 */
if (!class_exists('cakesession')) {
        require LIBS . 'cake_session.php';
}
/**
 * Session Helper.
 *
 * Session reading from the view.
 *
 * @package       cake
 * @subpackage    cake.cake.libs.view.helpers
 * @link http://book.cakephp.org/view/1465/Session
 */
class SessionHelper extends CakeSession {

/**
 * List of helpers used by this helper
 *
 * @var array
 */
        var $helpers = array();

/**
 * Used to determine if methods implementation is used, or bypassed
 *
 * @var boolean
 */
        var $__active = true;

/**
 * Class constructor
 *
 * @param string $base
 */
        function __construct($base = null) {
                if (Configure::read('Session.start') === true) {
                        parent::__construct($base, false);
                        $this->start();
                        $this->__active = true;
                } else {
                        $this->__active = false;
                }
        }

/**
 * Turn sessions on if 'Session.start' is set to false in core.php
 *
 * @param string $base
 * @access public
 */
        function activate($base = null) {
                $this->__active = true;
        }

/**
 * Used to read a session values set in a controller for a key or return values for all keys.
 *
 * In your view: `$session->read('Controller.sessKey');`
 * Calling the method without a param will return all session vars
 *
 * @param string $name the name of the session key you want to read
 * @return values from the session vars
 * @access public
 * @link http://book.cakephp.org/view/1466/Methods
 */
        function read($name = null) {
                if ($this->__active === true && $this->__start()) {
                        return parent::read($name);
                }
                return false;
        }

/**
 * Used to check is a session key has been set
 *
 * In your view: `$session->check('Controller.sessKey');`
 *
 * @param string $name
 * @return boolean
 * @access public
 * @link http://book.cakephp.org/view/1466/Methods
 */
        function check($name) {
                if ($this->__active === true && $this->__start()) {
                        return parent::check($name);
                }
                return false;
        }

/**
 * Returns last error encountered in a session
 *
 * In your view: `$session->error();`
 *
 * @return string last error
 * @access public
 * @link http://book.cakephp.org/view/1466/Methods
 */
        function error() {
                if ($this->__active === true && $this->__start()) {
                        return parent::error();
                }
                return false;
        }

/**
 * Used to render the message set in Controller::Session::setFlash()
 *
 * In your view: $session->flash('somekey');
 * Will default to flash if no param is passed
 *
 * @param string $key The [Message.]key you are rendering in the view.
 * @return boolean|string Will return the value if $key is set, or false if not set.
 * @access public
 * @link http://book.cakephp.org/view/1466/Methods
 * @link http://book.cakephp.org/view/1467/flash
 */
        function flash($key = 'flash') {
                $out = false;

                if ($this->__active === true && $this->__start()) {
                        if (parent::check('Message.' . $key)) {
                                $flash = parent::read('Message.' . $key);

                                if ($flash['element'] == 'default') {
                                        if (!empty($flash['params']['class'])) {
                                                $class = $flash['params']['class'];
                                        } else {
                                                $class = 'message';
                                        }
                                        $out = '<div id="' . $key . 'Message" class="' . $class . '">' . $flash['message'] . '</div>';
                                } elseif ($flash['element'] == '' || $flash['element'] == null) {
                                        $out = $flash['message'];
                                } else {
                                        $view =& ClassRegistry::getObject('view');
                                        $tmpVars = $flash['params'];
                                        $tmpVars['message'] = $flash['message'];
                                        $out = $view->element($flash['element'], $tmpVars);
                                }
                                parent::delete('Message.' . $key);
                        }
                }
                return $out;
        }

/**
 * Used to check is a session is valid in a view
 *
 * @return boolean
 * @access public
 */
        function valid() {
                if ($this->__active === true && $this->__start()) {
                        return parent::valid();
                }
        }

/**
 * Override CakeSession::write().
 * This method should not be used in a view
 *
 * @return boolean
 * @access public
 */
        function write() {
                trigger_error(__('You can not write to a Session from the view', true), E_USER_WARNING);
        }

/**
 * Determine if Session has been started
 * and attempt to start it if not
 *
 * @return boolean true if Session is already started, false if
 * Session could not be started
 * @access private
 */
        function __start() {
                if (!$this->started()) {
                        return $this->start();
                }
                return true;
        }
}