<?php /** * @link http://www.yiiframework.com/ * @copyright Copyright (c) 2008 Yii Software LLC * @license http://www.yiiframework.com/license/ */ namespace yii\web; use Yii; use yii\caching\Cache; use yii\base\InvalidConfigException; /** * CacheSession implements a session component using cache as storage medium. * * The cache being used can be any cache application component. * The ID of the cache application component is specified via [[cache]], which defaults to 'cache'. * * Beware, by definition cache storage are volatile, which means the data stored on them * may be swapped out and get lost. Therefore, you must make sure the cache used by this component * is NOT volatile. If you want to use database as storage medium, use [[DbSession]] is a better choice. * * @author Qiang Xue <qiang.xue@gmail.com> * @since 2.0 */ class CacheSession extends Session { /** * @var Cache|string the cache object or the application component ID of the cache object. * The session data will be stored using this cache object. * * After the CacheSession object is created, if you want to change this property, * you should only assign it with a cache object. */ public $cache = 'cache'; /** * Initializes the application component. */ public function init() { parent::init(); if (is_string($this->cache)) { $this->cache = Yii::$app->getComponent($this->cache); } if (!$this->cache instanceof Cache) { throw new InvalidConfigException('CacheSession::cache must refer to the application component ID of a cache object.'); } } /** * Returns a value indicating whether to use custom session storage. * This method overrides the parent implementation and always returns true. * @return boolean whether to use custom storage. */ public function getUseCustomStorage() { return true; } /** * Session read handler. * Do not call this method directly. * @param string $id session ID * @return string the session data */ public function readSession($id) { $data = $this->cache->get($this->calculateKey($id)); return $data === false ? '' : $data; } /** * Session write handler. * Do not call this method directly. * @param string $id session ID * @param string $data session data * @return boolean whether session write is successful */ public function writeSession($id, $data) { return $this->cache->set($this->calculateKey($id), $data, $this->getTimeout()); } /** * Session destroy handler. * Do not call this method directly. * @param string $id session ID * @return boolean whether session is destroyed successfully */ public function destroySession($id) { return $this->cache->delete($this->calculateKey($id)); } /** * Generates a unique key used for storing session data in cache. * @param string $id session variable name * @return mixed a safe cache key associated with the session variable name */ protected function calculateKey($id) { return array(__CLASS__, $id); } }