static public function session($name=null)
	{
	    $id = 'session';
	    if (!static::has($id)) {
	        static::setShared($id, function () {
	            // app option
	            $options = Config::get('session');
	            
	            if ($options['storage'] == 'file') {
	                if (!isset($options['save_path']) && isset($options['path'])) {
	                    $options['save_path'] = $options['path'];
	                }
	                $options['save_path'] = isset($options['save_path']) ? ltrim($options['save_path'], '/') : 'sessions';
	                $options['save_path'] = Config::getStoragePath() . $options['save_path'];
	            }
	            $obj = new Session($options);
	            $obj->start();
	            return $obj;
	        });
	    }
	    
	    return static::get($id);
	}