L5中的扩展会话在请求之间不持久

我正在扩展会话提供程序，以便保留一些所需的数据。我开始编辑AppServiceProvider's boot method:

'Session::extend('desk', function($app)
{
    return new Desk();
}); 

Desk类看起来像：

namespace App'Services;

use Illuminate'Session'ExistenceAwareInterface;
class Desk implements 'SessionHandlerInterface, ExistenceAwareInterface{
    /**
     * The existence state of the session.
     * @var bool
     */
    protected $exists;
    public function close()
    {
        return true;
    }
    public function destroy($session_id)
    {
        $session = $em->find('Session', $session_id);
        $em->remove($session);
        $em->flush();
        return true;
    }
    public function gc($maxlifetime)
    {
        // TODO: Implement gc() method.
    }
    public function open($save_path, $session_id)
    {
        return true;
    }
    public function read($session_id)
    {
        $session = $em->find('Session', $session_id);
        if ($sesion !== null){
            $this->exists = true;
            return  $session->getPayload();
        }
    }
    public function write($session_id, $session_data)
    {
        $session = $em->find('Session', $session_id);
        if ($session === null){
            $session = new Session($session_id, $session_data);
            $em->persist($session);
        }
        else{
            $session->setPayload($session_data);
        }
        $em->flush();
        $this->exists = true;
    }

    public function setExists($value)
    {
        $this->exists = $value;
        return $this;
    }
}

完成实现后，我将会话配置更改为：

return [
    'driver' => 'desk',
    'lifetime' => 120,
    'expire_on_close' => false,
    'encrypt' => false,
    'files' => storage_path().'/framework/sessions',
    'connection' => null,
    'table' => 'sessions',
    'lottery' => [2, 100],
    'cookie' => 'lote_session',
    'path' => '/',
    'domain' => null,
    'secure' => false,
];

当我加载页面时，没有问题，但在成功登录请求后，刷新页面，会话到期，用户再次成为访客。我错过什么了吗？

附加信息：如果我将会话驱动程序恢复为"文件"，一切都会好起来。