in defineWebSocketHandler how to allow authenticated users connecting?

 upgrade(req) {
    console.log(this)
    let session = '';
    const cookies = req.headers.cookie.split(';') as string[];
    cookies.forEach(el => {
      if(el.includes('session=')) session = el.split('session=')[1].trim();
    })

    if(session == '') {
      // socket.write('HTTP/1.1 401 Unauthorized\r\n\r\n');
      // socket.destroy();
      return;
    }

    return {headers: {}};
  },