socket下修改session的问题

	//session相关设置
	var Session = require('express-session');
	var MemoryStore = Session.MemoryStore;
	var sessionStore = new MemoryStore();
	app.use(Session({ secret: 'ta_shuo_session',
                  key: 'express.sid' ,
                  cookie: { maxAge: 60000},
                  store: sessionStore,
                  resave: true,
                  saveUninitialized: true
                }));
	...
	io.set('authorization', function (handshakeData, accept) {
		...
	}
	io.on('connection', function(socket){
		var cookie_t = cookie.parse(socket.handshake.headers.cookie);
    	var session_id = cookieParser.signedCookie(cookie_t['express.sid'], 'ta_shuo_session');
		socket.emit('connect');
		socket.on('test', function(data){
			//***这里有办法操作 sessionStore 来修改session值吗***
			
		});

如上，怎么在socket事件中修改session，session存储于mc中