ExpressJS & Websocket & session sharing

Question

I\'m trying to make a chat application based on Node.js. I\'d like to force websocket server (ws library) to using ExpressJS session system. Unfortunately, I\'ve got stuck.

Answer 1

I found this works for me. Not sure it's the best way to do this though. First, initialize your express application:

// whatever your express app is using here...
var session = require("express-session");
var sessionParser = session({
    store: session_store,
    cookie: {secure: true, maxAge: null, httpOnly: true}
});
app.use(sessionParser);

Now, explicitly call the session middleware from the WS connection. If you're using the express-session module, the middleware will parse the cookies by itself. Otherwise, you might need to send it through your cookie-parsing middleware first.

If you're using the websocket module:

ws.on("request", function(req){
    sessionParser(req.httpRequest, {}, function(){
        console.log(req.httpRequest.session);
        // do stuff with the session here
    });
});

If you're using the ws module:

ws.on("connection", function(req){
    sessionParser(req.upgradeReq, {}, function(){
        console.log(req.upgradeReq.session);
        // do stuff with the session here
    });
});

For your convenience, here is a fully working example, using express, express-session, and ws:

var app = require('express')();
var server = require("http").createServer(app);
var sessionParser = require('express-session')({
    secret:"secret",
    resave: true,
    saveUninitialized: true
});
app.use(sessionParser);

app.get("*", function(req, res, next) {
    req.session.working = "yes!";
    res.send("<script>var ws = new WebSocket('ws://localhost:3000');</script>");
});

var ws = new require("ws").Server({server: server});
ws.on("connection", function connection(req) {
    sessionParser(req.upgradeReq, {}, function(){
        console.log("New websocket connection:");
        var sess = req.upgradeReq.session;
        console.log("working = " + sess.working);
    });
});

server.listen(3000);

Answer 2

In version 3.2.0 of ws you have to do it a bit differently.

There is a full working example of express session parsing in the ws repo, specifically using a new feature verifyClient.

A very brief usage summary:

const sessionParser = session({
  saveUninitialized: false,
  secret: '$eCuRiTy',
  resave: false
})

const server = http.createServer(app)
const wss = new WebSocket.Server({
  verifyClient: (info, done) => {
    console.log('Parsing session from request...')
    sessionParser(info.req, {}, () => {
      console.log('Session is parsed!')
      done(info.req.session.userId)
    })
  },
  server
})

wss.on('connection', (ws, req) => {
  ws.on('message', (message) => {
    console.log(`WS message ${message} from user ${req.session.userId}`)
  })
})

Answer 3

I was able to get this working. I think you need to specify the secret on cookieParser instead of session store.

Example from my app:

var app = express();
var RedisStore = require('connect-redis')(express);
var sessionStore = new RedisStore();
var cookieParser = express.cookieParser('some secret');

app.use(cookieParser);
app.use(express.session({store: sessionStore}));


wss.on('connection', function(rawSocket) {

  cookieParser(rawSocket.upgradeReq, null, function(err) {
    var sessionID = rawSocket.upgradeReq.signedCookies['connect.sid'];
    sessionStore.get(sessionID, function(err, sess) {
      console.log(sess);
    });
  });

});

Answer 4

WS v3.0.0 and above, has changed the behaviour so the given answers won't work out of the box for those versions. For current versions, the signature of the connection method is [function(socket, request)] and the socket no longer contains a reference to the request.

ws.on(
    'connection',
    function (socket, req)
    {
        sessionParser(
            req,
            {},
            function()
            {
                console.log(req.session);
            }
        );
    }
);

Answer 5

Currently, below is my workaround which is working fine. I just don't know it's disadvantages and security. I just prevent the server from listening if it doesn't have a session. (Share session from express-session to ws)

I haven't fully tested this though.

var http = require('http');
var express = require('express');
var expressSession = require('express-session');
var router = express.Router();
var app = express();

const server = http.createServer(app);

router.get('/', function(req, res, next) {
    if(req.session.user_id) {
        // Socket authenticated
        server.listen(8080, function listening(){});
    }
});