Express-session req.session in Websocket Socket.io? - node.js

Question

I try to exchange sessions between express and socket.io -
When I connect to the Websocket, I can set userData in the session and also get it again on another Websocket event!
Server.ts
const session = require("express-session");
const sessionData = {
name: COOKIE_NAME,
secret:COOKIE_SECRET,
resave: false,
saveUninitialized: false,
store: store
}
const expressSession = expressSession(sessionData);
const socketSession = require("express-socket.io-session");
const sharedsession = socketSession(expressSession, {
autoSave:true
})
const io = new Server(httpsServer,{
cors: {
origin: "https://localhost:3000",
methods: ["GET", "POST"]
}
})
io.use(sharedsession);
io.on("connection", (socket: Socket) => {
socket.on("message",userdata=>{
var data = socket.handshake || socket.request;
(data as any).session.userdata = userdata;
(data as any).session.save();
console.log("From Session:",(data as any).session.userdata)
})
socket.on("getUser",()=>{
var data = socket.handshake || socket.request;
console.log("Got it: ",(data as any).session.userdata)// good!
})
});
But now... when I set a session in a express route like this:
app.get('/login', function (req, res) {
req.session.user = {_id: '', firstname:'Hide', lastname:'myPain',email:'Harold#hiden.com', hasPain: false, };
res.send('You are now logged in! => isLoggedIn:' + JSON.stringify(req.session.user));
});
And now I want to access this req.session.user in my Websocket event:
socket.on("getUser",()=>{
var data = socket.handshake || socket.request;
console.log("Got it: ",(data as any).session.user) // undefined!
})
the session.user which I set in express route on req.session.user is undefined.. why? Is it meant to work like this, or is it just for exchanging inbetween Websocket events?
Or do I just have to trigger the
(data as any).session.user= newUserDataFromExpressReq;
(data as any).session.save();
on my socketio when the user call my express endpoint for login? So its not really an automated exchange?

Answer 1

Ok, everything what was needed was to add "withCredentials" option to the client. This is needed when you have your client and server running on different servers/ports.
// client-side
const io = require("socket.io-client");
const socket = io("https://api.example.com", {
withCredentials: true,
extraHeaders: {
"my-custom-header": "abcd"
}
});