Integrating socket.io with express is it a good idea? and if so how to go about it?

Question

I'm must say I'm very new to back end development, I'm currently working on an exercise project of making a fake money poker website. I use Node.js socket.io/express-session/passport At first, I mainly used express with a HTTP server listening on one port. Averagely Like this:

const express = require("express")
const app = express()

app.get('/home',connectEnsureLogin.ensureLoggedIn("/loginPage"),function(req, res) {

 //console.log(req.user.username+": sessionId: "+req.sessionID);
  return res.sendFile( __dirname+"/website/index.html"); 
} 
); 
const PORT = process.env.PORT || 5000; 
app.listen(PORT, () => console.log("Poker site Server started on ${PORT})")

The website wasn't working very fast. When a client joined a poker table they needed to ask the server every second for new updates on the state of the game so that was a lot of HTTP requests coming into my server. So I decided without much theoretical certitude that it seemed like a good idea: To have the server use socket.io sockets to hand info for clients that are in poker tables, but when they are not in poker tables and are just browsing the site I use a HTTP server to handle their request. Code wise I feel I haven't really managed to do this correctly. My code with Express, express-session, and passport combined makes sure only to hand information to users authenticated. But since The socket.io servers seem totally separate from all the express code, they don't share the same authentication functionality as the express code. So I need to somehow link my express and socket.io code so I can check if a client is authenticated before handing him any info via sockets. here is the system I'm currently using I didn't put all my code but I tried to summarize the essential parts:

const express = require('express');
const app = express();
//i creat the http server that is somehow linked with my express app when this server is listening
//it will call express handling methods.
const http = require('http').Server(app); 
const io = require('socket.io')(http);

const path = require("path");
const passport = require("passport");
const connectEnsureLogin = require('connect-ensure-login');
const AccountInfo = require("./AccountInfo").AcccountInfo;
const expressSession = require('express-session')({
    secret: process.env.SESSION_SECRET,
    resave: false, 
    saveUninitialized: false
  });

//passport setup
passport.use(AccountInfo.createStrategy()); 
passport.serializeUser(AccountInfo.serializeUser()); 
passport.deserializeUser(AccountInfo.deserializeUser());

//body parser
app.use(express.json());
app.use(express.urlencoded({ extended: true }));

//Sessions
app.use(expressSession);

//!!!!here is where I connect socket.io with the sessions i found this in another forum.
// thanks to this code I can access the session that a client is using when their socket connects.
io.use(function(socket, next) {
  expressSession(socket.request, socket.request.res, next);
});

//so when a clients socket connects i save his socket.id to his session.
io.on('connection',function(socket) {
  console.log(`socket.io connected: ${socket.id}`);
  // save socket.io socket in the session
  socket.request.session.socketio = socket.id;
  socket.request.session.save();
});

//once the clients socket is connected directly after the clients sends a HTTP "PUT" request
//and this code answers it.
app.post('/Table/ConnectSocketToTable',Utilities.ensureLoggedIn(),function(req, res)
{
   
    //I retrieve the socket using the socket.id I had saved in the session. 
    let socket = io.sockets.sockets.get(req.session.socketio);

    let player = GetPlayerFromAnyTable(req.user.username);
    if(player==null)//the player can't be in two tables at once 
    {
//since now we are in an express callback, express made sure that the client is indeed
//authenticated with the middle-ware: "Utilities.ensureLoggedIn()" also just before I made sure
//the client is not in another table. So we are good to go we can now link the socket to the table
//and have the client receive all the info about the state of his table
        socket.join("table-"+req.session.passport.table);
        req.user.socket = socket;
        let table = GetTable(req.session.passport.table);
        table.sitPlayer(req.user);
    }
    else
    { 
//the player is already connected so we just update his socket to a new one
        player.requestUnseat=false;
        player.account.socket =io.sockets.sockets.get(req.session.socketio);
    }

    socket.on('chatMessage', function(data,time) {
        socket.to("table-"+req.session.passport.table).emit("chatMessage",req.user.username,data,time);
        console.log(`send chat message : ${data}`);
      });
    socket.on('disconnect', function() {
        GetTable(req.session.passport.table).requestUnsitUsername(req.user.username);
        console.log(req.user.username +" was disconnected so now requesting unsit");
      });

    console.log("the socket of "+req.user.username+" has being connected to table-"+req.session.passport.table);
    return res.sendStatus(200); 
});

So for me, the way I'm doing this seems pretty bad since "app.post('/Table/ConnectSocketToTable'...)" and "io.on('connection',...)" are two different request listening functions I feel I should probably just do everything in one. So should I do all the checks in the "io.on('connection',...)" function and somehow manage to make sure the client is authenticated within the callback of io.on('connection',callback) ? or should I find a way to make the socket connection happen in the initial HTTP call the client uses to join a table, which is what I initially wanted? But really I'm kinda lost because I'm telling myself maybe I don't even need Express anymore and I should just use socket.io for everything. I seem to clearly lack the general understanding that would allow me to know what approach I should be going for so any help is welcome. I started doing this self-made exercise to get into server-side development but also if there is any other recommended exercise to start up with back-end development I'm definitely interested in hearing about it.

Answer 1

From random testing I found out how to authenticate to my express session from the socket code you don't actually have to do it in the callback of io.on('connection',callback) you just need to add a few more middleware functions like this:

//connecting express sessions
io.use(function(socket, next) {
  expressSession(socket.request, socket.request.res, next);
});
//connecting passport
io.use(function(socket, next) {
  passport.initialize()(socket.request, socket.request.res, next);
});
//connecting passport sessions
io.use(function(socket, next) {
  passport.session()(socket.request, socket.request.res, next);
});

//check if client is authenticated returns error if authentication failed
io.use((socket, next) => {
  console.log("started socket Connection");
  if(!socket.request.isAuthenticated&&socket.request.isAuthenticated())
  {
    socket.request.session.socketio = socket.id;
    socket.request.session.save();
    console.log("table "+socket.request.session.passport.table);
    console.log("user.username "+socket.request.user.username);
    console.log(`is authentificated`);
    next();
  }
  else
  {
    console.log(`failed socket connection`);
    next(new Error("unauthorized"));
  }
});```