socket.io connects with same socket id - node.js

Question

my socket creates problem when frontend loads before the server,
My problems are
1.I get same the socketid from the cookies of multiple clients
2.I get only one client who is connected with multiple socketids from the server
3.When I get this problem, my API calls will not work and I won't get any data from my database
I also get this problem when I restart the server, and when I refresh the frontend multiple times with different clients
my server side code
const mongoose = require("mongoose");
express = require("express");
app = express();
bodyParser = require("body-parser");
cookieParser = require("cookie-parser");
cors = require("cors");
user = require("./routes/user");
message = require("./routes/message");
http = require("http");
server = http.createServer(app);
io = require("socket.io")(server);
var userdata = require("./controllers/user");
mongoose
.connect(process.env.DATABASE, {
useNewUrlParser: true,
useUnifiedTopology: true,
useCreateIndex: true,
})
.then(() => {
console.log("DB CONNECTED");
})
.catch((err) => console.log(err));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
app.use(cookieParser());
app.use(cors());
app.use(express.json());
app.use("/use", user);
app.use("/use", message);
let users = [];
io.on("connection", (socket) => {
socket.on("done", () => {
let userdata = require("./controllers/user");
console.log("connected");
userdata.userdata &&
users.push({ userid: userdata.userdata._id, socketid: socket.id });
console.log(users);
});
socket.broadcast.emit("message");
socket.on("more", function (c) {
console.log(c.a, c.b);
let d = users.find((s) => s.userid === c.b);
if (d) {
return io.to(d.socketid).emit("message", c);
}
});
socket.on("disconnect", () => {
console.log(socket.id);
if (users) {
for (let e = 0; users.length; e++) {
if (users[e] && users[e].socketid === socket.id) {
return users.splice(e, 1);
}
}
}
console.log(users);
return console.log("disconnected");
});
});
// app.use();
const port = process.env.PORT || 8000;
server.listen(port, () => {
console.log(`app is running at ${port}`);
});
I found that my problem is caused by userdata, when I had deleted everything related to userdata, I didn't get any problem even when the server is reloaded.
Here userdata comes from a middileware called isSignedIn,this middleware is called before every API call from this webpage, so userdata gets updated frequently by the frontend code.This is my isSignedIn function
exports.isSignedIn = async (req, res, next) => {
const header = req.headers["authorization"];
const token = header && header.split(" ")[1];
if (!token) return res.json("no token");
jwt.verify(token, "jsdhbcjsd", (err, User) => {
if (err) return res.json(`${err} not signedin`);
req.User = User;
exports.userdata = User;
next();
});
};
I tried to call isSignedIn() instead of importing userdata, which would be lot better, but I was getting an error from the headers, so I couldn't call this function.
error I get when I call this function isSignedIn()
Promise {
<rejected> TypeError: Cannot read property 'headers' of undefined
at exports.isSignedIn (D:\message\backend\controllers\user.js:86:22)
it tells about this line
const header = req.headers["authorization"];
I made sure that the socket gets connected in the frontend only after calling the APIs using await,so that the userdata gets updated before connecting to the socket.I had tested it in the console,socket gets connected only after calling APIs
async componentDidMount() {
//my API calls
await this.friends(token);
await this.findfriends(token);
//connect the socket
this.start();
this.recieve();
}}
My frontend code
const client = require("socket.io-client");
var socket
export default class Home extends Component {
constructor(props) {
super(props);
this.start = this.start.bind(this);
this.send = this.send.bind(this);
this.recieve = this.recieve.bind(this);
this.friends= this.friends.bind(this);
this.findfriends= this.findfriends.bind(this);
}
start(){
socket=client("http://localhost:8000");
}
send(){
socket.emit("more", c)
}
recieve(){
socket.on("message", c)
}
async componentDidMount() {
//my API calls
await this.friends(token);
await this.findfriends(token);
//connect the socket
this.start();
this.recieve();
}}
render(){
return(my data)
}
}

Answer 1

After thinking for a while about requesting headers,which isn't possible, I thought, why couldn't I get userid from the socket when just it gets connected, then I tried this code, it worked perfectly fine
client side
start = () => {
socket = client("http://localhost:8000");
socket.on("connect", () => {
return socket.emit("userinfo", this.state.User._id);
});
};
server side
socket.on("userinfo", function (user) {
users.push({ userid: user, socketid: socket.id });
console.log("C O N N E C T E D");
});

Answer 2

You can't reassign exports.userdata = User; in middleware. That will affect every single request that uses those exports so they will all end up looking at the same userdata, no matter which user they are. That's the source of your confusion. There's only one exports object for each module and everyone who uses that module sees the same exports object. So, you can't use exports for request-specific data.
I see you are already assigning req.User = User. That is an appropriate place to put request-specific data and other users of that data in the processing of the request should get the data from req.User, not from the exported object. That will keep the data separate for each request and each user.