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Im following the socket io documentation though still am getting an error
polling-xhr.js:157 GET http://localhost:3000/socket.io/?EIO=4&transport=polling&t=NtNlWd6 404 (Not Found)
it my be something very simple though I am stuck
below is my code
server.js
const express = require('express'); //Line 1
const app = express(); //Line 2
const port = process.env.PORT || 5000; //Line 3
const http = require('http').Server(app);
const io = require('socket.io')(http);
//Whenever someone connects this gets executed
io.on('connection', function(socket) {
console.log('A user connected');
//Whenever someone disconnects this piece of code executed
socket.on('disconnect', function () {
console.log('A user disconnected');
});
});
// This displays message that the server is running and listening to specified port
app.listen(port, () => console.log(`Listening on port ${port}`)); //Line 6
// create a GET route
app.get('/express_backend', (req, res) => { //Line 9
console.log("printing from the server f3f134g")
res.send({ express: "YOUR EXPRESS BACKEND IS CONNECTED TO REACT" }); //Line 10
}); //Line 11
index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<link rel="icon" href="%PUBLIC_URL%/favicon.ico" />
<meta
name="viewport"
content="width=device-width, initial-scale=1"
/>
<meta name="theme-color" content="#000000" />
<meta
name="description"
content="Web site created using create-react-app"
/>
<link
rel="apple-touch-icon"
href="%PUBLIC_URL%/logo192.png"
/>
</head>
<body>
<script src="https://cdn.socket.io/4.4.0/socket.io.min.js" integrity="sha384-1fOn6VtTq3PWwfsOrk45LnYcGosJwzMHv+Xh/Jx5303FVOXzEnw0EpLv30mtjmlj" crossorigin="anonymous"></script>
<script>
var socket = io();
</script>
<div id="root"></div>
</body>
</html>
please note both
```<script src="/socket.io/socket.io.js"></script>```
and
<script src="https://cdn.socket.io/4.4.0/socket.io.min.js" integrity="sha384-1fOn6VtTq3PWwfsOrk45LnYcGosJwzMHv+Xh/Jx5303FVOXzEnw0EpLv30mtjmlj" crossorigin="anonymous"></script>
give an error
214
asked Jan 19 '26 19:01
The problem is in your server code.
You bind socket.io to http, but only app listens on the port (5000). You need to make http listen on that port.
Change this line:
app.listen(port, () => console.log(`Listening on port ${port}`));
to
http.listen(port, () => console.log(`Listening on port ${port}`));
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