Needing a websocket with my website, I wanted to use socket.io.
However, I am experiencing a CORS issue:
Access to XMLHttpRequest at 'http://localhost:2021/socket.io/?EIO=4&transport=polling&t=NlbFGS2' from origin 'http://localhost:63341' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.
polling-xhr.js:202
GET http://localhost:2021/socket.io/?EIO=4&transport=polling&t=NlbFGS2 net::ERR_FAILED
So I found this code on the socket.io site that I tried but I still have the same problem...
const app = require('express')();
const http = require('http').createServer(app);
const io = require("socket.io")(http, {
cors: {
origin: ["http://localhost:63341/"],
methods: ["GET", "POST"]
}
})
And here is the code on the client side:
<script src="https://cdn.jsdelivr.net/npm/socket.io-client@4.1.2/dist/socket.io.msgpack.min.js"></script>
<script>
let socket = io('http://localhost:2021')
</script>
Follow these steps on your backend server:
Run npm install cors
Add this code after creating app:
app.use(cors({
origin: "http://localhost:63341"
}))
Restart your server and check if it works or not.
If it still doesn't work, then change your line 3 with this:
const io = require("socket.io")(http); // no cors configuration.
You could use this to just allow anything to connect... Don't do this in production though.
export const io = new Server(http, {
cors: { origin: "*" },
});