Managing Cross-Origin Resource Sharing in web socket communication

Question

Managing Cross-Origin Resource Sharing in web socket communication

While working on a client and server application that communicate over web sockets, I discovered that addressing CORS only on the web socket did not result in any additional CORS issues compared to handling CORS on the server side itself.

Prior to resolving the problem, the error I encountered on the client side was:

Access to XMLHttpRequest at 'http://localhost:5000/socket.io/?EIO=4&transport=polling&t=NOOM0wp' from origin 'http://localhost:3000' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

The absence of the "Access-Control-Allow-Origin" header on the response object only occurred when I implemented CORS handling on the server side.

However, I then faced an error on the client side:

GET http://localhost:5000/socket.io/?EIO=4&transport=polling&t=NOONjI6 net::ERR_CONNECTION_REFUSED

Although this seems like a straightforward issue, I would appreciate a detailed explanation for clarification.

javascript express websocket socket.io cors

Answer 1

Answer №1

Implement the use of cors configuration.

For more information, check out the guide on Handling CORS.

var express = require('express')
var app = express()
var app = express()
var server = require('http').createServer(app)
var io = require('socket.io')(server, {
  cors: {
    origin: "*" // specify your own origin, or '*' to allow any origins.
  }
})

Answer 2

Implement the use of cors configuration.

For more information, check out the guide on Handling CORS.

var express = require('express')
var app = express()
var app = express()
var server = require('http').createServer(app)
var io = require('socket.io')(server, {
  cors: {
    origin: "*" // specify your own origin, or '*' to allow any origins.
  }
})

Managing Cross-Origin Resource Sharing in web socket communication

Answer №1

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