Menu
I'm trying to getting started with socket.io and node.js.
Following the first example on the socket.io's site I'm getting the following error in the browser's console:
Failed to load resource: the server responded with a status of 404 (Not Found) http://localhost:3001/socket.io/socket.io.js
Uncaught ReferenceError: io is not defined
This is my server.js
var app = require('express').createServer()
, io = require('socket.io').listen(app);
app.listen(3001);
app.get('/', function (req, res) {
res.sendfile(__dirname + '/index.html');
});
io.sockets.on('connection', function (socket) {
socket.emit('news', { hello: 'world' });
socket.on('my other event', function (data) {
console.log(data);
});
});
And this is my index.html
<!DOCTYPE html>
<html>
<head>
<title></title>
<meta charset="UTF-8" />
</head>
<body>
<script src="/socket.io/socket.io.js"></script>
<script>
var socket = io.connect('http://localhost');
socket.on('news', function (data) {
console.log(data);
socket.emit('my other event', { my: 'data' });
});
</script>
</body>
</html>
I've already installed socket.io..
832
Error handling There is currently no built-in error handling in the Socket.IO library, which means you must catch any error that could be thrown in a listener.
Although Socket.IO indeed uses WebSocket as a transport when possible, it adds additional metadata to each packet. That is why a WebSocket client will not be able to successfully connect to a Socket.IO server, and a Socket.IO client will not be able to connect to a plain WebSocket server either.
First of all you need to be looking at the server port that the server is bound on (app.listen(3001);) on the client side in order to reach the server at all.
As for socket.io, adding http://localhost:3001 before the rest of the source in the link tag solves this problem. This is apparently due to the way the network binds ports to localhost, however I will try to find some more information on the cause;
The port binding for the server:
var socket = io.connect('http://localhost');
should be change to
var socket = io.connect('http://localhost:3001');
Making socket.io behave:
<script src="/socket.io/socket.io.js"></script>
should be change to
<script src="http://localhost:3001/socket.io/socket.io.js"></script>
156
If you are using express version 3.x there are Socket.IO compatibility issues that require a bit of fine tuning to migrate:
Socket.IO's
.listen()method takes anhttp.Serverinstance as an argument.
As of 3.x, the return value ofexpress()is not anhttp.Serverinstance. To get Socket.IO working with Express 3.x, make sure you manually create and pass yourhttp.Serverinstance to Socket.IO's.listen()method.
Here is a quick example:
var app = express()
, http = require('http')
, server = http.createServer(app)
, io = require('socket.io').listen(server);
server.listen(3000);
Firstly, the Socket.io "How To Use" documentation is vague (perhaps misleading); especially when documenting code for the Socket.io client.
Secondly the answers you've been given here on StackOverflow are too specific. You shouldn't have to manually hardcode the protocol, hostname, and port number for the Socket.io client; that's not a scalable solution. Javascript can handle this for you with the location object - window.location.origin.
Socket.io requires the installation of a server and client.
To install the servernpm install socket.io
To use the client, add this script to your document (index.html)<script src="https://cdn.socket.io/socket.io-1.4.5.js"></script>
Create the following files:
Server (app.js)
var app = require('express')();
var server = require('http').Server(app);
var io = require('socket.io')(server);
server.listen(80);
app.get('/', function (req, res) {
res.sendfile(__dirname + '/index.html');
});
io.on('connection', function (socket) {
socket.emit('news', { hello: 'world' });
socket.on('my other event', function (data) {
console.log(data);
});
});
Client (index.html)
<script src="https://cdn.socket.io/socket.io-1.4.5.js"></script>
<script>
// origin = http(s)://(hostname):(port)
// The Socket.io client needs an origin
// with an http(s) protocol for the initial handshake.
// Web sockets don't run over the http(s) protocol,
// so you don't need to provide URL pathnames.
var origin = window.location.origin;
var socket = io.connect(origin);
socket.on('news', function (data) {
console.log(data);
socket.emit('my other event', { my: 'data' });
});
</script>
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
