Develop Reference

What do I replace "http://localhost:3000" with when using a server and not local machine?

I've been doing a lot of online courses with node and express. I want to get sockets.io to work but I can't even establish a connection at the moment. I am using a cPanel virtual private server and running code in the server terminal and then trying to use a website hosted on the server to access the .js file running on the server.
I've tried all sorts of different things but I'm reducing it to its most basic level to try get a connection. All the videos I've seen are running on a local machine and using the command prompt on a local machine to run the .js file and the browser to access http://localhost:3000.
The .js file I'm running on my cPanel server looks like this;
var express = require('express');
var app = express();
app.get('/', function(req,res){
res.send('Hello world 2');
})
app.listen(3000);
So how do I then access that via the browser? I have tried http://mywebsite.com:3000 and http://11.22.33.444:3000 if 11.22.33.444 is the server ip, but the browser just times out and there is no output in the server console.
ultimately I need to run a socket.io command that looks like this;
var socket = io.connect('http://localhost:3000');
and in all the tutorials I've seen they use this localhost:3000 but no one explains how to access this if its on an actual server so I'm pretty lost.
There are other examples like;
...
const http = require('http').createServer();
...
http.listen(3000 => () => {
console.log('listening on port 3000');
});
That's just a snippet of the code but I'm wondering how I then access that 3000 port from the browser without http://localhost:3000

IF you read the docs you will see that there is a guide how to connect it with express: https://socket.io/docs/
var app = require('express')();
var server = require('http').Server(app);
var io = require('socket.io')(server);
server.listen(3000);
// WARNING: app.listen(3000) will NOT work here!
app.get('/', function (req, res) {
res.status(200).json({ message: "Connected" });
});
io.on('connection', function (socket) {
console.log("somebody connected");
});

Think I just solved it. I tried a different port and it worked :/

No need to specify any address in io.connect()
const app = express();
const http = require('http').Server(app);
const io = require('socket.io')(http);
http.listen(process.env.PORT || 3000, function() {
});
<script src="/socket.io/socket.io.js"></script>
var socket = io.connect();

Client unable to connect to server with socket.io

I'm having trouble with being able to connect to my node.js server from an external domain. It works fine when running it locally using the http web server through node however when connecting externally, it loads the socket.io.js file just fine but when trying to use the socket it removes the port from the URL and cannot connect.
Instead of doing this in the network requests:
http://external-domain.com:3000/socket.io/?EIO=3&transport=polling&t=M06GOUU
it does this:
http://external-domain.com/socket.io/?EIO=3&transport=polling&t=M06GOUU
I'm not sure how to make it not remove the port from the connection. How do I go about fixing this?
SERVER
const path = require('path');
const http = require('http');
const express = require('express');
const socketIO = require('socket.io');
const publicPath = path.join(__dirname, '../public');
var app = express();
var server = http.createServer(app);
var io = socketIO(server);
app.use(express.static(publicPath));
server.listen(3000, () => {
console.log(`Server is up on port 3000`);
});
CLIENT SCRIPT TAG
<script src="http://external-domain.com:3000/socket.io/socket.io.js"></script>
CLIENT JS ON A DIFFERENT DOMAIN
var socket = io();
socket.connect('http://external-domain.com:3000');
socket.on('connect', function () {
console.log('Connected to server.');
});

Change from this:
var socket = io();
socket.connect('http://external-domain.com:3000');
to just this:
var socket = io("http://external-domain.com:3000");
And, you don't use the socket.connect() as you will already have requested the connection with the io("http://external-domain.com:3000"); call.
Explanation
The code:
var socket = io();
uses the page URL to connect to a socket.io server at that origin. That is not what you want (apparently).
If you wanted to use the .connect() method, it would be like this:
var socket = io.connect("http://external-domain.com:3000");
Note: var socket = io(url) is simply a shortcut for var socket = io.connect(url).
socket.connect() does not accept a URL as a parameter so you simply weren't using that correctly. It's just a synonym for socket.open().

Use io.connect("url")
var socket = io.connect("http://external-domain.com:3000", { rejectUnauthorized: false });
// { rejectUnauthorized: false } is an optional parameter.
Hope this works for you.

Using socket io without returning the index.html throws an error

I would like to setup websocket without necessarily having to return the index.html file
Am still new to the socket io and this is what i have tried
installed socket io via
npm install socket.io --save
created index.js
var http = require('http');
var fs = require('fs');
// Loading socket.io
var io = require('socket.io');
// When a client connects, we note it in the console
io.sockets.on('connection', function (socket) {
console.log('A client is connected!');
});
server.listen(1100);
Now when i run node index am getting an error
io.sockets.on('connection', function (socket) {
^
TypeError: Cannot read property 'on' of undefined
What am trying to do is connect the websocet to my vuejs client side so ive skipped the part to display html part since i dont want to display html but to use the socket events.
where am i going wrong?

Hey you need to attach socket.io to an http server for your code to work and listen to incoming events.
var express = require('express');
var app = express();
var server = require('http').Server(app);
var io = require('socket.io').listen(server);
//io.on is the shorter form of io.sockets.on
io.on('connection', function(socket){
console.log('user connected');
});

400 bad request (making game with node and socket.io)

Making a game, I have no idea what I am doing when it comes to the online aspect.
I am using node.js using my computer as the server host and client (localhost:3000)
var express = require('express'); //no idea what I am doing here
var app = express();
var server = app.listen(3000);
var socket = require("socket.io");
var io = socket(server);
io.sockets.on('connection', newConnection);
app.use(express.static("public"));
console.log("server is up"); //tells me that the server is ready
function newConnection(socket) {
console.log("new player!", socket.id); //tells me when a new player connects.
}
also have this code within the main public javascript file
var socket;
socket = io.connect("localhost:3000");
Whenever a new player connects i get 400 bad request errors and the game thinks multiple players have joined.
picture to aid
so pls help.

You will need to handle what happens when someone connects to your server.
var express = require('express');
var app = express();
var server = require("http").createServer(app);
server.listen(3000) //server listens on port 3000
var io = require("socket.io")(server)
//this will be called when a new client connects
io.on("connection", (socket)=>{
//socket is the socket object of the new client
console.log("new socket connected with socket id = " + socket.id)
})
Look at socket.io docs for more info.

In my game, I had a constructor function called "Number" and that was causing the problem the entire time.
I'm assuming that the socket.io or node.js already had a function called "Number" and that's what caused the problem.

node.js - Hosting server on public IP with socket.io

Consider the server code:
express = require('express');
app = express();
app.use('/', express.static(__dirname + '/'));
http = require('http').Server(app);
io = require('socket.io')(http);
...
http.listen(80);
I have also tried http.listen(80, "::").
And the client code:
socket = io();
This leads to the following console error when entering http://[#PUBLIC_IPv6_OF_SERVER]:3000 in the browser:
ERR_NAME_NOT_RESOLVED
How can I successfully enable clients to connect to the server through its public IPv6 address?

You need to allow cross origin request on server side.
var domains = "http://localhost:*";
io = require('socket.io')(http, {origins:domains});