Can't get connection to socket server - socket.io

Question

I'm fairly new to a lot of this stuff and am trying to figure it out.
I have a hosted domain at <my.domain.com>. I host a game at this address that users can go to that address and the game loads in the browser for them.
On the same server I am running an Express nodejs (we'll call this HTTP SERVER) server to receive HTTP requests.
Also on the same server I am running a socket server using the Socket.io (we'll call this SOCKET SERVER) library.
HTTP SERVER can connect to SOCKET SERVER via localhost:<port> and they can communicate back and forth. I can send requests from my mobile device to HTTP SERVER which forwards those request to SOCKET SERVER and get a response back on the mobile device.
My problem now is I need to create another connection to SOCKET SERVER from my hosted game at <my.domain.com>. However, when I attempt to connect to localhost:<port> like I do from HTTP SERVER I get an ERR_CONNECTION_REFUSED error. I am assuming this has to do with with the host name being different. I've attempted to add
app.use(function(req, res, next) => {
res.header('Access-Control-Allow-Origin', '*');
});
But that doesn't seem to help. I'm not really sure where to go from here.
Socket server app.js
const app = require('express')();
const server = require('http').Server(app);
const io = require('socket.io')(server);
app.use(function(req, res, next) {
res.header('Access-Control-Allow-Origin', '*');
});
server.listen(8082);
io.on('connection', (socket) => {
console.log(`Socket server 'connection' event`);
});
Code in HTTP SERVER that does properly connect and send/receive messages
var socket = require('socket.io-client')('http://localhost:8082');
socket.on('connect', () => {
console.log(`HTTP server - 'connect' event to socket server`);
});
This is a javascript file that the game loads as an add-on. Hooks is provided by the game as an EventEmitter. I do not have direct access to the HTML pages the game displays, though I can manipulate them via this javascript add-on file.
let socket;
// a game hook when it's initialized
Hooks.on("init", function() {
// don't have direct access to game pages, so create a script tag and load
// the socket.io client library
const scriptRef = document.createElement('script');
scriptRef.setAttribute('type', 'text/javascript');
scriptRef.setAttribute('onload', 'window.socketLibraryLoaded()');
scriptRef.setAttribute('src', 'https://cdnjs.cloudflare.com/ajax/libs/socket.io/2.3.0/socket.io.js');
document.getElementsByTagName('head')[0].appendChild(scriptRef);
});
// handler for when library is loaded
window.socketLibraryLoaded = () => {
log('Socket library loaded');
// i assume this address is wrong since the host of the game is <my.domain.com> and it's trying to connect to localhost
socket = io('https://localhost:8082');
socket.on('connect', () => {
log('Connected to socket server');
});
socket.on('connect_error', error => {
log(error);
});
}

Answer 1

So after banging my head on the wall for more than 10 hours over this I finally found the issue. And of course a simple user error.
The CORs error wasn't really the problem. I was getting that error because the NGINX proxy was erroring which caused the proper headers not to get sent back so the browser showed that error.
The issue was that in one place in my NGINX configuration I was using 127.0.0.0 instead of 127.0.0.1