NodeJS Express App not calling app.use - node.js

Question

I have a NodeJS app I am using as a game server.
I am trying to setup CORS with it, but app.use doesn't seem to be getting called.
Anyone know why?
var util = require("util"); // Utility resources (logging, object inspection, etc)
var fs = require('fs');
var express = require("express");
var app = express();
var port = 3000;
app.use(function (req, res, next) {
// these never get printed out:
util.log( "app.use adding Access-Control-Allow-Origin" );
console.log( "app.use adding Access-Control-Allow-Origin" );
// Website you wish to allow to connect
res.setHeader('Access-Control-Allow-Origin', 'https://example.com');
// Request methods you wish to allow
res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS, PUT, PATCH, DELETE');
// Request headers you wish to allow
res.setHeader('Access-Control-Allow-Headers', 'X-Requested-With,content-type');
// Set to true if you need the website to include cookies in the requests sent
// to the API (e.g. in case you use sessions)
res.setHeader('Access-Control-Allow-Credentials', true);
// Pass to next layer of middleware
next();
});
var server = app.listen(port, function(){
console.log('CORS-enabled web server listening on port ' + port);
});
var io = require('socket.io').listen(server);

Answer 1

Checkout the npm cors package. https://www.npmjs.com/package/cors
Example usage where all requests will be CORS enabled:
var express = require('express')
, cors = require('cors')
, app = express();
app.use(cors());
app.get('/my_API_URL/:id', function(req, res, next){
res.json({msg: 'This is CORS-enabled for all origins!'});
});
app.listen(80, function(){
console.log('CORS-enabled web server listening on port 80');
});
On their page they also got other examples where the CORS are only enabled on a single route.
Also, just wondering how are you testing your application? You haven't defined any routes in the example code.
As pointed out in the comment section, #Nitzan Wilnai is not doing REST API, apologise for the confusion. It is suppose to be a simple server that listens on a certain port, so for this case you might not need express at all. Did some research and this solution came out;
io.configure('development', function(){
io.set('origins', '*:*');
}
OR
io.set( 'origins', '*domain.com*:*' );
References:
Socket.io doesn't set CORS header(s)
Just in case you are trying to build a chat program. Here is an example project;
https://github.com/socketio/socket.io