greenlock-express.js/examples/socket.io/server.js

// First and foremost:
// I'm not a fan of `socket.io` because it's huge and complex.
// I much prefer `ws` because it's very simple and easy.
// That said, it's popular.......
"use strict";

// Note: You DO NOT NEED socket.io
//       You can just use WebSockets
//       (see the websocket example)

function httpsWorker(glx) {
	var socketio = require("socket.io");
	var io;

	// we need the raw https server
	var server = glx.httpsServer();

	io = socketio(server);

	// Then you do your socket.io stuff
	io.on("connection", function(socket) {
		console.log("a user connected");
		socket.emit("Welcome");

		socket.on("chat message", function(msg) {
			socket.broadcast.emit("chat message", msg);
		});
	});

	// servers a node app that proxies requests to a localhost
	glx.serveApp(function(req, res) {
		res.setHeader("Content-Type", "text/html; charset=utf-8");
		res.end("Hello, World!\n\n💚 🔒.js");
	});
}

var pkg = require("../../package.json");
//require("greenlock-express")
require("../../")
	.init(function getConfig() {
		// Greenlock Config

		return {
			package: { name: "socket-io-example", version: pkg.version },
			maintainerEmail: "jon@example.com",
			cluster: false
		};
	})
	.serve(httpsWorker);