greenlock-express.js/examples/socket.io.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";

//var greenlock = require('greenlock-express');
var greenlock = require("../");
var options = require("./greenlock-options.js");
var socketio = require("socket.io");
var server;
var io;

// Any node http app will do - whether express, raw http or whatever
options.app = require("express")().use("/", function(req, res) {
	res.setHeader("Content-Type", "text/html; charset=utf-8");
	res.end("Hello, World!\n\n💚 🔒.js");
});

// The server that's handed back from `listen` is a raw https server
server = greenlock.create(options).listen(80, 443);
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);
	});
});