server.js

const express = require("express");
const path = require("path");
const http = require("http");
const app = express();
const server = http.createServer(app);
const io = require("socket.io").listen(server);

// Server all the static files from www folder
app.use(express.static(path.join(__dirname, "www")));
app.use(express.static(path.join(__dirname, "icons")));
app.use(express.static(path.join(__dirname, "node_modules/vue/dist/")));

// Get PORT from env variable else assign 3000 for development
const PORT = process.env.PORT || 3000;
server.listen(PORT, null, () => console.log("Listening on port " + PORT));

app.get("/legal", (req, res) => res.sendFile(path.join(__dirname, "www/legal.html")));

// All URL patterns should served with the same file.
app.get(["/", "/:room"], (req, res) => res.sendFile(path.join(__dirname, "www/index.html")));

const channels = {};
const sockets = {};

io.sockets.on("connection", (socket) => {
	const socketHostName = socket.handshake.headers.host.split(":")[0];

	socket.channels = {};
	sockets[socket.id] = socket;

	console.log("[" + socket.id + "] connection accepted");
	socket.on("disconnect", () => {
		for (const channel in socket.channels) {
			part(channel);
		}
		console.log("[" + socket.id + "] disconnected");
		delete sockets[socket.id];
	});

	socket.on("join", (config) => {
		console.log("[" + socket.id + "] join ", config);
		const channel = socketHostName + config.channel;

		// Already Joined
		if (channel in socket.channels) return;

		if (!(channel in channels)) {
			channels[channel] = {};
		}

		for (const id in channels[channel]) {
			channels[channel][id].emit("addPeer", { peer_id: socket.id, should_create_offer: false });
			socket.emit("addPeer", { peer_id: id, should_create_offer: true });
		}

		channels[channel][socket.id] = socket;
		socket.channels[channel] = channel;
	});

	const part = (channel) => {
		// Socket not in channel
		if (!(channel in socket.channels)) return;

		delete socket.channels[channel];
		delete channels[channel][socket.id];

		for (const id in channels[channel]) {
			channels[channel][id].emit("removePeer", { peer_id: socket.id });
			socket.emit("removePeer", { peer_id: id });
		}
	};

	socket.on("relayICECandidate", (config) => {
		let peer_id = config.peer_id;
		let ice_candidate = config.ice_candidate;
		console.log("[" + socket.id + "] relay ICE-candidate to [" + peer_id + "] ", ice_candidate);

		if (peer_id in sockets) {
			sockets[peer_id].emit("iceCandidate", { peer_id: socket.id, ice_candidate: ice_candidate });
		}
	});

	socket.on("relaySessionDescription", (config) => {
		let peer_id = config.peer_id;
		let session_description = config.session_description;
		console.log("[" + socket.id + "] relay SessionDescription to [" + peer_id + "] ", session_description);

		if (peer_id in sockets) {
			sockets[peer_id].emit("sessionDescription", {
				peer_id: socket.id,
				session_description: session_description,
			});
		}
	});
});