server.js

const PORT = process.env.PORT || 5000;

// Utilities
const nanoid = require('nanoid').nanoid;
require('colors');

const http = require('http');
const WebSocket = require('ws');
const express = require('express');

const app = express();
const server = http.createServer(app);

const wss = new WebSocket.Server({ server });

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

// Listen to HTTP requests
server.listen(PORT, '127.0.0.1', () => {
	console.log(`Listening at ${PORT}...`);
});

server.on('error', error => {
	console.log(error);
});

// Manage HTTP requests using Express
app.get('/', (req, res) => {
	res.sendFile(__dirname + '/client.html');
});

wss.on('error', error => {
	console.log(error);
});

// Manage WebSocket connections
wss.on('connection', socket => {
	socket.id = nanoid();

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

	socket.on('close', () => {
		for (var channel in socket.channels) {
			part(channel);
		}
		console.log(`[${socket.id}] has disconnected.`.red);
		delete sockets[socket.id];
		console.log(
			`${Object.keys(sockets).length} ${Object.keys(sockets)}`.yellow
		);
	});

	socket.on('message', message => {
		message = JSON.parse(message);
		switch (message.type) {
			case undefined || false:
				console.log('No message type provided by client -', message);
				break;
			case 'join':
				console.log(
					`${socket.id} wants to join channel ${
						message.channel
					}, he sent the following userData: ${JSON.stringify(
						message.userData
					)}`.blue
				);
				var channel = message.channel;
				var userData = message.userData;

				if (channel in socket.channels) {
					console.log(
						`[${socket.id}] ERROR: already exists in ${channel}`.red
					);
					return;
				}

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

				for (id in channels[channel]) {
					// Connect newly created peer to existing peers
					channels[channel][id].send(
						JSON.stringify({
							type: 'addPeer',
							config: {
								peer_id: socket.id,
								should_create_offer: false,
							},
						})
					);
					// Connect existing peers to our newly created peer
					socket.send(
						JSON.stringify({
							type: 'addPeer',
							config: { peer_id: id, should_create_offer: true },
						})
					);
				}

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

				console.log(
					`${Object.keys(sockets).length} ${Object.keys(sockets)}`
						.yellow
				);

				// 'join' handler break
				break;
			case 'part':
				part(message.channel);
				// 'part' handler break
				break;
			case 'relayICECandidate':
				var peer_id = message.peer_id;
				var ice_candidate = message.ice_candidate;
				console.log(
					`[${socket.id}] relaying ICE candidate to [${peer_id}]`
						.underline.blue
					// ice_candidate
				);

				if (peer_id in sockets) {
					sockets[peer_id].send(
						JSON.stringify({
							type: 'iceCandidate',
							peer_id: socket.id,
							ice_candidate,
						})
					);
				}
				// 'relayICECandidate' handler break
				break;
			case 'relaySessionDescription':
				var peer_id = message.peer_id;
				var session_description = message.session_description;
				console.log(
					`[${socket.id}] relaying session description to [${peer_id}]`
						.underline.blue
					// session_description
				);

				if (peer_id in sockets) {
					sockets[peer_id].send(
						JSON.stringify({
							type: 'sessionDescription',
							peer_id: socket.id,
							session_description: session_description,
						})
					);
				}
				// 'relaySessionDescription' handler break
				break;
			default:
				console.log(
					'Unknown message type received from client -',
					message.type
				);
				break;
		}
	});

	// Utility function "part"
	const part = channel => {
		console.log(`[${socket.id}] wants to part channel ${channel}`.blue);

		if (!(channel in socket.channels)) {
			console.log(`[${socket.id}] ERROR: not in ${channel}`.red);
			return;
		}

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

		for (id in channels[channel]) {
			channels[channel][id].send(
				JSON.stringify({
					type: 'removePeer',
					peer_id: socket.id,
				})
			);
			socket.send(
				JSON.stringify({
					type: 'removePeer',
					peer_id: id,
				})
			);
		}
	};

	console.log(`[${socket.id}] has connected.`.green);
});