dougal-software/lib/www/server/ws/index.js

const ws = require('ws');
const URL = require('url');
const { listen } = require('../lib/db/notify');
const channels = require('../lib/db/channels');

function start (server, pingInterval=30000) {

	const wsServer = new ws.Server({ noServer: true });
	wsServer.on('connection', socket => {
		socket.alive = true;
		socket.on('pong', function () { this.alive = true; })
		socket.on('message', message => console.log(message));
	});

	server.on('upgrade', (request, socket, head) => {
// 		console.log("Received upgrade request", request.url);
		const url = URL.parse(request.url);
		if (/^\/dougal-websocket\/?$/.test(url.pathname)) {
			wsServer.handleUpgrade(request, socket, head, socket => {
				wsServer.emit('connection', socket, request);
			});
		}
	});

	listen(channels, (data) => {
		wsServer.clients.forEach( (socket) => {
			socket.send(JSON.stringify(data));
		})
	});

	const interval = setInterval( () => {
		wsServer.clients.forEach( (socket) => {
			if (!socket.alive) {
				return socket.terminate();
			}
			socket.alive = false;
			socket.ping();
		})
	}, pingInterval);

	wsServer.on('close', () => clearInterval(interval));

	return wsServer;
}

module.exports = {
	start
}