const fs = require("fs"); const https = require("https"); const WebSocket = require("ws"); const PING_INTERVAL = 30000; // 30 seconds const server = https.createServer({ cert: fs.readFileSync("cert.pem"), key: fs.readFileSync("key.pem") }); const wss = new WebSocket.Server({ ...(process.env.NODE_ENV === "development" ? { port: 8081 } : { server }), verifyClient: info => !!info.origin.match( /^https?:\/\/([^.]+\.github\.io|localhost|live\.clocktower\.online|eddbra1nprivatetownsquare\.xyz)/i ) }); function noop() {} // calculate latency on heartbeat function heartbeat() { this.latency = Math.round((new Date().getTime() - this.pingStart) / 2); this.counter = 0; this.isAlive = true; } // map of channels currently in use const channels = {}; // a new client connects wss.on("connection", function connection(ws, req) { ws.channel = req.url .split("/") .pop() .toLocaleLowerCase(); if (ws.channel.match(/-host$/i)) { ws.isHost = true; ws.channel = ws.channel.substr(0, ws.channel.length - 5); // check for another host on this channel if ( channels[ws.channel] && channels[ws.channel].some( client => client !== ws && client.readyState === WebSocket.OPEN && client.isHost ) ) { console.log(ws.channel, "duplicate host"); ws.close(1000, `The channel "${ws.channel}" already has a host`); return; } } ws.isAlive = true; ws.pingStart = new Date().getTime(); ws.counter = 0; // add channel to list if (!channels[ws.channel]) { channels[ws.channel] = []; } channels[ws.channel].push(ws); // start ping pong ws.ping(noop); ws.on("pong", heartbeat); // remove client from channels on close ws.on("close", () => { const index = channels[ws.channel].indexOf(ws); if (index >= 0) { channels[ws.channel].splice(index, 1); } if (!channels[ws.channel].length) delete channels[ws.channel]; }); // handle message ws.on("message", function incoming(data) { // check rate limit (max 5msg/second) ws.counter++; if (ws.counter > (5 * PING_INTERVAL) / 1000) { console.log(ws.channel, "disconnecting user due to spam"); ws.close( 1000, "Your app seems to be malfunctioning, please clear your browser cache." ); return; } const isPing = data.match(/^\["ping/i); if (!isPing) { console.log(new Date(), wss.clients.size, ws.channel, data); } channels[ws.channel].forEach(function each(client) { if (client !== ws && client.readyState === WebSocket.OPEN) { // inject latency between both clients if ping message if (isPing && client.latency && ws.latency) { client.send(data.replace(/latency/, client.latency + ws.latency)); } else { client.send(data); } } }); }); }); // start ping interval timer const interval = setInterval(function ping() { wss.clients.forEach(function each(ws) { if (ws.isAlive === false) return ws.terminate(); ws.isAlive = false; ws.pingStart = new Date().getTime(); ws.ping(noop); }); }, PING_INTERVAL); // handle server shutdown wss.on("close", function close() { clearInterval(interval); }); // prod mode with stats API if (process.env.NODE_ENV !== "development") { console.log("server starting"); server.listen(8080); server.on("request", (req, res) => { res.writeHead(200); res.end( JSON.stringify({ players: wss.clients.size, channels: Object.keys(channels).length }) ); }); }