const fs = require("fs"); const https = require("https"); const WebSocket = require("ws"); const client = require("prom-client"); // Create a Registry which registers the metrics const register = new client.Registry(); // Add a default label which is added to all metrics register.setDefaultLabels({ app: "clocktower-online" }); 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 && !!info.origin.match( /^https?:\/\/([^.]+\.github\.io|localhost|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 = {}; // metrics const metrics = { players_concurrent: new client.Gauge({ name: "players_concurrent", help: "Concurrent Players", collect() { this.set(wss.clients.size); } }), channels_concurrent: new client.Gauge({ name: "channels_concurrent", help: "Concurrent Channels", collect() { this.set(Object.keys(channels).length); } }), channels_list: new client.Gauge({ name: "channel_players", help: "Players in each channel", labelNames: ["name"], collect() { for (let channel in channels) { this.set( { name: channel }, channels[channel].filter( ws => ws && (ws.readyState === WebSocket.OPEN || ws.readyState === WebSocket.CONNECTING) ).length ); } } }), messages_incoming: new client.Counter({ name: "messages_incoming", help: "Incoming messages" }), messages_outgoing: new client.Counter({ name: "messages_outgoing", help: "Outgoing messages" }), connection_terminated_host: new client.Counter({ name: "connection_terminated_host", help: "Terminated connection due to host already present" }), connection_terminated_spam: new client.Counter({ name: "connection_terminated_spam", help: "Terminated connection due to message spam" }), connection_terminated_timeout: new client.Counter({ name: "connection_terminated_timeout", help: "Terminated connection due to timeout" }) }; // register metrics for (let metric in metrics) { register.registerMetric(metrics[metric]); } // a new client connects wss.on("connection", function connection(ws, req) { // url pattern: clocktower.online// const url = req.url.toLocaleLowerCase().split("/"); ws.playerId = url.pop(); ws.channel = url.pop(); // check for another host on this channel if ( ws.playerId === "host" && channels[ws.channel] && channels[ws.channel].some( client => client !== ws && client.readyState === WebSocket.OPEN && client.playerId === "host" ) ) { console.log(ws.channel, "duplicate host"); ws.close(1000, `The channel "${ws.channel}" already has a host`); metrics.connection_terminated_host.inc(); 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); // handle message ws.on("message", function incoming(data) { metrics.messages_incoming.inc(); // 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." ); metrics.connection_terminated_spam.inc(); return; } const messageType = data .toLocaleLowerCase() .substr(1) .split(",", 1) .pop(); // don't log ping messages if (messageType !== '"ping"') { console.log(new Date(), wss.clients.size, ws.channel, ws.playerId, data); } // handle "direct" messages differently if (messageType === '"direct"') { try { const dataToPlayer = JSON.parse(data)[1]; channels[ws.channel].forEach(function each(client) { if ( client !== ws && client.readyState === WebSocket.OPEN && dataToPlayer[client.playerId] ) { client.send(JSON.stringify(dataToPlayer[client.playerId])); metrics.messages_outgoing.inc(); } }); } catch (e) { console.log("error parsing direct message JSON", e); } } else { // all other messages channels[ws.channel].forEach(function each(client) { if (client !== ws && client.readyState === WebSocket.OPEN) { // inject latency between both clients if ping message if (messageType === '"ping"' && client.latency && ws.latency) { client.send(data.replace(/latency/, client.latency + ws.latency)); } else { client.send(data); } metrics.messages_outgoing.inc(); } }); } }); }); // start ping interval timer const interval = setInterval(function ping() { // ping each client wss.clients.forEach(function each(ws) { if (ws.isAlive === false) { metrics.connection_terminated_timeout.inc(); return ws.terminate(); } ws.isAlive = false; ws.pingStart = new Date().getTime(); ws.ping(noop); }); // clean up empty channels for (let channel in channels) { if ( !channels[channel].length || !channels[channel].some( ws => ws && (ws.readyState === WebSocket.OPEN || ws.readyState === WebSocket.CONNECTING) ) ) { metrics.channels_list.remove([channel]); delete channels[channel]; } } }, 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.setHeader("Content-Type", register.contentType); register.metrics().then(out => res.end(out)); }); }