node-haxball/streamingServer/src/index.js

The most powerful and lightweight API that allows you to develop your original Haxball(www.haxball.com) host, client, and standalone applications both on node.js and browser environments and also includes every possible hack and functionality that you can

const { WebSocketServer } = require("ws");
const { createServer } = require("http");
const server = createServer();
const wss = new WebSocketServer({server});
var hostWs = null, clients = new Map(), counter = -1;

wss.on("connection", (clientSocket) => {
  var a1 = new Uint8Array(3), a2 = new Uint8Array(3);
  var dv1 = new DataView(a1.buffer), dv2 = new DataView(a2.buffer);
  function sendClientCount(){
    var c = clients.size;
    dv1.setUint8(0, 0);
    dv1.setUint16(1, c);
    hostWs?.send(a1);
  }
  function requestInitialData(clientId){
    dv2.setUint8(0, 1);
    dv2.setUint16(1, clientId);
    hostWs?.send(a2);
  }
  function broadcast(data){
    var it = clients.values(), c = it.next();
    while (!c.done){
      c.value.send(data);
      c = it.next();
    }
  }
  counter++;
  if (counter>0){
    clients.set(counter, clientSocket);
    sendClientCount();
    requestInitialData(counter);
    clientSocket.on("close", () => {
      clients.delete(counter);
      sendClientCount();
    });
    return;
  }
  hostWs = clientSocket;
  hostWs.on("message", (data) => {
    if (data[0]==1){
      //clientSocket.send(data);
      var v = new DataView(data.buffer, data.byteOffset, data.byteLength).getUint16(1);
      var c = clients.get(v);
      if (!c)
        return;
      c.send(data);
      return;
    }
    broadcast(data);
  });
  hostWs.on("close", () => {
    hostWs = null;
    clients.clear();
  });
});
server.listen(1935);