chat-server.node.mjs

// See ./README.md for instructions on how to run this benchmark.
const port = process.env.PORT || 4001;
const CLIENTS_TO_WAIT_FOR = parseInt(process.env.CLIENTS_COUNT || "", 10) || 16;

import { createRequire } from "module";
const require = createRequire(import.meta.url);
var WebSocketServer = require("ws").Server,
  config = {
    host: "0.0.0.0",
    port,
  },
  wss = new WebSocketServer(config, function () {
    console.log(`Waiting for ${CLIENTS_TO_WAIT_FOR} clients to connect..`);
  });

var clients = [];

wss.on("connection", function (ws, { url }) {
  const name = new URL(new URL(url, "http://localhost:3000")).searchParams.get(
    "name"
  );
  console.log(
    `${name} connected (${CLIENTS_TO_WAIT_FOR - clients.length} remain)`
  );
  clients.push(ws);

  ws.on("message", function (message) {
    const out = `${name}: ${message}`;
    for (let client of clients) {
      client.send(out);
    }
  });

  // when a connection is closed
  ws.on("close", function (ws) {
    clients.splice(clients.indexOf(ws), 1);
  });

  if (clients.length === CLIENTS_TO_WAIT_FOR) {
    sendReadyMessage();
  }
});

function sendReadyMessage() {
  console.log("All clients connected");
  setTimeout(() => {
    console.log("Starting benchmark");
    for (let client of clients) {
      client.send(`ready`);
    }
  }, 100);
}