blitzchat/chatSocket.js

const WebSocket = require("ws");

const port = 8082;

console.log(`chatSocket is running on port ${port}!`);

const wss = new WebSocket.Server({ port: port });

function noop() {}

function heartbeat() {
  this.isAlive = true;
}

wss.on("connection", ws => {
  ws.isAlive = true;
  ws.on("pong", heartbeat);

  ws.on("message", data => {
    const msg = JSON.parse(data);
    switch (msg.event) {
      case "joining":
        msg.color = "black";
        msg.style = "bold";
        ws.username = msg.username;
        break;
      default:
        msg.style = "normal";
        break;
    }

    msg.timestamp = new Date();
    msg.msg = escapeHTML(msg.msg);
    msg.username = escapeHTML(msg.username);

    stringMsg = JSON.stringify(msg);
    sendAll(stringMsg);
  });
});

const interval = setInterval(function ping() {
  const users = getAllUsers();
  wss.clients.forEach(function each(ws) {
    if (ws.isAlive === false) {
      console.log(ws.username, " has left");
      return ws.terminate();
    }

    ws.isAlive = false;
    ws.ping(noop);
    let msg = {
      event: "users",
      msg: users,
      timestamp: Date.now()
    };
    ws.send(JSON.stringify(msg));
  });
}, 10000);

function getAllUsers() {
  let users = [];
  wss.clients.forEach(ws => {
    users.push(ws.username);
  });
  if (users.length > 0) {
    console.log("following users are online: " + users);
  }
  return users;
}

function sendAll(stringMsg) {
  wss.clients.forEach(function each(client) {
    if (client.readyState === WebSocket.OPEN) {
      client.send(stringMsg);
    }
  });
}

function escapeHTML(string) {
  return string
    .replace(/&/g, "&")
    .replace(/</g, "&lt;")
    .replace(/>/g, "&gt;")
    .replace(/"/g, "&quot;")
    .replace(/'/g, "&apos;");
}