index-ws.js

const express = require("express");
const server = require("http").createServer();
const app = express();

app.get("/", function getRoot(req, res) {
  res.sendFile("index.html", { root: __dirname });
});

server.on("request", app);
server.listen(3000, function serverListen() {
  console.log("Server started on port 3000");
});

process.on("SIGINT", () => {
  wss.clients.forEach((client) => {
    client.close();
  });
  server.close(() => {
    shutdownDB();
  });
})

// Begin websocket
const WebSocketServer = require("ws").Server;

const wss = new WebSocketServer({ server: server });

wss.on("connection", function wsConnection(ws) {
  const numClients = wss.clients.size;
  console.log("Clients connected", numClients);

  wss.broadcast(`Current visitors: ${numClients}`);

  if (ws.readyState === ws.OPEN) {
    ws.send("Welcome to my server");
  }

  db.run(`INSERT INTO visitors (count, time)
    VALUES (${numClients}, datetime('now'))
  `);

  ws.on("close", function wsClose() {
    console.log("A client has disconnected");
    wss.broadcast(`Current visitors: ${numClients}`);
  });
});

wss.broadcast = function broadcast(data) {
  wss.clients.forEach((client) => {
    client.send(data);
  });
};

// End websockets

// Begin database
const sqlite = require('sqlite3');
const db = new sqlite.Database(':memory:');

db.serialize(() => {
  db.run(`
    CREATE TABLE visitors (
      count INTEGER,
      time TEXT
    )
  `)
});

const getCounts = () => {
  db.each("SELECT * FROM visitors", (err,row) => {
    console.log('row', row);
  });
}

const shutdownDB = () => {
  getCounts();
  console.log("Shutting down db");
  db.close();
}
// End database