index.js

var express = require('express');
var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);
var port = process.env.PORT || 80;

var userCount = 0;
var isRefreshed = false;

var links = [
  {
    command: '/attendance',
    link: '<a target="_blank" href="http://attendance.pscs.org">Attendance System</a>',
  },
  {
    command: '/manifesto',
    link: '<a target="_blank" href="https://docs.google.com/document/d/1sAaruzhYcoHRRGTIGUbJcbn1MFx_zi3x4Urf1En2Ty4">Manifesto</a>',
  },
  {
    command: '/pscsclicker',
    link: '<a target="_blank" href="https://coderlads.github.io/pscsclicker/">PSCS Clicker</a>',
  },
  {
    command: '/proyecto',
    link: '<a href="https://www.dropbox.com/s/pmsa9eu4rzunvd2/proyecto_especial.zip?dl=1">Proyecto</a>',
  }
];

app.use(express.static('public'));

app.get('/', function (req, res) {
  res.sendFile(__dirname + '/download.html');
});

app.get('/app', function (req, res) {
  res.sendFile(__dirname + '/index.html');
});

app.get('/count', function (req, res) {
  res.send({"users":userCount});
});


io.on('connection', function (socket) {
  io.emit('user count', userCount);
  socket.on('chat message', function (msg, color) {
    if(msg === '/help'){
      msg = "/help";
      links.forEach(item => {
        msg += ", " + item.command;
      });
    } else if(msg.startsWith('/link ')){
      msg = '<a target="_blank" href="' + msg.split("/link ")[1] + '" > ' + msg.split("/link ")[1] + '</a>';
    } else if(msg.startsWith('/image ')){
      msg = '<img target="_blank" src="' + msg.split("/image ")[1] + '" />';
    } else if(msg.startsWith('/video ')){
      msg = '<video target="_blank" src="' + msg.split("/video ")[1] + '" />';
    }

    links.forEach(item => {
      if(item.command === msg){
        msg = item.link;
      }
    });

    io.emit('chat message', msg, color);
  });
});

setInterval(() => {

  if (io.engine.clientsCount !== userCount) {
    userCount = io.engine.clientsCount;
    io.emit('user count', userCount);
    if (!isRefreshed) {
      io.emit('refresh', {});
      isRefreshed = true;
    }
  }

}, 1000);



http.listen(port, function () {
  console.log('listening on *:' + port);
});