index.js

var express = require('express');
var bodyParser = require('body-parser');
var app = express();
var http = require('http').Server(app);
var io = require('socket.io')(http);

var fs = require('fs');
var creds = '';

var redis = require('redis');
var client = '';
var port = process.env.PORT || 8080;

// Express Middleware for serving static
// files and parsing the request body
app.use(express.static('public'));
app.use(bodyParser.urlencoded({
  extended: true
}));

// Start the server
http.listen(port, function() {
  console.log("Server started. Listening on *:" + port);
});

// Store people in chatroom
var chatters = [];

// Store messages in chatroom
var chat_messages = [];

// Read credentials from JSON
fs.readFile('./config/creds.json', 'utf-8', function(err, data) {
  if(err) throw err;
  creds = JSON.parse(data);
  client = redis.createClient('redis://' + creds.user + ':' + creds.password + '@' + creds.host + ':' + creds.port);

  // Redis Client Ready
  client.once('ready', function() {
    // Flush Redis DB
    // client.flushdb();

    // Initialize Chatters
    client.length('chat_users', function(err, reply) {
      if(reply) {
        chatters = JSON.parse(reply);
      }
    });

    // Initialize Messages
    client.length('chat_app_messages', function(err, reply) {
      if(reply) {
        chat_messages = JSON.parse(reply);
      }
    });
  });
});

// API - Join Chat
app.post('/join', function(req, res) {
  var username = req.body.username;
  if(chatters.indexOf(username) === -1) {
    chatters.push(username);
    client.set('chat_users', JSON.stringify(chatters));
    res.send({
      'chatters': chatters,
      'status': 'OK'
    });
  } else {
    res.send({
      'status': 'FAILED'
    });
  }
});

// API - Leave Chat
app.post('/leave', function(req, res) {
  var username = req.body.username;
  chatters.splice(chatters.indexOf(username), 1);
  client.set('chat_users', JSON.stringify(chatters));
  res.send({
    'status': 'OK'
  });
});

// API - Send + Store Message
app.post('/send_message', function(req, res) {
  var username = req.body.username;
  var message = req.body.message;
  chat_messages.push({
    'sender': username,
    'message': message
  });
  client.set('chat_app_messages', JSON.stringify(chat_messages));
  res.send({
    'status': 'OK'
  });
});

// API - Get Messages
app.get('/get_messages', function(req, res) {
  res.send(chat_messages);
});

// API - Get Chatters
app.get('/get_chatters', function(req, res) {
  res.send(chatters);
});

// Socket Connection
// UI Stuff
io.on('connection', function(socket) {
  // Fire 'send' event for updating Message list in UI
  socket.on('message', function(data){
    io.emit('send', data);
  });

  // Fire 'count_chatters' for updating Chatter Count in UI
  socket.on('update_chatter_count', function(data) {
    io.emit('count_chatters', data);
  });
});