server.js

var express = require('express');
var bodyParser = require('body-parser');
var escape = require('html-escape');
var app = express();
var fs = require('fs');

var cfg = {
  port: process.env.PORT || 8080,
  hostname: process.env.IP || '127.0.0.1'
};

app.set('view engine', 'ejs');
app.use(bodyParser.urlencoded());
app.use(express.static('public'));

// CORS headers
app.use(function(req, res, next) {
  res.header("Access-Control-Allow-Origin", "*");
  res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
  next();
});

var server = app.listen(cfg.port, cfg.hostname, function () {
  console.log('listening on ' + cfg.hostname + ':' + cfg.port);
});


/* Message storage */

var messages = [];

if (fs.existsSync('messages.txt')) {
  messages = JSON.parse(fs.readFileSync('messages.txt', 'utf8'));
}


/* API Routes */

app.post('/send', function (req, res) {
  var user = req.body.user;
  var content = req.body.content;
  var timestamp = Date.now();

  user = user.substring(0, 30);
  content = content.substring(0, 100);

  content = escape(content);

  if (messages.length >= 1) {
    var lastMessage = messages[messages.length - 1];
    if (content === lastMessage.content) {
      res.status(400).send('stop spamming!');
      return;
    }
  }

  var object = {user: user, content: content, timestamp: timestamp};

  messages.push(object);

  if (messages.length > 10) {
    messages.shift();
  }
  fs.writeFileSync('messages.txt', JSON.stringify(messages), 'utf8');

  res.send('ok');
});

app.get('/messages', function (req, res) {
  res.send(messages);
});

/* Render homepage */

app.get('/', function (req, res) {
  res.render('index');
});