bot.js

var express = require('express'); //express handles routes
var http = require('http'); //need http module to create a server
var app = express(); //starting express
var url = "MY_KEY" //replace with your page token
var request = require('request');

app.set('port', process.env.PORT || 3000); //set port to cloud9 specific port or 3000
app.use(express.bodyParser()); //body parser used to parse request data
app.use(app.router);
app.get('/', verificationHandler);

var dictionary = {
    oi: 'oi, tudo bem?',
    tudobem: 'Tudo sim, e com você?'
};

var formatUserText = function(text) {    
    return text.replace(/(\?|!| |,)/g, '');
};

function sendHelp(id, message) {
    var options = {
        uri: url,
        method: 'POST',
        json: {
            "recipient": {
                "id": id
            },
            "message": {
                "text": message
            }
        }
    }
    request(options, function(error, response, body) {
        if (error) {
            console.log(error.message);
        }
    });
};

function verificationHandler(req, res) {
    console.log(req);
    if (req.query['hub.verify_token'] === 'verifycode') {
        res.send(req.query['hub.challenge']);
    }
    res.send('Error, wrong validation token!');
}

function handleMessage(req, res) {
    messaging_events = req.body.entry[0].messaging;
    for (i = 0; i < messaging_events.length; i++) {
        event = req.body.entry[0].messaging[i];
        sender = event.sender.id;
        if (event.message && event.message.text) {
            text = event.message.text;
            console.log('Event sender id' + sender + ' Message: ' + text);
            sendHelp(sender, dictionary[formatUserText(text)]);
        }
    }
    res.end('received!');
}

app.post('/', handleMessage);

http.createServer(app).listen(app.get('port'), function() {
    console.log('Express server listening on port ' + app.get('port'));
});