index.js

var cool = require('cool-ascii-faces');
var express = require('express');
var app = express();
var pg = require('pg');
var bodyParser = require('body-parser');
var receivedMessage = require('./chatBotFunction');

app.use(bodyParser.urlencoded({ extended: false }))

app.use(bodyParser.json());

app.set('port', (process.env.PORT || 5000));

app.use(express.static(__dirname + '/public'));

// views is directory for all template files

app.get('/', function(request, response) {
  response.send("HELLO WORLLD");
});

app.get('/webhook', function(req, res) {
  if (req.query['hub.mode'] === 'subscribe' &&
      req.query['hub.verify_token'] === 'super-secret-token') {
    console.log("Validating webhook");
    res.status(200).send(req.query['hub.challenge']);
  } else {
    console.error("Failed validation. Make sure the validation tokens match.");
    res.sendStatus(403);
  }
});

app.post('/webhook/', function (req, res) {
  var data = req.body;
  // Make sure this is a page subscription
  if (data.object === 'page') {

    // Iterate over each entry - there may be multiple if batched
    data.entry.forEach(function(entry) {
      var pageID = entry.id;
      var timeOfEvent = entry.time;

      // Iterate over each messaging event
      entry.messaging.forEach(function(event) {
        if (event.message) {
          receivedMessage.receivedMessage(event);
        } else {
          console.log("Webhook received unknown event: ", event);
        }
      });
    });

    // Assume all went well.
    //
    // You must send back a 200, within 20 seconds, to let us know
    // you've successfully received the callback. Otherwise, the request
    // will time out and we will keep trying to resend.
    res.sendStatus(200);
  }
});

app.listen(app.get('port'), function() {
  console.log('Node app is running on port', app.get('port'));
});