index.js

require("now-logs")(process.env.FACEBOOK_VERIFY_TOKEN);

const express = require("express");
const bodyParser = require("body-parser");
const message = require("./lib/message");

// Set up Express
let app = express();
app.use(bodyParser.json());
app.use(
  bodyParser.urlencoded({
    extended: true
  })
);

// Webhook validation
app.get("/webhook", function(req, res) {
  if (
    req.query["hub.mode"] === "subscribe" &&
    req.query["hub.verify_token"] === process.env.FACEBOOK_VERIFY_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);
  }
});

// Display the web page
app.get("/", function(req, res) {
  res.writeHead(200, { "Content-Type": "text/html" });
  res.write("hi");
  res.end();
});

// Message processing
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) {
          message.process(event);
        } else if (event.postback) {
          receivedPostback(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);
  }
});

function onboard() {}

function receivedPostback(event) {
  var senderID = event.sender.id;
  var recipientID = event.recipient.id;
  var timeOfPostback = event.timestamp;

  // The 'payload' param is a developer-defined field which is set in a postback
  // button for Structured Messages.
  var payload = event.postback.payload;

  console.log(
    "Received postback for user %d and page %d with payload '%s' " + "at %d",
    senderID,
    recipientID,
    payload,
    timeOfPostback
  );

  // When a postback is called, we'll send a message back to the sender to
  // let them know it was successful
  message.send(senderID, "Postback called");
}

// Set Express to listen out for HTTP requests
var server = app.listen(process.env.PORT || 3000, function() {
  console.log("Listening on port %s", server.address().port);
});