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Workflow Automation with Node.js and Express

One of the more abstract concepts you'll handle when building your business is what the workflow will look like.

At its core, setting up a standardized workflow is about enabling your service providers (agents, hosts, customer service reps, administrators, and the rest of the gang) to better serve your customers.

To illustrate a very real-world example, today we'll build a Node.js and Express webapp for finding and booking vacation properties — tentatively called Airtng.

Here's how it'll work:

A host creates a vacation property listing
A guest requests a reservation for a property
The host receives an SMS notifying them of the reservation request. The host can either Accept or Reject the reservation
The guest is notified whether a request was rejected or accepted

Learn how Airbnb used Twilio SMS to streamline the rental experience for 60M+ travelers around the world.

Workflow Building Blocks

We'll be using the Twilio REST API to send our users messages at important junctures. Here's a bit more on our API:

Sending Messages with Twilio API

Ready to go? Boldly click the button right after this sentence.

Authenticate Our Users

For this workflow to work, we need to handle user authentication. We're going to rely on Passport for Node.js.

Each User will need to have a countryCode and a phoneNumber which will be required to send SMS notifications later.

User Model to handle authentication

models/user.js


_17var mongoose = require('mongoose');
_17var passportLocalMongoose = require('passport-local-mongoose');
_17
_17var userSchema = new mongoose.Schema({
_17  email:       { type: String, required: true },
_17  username:    { type: String, required: true },
_17  password:    { type: String },
_17  countryCode: { type: String, required: true },
_17  phoneNumber: { type: String, required: true },
_17  date:        { type: Date, default: Date.now },
_17});
_17
_17userSchema.plugin(passportLocalMongoose);
_17
_17var user = mongoose.model('user', userSchema);
_17
_17module.exports = user;

Next let's model the vacation properties.

Vacation Property Model

In order to build our rentals company we'll need a way to create the property listings.

The Property belongs to the User who created it (we'll call this user the host moving forward) and contains only two properties: a description and an imageUrl.

The Vacation Property Model

models/property.js


_15var mongoose = require('mongoose');
_15
_15var propertySchema = new mongoose.Schema({
_15  description: { type: String, required: true },
_15  imageUrl:    { type: String, required: true },
_15  date:        { type: Date, default: Date.now },
_15  owner:       {
_15    type: mongoose.Schema.Types.ObjectId,
_15    ref: 'user'
_15  }
_15});
_15
_15var property = mongoose.model('property', propertySchema);
_15
_15module.exports = property;

Next up, the reservation model.

Reservation Model

The Reservation model is at the center of the workflow for this application.

It is responsible for keeping track of:

The guest who performed the reservation
The vacation_property the guest is requesting (and associated host )
The status of the reservation: pending , confirmed , or rejected

The Reservation Model

models/reservation.js


_22var mongoose = require('mongoose');
_22var deepPopulate = require('mongoose-deep-populate')(mongoose);
_22
_22var reservationSchema = new mongoose.Schema({
_22  message:  { type: String, required: true },
_22  status:   { type: String, default: 'pending' },
_22  date:     { type: Date, default: Date.now },
_22  property: {
_22    type: mongoose.Schema.Types.ObjectId,
_22    ref: 'property'
_22  },
_22  guest:     {
_22    type: mongoose.Schema.Types.ObjectId,
_22    ref: 'user'
_22  }
_22});
_22
_22reservationSchema.plugin(deepPopulate, {});
_22
_22var reservation = mongoose.model('reservation', reservationSchema);
_22
_22module.exports = reservation;

Next, let's look at triggering the creation of a new reservation.

Create a Reservation

The reservation creation form holds only a single field field: the message that will be sent to the host when reserving one of her properties. The rest of the information necessary to create a reservation is taken from the vacation property.

A reservation is created with a default status pending, so when the host replies with an accept or reject response our application knows which reservation to update.

Reservation creation

routes/reservations.js


_70var MessagingResponse = require('twilio').twiml.MessagingResponse;
_70var twilio = require('twilio');
_70var express = require('express');
_70var router = express.Router();
_70var Property = require('../models/property');
_70var Reservation = require('../models/reservation');
_70var User = require('../models/user');
_70var notifier = require('../lib/notifier');
_70
_70// POST: /reservations
_70router.post('/', function (req, res) {
_70  var propertyId = req.body.propertyId;
_70  var user = req.user;
_70
_70  Property.findOne({ _id: propertyId })
_70  .then(function (property) {
_70    var reservation = new Reservation({
_70      message: req.body.message,
_70      property: propertyId,
_70      guest: user.id
_70    });
_70
_70    return reservation.save();
_70  })
_70  .then(function () {
_70    notifier.sendNotification();
_70    res.redirect('/properties');
_70  })
_70  .catch(function(err) {
_70    console.log(err);
_70  });
_70});
_70
_70// POST: /reservations/handle
_70router.post('/handle', twilio.webhook({validate: false}), function (req, res) {
_70  var from = req.body.From;
_70  var smsRequest = req.body.Body;
_70
_70  var smsResponse;
_70
_70  User.findOne({phoneNumber: from})
_70  .then(function (host) {
_70    return Reservation.findOne({status: 'pending'});
_70  })
_70  .then(function (reservation) {
_70    if (reservation === null) {
_70      throw 'No pending reservations';
_70    }
_70    reservation.status = smsRequest.toLowerCase() === "accept" ? "confirmed" : "rejected";
_70    return reservation.save();
_70  })
_70  .then(function (reservation) {
_70    var message = "You have successfully " + reservation.status + " the reservation";
_70    respond(res, message);
_70  })
_70  .catch(function (err) {
_70    var message = "Sorry, it looks like you do not have any reservations to respond to";
_70    respond(res, message);
_70  });
_70});
_70
_70var respond = function(res, message) {
_70  var messagingResponse = new MessagingResponse();
_70  messagingResponse.message({}, message);
_70
_70  res.type('text/xml');
_70  res.send(messagingResponse.toString());
_70}
_70
_70module.exports = router;

In the next step, we'll take a look at how the SMS notification is sent to the host when the reservation is created.

Notify The Host

When a reservation is created, we want to notify the owner of said property that someone has made a reservation.

This is where we use Twilio Node Helper Library to send an SMS message to the host, using our Twilio phone number. As you can see, sending SMS messages using Twilio is just a few lines of code.

Now we just have to wait for the host to send an SMS response accepting or rejecting the reservation so we can notify the guest and host that the reservation information is updated.

Send out reservation notifications

Notify through SMS the host of the new reservation


_44var config = require('../config');
_44var client = require('twilio')(config.accountSid, config.authToken);
_44var Reservation = require('../models/reservation');
_44
_44var sendNotification = function() {
_44  Reservation.find({status: 'pending'})
_44  .deepPopulate('property property.owner guest')
_44  .then(function (reservations) {
_44    if (reservations.length > 1) {
_44      return;
_44    }
_44
_44    var reservation = reservations[0];
_44    var owner = reservation.property.owner;
_44
_44    // Send the notification
_44    client.messages.create({
_44      to: phoneNumber(owner),
_44      from: config.phoneNumber,
_44      body: buildMessage(reservation)
_44    })
_44    .then(function(res) {
_44      console.log(res.body);
_44    })
_44    .catch(function(err) {
_44      console.log(err);
_44    });
_44  });
_44};
_44
_44var phoneNumber = function(owner) {
_44  return "+" + owner.countryCode + owner.phoneNumber;
_44};
_44
_44var buildMessage = function(reservation) {
_44  var message = "You have a new reservation request from " + reservation.guest.username +
_44    " for " + reservation.property.description + ":\n" +
_44    reservation.message + "\n" +
_44    "Reply accept or reject";
_44
_44  return message;
_44};
_44
_44exports.sendNotification = sendNotification;

The next step shows how to handle and configure the host's SMS response.

Handle Incoming Messages

The reservations/handle endpoint handles our incoming Twilio request and does three things:

Checks for a pending reservation from the incoming user.
Updates the status of the reservation.
Responds to the host and sends notification to the guest.

Set Up Twilio Webhooks

In the Twilio console, you should change the 'A Message Comes In' webhook to call your application's endpoint in the route /handle:

One way to expose your machine to the world during development is to use ngrok. Your URL for the SMS web hook on your phone number should look something like this:


_10http://<subdomain>.ngrok.io/handle

An incoming request from Twilio comes with some helpful including the From phone number and the message Body.

We'll use the From parameter to lookup the host and check if she has any pending reservations. If she does, we'll use the message body to check if she accepted or rejected the reservation.

Deal with host responses

routes/reservations.js


_70var MessagingResponse = require('twilio').twiml.MessagingResponse;
_70var twilio = require('twilio');
_70var express = require('express');
_70var router = express.Router();
_70var Property = require('../models/property');
_70var Reservation = require('../models/reservation');
_70var User = require('../models/user');
_70var notifier = require('../lib/notifier');
_70
_70// POST: /reservations
_70router.post('/', function (req, res) {
_70  var propertyId = req.body.propertyId;
_70  var user = req.user;
_70
_70  Property.findOne({ _id: propertyId })
_70  .then(function (property) {
_70    var reservation = new Reservation({
_70      message: req.body.message,
_70      property: propertyId,
_70      guest: user.id
_70    });
_70
_70    return reservation.save();
_70  })
_70  .then(function () {
_70    notifier.sendNotification();
_70    res.redirect('/properties');
_70  })
_70  .catch(function(err) {
_70    console.log(err);
_70  });
_70});
_70
_70// POST: /reservations/handle
_70router.post('/handle', twilio.webhook({validate: false}), function (req, res) {
_70  var from = req.body.From;
_70  var smsRequest = req.body.Body;
_70
_70  var smsResponse;
_70
_70  User.findOne({phoneNumber: from})
_70  .then(function (host) {
_70    return Reservation.findOne({status: 'pending'});
_70  })
_70  .then(function (reservation) {
_70    if (reservation === null) {
_70      throw 'No pending reservations';
_70    }
_70    reservation.status = smsRequest.toLowerCase() === "accept" ? "confirmed" : "rejected";
_70    return reservation.save();
_70  })
_70  .then(function (reservation) {
_70    var message = "You have successfully " + reservation.status + " the reservation";
_70    respond(res, message);
_70  })
_70  .catch(function (err) {
_70    var message = "Sorry, it looks like you do not have any reservations to respond to";
_70    respond(res, message);
_70  });
_70});
_70
_70var respond = function(res, message) {
_70  var messagingResponse = new MessagingResponse();
_70  messagingResponse.message({}, message);
_70
_70  res.type('text/xml');
_70  res.send(messagingResponse.toString());
_70}
_70
_70module.exports = router;

In the last step, we'll use Twilio's TwiML and instruct Twilio to send SMS messages to the guest.

TwiML Response

After updating the reservation status, we must notify the host that he/she has successfully confirmed or rejected the reservation. If no reservation is found, we send an error message instead.

If a reservation is confirmed or rejected we send an additional SMS to the guest to pass along the news.

We use the verb Message from TwiML to instruct Twilio's server that it should send SMS messages.

Build the TwiML Response

routes/reservations.js


_70var MessagingResponse = require('twilio').twiml.MessagingResponse;
_70var twilio = require('twilio');
_70var express = require('express');
_70var router = express.Router();
_70var Property = require('../models/property');
_70var Reservation = require('../models/reservation');
_70var User = require('../models/user');
_70var notifier = require('../lib/notifier');
_70
_70// POST: /reservations
_70router.post('/', function (req, res) {
_70  var propertyId = req.body.propertyId;
_70  var user = req.user;
_70
_70  Property.findOne({ _id: propertyId })
_70  .then(function (property) {
_70    var reservation = new Reservation({
_70      message: req.body.message,
_70      property: propertyId,
_70      guest: user.id
_70    });
_70
_70    return reservation.save();
_70  })
_70  .then(function () {
_70    notifier.sendNotification();
_70    res.redirect('/properties');
_70  })
_70  .catch(function(err) {
_70    console.log(err);
_70  });
_70});
_70
_70// POST: /reservations/handle
_70router.post('/handle', twilio.webhook({validate: false}), function (req, res) {
_70  var from = req.body.From;
_70  var smsRequest = req.body.Body;
_70
_70  var smsResponse;
_70
_70  User.findOne({phoneNumber: from})
_70  .then(function (host) {
_70    return Reservation.findOne({status: 'pending'});
_70  })
_70  .then(function (reservation) {
_70    if (reservation === null) {
_70      throw 'No pending reservations';
_70    }
_70    reservation.status = smsRequest.toLowerCase() === "accept" ? "confirmed" : "rejected";
_70    return reservation.save();
_70  })
_70  .then(function (reservation) {
_70    var message = "You have successfully " + reservation.status + " the reservation";
_70    respond(res, message);
_70  })
_70  .catch(function (err) {
_70    var message = "Sorry, it looks like you do not have any reservations to respond to";
_70    respond(res, message);
_70  });
_70});
_70
_70var respond = function(res, message) {
_70  var messagingResponse = new MessagingResponse();
_70  messagingResponse.message({}, message);
_70
_70  res.type('text/xml');
_70  res.send(messagingResponse.toString());
_70}
_70
_70module.exports = router;

And that's a wrap! Next let's take a look at other features you might enjoy in your application.

Where to Next?

Node.js goes great with a helping of Twilio... let us prove it:

IVR: Phone Tree

Easily route callers to the right people and information with an IVR (interactive voice response) system.

Automated Survey

Instantly collect structured data from your users with a survey conducted over a voice call or SMS text messages.

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