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Workflow Automation with Ruby and Rails

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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 Ruby on Rails webapp for finding and booking vacation properties — tentatively called Airtng.

Here's how it'll work:

  1. A host creates a vacation property listing
  2. A guest requests a reservation for a property
  3. The host receives an SMS notifying them of the reservation request. The host can either Accept or Reject the reservation
  4. 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:

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      Application routes


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

      Boldly Move to the Next Step

      The Vacation Property Model

      The VacationProperty model 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 image_url.

      It has two associations in that it has many reservations and therefore many users through those reservations.

      The best way to generate the model and all of the basic CRUD scaffolding we'll need is to use the Rails command line tool:

      bin/rails generate scaffold VacationProperty 
      description:string image_url:string

      One of the benefits of using the Rails generator is that it creates all of our routes, controllers and views so that we have a fully functional CRUD interface out of the box. Nifty!

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          Vacation Property Model


          Let's jump into the stew and look next at the Reservation mode.

          Handle the Workflow

          The Reservation Model

          The Reservation model is at the center of the workflow for this application. It is responsible for keeping track of:

          • the VacationProperty it is associated with
          • the User who owns that vacation property (the host)
          • the guest name and phone number
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              The Reservation Model


              Since the reservation can only have one guest for our example we simplified the model by assigning a name and phone_number directly.

              We'll cover how we did this later. Next, however, we'll zoom in on the reservation status.

              Show Me Reservation Statuses

              Reservation Status

              First we validate some key properties and define the associations so that we can later lookup those relationships through the model. (If you'd like more context, the Rails guide explains models and associations quite well.)

              The main property we need to enable a reservation workflow is some sort of status that we can monitor. This is a perfect candidate for an enumerated status attribute.

              Enumerated Attributes

              Enumerated attributes allow us to store a simple integer in the table, while giving each status a searchable name. Here is an example:

              # reservation.pending! status: 0
              reservation.status = "confirmed"
              reservation.confirmed? # => true
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                  Once we have an attribute that can trigger our workflow events, it's time to write some callbacks. Let's look there next.

                  You Better Call Me Back

                  The Reservations Controller

                  We'll be posting our reservation details to the create route from the vacation property page.

                  After we create the reservation we want to notify the host that she has a request pending. After she accepts or rejects it we want to notify the guest of the news.

                  While the Reservation model handles the notification, we want to keep all these actions in the controller to show our intentions.

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                      Create a new reservation

                      The Reservation Controller

                      Create a new reservation

                      Next up, let's take a look at how exactly we'll notify the lucky host.


                      Notify the Host

                      In theory, notifying the host should be as simple as looking up the host User and send her an SMS. However:

                      How do we ensure our hosts are: a) responding to the correct reservation inquiry and b) not getting spammed?

                      Pending Reservations

                      Our simple solution to both problems:

                      • We only notify the host of the oldest pending reservation.
                      • We don't send another SMS until the host has dealt with the last reservation.

                      The easiest way to surface pending_reservations for a user is to create a helper method on the User model. We'll go over that in the next step.

                      Sending the SMS

                      If in fact the host only has one pending reservation, we're going to fire an SMS off to the host immediately.

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                          Let's now take a look at the User model.


                          The User Model

                          We have one model for both the guests and the hosts who are using Airtng.

                          When Airtng takes off it will merit creating two more classes that inherit from the base User class. Since we're still on the ground this should suit us fine (to boldly stay...).

                          First, we validate the 'uniqueness' of our user - they should be unique, just like everyone else. Specifically, it is important we ensure that the phone_number attribute is unique since we will use this to look up User records on incoming SMSes.

                          After that, we set up our associations for when we need to query for reservations.

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                              Arguably the most important task delegated to our User model is to send an SMS to the user when our app requests it. Click 'Next' below to move to that pane.


                              Send Messages Into the Void

                              Since we only send text messages in our application when we're communicating with specific users, it makes sense to create this function on the User class. And yes: these 7 lines are all you need to send SMSes with Ruby and Twilio! It's really just two steps:

                              1. We look up our app's phone number.
                              2. We initiate our Twilio client and build the message.

                              Now whenever we need to communicate with a user, whether host or guest, we can pass a message to this user method and... Voilà! We've sent them a text.

                              (If you peek below this method you'll see the helper methods for finding pending_reservations that we mentioned previously.)

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                                  Now we need a way to handle incoming texts so our lucky host can accept or reject a request. Let's look there next.


                                  Handle Incoming Messages

                                  The accept_or_reject controller handles our incoming Twilio request and does three things:

                                  1. Check for a pending reservation the user owns
                                  2. Update the status of the reservation
                                  3. Respond to the host (and guest)

                                  Incoming Twilio Request

                                  An incoming request from Twilio comes with some helpful parameters 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.

                                  Then we'll redirect the request to a TwiML response to send a message back to the user.

                                  TwiML Response

                                  Usually a Rails controller has a template associated with it that renders a webpage. In our case, the only request being made will be by Twilio's API so we don't need a public page. Instead we're using Twilio's Ruby API to render a custom TwiML response as raw XML on the page.

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                                      Webhook for handling Host's decision


                                      Next up, let's see how to notify the guest.


                                      Notify the Guest

                                      The final step in our workflow is to notify the guest that their reservation has been booked (or, ahem, rejected).

                                      We called this method earlier from the reservations_controller when we updated the reservation status. Here's what it does:

                                      • We lookup the guest with the reservation.phone_number
                                      • If the status was changed to an expected result we notify the guest of the change.

                                      And of course all we need to do to send the SMS message to the guest is call the send_message_via_sms method that is present on all users.

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                                          Let the guest have the host's decision


                                          Thank you so much for your help! Airtng now has a nice SMS based workflow in place and you're ready to add a workflow to your own application.

                                          On the next pane, we'll look at some other features you might enjoy adding for your use cases.

                                          What Else Can I Build?

                                          Where to Next?

                                          Ruby and Rails and Twilio: what an excellent combo. Here are a couple other ideas you might pursue:

                                          Masked Phone Numbers

                                          Protect your users' privacy by anonymously connecting them with Twilio Voice and SMS.

                                          Automated Survey

                                          Collect instant feedback from your customers with SMS or Voice.

                                          Did this help?

                                          Thanks for checking this tutorial out! Tweet to us @twilio with what you're building!

                                          Jarod Reyes Jose Oliveros Zachary Pitts Agustin Camino David Prothero Samuel Mendes Paul Kamp Andrew Baker Kat King

                                          Need some help?

                                          We all do sometimes; code is hard. Get help now from our support team, or lean on the wisdom of the crowd browsing the Twilio tag on Stack Overflow.

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