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:
We'll be using the Twilio REST API to send our users messages at important junctures. Here's a bit more on our API:
config/routes.rb
1Rails.application.routes.draw do23get "login/", to: "sessions#login", as: 'login'4get "logout/", to: "sessions#logout"5post "login_attempt/", to: "sessions#login_attempt"67resources :users, only: [:new, :create, :show]89resources :vacation_properties, path: "/properties"10resources :reservations, only: [:new, :create]11post "reservations/incoming", to: 'reservations#accept_or_reject', as: 'incoming'1213# Home page14root 'main#index', as: 'home'1516end
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:
1bin/rails generate scaffold VacationProperty2
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!
app/models/vacation_property.rb
1class VacationProperty < ActiveRecord::Base2belongs_to :user # host3has_many :reservations4has_many :users, through: :reservations #guests5end
Let's jump into the stew and look next at the Reservation mode.
The Reservation
model is at the center of the workflow for this application. It is responsible for keeping track of:
VacationProperty
it is associated with
User
who owns that vacation property (the
host
)
app/models/reservation.rb
1class Reservation < ActiveRecord::Base2validates :name, presence: true3validates :phone_number, presence: true45enum status: [ :pending, :confirmed, :rejected ]67belongs_to :vacation_property8belongs_to :user910def notify_host(force = true)11@host = User.find(self.vacation_property[:user_id])1213# Don't send the message if we have more than one or we aren't being forced14if @host.pending_reservations.length > 1 or !force15return16else17message = "You have a new reservation request from #{self.name} for #{self.vacation_property.description}:1819'#{self.message}'2021Reply [accept] or [reject]."2223@host.send_message_via_sms(message)24end25end2627def confirm!28self.status = "confirmed"29self.save!30end3132def reject!33self.status = "rejected"34self.save!35end3637def notify_guest38@guest = User.find_by(phone_number: self.phone_number)3940if self.status_changed? && (self.status == "confirmed" || self.status == "rejected")41message = "Your recent request to stay at #{self.vacation_property.description} was #{self.status}."42@guest.send_message_via_sms(message)43end44end45end
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.
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 allow us to store an integer in the table, while giving each status a searchable name. Here is an example:
1# reservation.pending! status: 02reservation.status = "confirmed"3reservation.confirmed? # => true4
app/models/reservation.rb
1class Reservation < ActiveRecord::Base2validates :name, presence: true3validates :phone_number, presence: true45enum status: [ :pending, :confirmed, :rejected ]67belongs_to :vacation_property8belongs_to :user910def notify_host(force = true)11@host = User.find(self.vacation_property[:user_id])1213# Don't send the message if we have more than one or we aren't being forced14if @host.pending_reservations.length > 1 or !force15return16else17message = "You have a new reservation request from #{self.name} for #{self.vacation_property.description}:1819'#{self.message}'2021Reply [accept] or [reject]."2223@host.send_message_via_sms(message)24end25end2627def confirm!28self.status = "confirmed"29self.save!30end3132def reject!33self.status = "rejected"34self.save!35end3637def notify_guest38@guest = User.find_by(phone_number: self.phone_number)3940if self.status_changed? && (self.status == "confirmed" || self.status == "rejected")41message = "Your recent request to stay at #{self.vacation_property.description} was #{self.status}."42@guest.send_message_via_sms(message)43end44end45end
Once we have an attribute that can trigger our workflow events, it's time to write some callbacks. Let's look there next.
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.
Create a new reservation
1class ReservationsController < ApplicationController23# GET /vacation_properties/new4def new5@reservation = Reservation.new6end78def create9@vacation_property = VacationProperty.find(params[:reservation][:property_id])10@reservation = @vacation_property.reservations.create(reservation_params)1112if @reservation.save13flash[:notice] = "Sending your reservation request now."14@reservation.notify_host15redirect_to @vacation_property16else17flast[:danger] = @reservation.errors18end19end2021# webhook for twilio incoming message from host22def accept_or_reject23incoming = Sanitize.clean(params[:From]).gsub(/^\+\d/, '')24sms_input = params[:Body].downcase25begin26@host = User.find_by(phone_number: incoming)27@reservation = @host.pending_reservation2829if sms_input == "accept" || sms_input == "yes"30@reservation.confirm!31else32@reservation.reject!33end3435@host.check_for_reservations_pending3637sms_reponse = "You have successfully #{@reservation.status} the reservation."38respond(sms_reponse)39rescue40sms_reponse = "Sorry, it looks like you don't have any reservations to respond to."41respond(sms_reponse)42end43end4445private46# Send an SMS back to the Subscriber47def respond(message)48response = Twilio::TwiML::Response.new do |r|49r.Message message50end51render text: response.text52end5354# Never trust parameters from the scary internet, only allow the white list through.55def reservation_params56params.require(:reservation).permit(:name, :phone_number, :message)57end5859end
Next up, let's take a look at how exactly we'll notify the lucky host.
To notify the host, we can look them up and send them an SMS message. However, how do we ensure our hosts are: a) responding to the correct reservation inquiry and b) not getting spammed?
Our solution to both problems:
To do this, we'll create a helper method on the User
model to surface the pending_reservations
method on a user. We'll go over that in the next step.
If in fact the host only has one pending reservation, we're going to fire an SMS off to the host immediately.
app/models/reservation.rb
1class Reservation < ActiveRecord::Base2validates :name, presence: true3validates :phone_number, presence: true45enum status: [ :pending, :confirmed, :rejected ]67belongs_to :vacation_property8belongs_to :user910def notify_host(force = true)11@host = User.find(self.vacation_property[:user_id])1213# Don't send the message if we have more than one or we aren't being forced14if @host.pending_reservations.length > 1 or !force15return16else17message = "You have a new reservation request from #{self.name} for #{self.vacation_property.description}:1819'#{self.message}'2021Reply [accept] or [reject]."2223@host.send_message_via_sms(message)24end25end2627def confirm!28self.status = "confirmed"29self.save!30end3132def reject!33self.status = "rejected"34self.save!35end3637def notify_guest38@guest = User.find_by(phone_number: self.phone_number)3940if self.status_changed? && (self.status == "confirmed" || self.status == "rejected")41message = "Your recent request to stay at #{self.vacation_property.description} was #{self.status}."42@guest.send_message_via_sms(message)43end44end45end
Let's now take a look at 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.
app/models/user.rb
1class User < ActiveRecord::Base2has_secure_password34validates :email, presence: true, format: { with: /\A.+@.+$\Z/ }, uniqueness: true5validates :name, presence: true6validates :country_code, presence: true7validates :phone_number, presence: true, uniqueness: true8validates_length_of :password, in: 6..20, on: :create910has_many :vacation_properties11has_many :reservations, through: :vacation_properties1213def send_message_via_sms(message)14@app_number = ENV['TWILIO_NUMBER']15@client = Twilio::REST::Client.new ENV['TWILIO_ACCOUNT_SID'], ENV['TWILIO_AUTH_TOKEN']16phone_number = "+#{country_code}#{self.phone_number}"17sms_message = @client.account.messages.create(18from: @app_number,19to: phone_number,20body: message,21)22end2324def check_for_reservations_pending25if pending_reservation26pending_reservation.notify_host(true)27end28end2930def pending_reservation31self.reservations.where(status: "pending").first32end3334def pending_reservations35self.reservations.where(status: "pending")36end3738end
Arguably the most important task delegated to our User
model is to send an SMS to the user when our app requests it, let's take a look.
Since we only send text messages in our application when we're communicating with specific users, it makes sense to create this function on the User
class. And yes: these 7 lines are all you need to send SMSes with Ruby and Twilio! It's really just two steps:
Now whenever we need to communicate with a user, whether host or guest, we can pass a message to this user method and... Voilà! We've sent them a text.
(If you peek below this method you'll see the helper methods for finding pending_reservations
that we mentioned previously.)
app/models/user.rb
1class User < ActiveRecord::Base2has_secure_password34validates :email, presence: true, format: { with: /\A.+@.+$\Z/ }, uniqueness: true5validates :name, presence: true6validates :country_code, presence: true7validates :phone_number, presence: true, uniqueness: true8validates_length_of :password, in: 6..20, on: :create910has_many :vacation_properties11has_many :reservations, through: :vacation_properties1213def send_message_via_sms(message)14@app_number = ENV['TWILIO_NUMBER']15@client = Twilio::REST::Client.new ENV['TWILIO_ACCOUNT_SID'], ENV['TWILIO_AUTH_TOKEN']16phone_number = "+#{country_code}#{self.phone_number}"17sms_message = @client.account.messages.create(18from: @app_number,19to: phone_number,20body: message,21)22end2324def check_for_reservations_pending25if pending_reservation26pending_reservation.notify_host(true)27end28end2930def pending_reservation31self.reservations.where(status: "pending").first32end3334def pending_reservations35self.reservations.where(status: "pending")36end3738end
Now we need a way to handle incoming texts so our lucky host can accept or reject a request. Let's look there next.
The accept_or_reject
controller handles our incoming Twilio request and does three things:
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.
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.
app/controllers/reservations_controller.rb
1class ReservationsController < ApplicationController23# GET /vacation_properties/new4def new5@reservation = Reservation.new6end78def create9@vacation_property = VacationProperty.find(params[:reservation][:property_id])10@reservation = @vacation_property.reservations.create(reservation_params)1112if @reservation.save13flash[:notice] = "Sending your reservation request now."14@reservation.notify_host15redirect_to @vacation_property16else17flast[:danger] = @reservation.errors18end19end2021# webhook for twilio incoming message from host22def accept_or_reject23incoming = Sanitize.clean(params[:From]).gsub(/^\+\d/, '')24sms_input = params[:Body].downcase25begin26@host = User.find_by(phone_number: incoming)27@reservation = @host.pending_reservation2829if sms_input == "accept" || sms_input == "yes"30@reservation.confirm!31else32@reservation.reject!33end3435@host.check_for_reservations_pending3637sms_reponse = "You have successfully #{@reservation.status} the reservation."38respond(sms_reponse)39rescue40sms_reponse = "Sorry, it looks like you don't have any reservations to respond to."41respond(sms_reponse)42end43end4445private46# Send an SMS back to the Subscriber47def respond(message)48response = Twilio::TwiML::Response.new do |r|49r.Message message50end51render text: response.text52end5354# Never trust parameters from the scary internet, only allow the white list through.55def reservation_params56params.require(:reservation).permit(:name, :phone_number, :message)57end5859end
Next up, let's see how to 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:
reservation.phone_number
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.
app/models/reservation.rb
1class Reservation < ActiveRecord::Base2validates :name, presence: true3validates :phone_number, presence: true45enum status: [ :pending, :confirmed, :rejected ]67belongs_to :vacation_property8belongs_to :user910def notify_host(force = true)11@host = User.find(self.vacation_property[:user_id])1213# Don't send the message if we have more than one or we aren't being forced14if @host.pending_reservations.length > 1 or !force15return16else17message = "You have a new reservation request from #{self.name} for #{self.vacation_property.description}:1819'#{self.message}'2021Reply [accept] or [reject]."2223@host.send_message_via_sms(message)24end25end2627def confirm!28self.status = "confirmed"29self.save!30end3132def reject!33self.status = "rejected"34self.save!35end3637def notify_guest38@guest = User.find_by(phone_number: self.phone_number)3940if self.status_changed? && (self.status == "confirmed" || self.status == "rejected")41message = "Your recent request to stay at #{self.vacation_property.description} was #{self.status}."42@guest.send_message_via_sms(message)43end44end45end
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.
Let's look at some other features you might enjoy adding for your use cases.
Ruby and Rails and Twilio: what an excellent combo. Here are a couple other ideas you might pursue:
Protect your users' privacy by anonymously connecting them with Twilio Voice and SMS.
Collect instant feedback from your customers with SMS or Voice.