SMS and MMS Notifications with Ruby and Sinatra

Time to read: 2 minutes

January 10, 2017
Written by
Jarod Reyes
Twilion
Reviewed by
Andrew T. Baker
Twilion
Paul Kamp
Twilion
Hector Ortega
Contributor
Opinions expressed by Twilio contributors are their own
Kat King
Twilion
Ricky Holtz
Twilion
Stephanie Marchante
Twilion

sms-mms-ruby-sinatra

Today we'll use Ruby and the Sinatra framework to demonstrate how to send SMS alerts to a list of system administrators when something goes wrong with your server.  We'll cover all the key details in depth so you can easily incorporate this important feature into your own application.

Clone our sample application from Github, then head to the application's README.md to see how to run the application locally.

Let's get started!

Configuring the Twilio REST Client

To send messages we'll need to create a Twilio REST client which requires reading a TWILIO_ACCOUNT_SID and TWILIO_AUTH_TOKEN from environment variables.

The values for your account SID and Auth Token will come from the Twilio console:

Account Credentials

 

Click the eyeball icon to expose your Auth Token in a form you can copy and paste.

This is a migrated tutorial. Clone the original code from https://github.com/TwilioDevEd/server-notifications-sinatra/

require 'yaml'
require 'twilio-ruby'

class Notifier
  def self.send_sms_notifications(e)
    new.send_sms_notifications(e)
  end

  def initialize
    account_sid = ENV['TWILIO_ACCOUNT_SID']
    auth_token  = ENV['TWILIO_AUTH_TOKEN']
    @client = Twilio::REST::Client.new(account_sid, auth_token)
  end

  def send_sms_notifications(e)
    alert_message = '[This is a test] ALERT!' \
      'It appears the server is having issues.' \
      "Exception: #{e}." \
      'Go to: http://newrelic.com for more details.'
    image_url = 'http://howtodocs.s3.amazonaws.com/new-relic-monitor.png'

    admins = YAML.load_file('config/administrators.yml')
    admins.each do |admin|
      phone_number = admin['phone_number']
      send_sms(phone_number, alert_message, image_url)
    end
  end

  private

  def send_sms(phone_number, alert_message, image_url)
    @client.messages.create(
      from:      ENV['TWILIO_NUMBER'],
      to:        phone_number,
      body:      alert_message,
      media_url: image_url
    )
  end
end

Our Twilio REST Client is now ready. Let's take a closer look at that administrator list, shall we?

A List of Server Admins - And Anyone Else Who Should be Hailed

Here we create a yaml list of people who should be notified if a server error occurs.

The only essential piece of data we need is a phone_number for each administrator.

-
  name: Doraj
  phone_number: '+15555679097'
-
  name: Nivek
  phone_number: '+15555679098'

Next, let's look at how we're going to piggyback on application exceptions.

Handling Application Exceptions

We use Sinatra Errors Handlers and send out the notifications when an exception occurs.

require 'dotenv'
require 'sinatra'
require_relative './lib/notifier'

# Load environment configuration
Dotenv.load

# Set the environment after dotenv loads
# Default to production
environment = (ENV['APP_ENV'] || ENV['RACK_ENV'] || :production).to_sym
set :environment, environment

require 'bundler'
Bundler.require :default, environment


module ServerNotifications
  class App < Sinatra::Base
    set :show_exceptions, false
    set :raise_errors, false
    set :root, File.dirname(__FILE__)

    get '/' do
      raise "Kaboom! Something went wrong!"
    end

    error do |exception|
      Notifier.send_sms_notifications(exception)
      'An error has ocurred'
    end
  end
end

Next up: sending a message to each administrator.

Trigger Notifications for Each Entry in the Administrator List

In our Notifier module, we read the administrators from our YAML file and send alert messages to each one of them with the method send_sms.

require 'yaml'
require 'twilio-ruby'

class Notifier
  def self.send_sms_notifications(e)
    new.send_sms_notifications(e)
  end

  def initialize
    account_sid = ENV['TWILIO_ACCOUNT_SID']
    auth_token  = ENV['TWILIO_AUTH_TOKEN']
    @client = Twilio::REST::Client.new(account_sid, auth_token)
  end

  def send_sms_notifications(e)
    alert_message = '[This is a test] ALERT!' \
      'It appears the server is having issues.' \
      "Exception: #{e}." \
      'Go to: http://newrelic.com for more details.'
    image_url = 'http://howtodocs.s3.amazonaws.com/new-relic-monitor.png'

    admins = YAML.load_file('config/administrators.yml')
    admins.each do |admin|
      phone_number = admin['phone_number']
      send_sms(phone_number, alert_message, image_url)
    end
  end

  private

  def send_sms(phone_number, alert_message, image_url)
    @client.messages.create(
      from:      ENV['TWILIO_NUMBER'],
      to:        phone_number,
      body:      alert_message,
      media_url: image_url
    )
  end
end

Next up, we will see how to send a text message.

Sending a Text Message

There are three parameters needed to send an SMS using the Twilio REST API: from, to, and body.

US and Canadian phone numbers can also send an image with the message.  Other countries will have an automatically shortened URL added to the message body.

require 'yaml'
require 'twilio-ruby'

class Notifier
  def self.send_sms_notifications(e)
    new.send_sms_notifications(e)
  end

  def initialize
    account_sid = ENV['TWILIO_ACCOUNT_SID']
    auth_token  = ENV['TWILIO_AUTH_TOKEN']
    @client = Twilio::REST::Client.new(account_sid, auth_token)
  end

  def send_sms_notifications(e)
    alert_message = '[This is a test] ALERT!' \
      'It appears the server is having issues.' \
      "Exception: #{e}." \
      'Go to: http://newrelic.com for more details.'
    image_url = 'http://howtodocs.s3.amazonaws.com/new-relic-monitor.png'

    admins = YAML.load_file('config/administrators.yml')
    admins.each do |admin|
      phone_number = admin['phone_number']
      send_sms(phone_number, alert_message, image_url)
    end
  end

  private

  def send_sms(phone_number, alert_message, image_url)
    @client.messages.create(
      from:      ENV['TWILIO_NUMBER'],
      to:        phone_number,
      body:      alert_message,
      media_url: image_url
    )
  end
end

It's as simple as that! 

We've just implemented an automated server notification system that can push out alerts if anything goes wrong.

Next, let's look at what other features the Twilio Ruby SDK makes simple to integrate.

Where to Next?

We've got a lot of other excellent Ruby code we'd love to share with you... but we'll keep our links to just two:

Two-Factor Authentication

Increase the security of your login system by verifying a user's mobile phone in addition to their password.

SMS and MMS marketing notifications

SMS and MMS messages are a personal way to engage with users, offering a much higher open rate than e-mail and more impact than a tweet.

Did this Help?

Thanks for checking out this tutorial! Tweet @twilio with what you thought, what you're thinking, and most importantly... what you're going to build.

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