Example of integrating a Ruby on Rails app with Zapier using the REST hooks pattern. With support for triggering the REST hooks from Resque background jobs.

contact.rb

class Contact < ActiveRecord::Base

  ...

  def after_create
    if Hook.hooks_exist?('new_contact', self)
      Resque.enqueue(Hook, self.class.name, self.id)
      # To trigger directly without Resque: Hook.trigger('new_contact', self)
    end
  end

end

contact_test.rb

class ContactTest < ActiveSupport::TestCase

  ...

  require 'fakeweb'
  def test_trigger_rest_hook_on_contact_creation
    account = Factory(:account)
    subscription_url = "https://zapier.com/hooks/standard/wpGRPPcRxZt2GxBbSSeUAlWPBnhLiRWB/"
    target_url = "https://zapier.com/hooks/standard/wpGRPPcRxZt2GxBbSSeUAlWPBnhLiRWB/"

    hook = Hook.create(
      {
        "event" => "new_contact",
        "account_id" => account.id,
        "subscription_url" => subscription_url,
        "target_url" => target_url
      }
    )

    FakeWeb.register_uri(
      :post,
      target_url,
      :body => 'irrelevant',
      :status => ['200', 'Triggered']
    )

    contact = Factory(:contact, :account => account,
      :first => 'Ryan', :last => 'Porter', :email => 'xyz@venuedriver.com')

    # Simulate a Resque worker.
    Hook.perform('Contact', contact.id)

    assert_equal "POST", FakeWeb.last_request.method
    assert_equal HookEncoder.encode(contact), FakeWeb.last_request.body
  end

end

hook.rb

require 'resque-retry'

class Hook < ActiveRecord::Base
  attr_accessible :event, :account_id, :subscription_url, :target_url
  validates_presence_of :event, :account_id, :subscription_url, :target_url

  # Looks for an appropriate REST hook that matches the record, and triggers the hook if one exists.
  def self.trigger(event, record)
    hooks = self.hooks(event, record)
    return if hooks.empty?

    unless Rails.env.development?
      # Trigger each hook if there is more than one for an account, which can happen.
      hooks.each do |hook|
        # These use puts instead of Rails.logger.info because this happens from a Resque worker.
        puts "Triggering REST hook: #{hook.inspect}"
        puts "REST hook event: #{event}"
        encoded_record = HookEncoder.encode(record)
        puts "REST hook record: #{encoded_record}"
        RestClient.post(hook.target_url, encoded_record) do |response, request, result|
          if response.code.eql? 410
            puts "Destroying REST hook because of 410 response: #{hook.inspect}"
            hook.destroy
          end
        end
      end
    end
  end

  # This method is called by a Resque worker.  Resque stores the record's class and ID, and the
  # Resque worker provides those values as parameters to this method.
  def self.perform(klass, id)
    # puts "Performing REST hook Resque job: #{klass} #{id}"
    event = "new_#{klass.to_s.underscore}"
    record = klass.camelize.constantize.find(id)
    Hook.trigger(event, record)
  end
  @queue = :rest_hook
  extend Resque::Plugins::Retry
  @retry_limit = 3
  @retry_delay = 5

  # Returns all hooks for a given event and account.
  def self.hooks(event, record)
    Hook.find(:all, :conditions => {
        :event => event,
        :account_id => record.account_id,
      })
  end

  # Tests whether any hooks exist for a given event and account, for deciding whether or not to
  # enqueue Resque jobs.
  def self.hooks_exist?(event, record)
    self.hooks(event, record).size > 0
  end

end

hook_test.rb

require 'test_helper'
require 'fakeweb'

class HookTest < ActiveSupport::TestCase

  def setup
    @account = Factory(:account)

    @subscription_url = "https://zapier.com/hooks/standard/wpGRPPcRxZt2GxBbSSeUAlWPBnhLiRWB/"
    @target_url = "https://zapier.com/hooks/standard/wpGRPPcRxZt2GxBbSSeUAlWPBnhLiRWB/"

    # Create the record before the hook is created or else the after_create Active Model hook
    # will trigger the REST hook prematurely during testing.
    @contact = Factory(:contact, :account => @account,
      :first => 'Ryan', :last => 'Porter', :email => 'xyz@venuedriver.com')

    @hook = Hook.create(
      {
        "event" => "new_contact",
        "account_id" => @account.id,
        "subscription_url" => @subscription_url,
        "target_url" => @target_url
      }
    )
  end

  def test_hooks_exist
    assert_equal true, Hook.hooks_exist?('new_contact', @contact)

    Hook.destroy_all

    assert_equal false, Hook.hooks_exist?('new_contact', @contact)
  end

  def test_hooks
    hooks = Hook.hooks('new_contact', @contact)
    assert_equal 1, hooks.size
    assert_equal @hook, hooks.first

    second_hook = Hook.create(
      {
        "event" => "new_contact",
        "account_id" => @account.id,
        "subscription_url" => @subscription_url,
        "target_url" => @target_url
      }
    )

    hooks = Hook.hooks('new_contact', @contact)
    assert_equal 2, hooks.size
    assert_equal second_hook, hooks.last
  end

  def test_trigger
    FakeWeb.register_uri(
      :post,
      @target_url,
      :body => 'irrelevant',
      :status => ['200', 'Triggered']
    )
    FakeWeb.allow_net_connect = false

    Hook.trigger('new_contact', @contact)

    assert_equal "POST", FakeWeb.last_request.method
    assert_equal HookEncoder.encode(@contact), FakeWeb.last_request.body
    assert_equal 1, Hook.count # The hook should not have been deleted.
  end

  def test_trigger_remove_hook_on_410_response
    FakeWeb.register_uri(
      :post,
      @target_url,
      :body => 'irrelevant',
      :status => ['410', 'Danger, Will Robinson!']
    )
    FakeWeb.allow_net_connect = false

    Hook.trigger('new_contact', @contact)

    assert_equal "POST", FakeWeb.last_request.method
    assert_equal HookEncoder.encode(@contact), FakeWeb.last_request.body

    assert_equal 0, Hook.count # The 410 response should trigger removal of the hook.
  end

  def test_resque_background_job
    FakeWeb.register_uri(
      :post,
      @target_url,
      :body => 'irrelevant',
      :status => ['200', 'Triggered']
    )
    FakeWeb.allow_net_connect = false

    # A Resque worker will normally do this, which should have the same effect as when the hook
    # is manually triggered in the test_trigger test.
    Hook.perform(Contact.name, @contact.id)

    assert_equal "POST", FakeWeb.last_request.method
    assert_equal HookEncoder.encode(@contact), FakeWeb.last_request.body
    assert_equal 1, Hook.count # The hook should not have been deleted.
  end

end

hooks_controller.rb

class HooksController < ApplicationController
  def create
    hook = Hook.new params
    render :nothing => true, :status => 500 and return unless hook.save
    Rails.logger.info "Created REST hook: #{hook.inspect}"
    # The Zapier documentation says to return 201 - Created.
    render :json => hook.to_json(:only => :id), :status => 201
  end

  def destroy
    hook = Hook.find(params[:id]) if params[:id]
    if hook.nil? && params[:subscription_url]
      hook = Hook.find_by_subscription_url(params[:subscription_url]).destroy
    end
    Rails.logger.info "Destroying REST hook: #{hook.inspect}"
    hook.destroy
    render :nothing => true, :status => 200
  end
end

hooks_controller_test.rb

require 'test_helper'
require 'fakeweb'

class HookTest < ActiveSupport::TestCase

  def setup
    @account = Factory(:account)

    @subscription_url = "https://zapier.com/hooks/standard/wpGRPPcRxZt2GxBbSSeUAlWPBnhLiRWB/"
    @target_url = "https://zapier.com/hooks/standard/wpGRPPcRxZt2GxBbSSeUAlWPBnhLiRWB/"

    # Create the record before the hook is created or else the after_create Active Model hook
    # will trigger the REST hook prematurely during testing.
    @contact = Factory(:contact, :account => @account,
      :first => 'Ryan', :last => 'Porter', :email => 'xyz@venuedriver.com')

    @hook = Hook.create(
      {
        "event" => "new_contact",
        "account_id" => @account.id,
        "subscription_url" => @subscription_url,
        "target_url" => @target_url
      }
    )
  end

  def test_hooks_exist
    assert_equal true, Hook.hooks_exist?('new_contact', @contact)

    Hook.destroy_all

    assert_equal false, Hook.hooks_exist?('new_contact', @contact)
  end

  def test_hooks
    hooks = Hook.hooks('new_contact', @contact)
    assert_equal 1, hooks.size
    assert_equal @hook, hooks.first

    second_hook = Hook.create(
      {
        "event" => "new_contact",
        "account_id" => @account.id,
        "subscription_url" => @subscription_url,
        "target_url" => @target_url
      }
    )

    hooks = Hook.hooks('new_contact', @contact)
    assert_equal 2, hooks.size
    assert_equal second_hook, hooks.last
  end

  def test_trigger
    FakeWeb.register_uri(
      :post,
      @target_url,
      :body => 'irrelevant',
      :status => ['200', 'Triggered']
    )
    FakeWeb.allow_net_connect = false

    Hook.trigger('new_contact', @contact)

    assert_equal "POST", FakeWeb.last_request.method
    assert_equal HookEncoder.encode(@contact), FakeWeb.last_request.body
    assert_equal 1, Hook.count # The hook should not have been deleted.
  end

  def test_trigger_remove_hook_on_410_response
    FakeWeb.register_uri(
      :post,
      @target_url,
      :body => 'irrelevant',
      :status => ['410', 'Danger, Will Robinson!']
    )
    FakeWeb.allow_net_connect = false

    Hook.trigger('new_contact', @contact)

    assert_equal "POST", FakeWeb.last_request.method
    assert_equal HookEncoder.encode(@contact), FakeWeb.last_request.body

    assert_equal 0, Hook.count # The 410 response should trigger removal of the hook.
  end

  def test_resque_background_job
    FakeWeb.register_uri(
      :post,
      @target_url,
      :body => 'irrelevant',
      :status => ['200', 'Triggered']
    )
    FakeWeb.allow_net_connect = false

    # A Resque worker will normally do this, which should have the same effect as when the hook
    # is manually triggered in the test_trigger test.
    Hook.perform(Contact.name, @contact.id)

    assert_equal "POST", FakeWeb.last_request.method
    assert_equal HookEncoder.encode(@contact), FakeWeb.last_request.body
    assert_equal 1, Hook.count # The hook should not have been deleted.
  end

end