Service Objects

Taxonomies

Who calls the service object?

• The controller (service-layer?)
• The AR model

What represents the service object?

• A role
• An external interface
• A use case

Version #8

• http://rails-vs-oo.heroku.com/
• http://confreaks.com/videos/1393-rubymanor3-rails-vs-object-oriented-design

class OrdersController < ActionController::Base
  def close
    #retrieval
    payment_handler = Payment.for(params[:method], params[:card])
    process = OrderProcess.new(order, payment_handler)
    process.close
    #rendering
  end
end

class Payment
  def self.for(method, card_details=nil)
    if method == "card"
      CardPayment.new(card_details)
    else
      new
    end
  end

  def handle_payment
    #default payment handling code
  end
end

class CardPayment
  #...

  def handle_payment
    ExternalPaymentService.new.charge(@card_details)
  end
end

class OrderProcess
  #...

  def close
    @payment_handler.handle_payment
    Delivery.create! :status => :pending, :order => @order
    @order.close!
  end
end

```ruby` class Order < ActiveRecord::Base #...

def close! self.closed = true self.save! end end