My way to use services objects

collector_role.rb

#in app/roles/
module CollectorRole
  def paintings
    ["Van Gogh"]
  end
end

message.rb

#in app/models/
class Message < Struct.new(:title, :message)
  def to_s
    title
  end
end

message_geocoder.rb

#in app/services/
class MessageGeocoder < Struct.new(:message)
  extend Service

  def call
    puts "Geocoding of #{message}"
  end
end

message_notifier.rb

#in app/services/
class MessageNotifier < Struct.new(:sender, :receiver, :message)
  extend Service

  def call
    receiver.extend(CollectorRole)
    puts "#{sender} send a message to #{receiver} to have information about #{receiver.paintings}"
    message = Message.new("Hello", "World")
  end
end

messages_controller.rb

#in app/controllers/
sender = User.new("Bob")
receiver = User.new("Arold")
notifier = MessageNotifier.new(sender, receiver)
notifier.call

MessageGeocoder.new(notifier.message).call

service.rb

# in lib/
module Service
  def self.call(*args)
    self.new(args).call
  end
end

user.rb

#in app/models
class User < Struct.new(:name, :email)
  def to_s
    name
  end
end

This is a simple example of what I do in an rails application. This is PORO but it's easily integrable in a Rails project. The controller call services objects which contains all the logic.

I think it's simpler than the DCI paradigm. It use roles too but in a simpler way. My models can stay only data but the controller is not tyrannized by the context.