Use roar to take you decorators to the next level

When writing ruby programs we usually write decorators to extend the methods of a particular object.Using them as form objects is one of the most common uses of a decorator.Ruby makes it simple and easy to create a decorator for a ruby object.

class StuffDecorator
  def initialize(og)
    @og = og
  end
  def stuff
    @og.class
  end
end

Now we can call the stuff method and it will easily return the class of the original object.

While working on an API backend I came across roar.Its a ruby library that allows you to add methods to your ruby object without breaking a sweat.

Here’s an example from the docs

require 'roar/decorator'
class Song
  include ActiveModel::Model
  attr_accessor :title
end

class SongRepresenter < Roar::Decorator
  include Roar::JSON

  property :title
end

song = Song.new(title: "Medicine Balls")

SongRepresenter.new(song).to_json #=> {"title":"Medicine Balls"}

As you can see the property method calls the original object and returns the response.The best part is now you can get the json serialized version of the object.

If you want to add a custom method you can easily add a method or even override and existing one.

class SongRepresenter < Roar::Decorator
  include Roar::JSON

  def more
    represented.title
  end
  property :title
  property :more, exec_context: :decorator
end

To make things better Roar allows you to serialize your decorator to JSON-API, XML, or even HAL.

All you have to do is include it in the decorator

class SongRepresenter < Roar::Decorator
  include Roar::JSON
  include Roar::XML

  property :title
end

song = Song.new(title: "Medicine Balls")

SongRepresenter.new(song).to_xml #=> "<sonepresenter>\n  <title>test</title>\n</sonepresenter>"