gistfile1.txt

class ListProfileDecorator < Decorator
  include ::Rails.application.routes.url_helpers
  include ::ActionDispatch::Routing::PolymorphicRoutes
  json_methods :tiny_photo, :path

  def tiny_photo
    @component.photo.tiny.url
  end

  def path
    polymorphic_path(@component)
  end
end


class Decorator < BasicObject
  # .. snip ..
  def self.json_methods(*args)
    @@json_methods = args.to_a
  end
  
  def as_json(options = {})
    json = @component.as_json(options).merge(::Hash[@@json_methods.map { |k| [k, self.send(k)] }])
    if @component.class.try(:include_root_in_json)
      {@component.class.to_s.underscore => json}
    else
      json
    end
  end
end