ActionDirector

gem 'action_director'

$ bundle

$ gem install action_director

class AgeLabeler
  include ActionDirector

  def initialize
    @labeling = directive('Labeling age').setup do
      with 1..17, 18..27, 28..37, 38..47, 48..57 do |age, range| "#{range.begin} - #{range.end}" end
      with 58..100000000000000000000000000000000 do |age, range| "#{range.begin} and above"      end
      otherwise                                  do |age, range| "Unknown"                       end
    end
  end

  def label(age)
    @labeling.from age
  end
end

class JsonResponseDirector < Struct.new(:controller)
  include ActionDirector

  def response
    direct controller do
      with /fail/    do |resource| render json: resource.errors, status: :unprocessable_entity end
      with /created/ do |resource| render action: 'show', status: :created, location: resource end
      otherwise      do |resource| head :no_content                                            end
    end
  end

  def method_missing(method_name, *args, &block)
    resource = args.first
    response.for resource, method_name
  end
end