Rails - Helper Singleton and Rails Route Helpers in a Presenter

Question

I can't seem to figure out why I'm getting a 500 Error when trying to utilize a route helper in my Presenter class

Have a Presenter class under /apps/presenters/base_presenter.rb /apps/presenters/object_presenter.rb

class BasePresenter

  def self.as_collection(collection)
    collection.collect{|object| self.new(object)}
  end

  def help
    Helper.instance
  end

  class Helper
    include Singleton
    include Rails.application.routes.url_helpers
    include ActionView::Helpers::TextHelper
    include ActionView::Helpers::TagHelper
    include ActionView::Helpers::UrlHelper
    include ApplicationHelper
    include UrlHelper
  end

end

so in my object presenter I do the following for an as_json. Every thing works until I add this url. Boggled as to why it won't access the Rails routes.

class ObjectPresenter < BasePresenter


  def initialize( object )
    @object = object
  end

  def as_json(*args)
    { 
        :url => blah_blah_url(@object, :subdomain => "www")
    }
  end

end

any help would be much appreciated because I'm stumped :)

Answer 1

ok I figured it out.

class Presenter
  include Rails.application.routes.url_helpers

  def self.as_collection(collection)
    collection.collect{|object| self.new(object)}
  end

  def help
    Helper.instance
  end

  class Helper
    include Singleton
    include ActionView::Helpers::TextHelper
    include ActionView::Helpers::TagHelper
    include ActionView::Helpers::UrlHelper
    include ApplicationHelper
    include UrlHelper
  end

end

then in my environment/development.rb

  Rails.application.routes.default_url_options = { :host => "lvh.me:3000" } # Fixes issue with Presenters not allowing Routes and Url Helper
  config.action_mailer.default_url_options = { :host => "lvh.me:3000" }

and my UrlHelper

module UrlHelper

  def with_subdomain(subdomain)
    subdomain = (subdomain || "")
    subdomain += "." unless subdomain.empty?
    host = Rails.application.routes.default_url_options[:host]
    [subdomain, host].join
  end

  def url_for(options = nil)
    if options.kind_of?(Hash) && options.has_key?(:subdomain)
      options[:host] = with_subdomain(options.delete(:subdomain))
    end
    super
  end

end