Rails 3.1: Better way to expose an engine's helper within the client app

Question

I have found a few articles addressing the issue of helpers within an engine not being accessible to the consuming (parent) application. To make sure we are all on the same

Answer 1

You can create an initializer to accomplish this like so:

module MyEngine
  class Engine < Rails::Engine
    initializer 'my_engine.action_controller' do |app|
      ActiveSupport.on_load :action_controller do
        helper MyEngine::ImportantHelper
      end
    end
  end
end

Answer 2

If you want to keep the code in the engine, instead of every implementing application, use this:

module MyEngine
  class Engine < Rails::Engine
    isolate_namespace MyEngine

    config.to_prepare do
      MyEngine::ApplicationController.helper Rails.application.helpers
    end

  end
end

Answer 3

I have written two blog posts about creating engines from scratch, and following them everything should work as expected (without additional configurations needed). Maybe you are still interested in:

• Rails 3.1 Engines: Part I – The engine
• Rails 3.1 Engines: Part II – The gem
• Rails 3.1 Engines: Part III – The environment

Update: It's three articles in the meantime, and there's still some info to come. Please give me feedback.

Answer 4

Include this code in engine.rb is also be very helpful

config.before_initialize do
  ActiveSupport.on_load :action_controller do
    helper MyEngine::Engine.helpers
  end
end

Basically your engine would look like

module MyEngine
  class Engine < Rails::Engine
    isolate_namespace MyEngine

    # Here comes the code quoted above 

  end
end

Answer 5

module YourEngine
  module Helpers
    def a_helper
    end

    ...
  end
end

ActionController::Base.send(:helper, YourEngine::Helpers)