Extending controllers of a Rails 3 Engine in the main app

Question

I am using a Rails engine as a gem in my app. The engine has PostsController with a number of methods and I would like to extend the controller logic in my main

Answer 1

You can use Ruby's send() method to inject your code into the controller at the time the engine is created...

# lib/cool_engine/engine.rb

module CoolEngine
  class Engine < ::Rails::Engine

    isolate_namespace CoolEngine

    initializer "cool_engine.load_helpers" do |app|
      # You can inject magic into all your controllers...
      ActionController::Base.send :include, CoolEngine::ActionControllerExtensions
      ActionController::Base.send :include, CoolEngine::FooBar

      # ...or add special sauce to models...
      ActiveRecord::Base.send :include, CoolEngine::ActiveRecordExtensions
      ActiveRecord::Base.send :include, CoolEngine::MoreStuff

      # ...even provide a base set of helpers
      ApplicationHelper.send :include, CoolEngine::Helpers
    end
  end
end

This method spares you from having to redefine the controller inheritance within your main app.