如何在常规Ruby类中包含rails ApplicationHelper模块

Question

I have a class in my Rails app's lib directory and I want to be able to use the helpers I created in ApplicationHelper from inside that class. I have the following:

module ApplicationHelper

  def works
    "Yay!"
  end   

  def breaks
    session[:username]
  end
end

class MyClass
  include ApplicationHelper
end

The following works

MyClass.new.works 

This breaks

MyClass.new.breaks

I get a message about Rails trying to delegate session to controller.session , but it can't do it because controller is nil.

What's the right way to include ApplicationHelper?

Answer 1

The issue is not with including the helper, but with accessing the session.

In the normal scenario, the ApplicationHelper is automatically included in all controllers, and some of the ActionView methods - including session - are delegated to the controller which is present in this case.

When included in a regular ruby class, there is no controller ; so any call to these methods will throw an error saying the controller is nil.

Not sure why you would need session information in a regular ruby class.