Helper in controller undefined when called

Hello, I'm pulling my hair out as I can't seem to find resolution to my
simple problem, which is calling methods from controllers to helpers.

in my application_controller.rb I have helper :all, which as i
understand should include all helpers all the time.
Then when i try to call methods in helpers i get undefined method error.

Is there another place where i have to include helpers to make them
available in controllers?

Helper methods are used in the template class (ActionView::Template),
not controllers. If I'm reading the documentation right, putting
"helper :all" in a controller makes all helpers found in app/helpers/
**/*rb available in that controller's views.

If you really want to use an existing Rails helper in your
controllers, do the following :

1. add the following the following code to your
application_controller (a singleton and a method):
  class Helper
    include Singleton
    include ActionView::Helpers::DateHelper
    include ActionView::Helpers::TextHelper
    # include other helpers

  def helpers

2. Use the helpers in your controller : @nice_string =