Why are all Rails helpers available to all views, all the time? Is there a way to disable this?

Question

Why can I access helper methods for one controller in the views for a different controller? Is there a way to disable this without hacking/patching Rails?

Answer 1

Actually in Rails 2, the default functionality of ActionController::Base was to include all helpers.

Changeset 6222 on 02/24/07 20:33:47 (3 years ago) by dhh: Make it a default assumption that you want all helpers, all the time (yeah, yeah)

change:

class ApplicationController < ActionController::Base 
  helper :all # include all helpers, all the time 
end 

As of Rails 3 beta 1, that is no longer the case as noted in the CHANGELOG:

• Added that ActionController::Base now does helper :all instead of relying on the default ApplicationController in Rails to do it [DHH]

Answer 2

In Rails 3, actioncontroller/base.rb (around line 224):

def self.inherited(klass)
  super
  klass.helper :all if klass.superclass == ActionController::Base
end

So yes, if you derive your class from ActionController::Base, all helpers will be included.

To come around this, call clear_helpers (AbstractClass::Helpers; included in ActionController::Base) at the beginning of your controller's code. Source code comment for clear_helpers:

# Clears up all existing helpers in this class, only keeping the helper
# with the same name as this class.

E.g.:

class ApplicationController < ActionController::Base
  clear_helpers
  ...
end

Answer 3

The answer depends on the Rails version.

Rails >= 3.1

Change the include_all_helpers config to false in any environment where you want to apply the configuration. If you want the config to apply to all environments, change it in application.rb.

config.action_controller.include_all_helpers = false

When false, it will skip the inclusion.

Rails < 3.1

Delete the following line from ApplicationController

helper :all

In this way each controller will load its own helpers.

Answer 4

@George Schreiber's method doesn't work as of Rails 3.1; the code has changed significantly.

However, there's now an even better way to disable this feature in Rails 3.1 (and hopefully later). In your config/application.rb, add this line:

config.action_controller.include_all_helpers = false

This will prevent ApplicationController from loading all of the helpers.

(For anyone who is interested, here's the pull request where the feature was created.)