CanCan makes two assumptions about your application.

• You have an Ability class which defines the permissions.
• You have a current_user method in the controller which returns the current user model.

You can override both of these by defining the current_ability method in your ApplicationController. The current method looks like this.

def current_ability
  @current_ability ||= Ability.new(current_user)
end

The Ability class and current_user method can easily be changed to something else.

# in ApplicationController
def current_ability
  @current_ability ||= AccountAbility.new(current_account)
end

Sometimes you might have a gem in your project which provides its own Rails engine which also uses CanCan such as LocomotiveCMS. In this case the current_ability override in the ApplicationController can also be useful.

# in ApplicationController
def current_ability
  if request.fullpath =~ /\/locomotive/
    @current_ability ||= Locomotive::Ability.new(current_user)
  else
    @current_ability ||= Ability.new(current_user)
  end
end

If your method that returns the currently logged in user just has another name than current_user, it may be the easiest solution to simply alias the method in your ApplicationController like this:

class ApplicationController < ActionController::Base
  alias_method :current_user, :name_of_your_method # Could be :current_member or :logged_in_user
end

That's it! See Accessing Request Data for a more complex example of what you can do here.