class ActionController::Caching::Sweeper

def callback(timing)
  controller_callback_method_name = "#{timing}_#{controller.controller_name.underscore}"
  action_callback_method_name     = "#{controller_callback_method_name}_#{controller.action_name}"
  __send__(controller_callback_method_name) if respond_to?(controller_callback_method_name, true)
  __send__(action_callback_method_name)     if respond_to?(action_callback_method_name, true)
end