Action Controller Helpers

The Rails framework provides a large number of helpers for working with assets, dates, forms, numbers and model objects, to name a few. These helpers are available to all templates by default.

In addition to using the standard template helpers provided, creating custom helpers to extract complicated logic or reusable functionality is strongly encouraged. By default, each controller will include all helpers. These helpers are only accessible on the controller through #helpers

In previous versions of Rails the controller will include a helper which matches the name of the controller, e.g., MyController will automatically include MyHelper. You can revert to the old behavior with the following:

# config/application.rb
class Application < Rails::Application
  config.action_controller.include_all_helpers = false
end

Additional helpers can be specified using the helper class method in ActionController::Base or any controller which inherits from it.

The to_s method from the Time class can be wrapped in a helper method to display a custom message if a Time object is blank:

module FormattedTimeHelper
  def format_time(time, format=:long, blank_message=" ")
    time.blank? ? blank_message : time.to_fs(format)
  end
end

FormattedTimeHelper can now be included in a controller, using the helper class method:

class EventsController < ActionController::Base
  helper FormattedTimeHelper
  def index
    @events = Event.all
  end
end

Then, in any view rendered by EventsController, the format_time method can be called:

<% @events.each do |event| -%>
  <p>
    <%= format_time(event.time, :short, "N/A") %> | <%= event.name %>
  </p>
<% end -%>

Finally, assuming we have two event instances, one which has a time and one which does not, the output might look like this:

23 Aug 11:30 | Carolina Railhawks Soccer Match
N/A | Carolina Railhawks Training Workshop

actionpack/lib/action_controller/metal/helpers.rb