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
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. To return old behavior set
Additional helpers can be specified using the
helper class method in ActionController::Base or any controller which inherits from it.
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_s(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
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
# File actionpack/lib/action_controller/metal/helpers.rb, line 118 def helpers @_helper_proxy ||= view_context end
Provides a proxy to access helper methods from outside the view.
© 2004–2019 David Heinemeier Hansson
Licensed under the MIT License.