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

In addition to using the standard template helpers provided in the Rails framework, creating custom helpers to extract complicated logic or reusable functionality is strongly encouraged. By default, the controller will include a helper whose name matches that of the controller, e.g., MyController will automatically include MyHelper.

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

Examples

The to_s method from the Time class can be wrapped in a helper method to display a custom message if the 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.find(:all)
  end
end

Then, in any view rendered by EventController, 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 Railhaws Training Workshop