Add view helpers to a Rails application, globally and locally

By the end of this post you will have a better idea of how to handle application data processing in Rails views.

For the first example, lets say you wanted to translate text in your footer like so:

<!-- _footer.html.erb -->

  <div><%= translate("copyright") %></div>
  <div><%= translate("privacy-policy") %></div>
  <div><%= translate("faq") %></div>

Since your footer will likely be a partial used across most if not all templates rendered by a controller you can add the translate view helper method used above to application_controller.rb. This will make the method accessible from any other controller and also if you invoke helper_method it will also be available across all view templates. This is what that would look like:

# application_controller.rb

helper_method :translate
def translate(text)
  # handle translation behavior

If you only wanted the method available in a specific template, you can add the method to the controller that renders that template:

# users_controller.rb

helper_method :translate_user_details
def translate_user_details(text)
  # handle translation behavior

After creating these functions and their helper methods they can be invoked in their respective views as shown in the _footer.html.erb example above.