How do you issue a 404 response from a rails controller action?

Question

What's the preferred way to issue a 404 response from a rails controller action?

Answer 1

This seems good...

# Rails 2 and below render :file => "#{RAILS_ROOT}/public/404.html",  :status => 404  # Rails 3 and up render :file => "#{Rails.root}/public/404.html",  :status => 404