module ActionController::EtagWithTemplateDigest

def determine_template_etag(options)
  if template = pick_template_for_etag(options)
    lookup_and_digest_template(template)
  end
end

def lookup_and_digest_template(template)
  ActionView::Digestor.digest name: template, finder: lookup_context
end

def pick_template_for_etag(options)
  options.fetch(:template) { "#{controller_name}/#{action_name}" }
end