Rails initializer that adds comments to generated markup identifying which template it came from

show_view_structure.rb

unless Rails.env.production?
  # Inspired by http://github.com/fcheung/tattler/blob/master/lib/tattler.rb
  #
  class ActionView::Template
    def render_with_comment(*args, &block)
      render_result = render_without_comment(*args, &block)
      if mime_type.nil? || mime_type.in?([Mime::HTML, Mime::XML])
        [
        "<!-- STARTTEMPLATE: #{identifier} -->",
         render_result,
         "<!-- ENDTEMPLATE: #{identifier} -->"
        ].join("\n").html_safe
      else
        render_result
      end
    end
    alias_method_chain :render, :comment
  end

end