Compile an arbitrary string of SCSS code in Rails controller

my_controller.rb

  # widget#custom_css is a string containing CSS or SCSS code
  def custom_css
    respond_to do |format|
      format.css {
        # I cant believe there isnt a better way to just compile a sass string. Sheesh.
        sprockets_env = Rails.application.assets
        opts = sprockets_env.context_class.sass_config
        ctx = sprockets_env.context_class.new(sprockets_env, "inmemory", Pathname(sprockets_env.root+"/app/assets/stylesheets"))
        opts = opts.merge( :syntax => :scss,
                           :load_paths => [Rails.root.join("app/assets/stylesheets")],
                           :filename => "embedded_css.css.scss",
                           :custom => {:resolver => Sass::Rails::Resolver.new(ctx)}
                         )
        render :text => Sass.compile(widget.custom_css, opts), :content_type => "text/css"
      }
    end
  end