xhr aware responder

xhr_aware_responder.rb

# Will render the the show method instead of redirecting when the action is an ajax request.
# Also adds an options xhr_show to render instead of show.
class XhrAwareResponder < ActionController::Responder
protected
  def navigation_behavior(error)
    if get?
      raise error
    elsif has_errors? && default_action
      render action: default_action, layout: options[:layout]
    elsif controller.request.xhr?
      render action: options[:xhr_show] || :show, layout: options[:layout]
    else
      redirect_to navigation_location
    end
  end
end