controller_class

# File actionpack/lib/action_dispatch/http/request.rb, line 85
    def controller_class
      check_path_parameters!
      params = path_parameters

      if params.key?(:controller)
        controller_param = params[:controller].underscore
        params[:action] ||= 'index'
        const_name = "#{controller_param.camelize}Controller"
        ActiveSupport::Dependencies.constantize(const_name)
      else
        PASS_NOT_FOUND
      end
    end