exec_handler

# File lib/webrick/httpservlet/filehandler.rb, line 230
      def exec_handler(req, res)
        raise HTTPStatus::NotFound, "`#{req.path}' not found" unless @root
        if set_filename(req, res)
          handler = get_handler(req, res)
          call_callback(:HandlerCallback, req, res)
          h = handler.get_instance(@config, res.filename)
          h.service(req, res)
          return true
        end
        call_callback(:HandlerCallback, req, res)
        return false
      end