无法在Symfony控制器中检索AJAX请求数据

Question

我正在尝试通过AJAX将数据发送到我的Symfony控制器路由。现在，我只是对一些东西（数据和动态URL）进行硬编码。

$('#add_assistant_next').click(function () {
        console.log('pressed');
       var that = $(this);
       $.ajax({
            url: '/courseSpace/20866/listAssistantEnrollment',
           type: "POST",
           dataType: "json",
           data: {"ajax-user": "test user string"},
           async: true,
           success: function (data) {
               console.log(data);
               $('div#ajax-results').html(data.output);
           }
       });
        return false;
    });

控制器

/**
     * @Route(name="list_assistant_enrollment", methods={"GET", "POST"}, path="/courseSpace/{courseSpaceId}/listAssistantEnrollment")
     *
     * @ParamConverter("courseSpace", class="AppBundle\Entity\CourseSpace")
     * @ParamConverter("listSettings", class="AppBundle\View\ListEnrollment\ListSettings", options={"activeTab" = ListSettings::ASSISTANT_TAB})
     *
     * @param Request $request
     * @param ListSettings $listSettings
     * @param CourseSpace $courseSpace
     *
     * @return Response
     */
    public function assistantEnrollmentAction(Request $request, ListSettings $listSettings, CourseSpace $courseSpace)
    {
        if ($request->isXmlHttpRequest()) {
            dump('request received');
            die();
        }

        if ($request->request->get('ajax-user')) {
            dump('request received');
            die();
        }
    }

我相信请求已正确发送，但是我无法在控制器端处理它。我一直收到404错误，直到我为该路由硬编码了一些有效的courseSpaceId参数