javascript - 对 django View 的 Ajax 请求未返回响应

Question

我正在制作一个网站，我想要加载用户提交的对元素的评论，并且我希望能够动态显示它们，而不是让网页必须一次加载它们。所以我设置了这个ajax请求功能:

function loadcomments(){
   $.ajax({
        url: '/ajax/getcomments/',
        data: {
            'identifier': {{ identifier }}
            'begin': 0,
            'end': 30
        },
        dataType: 'json',
        success: function (data) {
            alert(data.comments);
        }
   });
};

以及响应该请求的 View :

def obtain_comments(request, *args, **kwargs):
    begin = kwargs.get('begin');
    end = kwargs.get('end');
    comments = end - begin
    all_before = Comment.objects.order_by('-uploaded')[:end]
    data = {
        'comments': all_before.order_by('uploaded')[:comments]
    }
    return JsonResponse(data)

但我没有得到回复。我在浏览器控制台中没有看到任何错误，但是在 django runserver 终端中我看到:

Internal Server Error: /ajax/getcomments/
Traceback (most recent call last):
  File "/home/trie/Desktop/django/venv/lib/python3.5/site-packages/django/core/handlers/exception.py", line 35, in inner
    response = get_response(request)
  File "/home/trie/Desktop/django/venv/lib/python3.5/site-packages/django/core/handlers/base.py", line 128, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/home/trie/Desktop/django/venv/lib/python3.5/site-packages/django/core/handlers/base.py", line 126, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/home/trie/Desktop/django/vidmiotest/player/views.py", line 64, in obtain_comments
    comments = end - begin
TypeError: unsupported operand type(s) for -: 'NoneType' and 'NoneType'

或者如果我将 begin 和 end 设置为固定值而不是 kwargs:

Internal Server Error: /ajax/getcomments/
Traceback (most recent call last):
  File "/home/trie/Desktop/django/venv/lib/python3.5/site-packages/django/core/handlers/exception.py", line 35, in inner
    response = get_response(request)
  File "/home/trie/Desktop/django/venv/lib/python3.5/site-packages/django/core/handlers/base.py", line 128, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/home/trie/Desktop/django/venv/lib/python3.5/site-packages/django/core/handlers/base.py", line 126, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/home/trie/Desktop/django/vidmiotest/player/views.py", line 67, in obtain_comments
    'comments': all_before.order_by('uploaded')[:comments]
  File "/home/trie/Desktop/django/venv/lib/python3.5/site-packages/django/db/models/query.py", line 1012, in order_by
    "Cannot reorder a query once a slice has been taken."
AssertionError: Cannot reorder a query once a slice has been taken.

我尝试从“obtain_comments” View 中删除元素标识符，以便我可以在数据库中获取任何评论。不过，我希望该 View 能够响应我手动插入数据库的 1 条评论。

在urls.py中我定义了这样的url:

path('ajax/getcomments/', obtain_comments),

为什么我没有收到回复？

Answer 1

View 中的

args 和 kwargs 用于在 URL 中传递并在 URL 模式中捕获的参数。这些你都没有；您的 Ajax 正在发送 GET 查询字符串中的值。因此，您需要从 request.GET 获取它们。另请注意，这些值将是字符串，因此您需要将它们转换为整数。

begin = int(request.GET['begin'])
end = int(request.GET['end'])

另一个错误在错误消息本身中进行了解释；切片后不能订购。你应该先这样做。