python - Django REST 框架查询集对象没有属性 pk

Question

我正在构建一个更大的基于 Django 的网络应用程序，但我遇到了一个应该返回一些数据的 API View 的阻塞问题。

我的应用程序有一个模型 (mail.models.Message) 和一个匹配的序列化程序和 View 集。

对于报告功能，我需要获取经过过滤的结果集，并因此创建了一个单独的 rest_framework.views.APIView 用于报告目的。该模型位于一个应用程序中，而报告位于另一个应用程序中。

这是模型:

class Message(models.Model):
class Meta:
    ordering = ('-timestamp',)
    get_latest_by = 'timestamp'

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    from_address = models.CharField("From", max_length=511, blank=True, default="", db_index=True)
    from_domain = models.CharField(max_length=255, blank=True, default="", db_index=True)
    to_address = models.CharField("To", max_length=511, blank=True, default="", db_index=True)
    to_domain = models.CharField(max_length=255, blank=True, default="", db_index=True)
    subject = models.TextField(blank=True, default="", db_index=True)
    client_ip = models.GenericIPAddressField("Client IP", db_index=True, null=True)
    mailscanner_hostname = models.CharField(max_length=255, db_index=True)
    spam_score = models.DecimalField(db_index=True, default=0.00, max_digits=7, decimal_places=2)
    mcp_score = models.DecimalField(db_index=True, default=0.00, max_digits=7, decimal_places=2)
    timestamp = models.DateTimeField(db_index=True)
    size = models.FloatField(default=0)
    token = models.CharField(max_length=255, null=True)
    mailq_id = models.TextField("Mailqueue identification", null=True)
    whitelisted = models.BooleanField(db_index=True, default=False)
    blacklisted = models.BooleanField(db_index=True, default=False)
    is_spam = models.BooleanField(db_index=True, default=False)
    is_mcp = models.BooleanField(db_index=True, default=False)
    is_rbl_listed = models.BooleanField("Is RBL listed", db_index=True, default=False)
    quarantined = models.BooleanField(db_index=True, default=False)
    infected = models.BooleanField(db_index=True, default=False)
    released = models.BooleanField(db_index=True, default=False)

    def __str__(self):
        return str(self.id) + "[" + str(self.from_address) + " to " + str(self.to_address) + "]"

以及匹配的序列化器:

class MessageSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = Message
        fields = (
            'id',
            'url',
            'from_address',
            'from_domain',
            'to_address',
            'to_domain',
            'subject',
            'client_ip',
            'mailscanner_hostname',
            'spam_score',
            'timestamp',
            'size',
            'token',
            'whitelisted',
            'blacklisted',
            'is_spam',
            'is_rbl_listed',
            'quarantined',
            'infected'
        )

模型上有很多索引来提高搜索和过滤的性能，但我已经排除了这些。

为了报告，我创建了这个特殊 View :

class MessageListApiView(ReportApiView):
    serializer_class = MessageSerializer
    queryset = Message.objects.all()

    def get_queryset(self):
        if self.request.method == 'POST':
            filters = self.request.data
            return MessageQuerySetFilter.filter(MessageQuerySetFilter, self.queryset, filters)
        else:
            return self.queryset


    def post(self, request, format=None):
        filters = request.data
        qs = self.get_queryset()
        serializer = MessageSerializer(qs, context={'request': request})
        return Response(serializer.data, 200)

在 get_queryset 中，我使用了一个特殊的类，该类的唯一目的是对查询集应用适当的过滤并返回它。进行一些测试后，我发现问题发生在我必须返回 Response 时。

我得到这个回溯:

Internal Server Error: /api/reports/messages/
Traceback (most recent call last):
  File "/Users/kenneth/Code/mailware/lib/python3.6/site-packages/django/core/handlers/exception.py", line 35, in inner
response = get_response(request)
  File "/Users/kenneth/Code/mailware/lib/python3.6/site-packages/django/core/handlers/base.py", line 128, in _get_response
response = self.process_exception_by_middleware(e, request)
      File "/Users/kenneth/Code/mailware/lib/python3.6/site-packages/django/core/handlers/base.py", line 126, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/Users/kenneth/Code/mailware/lib/python3.6/site-packages/django/views/decorators/csrf.py", line 54, in wrapped_view
return view_func(*args, **kwargs)
  File "/Users/kenneth/Code/mailware/lib/python3.6/site-packages/django/views/generic/base.py", line 69, in view
return self.dispatch(request, *args, **kwargs)
  File "/Users/kenneth/Code/mailware/lib/python3.6/site-packages/rest_framework/views.py", line 494, in dispatch
response = self.handle_exception(exc)
  File "/Users/kenneth/Code/mailware/lib/python3.6/site-packages/rest_framework/views.py", line 454, in handle_exception
self.raise_uncaught_exception(exc)
  File "/Users/kenneth/Code/mailware/lib/python3.6/site-packages/rest_framework/views.py", line 491, in dispatch
response = handler(request, *args, **kwargs)
  File "/Users/kenneth/Code/mailware/src/reports/views.py", line 44, in post
return Response(serializer.data, 200)
  File "/Users/kenneth/Code/mailware/lib/python3.6/site-packages/rest_framework/serializers.py", line 537, in data
ret = super(Serializer, self).data
  File "/Users/kenneth/Code/mailware/lib/python3.6/site-packages/rest_framework/serializers.py", line 262, in data
self._data = self.to_representation(self.instance)
  File "/Users/kenneth/Code/mailware/lib/python3.6/site-packages/rest_framework/serializers.py", line 504, in to_representation
ret[field.field_name] = field.to_representation(attribute)
  File "/Users/kenneth/Code/mailware/lib/python3.6/site-packages/rest_framework/relations.py", line 376, in to_representation
url = self.get_url(value, self.view_name, request, format)
  File "/Users/kenneth/Code/mailware/lib/python3.6/site-packages/rest_framework/relations.py", line 312, in get_url
lookup_value = getattr(obj, self.lookup_field)
AttributeError: 'QuerySet' object has no attribute 'pk'
[19/Jan/2018 20:05:24] "POST /api/reports/messages/ HTTP/1.1" 500 16389

上面的APIView类继承了一个自定义的基类，也就是继承了rest_framework.views.APIView类。此类称为 ReportApiView 并简单地设置 paginator_class 和 permission_class

class ReportApiView(APIView):
    permission_classes = (IsAuthenticated,)
    pagination_class = PageNumberPaginationWithPageCount

在 MessageListApiView post 方法中 return 行似乎出错了，但我找不到它不起作用的原因

Answer 1

您需要将 many=True 添加到序列化程序查询集中:

serializer = MessageSerializer(qs, many=True, context={'request': request})