我在django rest框架view.py中修改响应。为什么我在测试过程中获得属性，而不是实际使用API​​？

Question

我的Django REST框架API正常工作。在view.py中，我修改订单视图集（def partial_update），将另一个键/值对添加到响应。数据将其保存到db之前。当我与Postman一起致电API时，它无济于事。

但是，当我运行相同功能的测试时，它会失败并返回：

request.data["submission_date"] = datetime.now()
AttributeError: This QueryDict instance is immutable

为什么在实际API使用过程中未发生该错误时会在测试过程中遇到此错误？

view.py

class OrderViewSet(viewsets.ModelViewSet):
    """ Includes custom PATCH functionality """
    queryset = Order.objects.all().order_by('-order_date')
    serializer_class = OrderSerializer
    authentication_classes = (authentication.TokenAuthentication,)
    permission_classes = [permissions.IsAuthenticated]

    def partial_update(self, request, *args, **kwargs):
        """ Update status and timestamp fields accordingly """
        status = request.data['status']

        if status == 'submitted':
            request.data["submission_date"] = datetime.now()

        if status == 'packaged':
            request.data["packaged_date"] = datetime.now()

        if status in ['sold', 'canceled', 'abandoned']:
            request.data["finished_date"] = datetime.now()

        return super().partial_update(request, *args, **kwargs)

test.py

def test_patch_order_status_from_cart_to_submitted(self):
    """ test patching order status from cart to submitted """
    order = sample_order(user=self.user)

    payload = {
        "status": "submitted"
    }

    res = self.client.patch(order_detail_url(order.id), payload)
    self.assertEqual(res.status_code, status.HTTP_200_OK)

    patched_order = Order.objects.get(id=order.id)
    self.assertEqual(patched_order.status, 'submitted')

def test_submitted_timestamp(self):
    """ test that patching order status to submitted also leaves timestamp """
    order = sample_order(user=self.user)

    payload = {
        "status": "submitted"
    }

    self.client.patch(order_detail_url(order.id), payload)

    patched_order = Order.objects.get(id=order.id)
    self.assertNotEqual(patched_order.submission_date, None)

编辑：

如果我要修改request.data的副本，如下所示，我该如何从函数中返回？

    def partial_update(self, request, *args, **kwargs):
    """ Update status and timestamp accordingly """
    modified_data = request.data.copy()
    status = request.data['status']

    if status == 'submitted':
        modified_data["submission_date"] = datetime.now()

    if status == 'packaged':
        modified_data["packaged_date"] = datetime.now()

    if status in ['sold', 'canceled', 'abandoned']:
        modified_data["finished_date"] = datetime.now()

    return super().partial_update(request, *args, **kwargs)

解决方案：现在测试通过。

views.py：serializers.py

    ...

    def partial_update(self, request, pk, *args, **kwargs):
        """ Update status and timestamp accordingly """
        order = Order.objects.get(id=pk)
        serializer = OrderSerializer(order, data=request.data, partial=True)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data)
        else:
            return Response(serializer.errors)

：

class OrderSerializer(serializers.ModelSerializer):

    def update(self, order, validated_data):
        """ Update status and timestamp accordingly """
        status = validated_data.get('status')
        order.status = status
        if status == 'submitted':
            order.submission_date = datetime.now()
        elif status == 'packaged':
            order.packaged_date = datetime.now()
        elif status in ['sold', 'canceled', 'abandoned']:
            order.finished_date = datetime.now()

        order.save()
        return order

    class Meta:
        model = Order
        fields = '__all__'
        read_only_fields = ('id', 'user')

Answer 1

您的意思是修改request.data？我以前也有这个错误。

然后我阅读 django文档“ request.data”：

• 是字典，而不是字典。

• 数据类型是不可变的。

• 在修改之前复制它，例如：

    req_data = request.data.copy（）
   req_data ['cubmission_date'] = dateTime.now（）
   

以及在实际API使用过程中未发生错误的原因，也许只是在这些条件下的状态。

另一方面，在这种情况下，我通常会设置Modified_at或create_at “ noreflow noreferrer”> DateTimeField 在型号。我觉得这很方便。

created_at = models.DateTimeField(auto_now_add=True, help_text="submission_date")
modified_at = models.DateTimeField(auto_now=True, help_text="re-submission_date")

编辑使用Modelialializer：

目的：我们不仅要直接基于request.data更新数据。
我们想使用其他一些逻辑：如果status =='提交'然后...

我想提交_date，packaged_date，dearter_date是顺序模型的字段。

views.py

def partial_update(self, request, pk, *args, **kwargs):
    order = Order.objects.get(id=pk)
    serializer = OrderSerializer(order, data=request.data, partial=True)
    if serializer.is_valid():
        serializer.save()
        return Response(serializer.data)
    else:
        return Response(serializer.errors)
    

serializers.py

class OrderSerializer(serializers.ModelSerializer):
    class Meta:
        model = Order
        fields = '__all__'

    def update(self, order, validated_data):
        status = validated_data.get('status')
        order.status = status
        if status == 'submitted':
            order.submission_date = datetime.now()
        elif status == 'packaged':
            order.packaged_date = datetime.now()
        elif status in ['sold', 'canceled', 'abandoned']:
            order.finished_date = datetime.now()

        order.save()
        return order