Question

我正在编写一个rest API。这是我的观点：

   func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
        if let text = textField.text {
            if let floatingLabelTextField = textField as? SkyFloatingLabelTextField {
                if(text.characters.count < 3 || !text.containsString("@")) {
                    floatingLabelTextField.errorMessage = "Invalid email"
                }
                else {
                    // The error message will only disappear when we reset it to nil or empty string
                    floatingLabelTextField.errorMessage = ""
                }
            }
        }
        return true
    }

这是它的模型：

class OrderDeleteAPIView(generics.RetrieveDestroyAPIView):
    queryset = Order.objects.all()
    serializer_class = OrderDeleteSerializer
    # permission_classes = (OwnerCanManageOrReadOnly,)
    lookup_field = 'id'

和

class Order(models.Model):
    product = models.ForeignKey(Product)
    customer = models.ForeignKey(Customer, null=True)WAITING = 'WA'
    PREPARATION = 'PR'
    READY = 'RD'
    DELIVERED = 'DV'
    STATUS_CHOICES = (
        (WAITING, 'waiting'),
        (PREPARATION, 'preparation'),
        (READY, 'ready'),
        (DELIVERED, 'delivered'),
        )
    status = models.CharField(
      max_length=2,
      choices=STATUS_CHOICES,
      default=WAITING,
    )

这是它的序列化器：

class Customer(models.Model):
    name = models.CharField(max_length=40)
    customer_email = models.EmailField()
    def __str__(self):
        return self.name

如果我想要删除对象（订单），只有当状态字段为“等待”时，我该怎么办？？

Answer 1

您可以在destroy中实施一些检查，并在遇到约束的情况下返回错误消息作为响应：

class OrderDeleteAPIView(generics.RetrieveDestroyAPIView):
    queryset = Order.objects.all()
    serializer_class = OrderDeleteSerializer
    # permission_classes = (OwnerCanManageOrReadOnly,)
    lookup_field = 'id'

     def destroy(self, request, *args, **kwargs):
        instance = self.get_object()
        if instance.status != Order.WAITING:
            return JsonResponse(
                status=412,
                data={'status':'false',
                      'message': 'status should be WAITING'}
            )
        super(OrderDeleteAPIView, self).destroy(request, *args, **kwargs)

当然，您可以返回任何类型的答案（不是本身 JSON响应，状态也不是412）。通常，HTTP状态代码412表示412 Precondion failed。

检查generics中的模型中的字段.RetrieveDestroyAPIView

1 个答案: