Question

我可以根据JSON数据创建产品。我想添加一个条件，那么如果一个产品已经存在且名称相同，我就不会创建任何内容，我的视图会返回现有产品。

对于创建没有问题，产品设置正确并且视图返回数据（我在DB中检查了它在这里）。但是当我尝试创建具有相同名称的第二个产品时，我有一个错误（这里我使用完全相同的JSON）。

查看：

class ProductCreate(generics.CreateAPIView):
        """ Create a new product """

        permission_classes = (permissions.IsRequestAllowed,)
        serializer_class = ProductSerializer

        def perform_create(self, serializer):

            product = product_service.get_product_from_name(serializer.validated_data['name'])

            if not product:
                LOG.debug('Creating Product from JSON data : {} '.format(serializer.validated_data))
                serializer.save()
            else:
                LOG.debug('{} already exists, JSON data : {} '.format(product, serializer.validated_data))

序列化程序：

class ProductSerializer(serializers.ModelSerializer):
    class Meta:  # pylint: disable=too-few-public-methods
        model = Product
        fields = ('id',
                  'actor',
                  'brand',
                  'creation_date',
                  'description',
                  'ean_code',
                  'image',
                  'internal_code',
                  'name',
                  'price_unit',
                  'product_group',
                  'url',)

型号：

class Product(models.Model):
    actor = models.ForeignKey(Actor, related_name='products', on_delete=models.CASCADE)
    brand = models.CharField(max_length=200, blank=True)
    creation_date = models.DateTimeField(auto_now_add=True)
    description = models.CharField(max_length=1000, blank=True)
    ean_code = models.CharField(max_length=200, blank=True)
    image = models.CharField(max_length=400, blank=True)
    internal_code = models.CharField(max_length=200, blank=True)
    name = models.CharField(max_length=200, blank=False)
    price_unit = models.CharField(max_length=200, blank=True)
    product_group = models.ForeignKey(
        ProductGroup, related_name='products', blank=True, null=True, on_delete=models.CASCADE)
    url = models.CharField(max_length=400, blank=True)

输入数据：

{ "actor": 1, "brand": "brand", "description": "my product desc", "ean_code": "1230456078900", "image": "img", "internal_code": "123456", "name": "my product name", "url": "my product url" }

错误：

Traceback (most recent call last):
File "/usr/local/lib/python3.6/site-packages/django/core/handlers/exception.py", line 41, in inner
        response = get_response(request)
File "/usr/local/lib/python3.6/site-packages/django/core/handlers/base.py", line 187, in _get_response
        response = self.process_exception_by_middleware(e, request)
File "/usr/local/lib/python3.6/site-packages/django/core/handlers/base.py", line 185, in _get_response
        response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/usr/local/lib/python3.6/site-packages/django/views/decorators/csrf.py", line 58, in wrapped_view
        return view_func(*args, **kwargs)
File "/usr/local/lib/python3.6/site-packages/django/views/generic/base.py", line 68, in view
        return self.dispatch(request, *args, **kwargs)
File "/usr/local/lib/python3.6/site-packages/rest_framework/views.py", line 494, in dispatch
        response = self.handle_exception(exc)
File "/usr/local/lib/python3.6/site-packages/rest_framework/views.py", line 454, in handle_exception
        self.raise_uncaught_exception(exc)
File "/usr/local/lib/python3.6/site-packages/rest_framework/views.py", line 491, in dispatch
        response = handler(request, *args, **kwargs)
File "/usr/local/lib/python3.6/site-packages/rest_framework/generics.py", line 192, in post
        return self.create(request, *args, **kwargs)
File "/usr/local/lib/python3.6/site-packages/rest_framework/mixins.py", line 22, in create
        headers = self.get_success_headers(serializer.data)
File "/usr/local/lib/python3.6/site-packages/rest_framework/serializers.py", line 537, in data
        ret = super(Serializer, self).data
File "/usr/local/lib/python3.6/site-packages/rest_framework/serializers.py", line 264, in data
        self._data = self.to_representation(self.validated_data)
File "/usr/local/lib/python3.6/site-packages/rest_framework/serializers.py", line 491, in to_representation
        attribute = field.get_attribute(instance)
File "/usr/local/lib/python3.6/site-packages/rest_framework/relations.py", line 177, in get_attribute
        return get_attribute(instance, self.source_attrs)
File "/usr/local/lib/python3.6/site-packages/rest_framework/fields.py", line 98, in get_attribute
        instance = instance[attr] KeyError: 'product_group'

Answer 1

您无事可做，DRF会帮您解决这个问题！

您可以在这里查看代码： https://github.com/encode/django-rest-framework/blob/2b6245db5359571f10d27ace16473d70e160dce2/rest_framework/mixins.py#L18

Django perform_create条件创建

1 个答案: