Django Rest API：如何在序列化模型时摆脱 json 中的 'UUID'？

Question

为什么 'UUID' 出现在 'profile' 键的值前面，如何正确删除它？

roster/serializers.py

class ShiftSerializer(serializers.ModelSerializer):

class Meta:
    model = Shift
    fields = ('id', 'profile', 'location', 'date', 'start_time', 'end_time')

profile/models.py

class Profile(models.Models):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=True)

roster/models.py

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=True)
    profile = models.ForeignKey('profiles.Profile', null=True, blank=True)

python manage.py shell

from roster.models import Shift
from roster.serializers import ShiftSerializer

myshift = Shift.objects.first()
serializer = ShiftSerializer(myshift)
serializer.data

输出：

{'id': '92ca258e-8624-434a-b61d-e1cd3b80e0e8', 'profile': UUID('0081b028-0a11-47fb-971e-c47177ed93be')

Answer 1

你可以试试，serializers.CharField

class ShiftSerializer(serializers.ModelSerializer):
     profile = serializers.CharField(read_only=True)

Answer 2

UUID 将在 JSONRenderer 渲染时得到更正。

Answer 3

你可以重写 representation ，像这样

class ShiftSerializer(serializers.ModelSerializer):
    class Meta:
        model = Shift
        fields = '__all__'

    def to_representation(self, obj):
        return {
            "id": obj.id,
            "profile": obj.profile.id,
            "location": obj.location,
            "date": obj.date,
            "start_time": obj.start_time,
        }

Answer 4

tl;dr

请参阅底部的解决方案。

问题

序列化器上的属性 .data 应该 return 序列化器和所有字段上对象 (http://www.django-rest-framework.org/api-guide/serializers/#baseserializer). This should be done by calling to_representation() method (http://www.django-rest-framework.org/api-guide/serializers/#to_representationself-obj) 的唯一原始表示。

@six.add_metaclass(SerializerMetaclass)
class Serializer(BaseSerializer):

    # ...
    # ...

    def to_representation(self, instance):
        """
        Object instance -> Dict of primitive datatypes.
        """
        # ...
        # ...

        for field in fields:

            # ...
            # ...

            if check_for_none is None:
                ret[field.field_name] = None
            else:
                ret[field.field_name] = field.to_representation(attribute)

        return ret

来源：https://github.com/encode/django-rest-framework/blob/master/rest_framework/serializers.py#L505-L529

以 uuid.UUID 作为主键的模型存在问题。 PrimaryKeyRelatedField returns uuid.UUID 实例 - 这显然不是导致例如UUID('') 不是 JSON 可序列化错误。

当PrimaryKeyRelatedField上的pk_field属性没有设置时，to_representation方法只是returns uuid.UUID实例，见相关代码：

class PrimaryKeyRelatedField(RelatedField):
    # ...

    def to_representation(self, value):
        if self.pk_field is not None:
            return self.pk_field.to_representation(value.pk)
        return value.pk

来源：https://github.com/encode/django-rest-framework/blob/master/rest_framework/relations.py#L269-L272

为什么会出问题

如其他答案和评论所述，JSONRenderer 将正确处理此问题 (http://www.django-rest-framework.org/api-guide/serializers/#serializing-objects)

from rest_framework.renderers import JSONRenderer

json_data = JSONRenderer().render(serializer.data)

但是有些情况下你不想使用JSONRenderer:

您在单元测试期间比较 .data；
您需要将 .data 存储在数据库、文件、...
您想通过 requests post .data 到某些 API: requests.post(..., json=serializer.data)
...

解决方法

将 PrimaryKeyRelatedField 上的 pk_field 属性设置为 UUIDField():

from rest_framework import serializers
from rest_framework.fields import UUIDField


class ExampleSerializer(serializers.ModelSerializer):
    id = serializers.PrimaryKeyRelatedField(required=True,
                                            allow_null=False,
                                            # This will properly serialize uuid.UUID to str:
                                            pk_field=UUIDField(format='hex_verbose'))

并且 uuid.UUID 个实例在访问 serializer.data 时将被正确序列化为 str。

Django Rest API：如何在序列化模型时摆脱 json 中的 'UUID'？

Django Rest API: How to get rid of 'UUID' in json when serializing models?

django

django-serializer

django-rest-framework