发布到Django休息框架API，但总是得到一个“这个字段是必需的”错误 [英] Post to Django rest framework API but always get a 'This field is required' error

问题描述

我正在使用Django休息框架3.2.1， GET 是完美的，但 POST 不工作

I'm using Django rest framework 3.2.1, the GET is perfect, but POST does not work.

这是模型：

class Sample(models.Model):
    ownerBuilding = models.ForeignKey(Building)
    coordinateX = models.IntegerField(default=0, help_text='X coordinate for this sampling point located in a building')
    coordinateY = models.IntegerField(default=0, help_text='Y coordinate for this sampling point located in a building')
    creation_Time = models.DateTimeField(auto_now_add=True)
    description = models.TextField(null=True,
                               help_text='additional description for this sample point.')

class Meta:
    unique_together = ('ownerBuilding', 'coordinateX','coordinateY')

def __str__(self):
    return "Sample for building " + str(self.ownerBuilding)

序列化器：

class SampleSerializer(serializers.HyperlinkedModelSerializer):
    ownerBuilding = serializers.HyperlinkedRelatedField(many=False, read_only=True, view_name='building-detail')

class Meta:
    model = Sample
    fields = ('url', 'ownerBuilding', 'coordinateX', 'coordinateY', 'creation_Time','description')

查看：

class SampleList(generics.ListCreateAPIView):
    queryset = Sample.objects.all()
    serializer_class = SampleSerializer
    permission_classes = (permissions.IsAuthenticated, IsTechniciansGroupOrReadOnly,)

    def get_queryset(self):
        queryset = Sample.objects.all()
        ownerBuildingId = self.request.query_params.get('ownerBuildingId', None)

        if ownerBuildingId is not None:
            queryset = queryset.filter(ownerBuilding=ownerBuildingId)

        return queryset

当我将 POST 具有数据的API：

When I test the POST to this API with data:

{"ownerBuilding":"http://rest.xxxxxxxx.xyz:8090/buildings/1/","coordinateX":33,"coordinateY":44,"description":"5dfadfasdfsadf5"}

我总是得到这个错误：

{
    "ownerBuilding": [
        "This field is required."
    ]
}

任何人都可以帮助？

http://rest.xxxxxxxx.xyz:8090/buildings/1/ 存在。

[edit0]：
如果我 POST 与：

[edit0]: if I POST with:

{"coordinateX":33,"coordinateY":44,"description":"5dfadfasdfsadf5"}

我仍然得到相同的结果。

I still get the same result.

推荐答案

序列化器字段是默认情况下需要。

另外，DRF ModelSerializer （和 HyperlinkedModelSerializer ）添加 UniqueTogetherValidator s所有模型的 unique_together 约束。这隐含地使得约束中的所有字段都需要，除了设置了默认值的字段之外。请参阅文档。

Also, DRF ModelSerializer (and HyperlinkedModelSerializer) adds UniqueTogetherValidators for all model's unique_together constraints. This implicitly makes all fields in the constraint required, with exception for fields for which defaults are set. See doc.

ownerBuilding 只能在序列化器上阅读：

ownerBuilding is read only on the serializer:

ownerBuilding = serializers.HyperlinkedRelatedField(many=False, \
                            read_only=True, view_name='building-detail')

，但是您不提供defualt或手动设置值，因此该字段被视为空，因此出现错误消息。

but you don't provide a defualt nor set the value manually, so this field is treated as empty, hence the error message.

删除 read_only 或设置默认值。

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