在django rest框架中限制对foreignkey的选择

Question

如何限制request.user的图像与节点链接.我希望我可以这样做:

photo = models.ForeignKey(
    Image,
    limit_choices_to={'owner': username},
)

但是request.user而不是username,我不想使用本地线程.

models.py

class Node(models.Model):
    owner = models.ForeignKey(User)
    content = models.TextField()
    photo = models.ForeignKey(Image)

class Image(models.Model):
    owner = models.ForeignKey(User)
    file = models.ImageField(upload_to=get_upload_file_name)

serializers.py

class ImageSerializer(serializers.ModelSerializer):
    owner = serializers.Field('owner.username')

    class Meta:
        model = Image
        fields = ('file', 'owner')

class NodeSerializer(serializers.HyperlinkedModelSerializer):

    class Meta:
        model = Node
        fields = ('content', 'photo', 'owner')

Answer 1

我会通过重写get_serializer_class在运行时动态返回一个序列化程序类来处理这个问题,在choices那里设置字段选项:

def get_serializer_class(self, ...):
    user = self.request.user
    owner_choices = ...  # However you want to restrict the choices

    class ImageSerializer(serializers.ModelSerializer):
        owner = serializers.Field('owner.username', choices=owner_choices)

        class Meta:
            model = Image
            fields = ('file', 'owner')

    return ImageSerializer

Answer 2

您可以创建自定义外键字段并get_queryset()在那里定义方法,以便仅将相关对象过滤为用户的对象.可以在上下文中从请求中检索当前用户:

class UserPhotoForeignKey(serializers.PrimaryKeyRelatedField):
    def get_queryset(self):
        return Image.objects.filter(owner=self.context['request'].user)

class NodeSerializer(serializers.HyperlinkedModelSerializer):
    photo = UserPhotoForeignKey()
    class Meta:
        model = Node
        fields = ('content', 'photo', 'owner')

此示例使用Django REST Framework版本3.