django - 如何将嵌套字段的初始值更改为零而不是空值。？

Question

如何将嵌套字段的初始值更改为零而不是空值。？

在我的情况下，奖品模型是一个OneToOneField模型专辑

串行器

class PrizeSerializer(serializers.ModelSerializer):
    class Meta:
        model = Prize
        fields = ['title', 'amount']

class AlbumSerializer(serializers.ModelSerializer):
    prize = PrizeSerializer(read_only=True)

    class Meta:
        model = Album
        fields = ['album_name', 'artist', 'prize']

有些项目有奖品数据，但有些没有奖品数据。如果没有奖品数据，它将显示为null，

>>> serializer.data
{
    "album_name": "The Grey Album",
    "artist": "Danger Mouse",
    "prize": null
}

如何将此空值更改为零。？

预期产出

>>> serializer.data
{
    "album_name": "The Grey Album",
    "artist": "Danger Mouse",
    "prize": "0.0"
}

标签： djangopython-3.xdjango-rest-frameworkserialization

Answer 1

您可以SerializerMethodField在您的 上使用 a AlbumSerializer，如下所示：

class AlbumSerializer(serializers.ModelSerializer):
    prize = serializers.SerializerMethodField()

    def get_prize(self, instance):
        if hasattr(instance, 'prize'):
            return PrizeSerializer(instance.prize).data
         return "0.0"

    class Meta:
        model = Album
        fields = ['album_name', 'artist', 'prize']