在DRF 3中的ModelSerializer上添加非模型字段

Question

如何在DRF 3中的ModelSerializer上添加非模型字段？即添加一个在我的实际模型中不存在的字段？

class TestSerializer(serializers.ModelSerializer):
    url = serializers.HyperlinkedIdentityField(view_name='vote_detail')
    non_field = serializers.CharField()  # no corresponding model property.


    class Meta:
        model = vote_model
        fields = ("url", "non_field")

    def create(self, validated_data):
      print(direction=validated_data['non_field'])

但是DRF 3给了我错误：

Got AttributeError when attempting to get a value for field `non_field` on serializer `TestSerializer`.
The serializer field might be named incorrectly and not match any attribute or key on the `Test` instance.
Original exception text was: 'Test' object has no attribute 'non_field'.

我搜索了具有非模型write_only字段的堆栈DRF-
ModelSerializer
，找到了一些解决方案，但这些解决方案是指我正在使用DRF
3的DRF2。在此版本上是否有解决方案？

Answer 1

class TestSerializer(serializers.ModelSerializer):
    url = serializers.HyperlinkedIdentityField(view_name='vote_detail')
    non_field = serializers.SerializerMethodField()  # no corresponding model property.

    class Meta:
        model = vote_model
        fields = ("url", "non_field")

    def create(self, validated_data):
        print(direction=validated_data['non_field'])

http://www.django-rest-framework.org/api-
guide/fields/#serializermethodfield

或通过此链接