Question

我有以下代码段

from django.db import models


class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField('date published')


class Choice(models.Model):
    question = models.ForeignKey(Question, on_delete=models.CASCADE)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)

class QuestionSerializer(serializers.ModelSerializer):
    class Meta:
        fields = '__all__'
        model = Question


class ChoiceSerializer(serializers.ModelSerializer):
    class Meta:
        fields = '__all__'
        model = Choice
        depth = 1

class ChoiceAPI(ModelViewSet):
    queryset = Choice.objects.all()
    serializer_class = ChoiceSerializer

目前我的输出为，

[
    {
        "id": 1,
        "choice_text": "choice-1",
        "votes": 1,
        "question": {
            "id": 1,
            "question_text": "Maximizing Assassin damage",
            "pub_date": "2018-07-13T13:29:36Z"
        }
    }
]

现在，我希望使用有效负载创建新的Choice实例，

{

        "choice_text": "choice-1",
        "votes": 1,
        "question": 1
}

但是，当我尝试上述有效负载时，

是我的例外

IntegrityError at /sample/test/
NOT NULL constraint failed: sample_choice.question_id.

搜索完Google之后，我找到了一种方法来解决此问题，方法是重写get_serializer_class()的{{1}}方法。

我的问题是，有没有办法做到这一点而不会覆盖ModelViewSet 的get_serializer_class()方法？

Answer 1

您可以覆盖__init__()类的ModerSerializer，

class ChoiceSerializer(serializers.ModelSerializer):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        if 'view' in self.context and self.context['view'].action == 'create':
            self.fields.update({"question": serializers.PrimaryKeyRelatedField(queryset=Question.objects.all())})

    class Meta:
        fields = '__all__'
        model = Choice
        depth = 1

您还可以使用viewset actions限制设置，有关更多详细信息，请阅读Viewset actions

注意：我没有测试该解决方案，但可能效果很好

参考：Django Rest Framework: Dynamically return subset of fields

如何为GET和POST使用相同的序列化程序？

1 个答案: