Django Rest Framework如何使用基于ID的相关字段保存模型

Question

我是DRF的新手.我有Record模型,看起来像这样:

class Records(models.Model):
    owner = models.ForeignKey(User, null=True)
    activity = models.ForeignKey(Activity, null=True)
    time_start = models.DateTimeField(null=True)
    time_end = models.DateTimeField(null=True)

  ...

RecordSerializer就是这样一个:

class RecordSerializer(serializers.ModelSerializer):

    now = datetime.today()
    owner = serializers.Field(source='owner.username')
    time_start = serializers.DateTimeField(source='now')

    class Meta:
        model = Records
        fields = ("owner", "activity", "time_start")

这就是观点:

class StartApiView(generics.CreateAPIView):
    model = Records
    serializer_class = RecordSerializer

    def pre_save(self, obj):
        obj.owner = self.request.user

POST请求是从Backbone发送的,它包含一个带有活动ID的字段,例如"{activity:12}".如果我希望视图保存Record并将活动设置为id为12的Activity,我该怎么办？

Answer 1

对于DRF v2.x,已接受的答案是正确的,但不再适用于较新的(3.x)版本,因为它会引发此问题AssertionError:

AssertionError:关系字段必须提供queryset参数或集合read_only=True.

对于较新的版本,只需添加queryset参数:

class RecordSerializer(serializers.ModelSerializer):
    activity = serializers.PrimaryKeyRelatedField(queryset=Activity.objects.all())
    // [...] 

Answer 2

Django REST Framework正是针对这种用例提供​​了一个。PrimaryKeyRelatedField

class RecordSerializer(serializers.ModelSerializer):
    activity = serializers.PrimaryKeyRelatedField()
    owner = serializers.CharField(read_only=True, source='owner.username')
    time_start = serializers.DateTimeField(source='now')

    class Meta:
        model = Records
        fields = ("owner", "activity", "time_start")

这将产生与您正在寻找的内容类似的输出，并且id当您想要更新它时，它将接受活动的 。