python - Django如何验证用户是否已经存在

Question

这是我的模型

class UserAttributes(models.Model):
    airport = models.ForeignKey('airport.Airport', related_name='user_attributes_airport', on_delete=models.SET_NULL, null=True, blank=True)
    location = PointField(blank=True, null=True)
    user =  models.ForeignKey(
        'users.AerosimpleUser', related_name='user_attributes',
        on_delete=models.CASCADE, null=True, blank=True) 

View .py

class LocationViewSet(viewsets.ModelViewSet):

    serializer_class=LocationRetrieveSerializer
    http_method_names = ['get', 'post', 'patch', 'put']

    def get_permissions(self):
            switcher = {
                'create': [IsAuthenticated],
                'list': [IsAuthenticated],
                'retrieve': [IsAuthenticated],
                'update': [IsAuthenticated],
                'partial_update': [IsAuthenticated],
            }
            self.permission_classes = switcher.get(self.action, [IsAdminUser])
            return super(self.__class__, self).get_permissions()
    def get_queryset(self):
        return UserAttributes.objects.filter(
            airport__id=self.request.user.aerosimple_user.airport_id).order_by('pk')

序列化程序.py

class LocationRetrieveSerializer(serializers.ModelSerializer):

    class Meta:
        model = UserAttributes
        fields = '__all__'

我想知道用户或机场是否已经存在？

Answer 1

在序列化程序上，实现 create 方法，以便您可以检查用户是否存在。
例子

class LocationRetrieveSerializer(serializers.ModelSerializer):

    class Meta:
        model = UserAttributes
        fields = '__all__'

    def create(self, validated_data):
        if UserAttributes.objects.filter(user=self.context["request"].user).exists():
            raise serializers.ValidationError("User Already exists.")
        user_attributes = UserAttributes.objects.create(**validated_data)
        return user_attributes