序列化程序类型错误..."UniqueTogetherValidator"对象不可迭代

Question

我有一个名为"following"的模型，其中一个用户可以使用Django rest框架跟随另一个用户。我正在尝试实现一个验证，这样你就不会跟踪某人两次，并尝试内置的UniqueTogetherValidator。

以下是我的模型的相关部分.py

class Following(models.Model):
user = models.ForeignKey('User', related_name='user', on_delete=models.CASCADE)
follower = models.ForeignKey('User', related_name='follower', on_delete=models.CASCADE)

和serializers.py:

class FollowingSerializer(serializers.HyperlinkedModelSerializer):
user = serializers.CharField(source='user.username')
follower = serializers.CharField(source='follower.username')
class Meta:
model = Following
fields = ['user', 'follower']
validators = UniqueTogetherValidator(
queryset = Following.objects.all(),
fields = ['user', 'follower'],
message = "You are already following that person!"
)

我有一些现有的数据：

HTTP 200 OK
Allow: GET, POST, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept
{
"count": 2,
"next": null,
"previous": null,
"results": [
{
"user": "mike",
"follower": "chelsea"
},
{
"user": "mike",
"follower": "chloe"
}
]
}

当我尝试使用API接口添加任何新的以下对象时，我会得到以下错误：

TypeError at /followings/
'UniqueTogetherValidator' object is not iterable
Request Method: POST
Request URL:    http://127.0.0.1:8000/followings/
Django Version: 3.0.5
Exception Type: TypeError
Exception Value:    
'UniqueTogetherValidator' object is not iterable
...

我哪里错了？提前感谢！

Answer 1

如中所述https://www.django-rest-framework.org/api-guide/validators/#uniquetogethervalidatorMeta下的validators变量应该是一个列表，

你的代码应该是

class FollowingSerializer(serializers.HyperlinkedModelSerializer):
user = serializers.CharField(source='user.username')
follower = serializers.CharField(source='follower.username')
class Meta:
model = Following
fields = ['user', 'follower']
validators = [
UniqueTogetherValidator(
queryset = Following.objects.all(),
fields = ['user', 'follower'],
message = "You are already following that person!"
)
]