Django Serialize 返回用户 ID，但我需要用户名

Question

这是我的模型：

class HighScore(models.Model):
    user = models.OneToOneField(UserManagement, on_delete=models.CASCADE)
    highScore = models.IntegerField(blank=True, null=True)
    createDate = models.DateTimeField()


    def __str__(self):
        return "{}_HighScore".format(self.user)

这是我的观点：

def pullUserNames(request):
    top_score = createHighScore()
    top_users = (HighScore.objects.order_by('-highScore').filter(highScore__in=top_score[:10]))
    top_users_serialized = serializers.serialize('json', top_users)
    top_users_json = json.loads(top_users_serialized)
    data = json.dumps(top_users_json)
    return HttpResponse(data)

回应是：

[{"model": "scoremg.highscore", "pk": 2, "fields": {"user": 2, "highScore": 650, "createDate": "2018-12-25T20:34:51.826Z"}}, {"model": "scoremg.highscore", "pk": 1, "fields": {"user": 1, "highScore": 271, "createDate": "2018-12-17T21:48:34.406Z"}}]

在这个响应{"user": 2, "highScore": 650, "createDate": "2018-12-25T20:34:51.826Z"} ，highScore 和 createDate 脸色不错，但是 user 是 id 不是 username，怎么会我编辑它以返回用户名？

我在上面视图的第二行之后测试了 print(top_users)，它打印了 --> user2_HighScore user1_HighScore

谢谢

Answer 1

使用 DRF 试试这个

serializer.py ：

class HighScoreSerializer(serializers.ModelSerializer):
        user = serializers.SlugRelatedField(
            slug_field='username'
        )

    class Meta:
        model = HighScore
        fields = '__all__'

Answer 2

在序列化程序文件中，添加此代码以获取用户名而不是用户 ID。 在这里，您将覆盖模型序列化程序的用户字段以获取用户名而不是用户 ID。

类 SearchHistorySerializer(serializers.ModelSerializer)：

user = serializers.SlugRelatedField(
    read_only=True,
    slug_field='username'
)
class Meta:
    model = SearchHistory
    fields = '__all__'

Answer 3

我认为，结合 QuerySet 的Annotation和序列化数据的自定义函数，您可以解决您的问题。

这是一个如何做到这一点的示例：

import json
from django.db.models import F

def custom_serializer(a):
    """
    Handy creation of the Queryset fields
    And we exclude the fields that starts by '__' 
    which are Django internal references
    This will lead to the representation of the annotated fields
    that are generated by the QuerySert annotation
    which are ignored by serializers.serialize() function
    """
    return [{
             'model': a.model.__name__, 'pk': k.pk, 'fields': {
                 i: j for i, j in k.__dict__.items() if not i.startswith('_')
             }
            } for k in a]

# Here we annotate a new field called username
# which holds the user's username using the F expression    
top_users = HighScore.objects.order_by('highScore').filter(
    highScore__in=top_score[:10]
).annotate(username=F('user__username'))

top_users_serialized = custom_serializer(top_users)
print(json.dumps(top_users_serialized))

你会得到这样的东西：

[{
   "model": "scoremg.highscore",
   "pk": 2,
   "fields": {
     "id": 2,  # pk
     "user_id": 2  # your user id
     "username": "test",  # your user's username
     "highScore": 650,
     "createDate": "2018-12-25T20:34:51.826Z"
    }
 },
 ...
]

编辑：

不使用自定义函数的更好方法，您可以使用queryset.values()方法，如下例所示：

top_users = HighScore.objects.order_by('highScore').filter(
    highScore__in=top_score[:10]
).annotate(username=F('user__username'))
top_users_serialized = [elm for elm in top.users.values()]
print(json.dumps(top_users_serialized))

你会得到这样的东西：

[{
   "id": 2,  # pk
   "user_id": 2  # your user id
   "username": "test",  # your user's username
   "highScore": 650,
   "createDate": "2018-12-25T20:34:51.826Z"
  },
  ...
]

更多信息请参考： F() 表达式、 QuerySet Annotation和QuerySet values

Answer 4

在serializer.py文件的serializer类中，添加如下代码行：

user = serializers.SlugRelatedField(
        read_only=True,
        slug_field='username'
    )

这将告诉您的序列化程序从 User 表中获取并返回用户名字段。