Django Serialize 返回用戶 ID，但我需要用戶名

Question

這是我的模型：

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)

這是我的觀點：

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)

回應是：

[{"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"}}]

在這個響應{"user": 2, "highScore": 650, "createDate": "2018-12-25T20:34:51.826Z"} ，highScore 和 createDate 臉色不錯，但是 user 是 id 不是 username，怎么會我編輯它以返回用戶名？

我在上面視圖的第二行之后測試了 print(top_users)，它打印了 --> user2_HighScore user1_HighScore

謝謝

Answer 1

使用 DRF 試試這個

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，添加此代碼以獲取用戶名而不是用戶 ID。 在這里，您將覆蓋模型序列化程序的用戶字段以獲取用戶名而不是用戶 ID。

類 SearchHistorySerializer(serializers.ModelSerializer)：

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

Answer 3

我認為，結合 QuerySet 的Annotation和序列化數據的自定義函數，您可以解決您的問題。

這是一個如何做到這一點的示例：

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))

你會得到這樣的東西：

[{
   "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"
    }
 },
 ...
]

編輯：

不使用自定義函數的更好方法，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))

你會得到這樣的東西：

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

更多信息請參考： F() 表達式、 QuerySet Annotation和QuerySet values

Answer 4

在serializer.py文件的serializer類中，添加如下代碼行：

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

這將告訴您的序列化程序從 User 表中獲取並返回用戶名字段。