python - 嵌套序列化器中的 Django Rest Framework 关系查询

Question

我在 Django REST Framework 中实现嵌套序列化器时遇到困难。
我正在构建一个在线记分板，目前我有三个模型，我正在尝试将其序列化为单个响应。

models.py

class Player(models.Model):
    first_name = models.CharField(max_length=50)
    last_name = models.CharField(max_length=50)

    def __str__(self):
        return self.first_name


class Event(models.Model):

    user = models.ManyToManyField("Player")
    name = models.CharField(max_length=50)  
    desc = models.CharField(max_length=225)

    def __str__(self):
        return self.name

class LeadBoard(models.Model):
    """model for LeadBoard"""

    player = models.ForeignKey(Player, on_delete=models.CASCADE, related_name='leadboard_player', null=True, blank=True)
    event = models.ForeignKey(Event, on_delete=models.CASCADE, related_name='leadboard_event', null=True, blank=True)
    score = models.IntegerField()

    def __str__(self):
        return self.score

事件模型代表某种体育赛事，每个事件可以有多个玩家(用户在事件模型中归档)，LeadBoard 模型存储每个事件中玩家的得分。

序列化器.py

class PlayerSerializer(serializers.ModelSerializer): 

    class Meta:
        model = Player
        fields = ('id','first_name', 'last_name', 'bio')


class EventSerializer(serializers.ModelSerializer):
    
    user = PlayerSerializer(read_only=True, many=True)
    class Meta:
        model = Event
        fields = ('id', 'name', 'user', 'desc')


class LeadBoardSerializer(serializers.ModelSerializer):

    event = EventSerializer(read_only=True)
    
    class Meta:
        model = LeadBoard
        fields = ('id', 'event', 'score')

我添加了两个玩家

         [
            {
                "id": 1,
                "first_name": "Jhon",
                "last_name": "Doe"
            },
            {
                "id": 3,
                "first_name": "Anna",
                "last_name": "Doe"
            }
        ]

以及他们在 LeadBoard 模型中的得分

[
    {
        "id": 1,
        "player": 1,
        "event": 1,
        "score": 20
    },
    {
        "id": 2,
        "player": 3,
        "event": 1,
        "score": 90
    }
]

这是LeadBoard的回应，

[
    {
        "id": 1,
        "event": {
            "id": 1,
            "name": "event2020",
            "user": [
                {
                    "id": 1,
                    "first_name": "Jhon",
                    "last_name": "Doe"
                },
                {
                    "id": 3,
                    "first_name": "Anna",
                    "last_name": "Doe"
                }
            ],
            "desc": "event description"
        },
        "score": 20
    },
    {
        "id": 2,
        "event": {
            "id": 1,
            "name": "event2020",
            "user": [
                {
                    "id": 1,
                    "first_name": "Jhon",
                    "last_name": "Doe"
                },
                {
                    "id": 3,
                    "first_name": "Anna",
                    "last_name": "Doe"
                }
            ],
            "desc": "event description"
        },
        "score": 90
    }
]

但是我期望得到的是这样的响应，它会正确返回事件的玩家(用户)及其分数。

[
    {
        "id": 1,
        "event": {
            "id": 1,
            "name": "event2020",
            "user": [
                {
                    "id": 1,
                    "first_name": "Jhon",
                    "last_name": "Doe",
                    "score": 20
                },
                {
                    "id": 3,
                    "first_name": "Anna",
                    "last_name": "Doe",
                    "score": 90
                }
            ],
            "desc": "event description"
        }
    }
]

我在这里缺少什么？

我是 Django 和 Django Rest Framework 的新手。

Answer 1

您需要按事件而不是排行榜做出响应。

class PlayerSerializer(serializers.ModelSerializer): 

   class Meta:
        model = Player
        fields = ('id','first_name', 'last_name', 'bio')

class LeadBoardSerializer(serializers.ModelSerializer):

    player = PlayerSerializer(read_only=True)

    class Meta:
        model = LeadBoard
        fields = ('id', 'player', 'score')

class EventSerializer(serializers.ModelSerializer):

    leadboard_event = LeadBoardSerializer(read_only=True, many=True)

    class Meta:
        model = Event
        fields = ('id', 'name', 'desc', 'leadboard_event')

现在使用 View 来获取事件列表

更新 1如果你想在玩家中获得分数。

class PlayerSerializer(serializers.Serializer):  
    player_id = serializers.IntegerField()
    first_name = serializers.CharField(max_length=256)
    last_name = serializers.CharField(max_length=256)
    score = serializers.IntegerField()

class LeadBoardSerializer(serializers.ModelSerializer):

    player = serializers.SerializerMethodField()

    class Meta:
        model = LeadBoard
        fields = ('id', 'player')

    def get_player(self,obj):
        player_dict = {'player_id': obj.player.id, 'first_name': obj.player.first_name, 'last_name': obj.player.last_name, 'score': obj.score}
        result = PlayerSerializer(data=player_dict)
        return result

class EventSerializer(serializers.ModelSerializer):

    leadboard_event = LeadBoardSerializer(read_only=True, many=True)

    class Meta:
        model = Event
        fields = ('id', 'name', 'desc', 'leadboard_event')

尝试一下。