如何更新 DRF 中的多对多字段答案

【问题标题】：How to update a many to many field in DRF如何更新 DRF 中的多对多字段
【发布时间】：2022-08-10 09:04:23
【问题描述】：

所以在我的项目中，我有一个用户模型和一个学校模型。我的用户模型有一个 schools 字段，该字段与 School 模型具有 M2M 关系。现在我想知道的是，如何创建一个可以获取用户电子邮件和学校 ID 的视图，并从 user 所属的学校中添加或删除学校。

这是我的user model：

class User(AbstractBaseUser, PermissionsMixin):
    username = models.CharField(max_length=255, unique=True, db_index=True)
    email = models.EmailField(max_length=255, unique=True, db_index=True)
    is_verified = models.BooleanField(default=False)
    is_active = models.BooleanField(default=False)
    is_staff = models.BooleanField(default=False)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now_add=True)
    schools = models.ManyToManyField(\"School\", related_name=\"members\")

    USERNAME_FIELD = \'email\'
    REQUIRED_FIELDS = [\'username\']

    objects = UserManager()

    def __str__(self):
        return self.email

    def tokens(self):
        refresh = RefreshToken.for_user(self)
        return {
            \'refresh\': str(refresh),
            \'access\': str(refresh.access_token)
        }

学校：

class School(models.Model):
    name = models.CharField(max_length=300, verbose_name=\'school name\', )
    principal = models.ForeignKey(\"User\", related_name=\"my_schools\", on_delete=CASCADE)
    address = models.CharField(max_length=200)

    class Type(models.IntegerChoices):
        PUBLIC = 1, \"Public\"
        PRIVATE = 2, \"Private\"

    type = models.PositiveSmallIntegerField(choices=Type.choices, default=Type.PUBLIC)

    class Level(models.IntegerChoices):
        NATIONAL = 1, \"National\"
        EXTRACOUNTY = 2, \"Extra County\"
        COUNTY = 3, \"County\"
        SUBCOUNTY = 4, \"Subcounty\"

    level = models.PositiveSmallIntegerField(choices=Level.choices, default=Level.COUNTY)

    def __str__(self):
        return self.name

这是注册成员的序列化程序：

class EnrollSchoolMembersSerializer():
    class Meta:
        model = User
        field = (\'email\')

标签： python django django-models django-rest-framework django-serializer

【解决方案1】：

我认为您可以使用函数 API 视图来实现它。首先，您可以定义序列化程序。

from rest_framework import serializers as sz

class SchoolUpdateSerializer(sz.Serializer):
    school_id = sz.IntegerField()
    email = sz.EmailField()
    mode = sz.CharField()      # can be either 'add' or 'delete'

在views.py 中，您可以编写处理程序。

from rest_framework.response import Response
from rest_framework status
from rest_framework.decorators import api_view, permission_classes
from .models import School, User
from .serializers import SchoolUpdateSerializer

@api_view(['POST'])
@permission_classes([permissions.AllowAny])
def update_school_data(request):
    serializer = SchoolUpdateSerializer(data = request.data)
    if serializer.is_valid():
        input_data = serializer.validated_data
        email = input_data.get('email')
        mode = input_data.get('mode')
        school_id = input_data.get('school_id')
        try:
            user = User.objects.get(email = email)
            school = School.objects.get(pk = school_id)
            if mode == "add":
                user.schools.add(school)
            else:
                user.schools.remove(school)
            return Response(status = status.HTTP_200_OK)       
        except (User.DoesNotExist, School.DoesNotExist):
            return Response(status = status.HTTP_400_BAD_REQUEST)
    else:
        return Response(status = status.HTTP_400_BAD_REQUEST)

最后，在前端，您可以使用 POST API。有效载荷可以是

{
    "email": "test@example.com",
    "school_id": 1,
    "mode": "add"
}

【讨论】：

你能给我看看 urls.py 和 serializers.py 文件吗？还有错误？

【解决方案2】：

请参阅https://www.django-rest-framework.org/api-guide/serializers/#writing-update-methods-for-nested-representations 处的 Django REST 框架文档

【讨论】：