python - 在 Django 中检查多对多集合中的成员

Question

我有以下用户类，

class User(AbstractBaseUser, PermissionsMixin, Base):
    email = models.EmailField(db_index=True, unique=True, max_length=255)
    mobile = PhoneNumberField(null=True)
    username = models.CharField(db_index=True, null=False, unique=True, max_length=255)

我有以下房间对象，

class Room(Base):
    name = models.CharField(db_index=True, unique=True, max_length=255)
    status = models.CharField(default=RoomStatus.ACTIVE, max_length=255, null=True)
    members = models.ManyToManyField(User)
    last_activity = models.DateTimeField(default=timezone.now)

我正在尝试查找用户是否作为成员出现在房间中，

user = User.objects.get(id=kwargs.get('user_id'))
room = Room.objects.get(id=kwargs.get('room_id'))

这行不通，

member = room.members.filter(user=user)

我怎样才能正确地做到这一点

Answer 1

通过单个查询，您可以过滤:

Room.objects.filter(id=kwargs['room_id'], members__id=kwargs['user_id']).exists()

或者如果你无论如何都需要 Room 和 User:

room = Room.objects.get(id=kwargs['room_id'])
user = User.objects.get(id=kwargs.get('user_id'))
if user in room.members.all():
    # ...
    pass

您还可以为 id=user_id 过滤 room.members:

if room.members.filter(id=kwargs['user_id']).exists():
    # ...
    pass