Question

我正在尝试创建一个django应用，其中一个用户可以将其他用户添加为朋友。这就是我做的，

models.py，

class Friend(models.Model):
    users = models.ManyToManyField(User)
    current_user = models.ForeignKey(User, related_name='all', null=True)

views.py

# view for adding or removing friends
def change_friends(request, pk):
    new_friend = User.objects.get(pk=pk)
    data = Friend.objects.get(current_user=request.user)
    frnds = data.users.all()
    new_friend in frnds:
        data.users.remove(new_friend)
    else:
        data.users.add(new_friend)
    redirect(request.META['HTTP_REFERER'])


# Displaying frinends,
def following(request, id=None):
    my_friend, created = Friend.objects.get_or_create(current_user_id=id)
    all_friends = my_friend.users.all()
    return render(request, 'all/follow.html', {'all_friends': all_friends})

此代码工作正常，直到我只添加了1个帐户的朋友，但当我从多个帐户添加了几个朋友时，它开始显示错误get() returned more than one Friend -- it returned 2!。

我们如何解决这个问题？谢谢！

Answer 1

删除管理员中的所有朋友实例并将模型更改为：

   class Friend(models.Model):
       users = models.ManyToManyField(User)
       current_user = models.OneToOne(User, related_name='friend', on_delete=models.CASCADE, null=True)

那么观点应该是：

# view for adding or removing friends
def change_friends(request, pk):
    new_friend = User.objects.get(pk=pk)
    friends = request.user.friend.users.all()
    new_friend in friends:
        request.user.users.remove(new_friend)
    else:
        request.user.users.add(new_friend)
    redirect(request.META['HTTP_REFERER'])


# Displaying frinends,
def following(request, id=None):
    my_friend, created = Friend.objects.get_or_create(current_user_id=id)
    all_friends = my_friend.users.all()
    return render(request, 'all/follow.html', {'all_friends': all_friends})

如果您使用many_to_many来记录朋友关系，最好将模型设置为：

current(OneToOne) users(ManyToMany)

如果您使用ForeignKey来记录朋友关系，最好将模型设置为：

current(ForeignKey) user(ForeignKey)

<强>更新如果您无法再更改模型，只需将代码更改为：

def change_friends(request, pk):
    new_friend = User.objects.get(pk=pk)
    data = Friend.objects.filter(current_user=request.user)
    has_user = False
    for x in data:
        if new_friend in x.users.all():
            has_user = True
            x.users.remove(new_friend)
    if not has_user:
        firend = Friend.objects.filter(current_user=request.user).first()
        if friend:
            friend.users.add(new_friend)
        else:
            friend = Friend.objects.create(current_user=request.user)
            friend.users.add(new_friend)
    redirect(request.META['HTTP_REFERER'])

Answer 2

在更改好友功能中，这行代码会像这样改变

 new_friend = User.objects.filter(pk=pk).first()

试试这个......

get（）返回了多个朋友 - 它返回2

2 个答案: