在Django中，如何在Group添加或删除用户时获取信号？ [英] In Django, how do I get a signal for when a Group has a User added or removed?

问题描述

在Django管理员中，我有时会向或从（现有）组添加或删除用户。发生这种情况时，我希望能够运行一个功能。

In the Django admin I sometimes add or delete users to or from (existing) groups. When this happens I'd like to be able to run a function.

我只是使用标准的用户和组模型。

I'm just using the standard User and Group models.

我已经看过通过m2m_changed的信号，但似乎需要一个通过类 - 我不认为在这种情况下有一个。

I have looked at doing it with signals, through m2m_changed, but it seems to need a Through class - and I don't think there is one in this case.

推荐答案

从 django doc ：

发件人 - 描述ManyToManyField的中间模型类。当定义多对多字段时，会自动创建此类;您可以使用多对多字段中的通过属性来访问它。

sender - The intermediate model class describing the ManyToManyField. This class is automatically created when a many-to-many field is defined; you can access it using the through attribute on the many-to-many field.

订阅m2m_changed如下所示：

When subscribing to m2m_changed like so:

@receiver(m2m_changed)
def my_receiver(**kwargs):
    from pprint import pprint
    pprint(kwargs)

您将收到一堆像这样的信号（缩写）：

You will receive a bunch of signals like this (shortened):

{'sender': <class 'django.contrib.auth.models.User_groups'>,
 'action': 'post_add',
 'instance': <User: bouke>,
 'model': <class 'django.contrib.auth.models.Group'>,
 'pk_set': set([1]),
 'reverse': False,
 'signal': <django.dispatch.dispatcher.Signal object at 0x101840210>,
 'using': 'default'}

所以用户 bouke 已添加到 pk_set 组： [1] 。但是我注意到，管理员布局会清除所有组，然后将所选组添加回来。您将收到的信号为 pre_clear ， post_clear ， pre_add ， post_add 。使用这些信号的组合，您可以存储前和后组。对这些列表进行区分，您可以为用户添加删除和添加的组。

So the user bouke has been added to pk_set groups: [1]. However I noted that the admin layout clears all groups and then adds the selected groups back in. The signals you will receive are pre_clear, post_clear, pre_add, post_add. Using a combination of these signals you could store the pre and post groups. Doing a diff over these lists, you have the deleted and added groups for the user.

请注意，信号是相反的（ pk_set 和实例）编辑组而不是用户。

Note that the signals are the other way around (pk_set and instance) when editing a group instead of a user.

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