保存后更新实例，在某些情况下通过有条件地引用实例来使用信号 [英] Update the instance after save, using signals by conditionally refference back to the instance in some cases

问题描述

我有以下抽象类：

class UserStamp(models.Model):
    created_by = models.ForeignKey(settings.AUTH_USER_MODEL, blank=True,
                                   related_name='%(app_label)s_%(class)s_created_by', on_delete=models.CASCADE)
    updated_by = models.ForeignKey(settings.AUTH_USER_MODEL, blank=True, null=True,
                                   related_name='%(app_label)s_%(class)s_updated_by', on_delete=models.CASCADE)

    class Meta:
        abstract = True

我有一个自定义用户，该用户继承自User。

I have a custom User that inherits from User.

class User(AbstractBaseUser,PermissionsMixin, UserStamp):
    account = models.ForeignKey(Account, blank=True, null=True, related_name='owner',on_delete=models.CASCADE)

用户可以创建或更新自己或其他用户。

The User can create/update himself or by other user.

当用户自己创建/更新时，我什么都没有

When the user create/update himself I don't have anything for created_by, update_by.

可以使用Django Admin或在Django Admin外部创建用户。

The user can be created using Django Admin or outside Django Admin;

在Django Admin中，用户可以由工作人员创建，而Django之外的用户可以自行创建；

In Django Admin the user can be created by staff, outside Django is self created;

还有在终端中创建的超级用户；

Also there is superuser that is created in terminal;

关于更新，无论是Django Admin还是外部用户，都可以自我更新或由其他用户进行更新。

Regarding the update the user in both Django Admin and outside can be self updated or by another user.

我考虑使用post_save或自定义信号。问题是request.user在模型中不可用，但在View中不可用，并且在Admin和终端（超级用户）中控制View是一个瓶颈。

I thought on using post_save or a custom signal. The issue is that request.user is not available in the model, but in View, and controlling the View in Admin and also in terminal(superuser) is a bottleneck.

也许在保存通过实例后尝试进行查询，但是我不完全知道如何将所有这些信号/查询结合起来，检查超级用户。

Maybe trying to do a query after save passing the instance, but I don't exactly know how to combine all of them signal/query, check superuser.

推荐答案

创建自己的 自定义信号 。

from django.dispatch import Signal 
# you can pass any number of arguments as per your requirement.
manage_user = Signal(providing_args=["user", "is_updated"])


def user_handler(sender, **kwargs):
    # `user` who created/updated object i.e `request.user`
    user = kwargs['user']
    # `is_updated` will be `False` if user object created.
    is_updated = kwargs['is_updated']
    # `sender` is the user object which is created/updated.
    ...
    # do your stuff

manage_user.connect(user_handler)

models.py

覆盖 save（）

from .signals import manage_user

class User(...):
    ...
    # call this save method like obj.save(created_by=request.user)
    def save(self, created_by, *args, **kwargs):
        super().save(*args, **kwargs)
        # is_updated will be True if user object is updated 
        manage_user.send(sender=self, user=created_by, is_updated=True if self.id else False)

发送 manage_user 在用户模型更改时发出信号，就像 post_save 信号一样，
，但是现在您可以控制参数了。

send manage_user signal when user model changed, just like post_save signal, but now you have control over parameters.

更新

如果您使用django admin创建用户，则可以覆盖 save_model ，您在那里有请求对象。

UPDATE

If you are using django admin to create user you can overide save_model, you have request object there.

from django.contrib import admin

@admin.register(User)
class UserAdmin(admin.ModelAdmin):
     def save_model(self, request, obj, form, change):
         super(UserAdmin, self).save_model(request, obj, form, change)
         manage_user.send(sender=self, user=request.user, is_updated=True if self.id else False)

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