18.Django信号signals
Django信号是一种用于在应用程序中发送和接收通知的机制。它们允许您将代码解耦并使其更加模块化。当某个事件发生时，Django会发送一个信号，然后您的代码可以监听该信号并在事件发生时执行相应的操作。
以下是一些常用的Django信号及其示例代码：
- post_save
from django.db.models.signals import post_save
from django.dispatch import receiver
from myapp.models import MyModel@receiver(post_save, sender=MyModel)
def do_something(sender, **kwargs):# do something after MyModel instance is saved
- pre_save信号
当模型实例被保存之前发送该信号。可以用来在保存之前修改实例属性。
from django.db.models.signals import pre_save
from django.dispatch import receiver
from myapp.models import MyModel@receiver(pre_save, sender=MyModel)
def do_something(sender, instance, **kwargs):# modify instance attributes before MyModel instance is saved
- post_delete信号
当模型实