Model signals
  pre_init          # django的modal执行其构造方法前，自动触发
  post_init          # django的modal执行其构造方法后，自动触发
  pre_save          # django的modal对象保存前，自动触发
  post_save          # django的modal对象保存后，自动触发
  pre_delete         # django的modal对象删除前，自动触发
  post_delete         # django的modal对象删除后，自动触发
  m2m_changed         # django的modal中使用m2m字段操作第三张表（add,remove,clear）前后，自动触发
  class_prepared       # 程序启动时，检测已注册的app中modal类，对于每一个类，自动触发
Management signals
  pre_migrate         # 执行migrate命令前，自动触发
  post_migrate        # 执行migrate命令后，自动触发
Request/response signals
  request_started       # 请求到来前，自动触发
  request_finished      # 请求结束后，自动触发
  got_request_exception    # 请求异常后，自动触发
Test signals
  setting_changed       # 使用test测试修改配置文件时，自动触发
  template_rendered      # 使用test测试渲染模板时，自动触发
Database Wrappers
  connection_created     # 创建数据库连接时，自动触发

django.db.models.signals.pre_save
django.db.models.signals.post_save

django.db.models.signals.pre_delete
django.db.models.signals.post_delete

django.db.models.signals.m2m_changed

django.core.signals.request_started
django.core.signals.request_finished

Signal.connect(receiver, sender=None, weak=True, dispatch_uid=None)[source]

from django.core.signals import request_finished
from django.dispatch import receiver

@receiver(request_finished)
def my_callback(sender, **kwargs):
  print("Request finished!")

from django.db.models import signals
from django.dispatch import receiver

@receiver(signals.post_save, sender=MyModel)
def demo_callback(sender: MyModel, instance: MyModel, **kwargs):
  pass

from django.core.signals import request_finished

request_finished.connect(my_callback, dispatch_uid="my_unique_identifier")

Signal.disconnect(receiver=None, sender=None, dispatch_uid=None)[source]