Django的信号机制详解大数据

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

from django.core.signals import request_finished 
    from django.core.signals import request_started 
    from django.core.signals import got_request_exception 
 
    from django.db.models.signals import class_prepared 
    from django.db.models.signals import pre_init, post_init 
    from django.db.models.signals import pre_save, post_save 
    from django.db.models.signals import pre_delete, post_delete 
    from django.db.models.signals import m2m_changed 
    from django.db.models.signals import pre_migrate, post_migrate 
 
    from django.test.signals import setting_changed 
    from django.test.signals import template_rendered 
 
    from django.db.backends.signals import connection_created 
 
#第一种注册方式 
    def callback(sender, **kwargs): 
        print(" connection_created_callback") 
        print(sender,kwargs) 
 
    connection_created.connect(callback) 
#第二种注册方式，使用装饰器注册 
from django.core.signals import request_finished 
from django.dispatchimport receiver 
   
@receiver(request_finished) 
def my_callback(sender, **kwargs): 
  print("Request finished!")

import django.dispatch 
pizza_done=django.dispatch.Signal(providing_args=["toppings", "size"])

def callback(sender, **kwargs): 
 
    print("callback") 
 
    print(sender,kwargs) 
 
  
 
pizza_done.connect(callback)

from 路径 import pizza_done 
  
pizza_done.send(sender='seven',toppings=123, size=456)