Django中提供了“信号调度”,用于在框架执行操作时解耦。通俗来讲,就是一些动作发生的时候,信号允许特定的发送者去提醒一些接受者。
1、Django内置信号
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
对于Django内置的信号,仅需注册指定信号,当程序执行相应操作时,自动触发注册函数:
1 from django.core.signals import request_finished 2 from django.core.signals import request_started 3 from django.core.signals import got_request_exception 4 5 from django.db.models.signals import class_prepared 6 from django.db.models.signals import pre_init, post_init 7 from django.db.models.signals import pre_save, post_save 8 from django.db.models.signals import pre_delete, post_delete 9 from django.db.models.signals import m2m_changed 10 from django.db.models.signals import pre_migrate, post_migrate 11 12 from django.test.signals import setting_changed 13 from django.test.signals import template_rendered 14 15 from django.db.backends.signals import connection_created 16 17 18 def callback(sender, **kwargs): 19 print("xxoo_callback") 20 print(sender,kwargs) 21 22 xxoo.connect(callback) 23 # xxoo指上述导入的内容
1 from django.core.signals import request_finished 2 from django.dispatch import receiver 3 4 @receiver(request_finished) 5 def my_callback(sender, **kwargs): 6 print("Request finished!")
2、自定义信号
a. 定义信号
import django.dispatch pizza_done = django.dispatch.Signal(providing_args=["toppings", "size"])
b. 注册信号
def callback(sender, **kwargs): print("callback") print(sender,kwargs) pizza_done.connect(callback)
c. 触发信号
from 路径 import pizza_done pizza_done.send(sender=‘seven‘,toppings=123, size=456)
由于内置信号的触发者已经集成到Django中,所以其会自动调用,而对于自定义信号则需要开发者在任意位置触发。
原博客:http://www.cnblogs.com/wupeiqi/articles/5246483.html
原文地址:https://www.cnblogs.com/qiangayz/p/9000402.html
时间: 2024-10-03 22:57:36