django 信号

Posted 2020-10-08

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 增加钱增加后
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

 

 

 

使用

 

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


def xxxxxxxx(sender, **kwargs):
    print("post_save.xxxxxxxx")
    print(sender, kwargs)

post_save.connect(xxxxxxxx)


视图

def get(self, request, *args,**kwargs):

    models.UserType.objects.create(title=‘zhangsan‘)
    print(‘login‘)
    return  HttpResponse(‘login‘)

输出结果
<class ‘app01.models.UserType‘> {‘raw‘: False, ‘update_fields‘: None, ‘instance‘: <UserType: UserType object>, ‘using‘: ‘default‘, ‘created‘: True, ‘signal‘: <django.db.models.signals.ModelSignal object at 0x0000000002D97780>}


解释：
信号类似于django里面的触发机制。上面usettype create操作后马上就运行了这个函数