Django信号1内置

from django.core.signals import request_finished
from django.core.signals import request_started
from django.core.signals import got_request_exception
#信号放到项目的init文件里面
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 callback(sender, **kwargs):
    print("xxoo_callback")
    print(sender,kwargs)


pre_migrate.connect(callback)