在Django中创建模型时执行代码

Question

我想在第一次创建时在Django模型中执行一些代码。之后，每当它被保存时，我想执行一些其他代码。通过重写save（）方法可以轻松完成第二项任务。 我该怎么做第一项任务？

Answer 1

可以使用django signals：使用receiver装饰“post_save

# models.py 

from django.db.models import signals 

class MyModel(models.Model): 
    pass 

def my_model_post_save(sender, instance, created, *args, **kwargs): 
    """Argument explanation: 

     sender - The model class. (MyModel) 
     instance - The actual instance being saved. 
     created - Boolean; True if a new record was created. 

     *args, **kwargs - Capture the unneeded `raw` and `using`(1.3) arguments. 
    """ 
    if created: 
     # your code goes here 


# django 1.3+ 
from django.dispatch import dispatcher 
dispatcher.connect(my_model_post_save, signal=signals.post_save, sender=MyModel) 

# django <1.3 
from django.db.models.signals import post_save 
post_save.connect(my_model_post_save, sender=MyModel) 

Answer 2

扩展sdolan的answer：

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

class MyModel(models.Model): 
    pass 

@receiver(models.signals.post_save, sender=MyModel) 
def execute_after_save(sender, instance, created, *args, **kwargs): 
    if created: 
     # code