add如何使django post_save信号仅在创建期间运行 [英] addHow to make django post_save signal run only during creation
问题描述
我在我的项目中使用django-notifications,我想在使用信号创建模型时通知特定用户,但是在更新模型时post_save也会运行,我如何防止这种情况并且仅使创建模型后运行post_save方法。
models.py
class Card(models.Model):
用户= models.ForeignKey(User,on_delete = models.CASCADE)
title = models.CharField(max_length = 100)
description = models.TextField (空白=真)
列表=模型.ForeignKey(列表,related_name ='卡片')
story_points =模型.IntegerField(空=真,空白=真)
业务值=模型.IntegerField (空=真,空白=真)
def __str __(self):
return Card:{}。format(self.title)
def my_handler(发件人,实例,**假):
如果instance.pk为None:
notify.send(instance.user,收件人= User.objects.get(pk = 1),target =实例,verb ='create d')
post_save.connect(my_handler,sender = Card)
我尝试使用if instance.pk为None,但是当我添加此条件时,它根本不运行。
def my_handler(发件人,实例,创建的,**假的):
如果创建的话:
notify.send(instance .user,receiver = User.objects.get(pk = 1),target = instance,动词='created')
有一个已创建的命名参数,如果它是一个新对象,则将其设置为True。
有一个看看这里- https://docs.djangoproject.com/en/1.10 / ref / signals /#post-保存
def my_func(发送方,实例,创建的,** kwargs) :
print( Created:,created)
class MyModel(models.Model):
x = models.CharField(max_length = 255)
p ost_save.connect(my_func,sender = MyModel)
>> MyModel.objects.create(f ='asdf')
创建:True
>>> m = MyModel.objects.all()。first()
>>> m.x
'asdf'
>>> m.x =‘a’
>>> m.save()
创建:False
I'm using django-notifications in my project and I want to notify a particular user whenever a model is created using the signal, but the post_save also runs when a model is being updated how do I prevent this and only make the post_save method run when a model is created.
models.py
class Card(models.Model):
user = models.ForeignKey(User,on_delete=models.CASCADE)
title = models.CharField(max_length=100)
description = models.TextField(blank=True)
list = models.ForeignKey(List, related_name='cards')
story_points = models.IntegerField(null=True, blank=True)
business_value = models.IntegerField(null=True, blank=True)
def __str__(self):
return "Card: {}".format(self.title)
def my_handler(sender, instance, **kwargs):
if instance.pk is None:
notify.send(instance.user, recipient=User.objects.get(pk=1), target=instance, verb='created')
post_save.connect(my_handler, sender=Card)
I tried using if instance.pk is None, but when I add this condition it doesn't run at all.
EDITED: The code checking if created
def my_handler(sender, instance, created, **kwargs):
if created:
notify.send(instance.user, recipient=User.objects.get(pk=1), target=instance, verb='created')
There is a created named argument which will be set to True if it's a new object.
Have a look here - https://docs.djangoproject.com/en/1.10/ref/signals/#post-save
def my_func(sender, instance, created, **kwargs):
print("Created: ", created)
class MyModel(models.Model):
x = models.CharField(max_length=255)
post_save.connect(my_func, sender=MyModel)
>>> MyModel.objects.create(f='asdf')
Created: True
>>> m = MyModel.objects.all().first()
>>> m.x
'asdf'
>>> m.x = 'a'
>>> m.save()
Created: False
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