英文:
Moving from Django signals to save override: How to translate the "created" parameter of a Django post_save signal for a save method override
问题
关于如何更改处理Django模型上的post_save事件的方法，您可以考虑以下方式。要替代接收器函数中的if created:语句，您可以重写MyModel的save方法，如下所示：
class MyModel(models.Model):
# ...
def save(self, *args, **kwargs):
if not self.pk: # Check if the instance is being created
self.do_something()
super().save(*args, **kwargs)
这里，我们检查self.pk是否存在，如果不存在，则表示正在创建新实例，然后调用self.do_something()。然后，我们调用super().save(*args, **kwargs)来执行模型的默认保存操作。
对于pre_save信号，您可以采用类似的方法来检查是否正在创建实例。不过，pre_save信号在保存之前触发，所以您需要注意如何处理它，以避免不必要的操作。
如果您需要更多帮助或有其他建议，请随时告诉我。
英文:
I have made some bad decisions earlier regarding how I handle post_save events on a Django model and I am currently looking into changing my approach.
Let's begin by making my example. Here is my model.
class MyModel(models.Model):
#... all my model creation and logic are here
def do_something(self):
# Actually do something, for the sake of simplifying the example, just write pass
pass
Now, what I am using is a receiver function like this one. It works, but for many reasons that are mine, I want to stop using signal in this case.
@receiver(post_save, sender=MyModel)
def foo(sender, instance, created, **kwargs):
if created:
instance.do_something()
I imagine I could override the MyModel.save method, something like this:
class MyModel(models.Model):
#...
def save(self):
super().save()
if created: # It is this line that I need to figure how to do.
self.do_something()
By what should I replace the if created: of my receiver function if I want to override the save() method? Or do you have something else to recommend?
I would also be curious if it is the same thing for pre_save signals.
答案1
得分: 1
如果我理解你的问题，你可以尝试检查当前模型实例的主键是否可用或不可用。
def save(self, *args, **kwargs):
is_created = self.pk is None # 检查实例是否正在创建
super().save(*args, **kwargs)
if is_created:
self.do_something()
英文:
If i understand your question you can try checking if current model instance pk is available or not
def save(self, *args, **kwargs):
is_created = self.pk is None # Check if the instance is being created
super().save(*args, **kwargs)
if is_created:
self.do_something()
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