尽管存在uid，但Django post save信号被调用了两次 [英] Django post save signal getting called twice despite uid

问题描述

我已经使用@receiver装饰器在回调函数中注册了信号

I have registered my signal with the callback using the @receiver decorator

@receiver(post_save, sender=User, dispatch_uid='ARandomUniqueString') 
def do_callback(sender, **kwargs):

我已经将from app.signals import *代码放入了__init__.py中，并且可以看到它被导入了两次，并且我认为没有很好的方法来修复它，这可能是由于settings.py中的installed apps导致的.我不明白为什么尽管使用dispatch_uid并且modelInstance.save仅被调用一次，却仍然运行do_callback两次.有什么建议吗?

I have put the from app.signals import * code in __init__.py and I can see that it gets imported twice and I do not think there is a good way to fix it, possibly happening due to installed apps in settings.py. I cannot understand why despite using dispatch_uid and the modelInstance.save being invoked only once, it still runs do_callback twice. Any suggestions?

推荐答案

好，所以我将导入移动到了views.py(或models.py，并且只导入了一次，却被调用了两次).

Ok so I moved the import to views.py (or models.py and while it was getting imported only once, it was getting called twice.

问题是在创建和保存对象时会调用post_save信号.我不知道为什么，所以我添加了一个现在可以解决的解决方法

The problem was that the post_save signal was getting called when the object was created as well as saved. I have no idea why so I added a workaround which now works

created = False

    #Workaround to signal being emitted twice on create and save
    if 'created' in kwargs:
        if kwargs['created']:
            created=True

    #If signal is from object creation, return
    if created:
        return

post_save被调用了两次，因为我使用了.create(...)，它等同于__init__(...)和.save().

post_save was getting called twice because I used .create(...) which is equivalent to __init__(...) and .save().

结论

dispatch_uid确实有效，并且单次导入仍然是一个好习惯.

dispatch_uid does work and doing single imports is still a good practice.

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