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Django pre_save触发了两次

[英]Django pre_save triggered twice

I am using django signals for data denormalization. 我正在使用django信号进行数据非规范化。 Here is my code: 这是我的代码:

# vote was saved
@receiver(pre_save, sender=Vote)
def update_post_votes_on_save(sender, instance, **kwargs):
    """ Update post rating """
    # is vote is being updated, then we must remove previous value first
    if instance.id:
        old_vote = Vote.objects.get(pk=instance.id)
        instance.post.rating -= old_vote.value
    # now adding the new vote
    instance.post.rating += instance.value
    instance.post.save()

I cannot understand why, but when my Vote instance is being saved, update_post_votes_on_save() is being called twice. 我无法理解为什么,但是当我的Vote实例被保存时, update_post_votes_on_save()被调用两次。 I thought there was a bug in my code, but saving through admin interface gives the same result. 我认为我的代码中存在一个错误,但通过管理界面保存会产生相同的结果。

Docs say something about using dispatch_uid to prevent duplicate calls , but I cannot understand if this is the case. 文档说了一些关于使用dispatch_uid来防止重复调用的事情,但我不明白是否是这种情况。 How to use dispatch_uid ? 如何使用dispatch_uid I've tried this, but with no luck: 我试过这个,但没有运气:

@receiver(pre_save, sender=Vote, dispatch_uid="my_unique_identifier")

Any ideas why function is being called twice and how to avoid it? 任何想法为什么函数被调用两次以及如何避免它?

I'm sorry, for the confusement, but dispatch_uid solved the problem, after all. 对不起,对于娱乐,但是dispatch_uid毕竟解决了这个问题。 Just remember, that you might have to restart the development server to see the effect, before asking a question on SO :) 请记住,您可能需要重新启动开发服务器才能看到效果,然后再询问SO :)

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