django暂时禁用信号 [英] django temporarily disable signals

问题描述

我在django中有一个信号回调：

I have a signal callback in django:

@receiver(post_save, sender=MediumCategory)
def update_category_descendants(sender, **kwargs):

    def children_for(category):
        return MediumCategory.objects.filter(parent=category)

    def do_update_descendants(category):
        children = children_for(category)
        descendants = list() + list(children)

        for descendants_part in [do_update_descendants(child) for child in children]:
            descendants += descendants_part

        category.descendants.clear()
        for descendant in descendants:
            if category and not (descendant in category.descendants.all()):
                category.descendants.add(descendant)
                category.save()
        return list(descendants)

    # call it for update
    do_update_descendants(None)

但在func我正在使用 .save（）在模型 MediumCategory 上，它再次发出信号。如何禁用它？完美的解决方案将是一个，其中包含语句，其中包含一些魔术。

but in the function body I'm using .save() on models MediumCategory that couses that the signal is dispatched again. How can I disable it; the perfect solution would be a with statement with some 'magic' inside.

更新： strong>
这是最终解决方案，如果有兴趣的话。

UPDATE: That's final solution, if anyone interested.

class MediumCategory(models.Model):
    name = models.CharField(max_length=100)
    slug = models.SlugField(blank=True)
    parent = models.ForeignKey('self', blank=True, null=True)
    parameters = models.ManyToManyField(AdvertisementDescriptonParameter, blank=True)
    count_mediums = models.PositiveIntegerField(default=0)
    count_ads = models.PositiveIntegerField(default=0)

    descendants = models.ManyToManyField('self', blank=True, null=True)

    def save(self, *args, **kwargs):
        self.slug = slugify(self.name)
        super(MediumCategory, self).save(*args, **kwargs)

    def __unicode__(self):
        return unicode(self.name)
(...)
@receiver(post_save, sender=MediumCategory)
def update_category_descendants(sender=None, **kwargs):
    def children_for(category):
        return MediumCategory.objects.filter(parent=category)

    def do_update_descendants(category):
        children = children_for(category)
        descendants = list() + list(children)

        for descendants_part in [do_update_descendants(child) for child in children]:
            descendants += descendants_part

        if category:
            category.descendants.clear()
            for descendant in descendants:
                category.descendants.add(descendant)
        return list(descendants)

    # call it for update
    do_update_descendants(None)

推荐答案

也许我错了，但我认为 category.save（）不需要你的代码，add（）是足够的，因为更改是在后代，但在类别。

Perhaps I'm wrong, but I think that category.save() is not needed in your code, add() is enough because change is made in descendant but in category.

另外，为了避免信号，您可以：

Also, to avoid signals you can:

• 断开信号并重新连接。


• 使用更新： Descendant.objects.filter（pk = descendant.pk）.update（category = category）

• Disconnect signal and reconnect.
• Use update: Descendant.objects.filter( pk = descendant.pk ).update( category = category )

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