django temporarily disable signals

Question

I have a signal callback in django:

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


        

Answer 1

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.

Also, to avoid signals you can:

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

Answer 2

To disable a signal on your model, a simple way to go is to set an attribute on the current instance to prevent upcoming signals firing.

This can be done using a simple decorator that checks if the given instance has the 'skip_signal' attribute, and if so prevents the method from being called:

from functools import wraps

def skip_signal():
    def _skip_signal(signal_func):
        @wraps(signal_func)
        def _decorator(sender, instance, **kwargs):
            if hasattr(instance, 'skip_signal'):
                return None
            return signal_func(sender, instance, **kwargs)  
        return _decorator
    return _skip_signal

You can now use it this way:

from django.db.models.signals import post_save
from django.dispatch import receiver

@receiver(post_save, sender=MyModel)
@skip_signal()
def my_model_post_save(sender, instance, **kwargs):
    instance.some_field = my_value
    # Here we flag the instance with 'skip_signal'
    # and my_model_post_save won't be called again
    # thanks to our decorator, avoiding any signal recursion
    instance.skip_signal  = True
    instance.save()

Hope This helps.