Disconnect signals for models and reconnect in django

Question

I need make a save with a model but i need disconnect some receivers of the signals before save it.

I mean,

I have a model:

class MyModel(models.Model):
    ...

def pre_save_model(sender, instance, **kwargs):
    ...

pre_save.connect(pre_save_model, sender=MyModel)

and in another place in the code i need something like:

a = MyModel()
...
disconnect_signals_for_model(a)
a.save()
...
reconnect_signals_for_model(a)

Because i need in this case, save the model without execute the function pre_save_model.

Answer 1

I haven't tested the following code, but it should work:

from django.db.models.signals import pre_save


def save_without_the_signals(instance, *args, **kwargs):
    receivers = pre_save.receivers
    pre_save.receivers = []
    new_instance = instance.save(*args, **kwargs)
    pre_save.receivers = receivers
    return new_instance

It will silence signals from all sender's though not just instance.__class__.

---

This version disables only the given model's signals:

from django.db.models.signals import pre_save
from django.dispatch.dispatcher import _make_id


def save_without_the_signals(instance, *args, **kwargs):
    receivers = []
    sender_id = _make_id(instance.__class__)
    for index in xrange(len(self.receivers)):
        if pre_save.receivers[index][0][1] == sender_id:
            receivers.append(pre_save.receivers.pop(index))
    new_instance = instance.save(*args, **kwargs)
    pre_save.receivers.extend(receivers)
    return new_instance

Answer 2

If you only want disconnect and reconnect one custom signal, you may use this code:

def disconnect_signal(signal, receiver, sender):
    disconnect = getattr(signal, 'disconnect')
    disconnect(receiver, sender)

def reconnect_signal(signal, receiver, sender):
    connect = getattr(signal, 'disconnect')
    connect(receiver, sender=sender)

In this way you can make this:

disconnect_signal(pre_save, pre_save_model, MyModel)
a.save()
reconnect_signal(pre_save, pre_save_model, MyModel)