[Fixed]-Possible to change order of Django signals?

by

12👍

✅

I’m not positive, but I’d say it’s doubtful. Kinda more important is that the idea behind signals is that they should be atomic. A signal handler should respond the signal and shouldn’t care about other signals. Relying on the order of two unrelated signals (obviously you can rely on the order of pre_save and post_save for example) is not safe in general. So even though I don’t have a firm answer on your question, I’d offer the advice that yo should think carefully about the design.

👤John

19👍

No, you cannot change the order that signals are executed.

Signal priority has been proposed, but the core developers have said they will not implement this feature:

https://code.djangoproject.com/ticket/16547

👤Derek Curtis

4👍

I know this is a very old question, but I was surprised by the lack of anything I found related to a workaround for handler ordering. So here is a subclass of the dispatcher which implements priorities.

from django.dispatch import Signal as BaseSignal
from django.dispatch.dispatcher import _make_id


class Signal(BaseSignal):

    def connect(self, receiver, sender=None, weak=True, dispatch_uid=None, priority=50):
        if dispatch_uid is None:
            dispatch_uid = _make_id(receiver)

        inner_uid = '{0}{1}'.format(priority, dispatch_uid)
        super(Signal, self).connect(receiver, sender=sender, weak=weak, dispatch_uid=inner_uid)
        self.receivers.sort()

While this won’t help you with third-party apps, you can create your own signals with this class, and attach them to the built-in signals, allowing you to order the handlers within your own app.

👤AgDude

0👍

Have you considered using one signal that calls create_social_profile and create_user_profile. perhaps you could attach this signal to post_save?

👤Al W

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