Django OneToOneField and signals

Question

I have a model called DeviceStatus which has a OneToOne relationship with another model called Device. I want to get the id passed to the DeviceStatus object before saving, but all I get is a ForwardManyToOneDescriptor object.

class DeviceStatus(TimeStampedModel):
    device = models.OneToOneField(Device)
    # other fields

    def __unicode__(self):
        return u'{}'.format(self.device)

    def copy_to_archive(**kwargs):
        print DeviceStatus.device

    pre_save.connect(copy_to_archive)

Can somebody guide me through how to get the Device id being passed? TIA

If you want to use class method as signal handler read http://stackoverflow.com/a/11647745/3627387 — Sardorbek Imomaliev, Oct 03 '16 at 10:35

score 3 · Accepted Answer · edited May 23 '17 at 12:19

3

Should be instance method

def copy_to_archive(self, **kwargs):
    print self.device

Also connecting signal like this won't work. But this is different question.

Answering comment and extending my answer in comment to post

This what needed to be done

class MyClass(models.Model):
    #....
    @classmethod
    def before_save(cls, sender, instance, *args, **kwargs):
        instance.test_field = "It worked"

pre_save.connect(MyClass.before_save, sender=MyClass)

Django 1.2: How to connect pre_save signal to class method

edited May 23 '17 at 12:19

Community

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answered Oct 03 '16 at 10:12

Sardorbek Imomaliev

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it won't allow me to pass `self` here – Venu Saini Oct 03 '16 at 10:21
@VenuSaini who won't? Does your signal get called? – Sardorbek Imomaliev Oct 03 '16 at 10:26
if i try to pass `self` like you did, the signal wants me to pass something corresponding to that in `pre_save.connect(copy_to_archive)` – Venu Saini Oct 03 '16 at 10:43
yes the signal does get called. I'm just not able to figure out how to get the id of the selected `Device` – Venu Saini Oct 03 '16 at 10:44

Django OneToOneField and signals

1 Answers1