custom save method on model - django

Question

I am overriding the save method on one of my models:

def save(self, *args, **kwargs):
    self.set_coords()
    super(Post, self).save(*args, **kwargs)

def __unicode__(self):
    return self.address

# set coordinates
def set_coords(self):
    toFind = self.address + ', ' + self.city + ', ' + \
        self.province + ', ' + self.postal

    (place, location) = g.geocode(toFind)

    self.lat = location[0]
    self.lng = location[1]

However, I only want to run set_coords() once, when the post is being created. This function should not run when the model is being updated.

How can I accomplish this? Is there any way of detecting if the model is being created or updated?

score 33 · Accepted Answer · edited Jan 23 '23 at 02:40

33

def save(self, *args, **kwargs):
    if not self.pk:
        self.set_coords()
    super(Post, self).save(*args, **kwargs)

edited Jan 23 '23 at 02:40

artu-hnrq

1,343
1
8
30

answered Jul 12 '12 at 17:05

jagm

576
4
6

Can you please tell me that. Return should be used or not on line `super(Post, self).save(*args, **kwargs)`. It works without return. – Vaibhav Jain Oct 12 '14 at 13:15

Abdeslem Daaif · Answer 2 · 2012-07-12T17:45:02.847

3

I think the correct way to do it is using post_save signal:

def set_coords(sender, **kw):
    model_instance = kw["instance"]
    if kw["created"]:
        toFind = model_instance.address + ', ' + model_instance.city + ', ' + \
        model_instance.province + ', ' + model_instance.postal
        (place, location) = g.geocode(toFind)
        model_instance.lat = location[0]
        model_instance.lng = location[1]
        model_instance.save()
post_save.connect(set_coords, sender=MyModel)

edited Jul 12 '12 at 17:45

answered Jul 12 '12 at 17:36

Abdeslem Daaif

41
2

1

I would say that signals are a better call to change behaviour of models we don't have access to. Despite of being useful either way. ;) – Jayme Tosi Neto Jan 11 '17 at 23:01

custom save method on model - django

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