How to update date automatically after a value change in django

Question

In the following django model:

class MyModel(models.Model):
    published = models.BooleanField(default=False)
    pub_date = models.DateTimeField('date published')

I want the pub_date field to be automatically updated with the current date, every time the published field changes to True.

Any help?

Answer 1

Hello @kartik,

Only change your pub_date if published has been modified from False to True:

from datetime import datetime

def __init__(self, *args, **kwargs):
    super(MyModel, self).__init__(*args, **kwargs)
    self.old_published = self.published

def save(self, *args, **kwargs):
    if self.published and self.old_published != self.published:
        self.pub_date = datetime.now()
    super(Model, self).save(*args, **kwargs)

Hope it helps!

Thanks!