Populating django field with pre_save()?

Question

class TodoList(models.Model):
    title = models.CharField(maxlength=100)
    slug = models.SlugField(maxlength=100)
    def save(self):
        self.slug = title
           


        

Answer 1

Most likely you are referring to django's pre_save signal. You could setup something like this:

from django.db.models.signals import pre_save
from django.dispatch import receiver
from django.template.defaultfilters import slugify

@receiver(pre_save)
def my_callback(sender, instance, *args, **kwargs):
    instance.slug = slugify(instance.title)

If you dont include the sender argument in the decorator, like @receiver(pre_save, sender=MyModel), the callback will be called for all models.

You can put the code in any file that is parsed during the execution of your app, models.py is a good place for that.