Snippet

Django Signal for Automatic Slug Generation

Django signals allow you to execute code when certain events occur in the ORM. This pre_save signal automatically generates a unique URL-friendly slug from the product name, handling duplicates by appending incremental numbers.

snippet.py

python

from django.db.models.signals import pre_save
from django.dispatch import receiver
from django.utils.text import slugify
from .models import Product
 
@receiver(pre_save, sender=Product)
def generate_slug(sender, instance, **kwargs):
    if not instance.slug:
        base_slug = slugify(instance.name)
        slug = base_slug
        counter = 1
 
        while Product.objects.filter(slug=slug).exists():
            slug = f"{base_slug}-{counter}"
            counter += 1
 
        instance.slug = slug

django

Breakdown

@receiver(pre_save, sender=Product)

Decorator registers this function to run before a Product instance is saved

slugify(instance.name)

Django utility converts 'iPhone 15 Pro' to 'iphone-15-pro' for URL compatibility

while Product.objects.filter(slug=slug).exists():

Check if generated slug already exists in database to ensure uniqueness

slug = f"{base_slug}-{counter}"

Append counter suffix to create unique slug like 'iphone-15-pro-2'

Previous snippet Next snippet

More Intermediate Python exercises →

Django Signal for Automatic Slug Generation

Related