Django : Generate unique slug

django_signals_slugify.py

# import signals and slugify
from django.db.models import signals
from django.template.defaultfilters import slugify


class Post(models.Model):
    text = models.TextField("Post text")


# function for use in pre_save
def post_pre_save(signal, instance, sender, **kwargs):
    if not instance.slug:
        slug = slugify(instance.attribute)  # change the attibute to the field that would be used as a slug
        new_slug = slug
        count = 0
        while Post.objects.filter(slug=new_slug).exclude(id=instance.id).count() > 0:
            count += 1
            new_slug = '{slug}-{count}'.format(slug=slug, count=count)
        
        instance.slug = new_slug

# Execute signals pre_save
signals.pre_save.connect(post_pre_save, sender=Post)

@Radi85 Today I really think the best approach is use a external_id field with last parameter of URL instead the count on post save.

e.g.

urlpatterns = [
    path("<slug:str>-<external_id:str>/", PostDetailView.as_view(), name="detail"),
]