Create unique slugs in Django

models.py

from django.template.defaultfilters import slugify

def slugify_unique(value, model, slugfield="slug", max_length=None):
    """
    Check against the database that the slug is unique and automatically increase a counter.
    Optionally check that the slug doesn't grow too long for the slug field.
    """
    slug = baseslug = slugify(value)

    counter = 1
    while model.objects.filter(**{ slugfield: slug }).count() > 0:
        counter += 1
        if max_length is not None:
            baseslug = baseslug[:max_length - len(str(counter)) - 1]
        slug = "%s-%d" % (baseslug, counter)

    return slug