Changes between Initial Version and Version 1 of SlugifyUniquely

Timestamp:

Nov 16, 2006, 4:15:04 PM (17 years ago)

Author:

WilliamMcVey

Comment:

How to automagically choose a slug unique within a model

SlugifyUniquely

@@ +1 @@
+It's common for me to want a unique slug based on a user supplied name of an object. Following the pattern outlined at [http://www.b-list.org/weblog/2006/11/02/django-tips-auto-populated-fields djang-tips-auto-populated-fields], it's easy to get the field populated without user intervention. However, by setting the slug field in the save() method the field isn't validated and thus unique=True restrictions aren't checked. I wrote the following code to attempt to pick slugs which are unique within a particular model. It's certainly not ideal (it suffers from race condition as well as potential for pounding a database with lots of small queries until it finds a good slug field), but it works for my small/mid-sized apps.
+
+Feel free to suggest improvements to 'wam-djangowiki spam@wamber.net' (remove the ' spam' from the address there).
+
+{{{
+def SlugifyUniquely(value, model, slugfield="slug"):
+        """Returns a slug on a name which is unique within a model's table
+
+        This code suffers a race condition between when a unique
+        slug is determined and when the object with that slug is saved.
+        It's also not exactly database friendly if there is a high
+        likelyhood of common slugs being attempted.
+
+        A good usage pattern for this code would be to add a custom save()
+        method to a model with a slug field along the lines of:
+
+                from django.template.defaultfilters import slugify
+
+                def save(self):
+                    if not self.id:
+                        # replace self.name with your prepopulate_from field
+                        self.slug = SlugifyUniquely(self.name, self.__class__)
+                super(self.__class__, self).save()
+
+        Original pattern discussed at
+        http://www.b-list.org/weblog/2006/11/02/django-tips-auto-populated-fields
+        """
+        suffix = 0
+        potential = base = slugify(value)
+        while True:
+                if suffix:
+                        potential = "-".join([base, str(suffix)])
+                if not model.objects.filter(**{slugfield: potential}).count():
+                        return potential
+                # we hit a conflicting slug, so bump the suffix & try again
+                suffix += 1
+}}}