SingleObjectMixin should accept parameters for overriding the URL keywords for pk and slug

[AndrewIngram]

Currently, in SingleObjectMixin, Django looks for a 'pk' or 'slug' keyword argument to use for looking up an instance of a model. You can override slug_field when the field on the model is something other than "slug". What you can't do is designate different URL keywords to use for these lookup, and to override this in a subclass the whole get_object method needs to be reimplemented.

My proposition is to have a 'pk_keyword' and 'slug_keyword' field on SingleObjectMixin which default to 'pk' and 'slug' respectively, but can easily be overridden.

Use case:

I have a product app with a URL like this:

r'^(?P<item_class_slug>[\w-]+)/(?P<item_slug>[\w-]*)-(?P<pk>\d+)/$'

The view uses a subclass of DetailView with the pk keyword being used for fetching the product. But we also have optional product review URLs which are only included if the reviews app is installed, and are included like this:

url(r'^(?P<item_class_slug>[\w-]+)/(?P<item_slug>[\w-]*)-(?P<pk>\d+)/reviews', include(self.reviews_app.urls)),

Within the reviews URLs we have a review detail view which also uses DetailView, this means I end up with two pk keywords in the URLs. Now I could just use a different keyword for the product pk keyword for this include, but I prefer consistency in my URL patterns. I would rather use 'item_pk' and 'review_pk' in all cases, which I can't currently do.
I've had a look at the code and it seems like a straightforward change, I'm happy to submit the patch myself if this issue is accepted.

[AndrewIngram]

I made an error in my initial ticket, aside from accidentally supertexting the URLs, 'reviews' should be at the end of the second URL definition, before the include.

[Julien Phalip]

(Fixed the ticket description's formatting).

Accepting as this seems like a simple and reasonable way of increasing SingleObjectMixin's flexibility. Like for any new feature, the patch will need to include tests and documentation.

[Julien Phalip]

Just a note. slug_keyword and pk_keyword don't feel very explicit to me. I wonder if they shouldn't be slug_url_kwarg and pk_url_kwarg instead. Not the prettiest but at least more explicit, and also consistent with django.views.generic.edit.FormMixin.get_form_kwargs().

[AndrewIngram]

Added pk_url_kwarg and slug_url_kwarg to SingleObjectMixin so the defaults of 'pk' and 'slug' can be overridden.

[AndrewIngram]

Added pk_url_kwarg and slug_url_kwarg to SingleObjectMixin so the defaults of 'pk' and 'slug' can be overridden.

[Julien Phalip]

Thanks for the patch! I've slightly tweaked the doc, added release notes and removed the get_slug_url_kwarg() and get_pk_url_kwarg() as those complicated things and didn't add real value. I'll just seek for external opinion on the naming ("pk_url_kwarg" and "slug_url_kwarg") before RFC'ing this ticket.

[Julien Phalip]

Patch updated to latest trunk

[Jannis Leidel]

I'm not thrilled about the names, slug_url_argument and pk_url_argument would be a bit more explicit, but that's not a show stopper, IMO.

[Jannis Leidel]

In [16569]:

Fixed #16101 -- Added parameters to SingleObjectMixin to override the name of the URL keyword arguments used for pk and slug. Thanks, Andrew Ingram and Julien Phalip.