It's surprising to me that Django doesn't already have this, but I can't remember seeing it anywhere. Change looks fine.
Make URL method configurable
Review Request #98 — Created June 23, 2007 and submitted
We currently hard-code "http" inside our e-mail templates, which means that people can't run with https. It'd be nice if we could store this inside our site model, but django sites don't have that field. This change adds a DOMAIN_METHOD key to settings.py (which can be overridden in settings_local.py) and plumbs it through to the templates.