The sub-domain handling in Routes could perhaps be made more explicit and less aggressive. As an example, if I have sub_domains turned on and have a domain for serving the static side of the site, imaginatively called static.example.com and the normal www.example.com. All calls to url_for() that don't include a sub_domain keyword will behave as if sub_domain=None has been specified and will generate urls' w/o the www, such as http://example.com/index.html. Note that this is w/o anything being set for sub_domains_ignore.

This is probably acceptable if you have complete control over the domain and can setup your web server to handle the missing www. However, if you run a web server on a dynamic dns setup as I do, then Routes strips off the vital sub-domain entry, e.g. pylons.dyndns.org ends up with url's pointing to dyndns.org which is not usable.

I wonder if a small change to _subdomain_check() in Routes utils.py is warranted, so that it only processed sub-domains if the keyword args explicitly contained sub_domain, i.e. the first line becomes:

if config.mapper.sub_domains and kargs.has_key('sub_domain'): ...

This way no sub-domain processing is performed unless it is explicitly asked for and the sub_domain=None behaviour is unchanged.

Thoughts?

Robert