Rails - Mar 2005 - subdomaining questions: default routes and db partitioning (ThreadLocals?)

I''m working on adding subdomain mapping to my blog/bbs/aim/whatever
program myelinate.  I''m following the idiom of added a before filter
in application.rb to look up my "Site" object, and setting that in the
base controller.  It''s accessable in all the views, so pulling things
like the title out in a layout is working great.  I''m also using the
layout :function to choose which layout to render based upon the DB
value.

But a couple issues.

1) I''d like to be able to override the default route mapping -- some
sites will, say, render EntryController.recent and some will render
EntryController.show( site.default ).  In the before filter I''m able
to:
	c.params[:action] = ''show''
	c.params[:id] = c.site.default_key
which works great, but
a) Is there a better way to do this using the route system?
b) What''s the best way to determin that I''m hitting the
default route?
(i.e. "" )?

2) I''d like to have multiple sites running coexisting on one machine. 
Is the best way to do this having a ''site_id'' in every model
that I
want to partition, or is it to have a different schema for every
domain?  I can see advantages of both ways, but I''m leaning towards
slightly more complicated SQL and much less DB maintence.  So... I
need a way to get to my site object inside of all my queries.  Putting
site as an attribute inside of the base controller works great for the
controllers and the views; not so much for the models.  I don''t want
to pass in the site on every finder method because that would make me
a little insane.  I''m thinking about using a ThreadLocal (I''m
not sure
what the (non java) Ruby terminology is, but Thread.current[:site] is
the Ruby code) from the model finder methods.  Is there a cleaner way?

Thanks,
-w

-- 
Will Schenk
http://www.sublimeguile.com
http://www.myelinate.com