Comment by LeafStorm

The title ("SMTP and Sinatra") made me expect something written in Ruby. Also:

    def subscribe(self, route=r'subscribe-(?P<name>[^@]*)@.*'):

No. No. No. No. No. No. No. Default arguments are not for specifying metadata about your functions. That's what decorators are for. And for the love of Guido, why are you accessing per-request information from instance variables? It seems to me that you would much rather be programming this in Ruby.