Today DHH showed an example on a Rack support of Rails.
I think it’s a nice idea to interface Rails with Rack for two main raisons:
- it’s a de facto standard in Ruby frameworks
- it enables you to put “something in the middle”
So for example, you can dice your application to be served by a small-and-fast framework (Sinatra?) for certain request, and by Rails for others. It’s not the kind of optimization I personally like more… but it’s better than nothing. :)