I’ve been looking for a microframework for Ruby that is simple like Camping but supports RESTful resources like Rails. A tip from the Denver Rails UG pointed me to Sinatra via Adam @ Heroku’s Blog:
Sinatra apps are typically written in a single file. It starts up and shuts down nearly instantaneously. It doesn’t use much memory and it serves requests very quickly. But, it also offers nearly every major feature you expect from a full web framework: RESTful resources, templating (ERB, Haml/Sass, and Builder), mime types, file streaming, etags, development/production mode, exception rendering. It’s fully testable with your choice of test or spec framework. It’s multithreaded by default, though you can pass an option to wrap actions in a mutex. You can add in a database by requiring ActiveRecord or DataMapper. And it uses Rack, running on Mongrel by default.