I’m watching the Rails Online Conference, February 2010 Exploring Rails 3 and really like how they setup the rack middleware.

...From the slides.

Rack Middleware

http://github.com/rack/rack/tree/master/lib/rack

Content Modifying

Rack::Chunked
Rack::ContentLength
Rack::ConditionalGet
Rack::ContentType
Rack::Deflater
Rack::ETag
Rack::Head
Rack::MethodOverride
Rack::Runtime
Rack::Sendfile
Rack::ShowStatus

Behavioral

Rack::CommonLogger
Rack::Lint
Rack::Lock
Rack::Reloader

Routing

Rack::Cascade
Rack::Recursive
Rack::Static
Rack::URLMap

Rack::Contrib

http://github.com/rack/rack-contrib

Rack::AcceptFormat
Rack::Access
Rack::Backstage
Rack::Callbacks
Rack::Config
Rack::Cookies
Rack::CSSHTTPRequest
Rack::Deflect
Rack::Evil
Rack::HostMeta
Rack::JSONP
Rack::LighttpdScriptNameFix
Rack::Locale
Rack::MailExceptions
Rack::NestedParams
Rack::NotFound
Rack::ProcTitle
Rack::Profiler
Rack::ResponseCache
Rack::ResponseHeaders
Rack::RelativeRedirect
Rack::Signals
Rack::SimpleEndpoint
Rack::TimeZone

Coderack.org

Check also out http://coderack.org ...99 pieces of Rack Middleware

RailsGuide: Rails On Rack

http://guides.rubyonrails.org/rails_on_rack.html