Private Rack middleware purpose is to protect your Rack application from anonymous via a secret code form.

A simple profiler for Rack applications, only depending on ActiveSupport::Notifications

Rack middleware used to automagically format your code blocks using pygmentize

Rack::RequestID is a Rack middleware for generating request IDs. It generates a request GUID for every request (if one was not already provided) and inserts the request ID as a response header.

Rescue Handler for Rack

This midleware allows an application to support multiple versions of a RESTful API following the best RESTful practices to encode the version information in the HTTP request. It's inspired by this article: http://barelyenough.org/blog/2008/05/versioning-rest-web-services/.

Adds an extra X-REVISION header with source code revision string (git, svn, etc)

Serve static files from S3 via Rack

Rack::Sanitizer is a Rack middleware which cleans up invalid UTF8 characters in request URI and headers.

Security related HTTP headers for Rack applications

Rack session store for Sequel

Slightly smarter session cookies for Rack 2 apps

A rack middleware to enforce appending or removing trailing slashes.

Simple Rack middleware which detect the request comes from smartphone

Not much to explain. Not a lot of code, but wanted it packaged up for easy use/deployment.

Rack middleware for building multi-protocol streaming rack endpoints

Rack middleware to remove cookies at user-defined paths.

Rack middleware to route requests with subdomains to specified routes with substitutions

Rack::TestApp is another testing helper library for Rack application. IMO it is more intuitive than Rack::Test.

Allow web service clients to specify the request time zone in an HTTP header.