Rack is a Ruby web server interface specification that provides a minimal abstraction layer between web servers and web applications to handle HTTP requests and responses. It aims to standardize how web applications interface with servers so that server interfacing code only needs to be written once. The Rack specification defines a simple API for web applications to handle requests and responses that various web servers and frameworks can implement, reducing duplicated work.

1. Introducing Rack
Christian Neukirchen
Editor in Chief of Anarchaia

2. A Google Image Search
for “ruby rack” reveals:

3. Overview
• What is Rack?
• Why do we need Rack?
• The design of Rack
• The Rack distribution
• Coset: a RESTful Rack framework
• Real World Rack

4. What is Rack?
• Rack is a specification (and implementation)
of a minimal abstract Ruby API that models
HTTP

5. Why do we need Rack?
• Developing a Ruby web framework is
not hard…
• …but it’s lots of repetitive, boring work:
• Again, write interfaces to all the servers!
• Again, write decoding code or copy cgi.rb