Rack is the minimal, modular, and adaptable interface that Ruby frameworks like Rails and Sinatra are built on. Learn what makes Rack an adaptable interface for building Ruby applications and middleware, and then walk through a Rack application utilizing custom Rack middleware.
I gave this talk towards the end of my apprenticeship at 8th Light. I detail what Rack is and talk a little bit about how Ruby frameworks use it. I show how to build a Rack application featuring custom middleware, mounted Rack apps, static assets, OAuth with GitHub, user sessions, routing, and template rendering.
You can view the source code for the application here.