Ben Orenstein is joined by Joe Ferris, CTO of thoughtbot, and Josh Clayton, developer at thoughtbot and the lead maintainer of FactoryGirl. In this Rails focused episode, Ben, Joe, and Josh dish on ActiveRecord callbacks, observers, state machines, and before_filters vs. middleware. They discuss the good, the bad, and the ugly of each, and how to keep your app clean while doing the right thing. Then they touch on what's new in FactoryGirl, how using build_stubbed can speed up your test suite, and much more. Rails Guide: Active Record Validations and Callbacks Rails Guide: Action Controller, Filters Blog post: Ruby and KISS, Sitting in a Tree Method Object Feature Envy Rack: a Ruby Webserver Interface Rails Guide: Rails on Rack Rack::Cache Blog post: Use Factory Girl’s build_stubbed for a Faster Test Suite Blog post: Mind-Bending Factories Metaprogramming in the Wild: Source-Diving FactoryGirl Follow @thoughtbot, @joeferris, and @joshuaclayton on twitter.