becomes casts an ActiveRecord record to a different STI class so Rails can treat it as another type, while both instances share the same attributes.

Artifice allows you to replace the Net::HTTP subsystem of Ruby with an equivalent that routes all requests to a Rack application.

You can use Sinatra, raw Rack, or even Rails as your application, allowing you to build up an equivalent to the remote service you are mocking out using familiar and convenient tools to route requests and build up responses.

mitmproxy is an SSL-capable, intercepting HTTP proxy. It provides a console interface that allows traffic flows to be inspected and edited on the fly.

Rails 2 and some Rails 3.x versions let chained scopes overwrite hash conditions on the same attribute, creating authorization leaks. chain_safely avoids that overwrite.

Unexplained whitespace at the top of a page can come from a BOM in one of the rendered views; saving the file without a BOM removes it.

Imperative and declarative user-story scenarios suit different situations; declarative phrasing offers advantages in RSpec Story Runner and Cucumber testing.

Google’s Font Directory and API for web fonts could have a transformative effect on how we read the web. The only problem is, Google has made it very difficult to download all of the actual font files.

Web designers must be free to experiment with these new fonts, to sketch, comp and get to know these typefaces in browser and non-browser applications. This is why I’m providing this archive.

Use hash_including in RSpec to verify a hash or method call contains only the expected key-value pairs without matching the full structure.

Different styling for Internet Explorer can be generated with Sass variables and conditional imports without relying on CSS hacks.

ActionMailer can send empty messages when recipient arrays are generated dynamically; overriding deliver! prevents delivery when to, cc, and bcc are all blank.

tetex is no longer supported on Ubuntu 10.10; texlive provides a supported LaTeX installation via apt-get.

Rails startup can fail with a NameError when version_requirements is missing on Rails::GemDependency; a small environment.rb patch restores compatibility with newer RubyGems.

Capybara now includes an RSpec acceptance-testing DSL, replacing much of Steak’s earlier role and making end-to-end testing in RSpec more seamless.

Liquid Canvas is a JavaScript library which allows you to draw inside an HTML canvas element with an easy yet powerful description language.

It can be used to add graphics to your web page without ever touching an image creation tool such as The Gimp, Inkscape or Photoshop.

Check out the Demo and the basic example and then download version 0.3.

Rails can fail to boot after a Bundler upgrade when the new YAML engine cannot handle symbol values in localization files.

Upgrading Ubuntu from Ruby 1.8.7 to 1.9.2 can break Rails 2 apps using RSpec and removes installed gems, but Bundler can restore dependencies.

PhantomJS is a minimalistic headless WebKit.

It has fast and native support for various web standards:

DOM handling, CSS selector, JSON, Canvas, and SVG.

PhantomJS can be fully scripted using JavaScript. It is an optimal solution for headless testing of web-based applications, site scraping, pages capture, SVG renderer, PDF converter and many other usages.

Changing a persisted association can leave cached counts inconsistent; freezing an ActiveRecord foreign key prevents updates that would otherwise require extra bookkeeping.

ActiveRecord#touch updates updated_at but also triggers callbacks and validations, making frequent timestamp updates expensive. touch_gently and touch_all_gently refresh timestamps without callbacks.

Blueprint inspects installed packages, changed config files, and locally built software to generate Puppet, Chef, or shell code from an Ubuntu system state.

List of global variables available to a Ruby script.

Rails 2-compatible versions of Cucumber, Capybara, and related gems avoid breakage from newer dependencies and Capybara API changes.