Ruby adapter for github.com/css/csso.
CSSO does structure-optimization for CSS. CSS is usually reduced more than in half in uncompressed and around 15% in gzipped.
A living rails application CSS – some written in less, some handwritten):
| Original | sass | yui 2.4.7 | csso | % of original | |
|---|---|---|---|---|---|
| Plain | 129497 | 107006 | 60758 | 60874 | 47% |
| GZipped | 14046 | 12047 | 10558 | 10472 | 74% |
Very close to yui compressor, wining in gzipped (you’re using nginx mod\_gzip_static, don’t you?)
A more hard example – twitter bootstrap.css, already minified:
| Original | lessc | yui 2.4.7 | csso | % of original | |
|---|---|---|---|---|---|
| Plain | 81443 | 71520 | 68755 | 67679 | 83% |
| GZipped | 12384 | 11633 | 11652 | 11477 | 92% |
Please note than benchmark was taken in summer of 2012, since then things may have changed.
Add gem 'csso-rails' to your gemfile, and that’s it!
(also you may want to add some javascript runtime for ExecJS to pick up, like gem 'therubyracer')
Upon including it becomes the default compressor even if sass is included too.
More explicit way – set in config/environment/production.rb:
config.assets.css_compressor = :cssoIf you use Sprockets without Rails:
require 'csso'
Csso.install(sprockets_env)require 'csso'
puts Csso.optimize("a{ color: #FF0000; }") # produces "a{color:red}"In maniac mode (Csso.optimize(css, true), default for pipeline) CSS is processed several times until it stops getting lighter (there're cases when original csso does not do all optimizations for no reason).
ruby_csso non_optimized.css > optimized.css
Original CSSO code - Copyright (C) 2011 by Sergey Kryzhanovsky.
ruby gem - Copyright(C) 2012 Vasily Fedoseyev
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