Jekyll plugin to render LESS CSS

lessjs.rb

# encoding: utf-8

require 'jekyll/utils'
require 'open3'

# The official Node.JS `lessc` binary needs to be availible in the shell.
# `less_dir` defaults to `_less` but can be changed in `_config.yml`.
module Jekyll
  class LessConverter < Converter
    safe true
    priority :low

    def matches(ext)
      ext =~ /less|lcss/i
    end

    def output_ext(ext)
      ".css"
    end

    def convert(content)
      include_path = @config["less_dir"] || "_less"
      begin
        converted, status = Open3.capture2('lessc',
                                           "--include-path=#{include_path}",
                                           '-', # Use STDIN
                                           :stdin_data=>content)

        raise "LESS compilation error" if status.to_i != 0

        return converted
      end
    end
  end
end