LESS CSS FCGI script. Using this with a FastCGI server will mean you can serve your LESS files directly as CSS, compiling them on-the-fly as a request is made. Uses the content of the LESS source file to generate an Etag for Validation caching.

gistfile1.rb

#!/usr/bin/ruby

require 'fcgi'
require 'less'
require 'digest/sha1'

FCGI.each do |request|
  out = request.out
  source = File.new(request.env["SCRIPT_FILENAME"], 'r').read;
  hash = Digest::SHA1.hexdigest(source).inspect
  
#  if request.env["HTTP_IF_NONE_MATCH"] == hash
#    out.print request.env["SERVER_PROTOCOL"]+" 304 Not Modified\r\n"
#    out.print "\r\n"
#  else
    Dir.chdir File.dirname request.env["SCRIPT_FILENAME"]
    
    begin
      code = Less::Parser.new.parse(source).to_css :compress => true
    rescue Exception => err
      out.print request.env["SERVER_PROTOCOL"]+"500 Internal Server Error\r\nContent-Type: text/css\r\n\r\n/* * *\r\n"
      out.print err.message
      out.print "\r\n* * */"
    else
      out.print "Content-Type: text/css\r\n"
      out.print "Etag: "+hash+"\r\n"
      out.print "\r\n"
      out.print code
    end
  request.finish
end

19/09/2011: Removed 304 stuff, which was causing problems for me. Also made it do a chdir to the location of the LESS file, so @import works properly.

24/09/11: Made it report LESS parsing errors (in admittedly crappy way, compared to viewing errors with the lessc command-line tool), and enabled minification of the compiled CSS. (remove :compress => true from line 19 to disable)