jammit.rake

require "digest/md5"

namespace :jammit do
  
  desc "Lock packages to md5sum"
  task :lock do
    srcdir = File.join(Rails.root, "public", "packages")
    dstdir = File.join(Rails.root, "public", "cache")
    lockfile = File.join(Rails.root, "config", "assets.yml.lock")
    locks = {}
    Dir.new(srcdir).each do |file|
      if file =~ /\.(css|js|gz)/
        hash = Digest::MD5.hexdigest(File.join(srcdir, file))
        locks[file] = hash
        FileUtils.mkdir_p(File.join(dstdir, hash))
        File.symlink(File.join(srcdir, file), File.join(dstdir, hash, file))
      end
    end
    File.open(lockfile, "w") do |file|
      file.puts locks.to_yaml
    end
  end
  
  
end

jammit.rb

module Jammit

  HASHES = YAML.load_file(File.join(Rails.root, "config", "assets.yml.lock")) || {}

  def self.asset_url(package, extension, suffix=nil, mtime=nil)
    file = filename(package, extension, suffix)
    hash = HASHES[file]
    "/cache/#{hash}/#{file}"
  end

end