Sprockets precompile Rake task

sprockets.rake

namespace :assets do
  require 'sprockets'
  require 'uglifier'
  require 'yui/compressor'
  sprockets = Sprockets::Environment.new { |env| env.logger = Logger.new(STDOUT) }
  sprockets.css_compressor = YUI::CssCompressor.new
  sprockets.js_compressor = :uglifier
  sprockets.append_path File.expand_path('../lib/web/assets', __FILE__)

  output_path = File.expand_path('../lib/web/public', __FILE__)

  task :precompile_css do
    asset = sprockets['styles.css']
    outfile = Pathname.new(output_path).join('css/styles.css')
    FileUtils.mkdir_p outfile.dirname
    asset.write_to(outfile)
    puts "successfully compiled css assets"
  end

  task :precompile_img do
    image_path = File.join(output_path, 'img')
    FileUtils.mkdir_p(image_path)
    Dir.glob(File.expand_path("../lib/web/assets/img/*", __FILE__)).each do |f|
      FileUtils.cp(f, image_path)
      sprockets.logger.debug("Copied #{File.basename(f)}")
    end
    puts "successfully copied images"
  end

  task :precompile_js do
    asset = sprockets['app.js']
    outfile = Pathname.new(output_path).join('js/app.js')
    FileUtils.mkdir_p outfile.dirname
    asset.write_to(outfile)
    puts "successfully compiled javascript assets"
  end

  desc 'precompile all assets'
  task :precompile => [:precompile_css, :precompile_img, :precompile_js]
end