global

def asset_url(path, prefix="", request=nil)
  http_path = pre_cache_buster_asset_url(path, prefix, request)
  
  if http_path.include?("://") || !%w(.css .png .jpg .js .gif).include?(File.extname(http_path))
    http_path
  else
    begin
      prefix = self.images_dir if prefix == self.http_images_path
    rescue
    end
    
    real_path = File.join(self.public, prefix, path)
    http_path << "?" + File.mtime(real_path).strftime("%s") if File.readable?(real_path)
    http_path
  end
end