def static!
      return if (public_dir = settings.public_folder).nil?
      public_dir = File.expand_path(public_dir)

      path = File.expand_path(public_dir + unescape(request.path_info))
      return unless path.start_with?(public_dir) and File.file?(path)

      env['sinatra.static_file'] = path
      cache_control(*settings.static_cache_control) if settings.static_cache_control?
      send_file path, :disposition => nil
    end
def static!
      return if (public_dir = settings.public_folder).nil?
      public_dir = File.expand_path(public_dir)

      path = File.expand_path(public_dir + unescape(request.path_info))
      return unless path.start_with?(public_dir) and File.file?(path)

      env['sinatra.static_file'] = path
      cache_control(*settings.static_cache_control) if settings.static_cache_control?
      send_file path, :disposition => nil
    end
Attempt to serve static files from public directory. Throws :halt when
 a matching file is found, returns nil otherwise.