class Sinatra::Base

def static!

a matching file is found, returns nil otherwise.
Attempt to serve static files from public directory. Throws :halt when 
def static!
  return if (public_dir = settings.public).nil?
  public_dir = File.expand_path(public_dir)
  path = File.expand_path(public_dir + unescape(request.path_info))
  return if path[0, public_dir.length] != public_dir
  return unless File.file?(path)
  env['sinatra.static_file'] = path
  send_file path, :disposition => nil
end