class ActionDispatch::Static

def call(env)
  path   = env['PATH_INFO'].chomp('/')
  method = env['REQUEST_METHOD']
  if FILE_METHODS.include?(method)
    if file_exist?(path)
      return @file_server.call(env)
    else
      cached_path = directory_exist?(path) ? "#{path}/index" : path
      cached_path += ::ActionController::Base.page_cache_extension
      if file_exist?(cached_path)
        env['PATH_INFO'] = cached_path
        return @file_server.call(env)
      end
    end
  end
  @app.call(env)
end