# File lib/rack/static.rb, line 109
    def call(env)
      path = env[PATH_INFO]

      if can_serve(path)
        env["PATH_INFO"] = (path =~ /\/$/ ? path + @index : @urls[path]) if overwrite_file_path(path)
        path = env["PATH_INFO"]
        response = @file_server.call(env)

        headers = response[1]
        applicable_rules(path).each do |rule, new_headers|
          new_headers.each { |field, content| headers[field] = content }
        end

        response
      else
        @app.call(env)
      end
    end