if-modified-since造句

• The if - modified - since header , which specifies that the requested operation should be performed only if the requested resource has been modified since the indicated data and time
  If - modified - since标头，指定仅当自指示的数据和时间之后修改了请求的资源时，才执行请求的操作。
• Demonstrates how to send the last - modified response header and check for the if - modified - since request header to avoid generating a response body and transmitting data to the client unnecessarily
  说明如何发送last - modified响应标题并检查if - modified - since请求标题，以避免不必要地生成响应正文和将数据传输到客户端。