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personnages

Retry-After响应的 HTTP 报头指示所述用户代理应该多长时间使一个后续请求之前等待。有两种主要的情况使用这个头文件:

  • When sent with a 503 (Service Unavailable) response, it indicates how long the service is expected to be unavailable.

  • 当使用重定向响应(如301永久移动)发送时,它表示用户代理在发出重定向请求之前要求等待的最短时间。

Header type

Response header

Forbidden header name

no

句法

Retry-After: <http-date>Retry-After: <delay-seconds>

指令

<http-date> 之后重试的日期。有关DateHTTP 日期格式的更多详细信息,请参阅标头。<delay-seconds> 一个非负十进制整数,表示接收到响应后的延迟秒数。

例子

处理预定的停机时间

Retry-After对客户端和服务器上的标头的支持仍然不一致。但是,像 Googlebot 这样的一些抓取工具和抓取工具可以很好地尊重Retry-After标题。将它与503(服务不可用)响应一起发送是非常有用的,这样当停机时间结束时,搜索引擎将继续为您的站点编制索引。

Retry-After: Wed, 21 Oct 2015 07:28:00 GMT
Retry-After: 120

产品规格

Specification

Title

RFC 7231, section 7.1.3: Retry-After

Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content

浏览器兼容性

Feature

Chrome

Edge

Firefox

Internet Explorer

Opera

Safari

Basic Support

?

(Yes)

No1

?

?

?

Feature

Android

Chrome for Android

Edge mobile

Firefox for Android

IE mobile

Opera Android

iOS Safari

Basic Support

?

?

(Yes)

?

?

?

?

  1. 见错误230260。参阅

  • Google 网站管理员博客:如何处理计划的网站停机时间

  • 503 (暂停服务)

  • 301 (永久移动)

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