HTTP参考手册

标题 | Headers

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.

Header type	Response header
Forbidden header name	no

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

<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。

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

Specification	Title
RFC 7231, section 7.1.3: Retry-After	Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content

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.Accept
2.Accept-Charset
3.Accept-Encoding
4.Accept-Language
5.Accept-Ranges
6.Access-Control-Allow-Credentials
7.Access-Control-Allow-Headers
8.Access-Control-Allow-Methods
9.Access-Control-Allow-Origin
10.Access-Control-Expose-Headers
11.Access-Control-Max-Age
12.Access-Control-Request-Headers
13.Access-Control-Request-Method
14.Age
15.Allow
16.Authorization
17.Cache-Control
18.Connection
19.Content-Disposition
20.Content-Encoding
21.Content-Language
22.Content-Length
23.Content-Location
24.Content-Range
25.Content-Type
26.Cookie
27.Cookie2
28.Date
29.DNT
30.ETag
31.Expect
32.Expires
33.Forwarded
34.From
35.Headers
36.Host
37.If-Match
38.If-Modified-Since
39.If-None-Match
40.If-Range
41.If-Unmodified-Since
42.Keep-Alive
43.Large-Allocation
44.Last-Modified
45.Location
46.Origin
47.Pragma
48.Proxy-Authenticate
49.Proxy-Authorization
50.Public-Key-Pins
51.Public-Key-Pins-Report-Only
52.Range
53.Referer
54.Referrer-Policy
55.Server
56.Set-Cookie
57.Set-Cookie2
58.SourceMap
59.Strict-Transport-Security
60.TE
61.Tk
62.Trailer
63.Transfer-Encoding
64.Upgrade-Insecure-Requests
65.User-Agent
66.User-Agent: Firefox
67.Vary
68.Via
69.Warning
70.WWW-Authenticate
71.X-Content-Type-Options
72.X-DNS-Prefetch-Control
73.X-Forwarded-For
74.X-Forwarded-Host
75.X-Forwarded-Proto
76.X-Frame-Options
77.X-XSS-Protection

HTTP

超文本传输协议（ HTTP，HyperText Transfer Protocol ) 是互联网上应用最为广泛的一种网络协议。所有的 WWW 文件都必须遵守这个标准。

1.指南 \| Guides
2.指南：基础 \| Guides: Basics
3.CSP
4.标题 \| Headers
5.方法 \| Methods
6.RFC 2616: HTTP/1.1
7.RFC 4918: WebDAV
8.RFC 5023: The Atom Publishing Protocol
9.RFC 7230: Message Syntax and Routing
10.RFC 7231: Semantics and Content
11.RFC 7232: Conditional Requests
12.RFC 7233: Range Requests
13.RFC 7234: Caching
14.RFC 7235: Authentication
15.状态 \| Status
16.HTTP 请求方法
17.HTTP状态码
18.HTTP 响应头信息
19.HTTP 教程