HTTP参考手册

状态 | Status

412 Precondition Failed

HTTP 412 Precondition Failed客户端错误响应代码指示对目标资源的访问已被拒绝。这种情况与上比其他方法条件请求GET或者HEAD当被定义的条件If-Unmodified-Since或If-None-Match头部不被满足。在这种情况下，无法进行请求（通常是上载或修改资源），并且发送此错误响应。

状态

412 Precondition Failed

规范

规范	标题
RFC 7232，第4.2节：412先决条件失败	超文本传输协议（HTTP / 1.1）：条件请求

浏览器兼容性

Feature	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari
Basic Support	(Yes)	(Yes)	(Yes)	(Yes)	(Yes)	(Yes)

Feature	Android	Chrome for Android	Edge mobile	Firefox for Android	IE mobile	Opera Android	iOS Safari
Basic Support	(Yes)	(Yes)	(Yes)	(Yes)	(Yes)	(Yes)	(Yes)

也可以看看

304

If-Unmodified-Since

If-None-Match

428

状态 | Status相关

1.100 Continue
2.101 Switching Protocols
3.200 OK
4.201 Created
5.202 Accepted
6.203 Non-Authoritative Information
7.204 No Content
8.205 Reset Content
9.206 Partial Content
10.300 Multiple Choices
11.301 Moved Permanently
12.302 Found
13.303 See Other
14.304 Not Modified
15.307 Temporary Redirect
16.308 Permanent Redirect
17.400 Bad Request
18.401 Unauthorized
19.403 Forbidden
20.404 Not Found
21.405 Method Not Allowed
22.406 Not Acceptable
23.407 Proxy Authentication Required
24.408 Request Timeout
25.409 Conflict
26.410 Gone
27.411 Length Required
28.413 Payload Too Large
29.414 URI Too Long
30.415 Unsupported Media Type
31.416 Range Not Satisfiable
32.417 Expectation Failed
33.426 Upgrade Required
34.428 Precondition Required
35.429 Too Many Requests
36.431 Request Header Fields Too Large
37.451 Unavailable For Legal Reasons
38.500 Internal Server Error
39.501 Not Implemented
40.502 Bad Gateway
41.503 Service Unavailable
42.504 Gateway Timeout
43.505 HTTP Version Not Supported
44.511 Network Authentication Required
45.Status

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。

HTTP目录

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