HTTP request header information description

protocol header	illustrate	example	state
Accept	Acceptable response content types (Content-Types).	Accept: text/plain	fixed
Accept-Charset	Acceptable character set	Accept-Charset: utf-8	fixed
Accept-Encoding	Acceptable encodings for response content.	Accept-Encoding: gzip, deflate	fixed
Accept-Language	List of acceptable response content languages.	Accept-Language: en-US	fixed
Accept-Datetime	Acceptable response content versions expressed in terms of time	Accept-Datetime: Sat, 26 Dec 2015 17:30:00 GMT	temporary
Authorization	It is used to indicate the authentication information of resources that need to be authenticated in the HTTP protocol	Authorization: Basic OSdjJGRpbjpvcGVuIANlc2SdDE==	fixed
Cache-Control	Used to specify whether to use the cache mechanism in the current request/reply.	Cache-Control: no-cache	fixed
Connection	The connection type that the client (browser) wants to use preferentially	Connection: keep-alive Connection: Upgrade	fixed
Cookie	An HTTP protocol cookie set by the previous server via Set-Cookie (see below)	Cookie: $Version=1; Skin=new;	Fixed: Standard
Content-Length	The length of the request body expressed in octal	Content-Length: 348	fixed
Content-MD5	The binary MD5 hash (digital signature) of the content of the request body, the result encoded in Base64	Content-MD5: oD8dH2sgSW50ZWdyaIEd9D==	abandoned
Content-Type	The MIME type of the request body (used in POST and PUT requests)	Content-Type: application/x-www-form-urlencoded	fixed
Date	The date and time the message was sent (in the "HTTP Date" format defined in RFC 7231 )	Date: Dec, 26 Dec 2015 17:30:00 GMT	fixed
Expect	Indicates that the client requires the server to perform a specific action	Expect: 100-continue	fixed
From	The email address of the user who initiated this request	From: [email protected]	fixed
Host	Indicates the domain name of the server and the port number the server listens on. The port number can be omitted if the requested port is the standard port (80) of the corresponding service.	Host: www.itbilu.com:80 Host: www.itbilu.com	fixed
If-Match	The corresponding operation is only performed if the entity provided by the client matches the corresponding entity on the server. Primarily used in methods like PUT to update a resource only if it has not been modified since the user last updated it.	If-Match: "9jd00cdj34pss9ejqiw39d82f20d0ikd"	fixed
If-Modified-Since	Allows to return 304 Not Modified if the corresponding resource has not been modified	If-Modified-Since: Dec, 26 Dec 2015 17:30:00 GMT	fixed
If-None-Match	It is allowed to return 304 not modified ( 304 Not Modified ) if the corresponding content has not been modified, refer to the entity mark of the hypertext transfer protocol	If-None-Match: "9jd00cdj34pss9ejqiw39d82f20d0ikd"	fixed
If-Range	If the entity has not been modified, the missing part or parts are returned. Otherwise, return the whole new entity	If-Range: "9jd00cdj34pss9ejqiw39d82f20d0ikd"	fixed
If-Unmodified-Since	Only send a response if the entity has not been modified since a certain time.	If-Unmodified-Since: Dec, 26 Dec 2015 17:30:00 GMT	固定
Max-Forwards	限制该消息可被代理及网关转发的次数。	Max-Forwards: 10	固定
Origin	发起一个针对跨域资源共享的请求（该请求要求服务器在响应中加入一个Access-Control-Allow-Origin的消息头，表示访问控制所允许的来源）。	Origin: http://www.itbilu.com	固定: 标准
Pragma	与具体的实现相关，这些字段可能在请求/回应链中的任何时候产生。	Pragma: no-cache	固定
Proxy-Authorization	用于向代理进行认证的认证信息。	Proxy-Authorization: Basic IOoDZRgDOi0vcGVuIHNlNidJi2==	固定
Range	表示请求某个实体的一部分，字节偏移以0开始。	Range: bytes=500-999	固定
Referer	表示浏览器所访问的前一个页面，可以认为是之前访问页面的链接将浏览器带到了当前页面。Referer其实是Referrer这个单词，但RFC制作标准时给拼错了，后来也就将错就错使用Referer了。	Referer: http://itbilu.com/nodejs	固定
TE	浏览器预期接受的传输时的编码方式：可使用回应协议头Transfer-Encoding中的值（还可以使用"trailers"表示数据传输时的分块方式）用来表示浏览器希望在最后一个大小为0的块之后还接收到一些额外的字段。	TE: trailers,deflate	固定
User-Agent	浏览器的身份标识字符串	User-Agent: Mozilla/……	固定
Upgrade	要求服务器升级到一个高版本协议。	Upgrade: HTTP/2.0, SHTTP/1.3, IRC/6.9, RTA/x11	固定
Via	告诉服务器，这个请求是由哪些代理发出的。	Via: 1.0 fred, 1.1 itbilu.com.com (Apache/1.1)	固定
Warning	一个一般性的警告，表示在实体内容体中可能存在错误。	Warning: 199 Miscellaneous warning	固定