header fields 详解

参考

List of HTTP header fields

翻译

标准要求字段

字段名	说明	例子	状态
A-IM	可接受实例操作的请求	A-IM: feed	永久的
Accept	对于响应来说是(/是)可接受的媒体类型。看到内容协商。	Accept: text/html	永久的
Accept-Charset	可接受的字符集。	Accept-Charset: utf-8	永久的
Accept-Datetime	可接受的版本。	Accept-Datetime: Thu, 31 May 2007 20:35:00 GMT	临时的
Accept-Encoding	可接受的编码列表。看到HTTP压缩。	Accept-Encoding: gzip, deflate	永久的
Accept-Language	可接受的人类语言列表。看到内容协商。	Accept-Language: en-US	永久的
Access-Control-Request-Method Access-Control-Request-Headers[8]	启动与Origin共享跨源资源的请求(如下所示)。	Access-Control-Request-Method: GET	永久的
Authorization	HTTP身份验证的身份验证凭据。	Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==	永久的
Cache-Control	用于指定沿着请求-响应链的所有缓存机制必须遵守的指令。	Cache-Control: no-cache	永久的
Connection	当前连接的控制选项和逐跳请求字段的列表。	Connection: keep-alive Connection: Upgrade	永久的
Content-Length	请求体的长度(8位字节)。	Content-Length: 348	永久的
Content-MD5	请求体内容的一种base64编码的二进制MD5的和。	Content-MD5: Q2hlY2sgSW50ZWdyaXR5IQ==	废弃的
Content-Type	请求主体的媒体类型(与POST和PUT请求一起使用)。	Content-Type: application/x-www-form-urlencoded	永久的
Cookie	先前服务器通过Set-Cookie发送的HTTP cookie(如下所示)。	Cookie: $Version=1; Skin=new;	永久的
Date	消息发出的日期和时间(以RFC 7231日期/时间格式定义的“HTTP-date”格式)。	Date: Tue, 15 Nov 1994 08:12:31 GMT	永久的
Expect	指示客户端需要特定的服务器行为。	Expect: 100-continue	永久的
Forwarded	通过HTTP代理.公开连接到web服务器的客户机的原始信息	Forwarded: for=192.0.2.60;proto=http;by=203.0.113.43 Forwarded: for=192.0.2.43, for=198.51.100.17	永久的
From	发出请求的用户的电子邮件地址。	From: [email protected]	永久的
Host	主机	Host: en.wikipedia.org:8080 Host: en.wikipedia.org	永久的
If-Match	只有当客户机提供的实体与服务器上的相同实体匹配时，才执行该操作。这主要是针对像PUT to这样的方法，如果资源在用户上次更新后没有被修改，则只更新它。	If-Match: “737060cd8c284d8af7ad3082f209582d”	永久的
If-Modified-Since	如果内容不变，则允许返回未修改的304。	If-Modified-Since: Sat, 29 Oct 1994 19:43:31 GMT	永久的
If-None-Match	如果内容不变，允许返回不修改的304，请参阅HTTP ETag。	If-None-Match: “737060cd8c284d8af7ad3082f209582d”	永久的
If-Range	如果实体不变，请将我遗漏的部分发送给我;否则，将整个新实体发送给我。	If-Range: “737060cd8c284d8af7ad3082f209582d”	永久的
If-Unmodified-Since	Only send the response if the entity has not been modified since a specific time.	If-Unmodified-Since: Sat, 29 Oct 1994 19:43:31 GMT	永久的
Max-Forwards	Limit the number of times the message can be forwarded through proxies or gateways.	Max-Forwards: 10	永久的
Origin[8]	Initiates a request for cross-origin resource sharing (asks server for Access-Control-* response fields).	Origin: http://www.example-social-network.com	永久的
Pragma	Implementation-specific fields that may have various effects anywhere along the request-response chain.	Pragma: no-cache	永久的
Proxy-Authorization	Authorization credentials for connecting to a proxy.	Proxy-Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==	永久的
Range	Request only part of an entity. Bytes are numbered from 0. See Byte serving.	Range: bytes=500-999	永久的
Referer [sic]	This is the address of the previous web page from which a link to the currently requested page was followed. (The word “referrer” has been misspelled in the RFC as well as in most implementations to the point that it has become standard usage and is considered correct terminology)	Referer: http://en.wikipedia.org/wiki/Main_Page	永久的
TE	The transfer encodings the user agent is willing to accept: the same values as for the response header field Transfer-Encoding can be used, plus the “trailers” value (related to the “chunked” transfer method) to notify the server it expects to receive additional fields in the trailer after the last, zero-sized, chunk.Only trailers is supported in HTTP/2.	TE: trailers, deflate	永久的
Upgrade	Ask the server to upgrade to another protocol. Must not be used in HTTP/2.	Upgrade: h2c, HTTPS/1.3, IRC/6.9, RTA/x11, websocket	永久的
User-Agent	The user agent string of the user agent.	User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20100101 Firefox/12.0	永久的
Via	Informs the server of proxies through which the request was sent.	Via: 1.0 fred, 1.1 example.com (Apache/1.1)	永久的
Warning	A general warning about possible problems with the entity body.	Warning: 199 Miscellaneous warning	永久的

常见的非标准要求字段

Field name	Description	Example
Upgrade-Insecure-Requests	Tells a server which (presumably in the middle of a HTTP -> HTTPS migration) hosts mixed content that the client would prefer redirection to HTTPS and can handle Content-Security-Policy: upgrade-insecure-requests Must not be used with HTTP/2	Upgrade-Insecure-Requests: 1
X-Requested-With	Mainly used to identify Ajax requests. Most JavaScript frameworks send this field with value of XMLHttpRequest	X-Requested-With: XMLHttpRequest
DNT	Requests a web application to disable their tracking of a user. This is Mozilla’s version of the X-Do-Not-Track header field (since Firefox 4.0 Beta 11). Safari and IE9 also have support for this field. On March 7, 2011, a draft proposal was submitted to IETF.[18] The W3C Tracking Protection Working Group is producing a specification.	DNT: 1 (Do Not Track Enabled) DNT: 0 (Do Not Track Disabled)
X-Forwarded-For	A de facto standard for identifying the originating IP address of a client connecting to a web server through an HTTP proxy or load balancer. Superseded by Forwarded header.	X-Forwarded-For: client1, proxy1, proxy2
X-Forwarded-Host	A de facto standard for identifying the original host requested by the client in the Host HTTP request header, since the host name and/or port of the reverse proxy (load balancer) may differ from the origin server handling the request. Superseded by Forwarded header.	X-Forwarded-Host: en.wikipedia.org:8080 X-Forwarded-Host: en.wikipedia.org
X-Forwarded-Proto	A de facto standard for identifying the originating protocol of an HTTP request, since a reverse proxy (or a load balancer) may communicate with a web server using HTTP even if the request to the reverse proxy is HTTPS. An alternative form of the header (X-ProxyUser-Ip) is used by Google clients talking to Google servers. Superseded by Forwarded header.	X-Forwarded-Proto: https
Front-End-Https	Non-standard header field used by Microsoft applications and load-balancers	Front-End-Https: on
X-Http-Method-Override	Requests a web application to override the method specified in the request (typically POST) with the method given in the header field (typically PUT or DELETE). This can be used when a user agent or firewall prevents PUT or DELETE methods from being sent directly (note that this is either a bug in the software component, which ought to be fixed, or an intentional configuration, in which case bypassing it may be the wrong thing to do).	X-HTTP-Method-Override: DELETE
X-ATT-DeviceId	Allows easier parsing of the MakeModel/Firmware that is usually found in the User-Agent String of AT&T Devices	X-Att-Deviceid: GT-P7320/P7320XXLPG
X-Wap-Profile	Links to an XML file on the Internet with a full description and details about the device currently connecting. In the example to the right is an XML file for an AT&T Samsung Galaxy S2.	x-wap-profile: http://wap.samsungmobile.com/uaprof/SGH-I777.xml
Proxy-Connection	Implemented as a misunderstanding of the HTTP specifications. Common because of mistakes in implementations of early HTTP versions. Has exactly the same functionality as standard Connection field.Must not be used with HTTP/2.[10]	Proxy-Connection: keep-alive
X-UIDH	Server-side deep packet insertion of a unique ID identifying customers of Verizon Wireless; also known as “perma-cookie” or “supercookie”	X-UIDH: …
X-Csrf-Token	Used to prevent cross-site request forgery. Alternative header names are: X-CSRFToken[32] and X-XSRF-TOKEN[33]	X-Csrf-Token: i8XNjC4b8KVok4uw5RftR38Wgp2BFwql
X-Request-ID X-Correlation-ID	Correlates HTTP requests between a client and server.	X-Request-ID: f058ebd6-02f7-4d3f-942e-904344e8cde5
Save-Data	The Save-Data client hint request header available in Chrome, Opera, and Yandex browsers lets developers deliver lighter, faster applications to users who opt-in to data saving mode in their browser.	Save-Data: on

标准回复字段

Field name	Description	Example	Status
Access-Control-Allow-Origin Access-Control-Allow-Credentials Access-Control-Expose-Headers Access-Control-Max-Age Access-Control-Allow-Methods Access-Control-Allow-Headers	Specifying which web sites can participate in cross-origin resource sharing	Access-Control-Allow-Origin: *	Permanent: standard
Accept-Patch	Specifies which patch document formats this server supports	Accept-Patch: text/example;charset=utf-8	Permanent
Accept-Ranges	What partial content range types this server supports via byte serving	Accept-Ranges: bytes	Permanent
Age	The age the object has been in a proxy cache in seconds	Age: 12	Permanent
Allow	Valid methods for a specified resource. To be used for a 405 Method not allowed	Allow: GET, HEAD	Permanent
Alt-Svc	A server uses “Alt-Svc” header (meaning Alternative Services) to indicate that its resources can also be accessed at a different network location (host or port) or using a different protocol
When using HTTP/2, servers should instead send an ALTSVC frame. [40]
Alt-Svc: http/1.1=”http2.example.com:8001”; ma=7200	Permanent
Cache-Control	Tells all caching mechanisms from server to client whether they may cache this object. It is measured in seconds	Cache-Control: max-age=3600	Permanent
Connection	Control options for the current connection and list of hop-by-hop response fields.[9]
Must not be used with HTTP/2.[10]
Connection: close	Permanent
Content-Disposition[41]	An opportunity to raise a “File Download” dialogue box for a known MIME type with binary format or suggest a filename for dynamic content. Quotes are necessary with special characters.	Content-Disposition: attachment; filename=”fname.ext”	Permanent
Content-Encoding	The type of encoding used on the data. See HTTP compression.	Content-Encoding: gzip	Permanent
Content-Language	The natural language or languages of the intended audience for the enclosed content[42]	Content-Language: da	Permanent
Content-Length	The length of the response body in octets (8-bit bytes)	Content-Length: 348	Permanent
Content-Location	An alternate location for the returned data	Content-Location: /index.htm	Permanent
Content-MD5	A Base64-encoded binary MD5 sum of the content of the response	Content-MD5: Q2hlY2sgSW50ZWdyaXR5IQ==	Obsolete[11]
Content-Range	Where in a full body message this partial message belongs	Content-Range: bytes 21010-47021/47022	Permanent
Content-Type	The MIME type of this content	Content-Type: text/html; charset=utf-8	Permanent
Date	The date and time that the message was sent (in “HTTP-date” format as defined by RFC 7231) [43]	Date: Tue, 15 Nov 1994 08:12:31 GMT	Permanent
Delta-Base	Specifies the delta-encoding entity tag of the response[7].	Delta-Base: “abc”	Permanent
ETag	An identifier for a specific version of a resource, often a message digest	ETag: “737060cd8c284d8af7ad3082f209582d”	Permanent
Expires	Gives the date/time after which the response is considered stale (in “HTTP-date” format as defined by RFC 7231)	Expires: Thu, 01 Dec 1994 16:00:00 GMT	Permanent: standard
IM	Instance-manipulations applied to the response[7].	IM: feed	Permanent
Last-Modified	The last modified date for the requested object (in “HTTP-date” format as defined by RFC 7231)	Last-Modified: Tue, 15 Nov 1994 12:45:26 GMT	Permanent
Link	Used to express a typed relationship with another resource, where the relation type is defined by RFC 5988	Link: ; rel=”alternate”[44]	Permanent
Location	Used in redirection, or when a new resource has been created.
Example 1: Location: http://www.w3.org/pub/WWW/People.html
Example 2: Location: /pub/WWW/People.html
Permanent
P3P	This field is supposed to set P3P policy, in the form of P3P:CP=”your_compact_policy”. However, P3P did not take off,[45] most browsers have never fully implemented it, a lot of websites set this field with fake policy text, that was enough to fool browsers the existence of P3P policy and grant permissions for third party cookies.	P3P: CP=”This is not a P3P policy! See https://en.wikipedia.org/wiki/Special:CentralAutoLogin/P3P for more info.”	Permanent
Pragma	Implementation-specific fields that may have various effects anywhere along the request-response chain.	Pragma: no-cache	Permanent
Proxy-Authenticate	Request authentication to access the proxy.	Proxy-Authenticate: Basic	Permanent
Public-Key-Pins[46]	HTTP Public Key Pinning, announces hash of website’s authentic TLS certificate	Public-Key-Pins: max-age=2592000; pin-sha256=”E9CZ9INDbd+2eRQozYqqbQ2yXLVKB9+xcprMF+44U1g=”;	Permanent
Retry-After	If an entity is temporarily unavailable, this instructs the client to try again later. Value could be a specified period of time (in seconds) or a HTTP-date.[47]
Example 1: Retry-After: 120
Example 2: Retry-After: Fri, 07 Nov 2014 23:59:59 GMT
Permanent
Server	A name for the server	Server: Apache/2.4.1 (Unix)	Permanent
Set-Cookie	An HTTP cookie	Set-Cookie: UserID=JohnDoe; Max-Age=3600; Version=1	Permanent: standard
Strict-Transport-Security	A HSTS Policy informing the HTTP client how long to cache the HTTPS only policy and whether this applies to subdomains.	Strict-Transport-Security: max-age=16070400; includeSubDomains	Permanent: standard
Trailer	The Trailer general field value indicates that the given set of header fields is present in the trailer of a message encoded with chunked transfer coding.	Trailer: Max-Forwards	Permanent
Transfer-Encoding	The form of encoding used to safely transfer the entity to the user. Currently defined methods are: chunked, compress, deflate, gzip, identity.
Must not be used with HTTP/2.[10]
Transfer-Encoding: chunked	Permanent
Tk	Tracking Status header, value suggested to be sent in response to a DNT(do-not-track), possible values: ` “!” — nder construction
“?” — dynamic
“G” — gateway to multiple parties
“N” — not tracking
“T” — tracking
“C” — tracking with consent
“P” — tracking only if consented
“D” — disregarding DNT
“U” — updated
Tk: ?	Permanent
Upgrade	Ask the client to upgrade to another protocol.
Must not be used in HTTP/2[10]
Upgrade: h2c, HTTPS/1.3, IRC/6.9, RTA/x11, websocket	Permanent
Vary	Tells downstream proxies how to match future request headers to decide whether the cached response can be used rather than requesting a fresh one from the origin server.
Example 1: Vary: *
Example 2: Vary: Accept-Language
Permanent
Via	Informs the client of proxies through which the response was sent.	Via: 1.0 fred, 1.1 example.com (Apache/1.1)	Permanent
Warning	A general warning about possible problems with the entity body.	Warning: 199 Miscellaneous warning	Permanent
WWW-Authenticate	Indicates the authentication scheme that should be used to access the requested entity.	WWW-Authenticate: Basic	Permanent
X-Frame-Options[48]	Clickjacking protection: deny - no rendering within a frame, sameorigin - no rendering if origin mismatch, allow-from - allow from specified location, allowall - non-standard, allow from any location	X-Frame-Options: deny	Obsolete[49]

常见的非标准响应领域

Field name	Description	Example
Content-Security-Policy,
X-Content-Security-Policy,
X-WebKit-CSP[50]	Content Security Policy definition.	X-WebKit-CSP: default-src ‘self’
Refresh	Used in redirection, or when a new resource has been created. This refresh redirects after 5 seconds. Header extension introduced by Netscape and supported by most web browsers.	Refresh: 5; url=http://www.w3.org/pub/WWW/People.html
Status	CGI header field specifying the status of the HTTP response. Normal HTTP responses use a separate “Status-Line” instead, defined by RFC 7230.[51]	Status: 200 OK
Timing-Allow-Origin	The Timing-Allow-Origin response header specifies origins that are allowed to see values of attributes retrieved via features of the Resource Timing API, which would otherwise be reported as zero due to cross-origin restrictions.[52]	Timing-Allow-Origin: *
Timing-Allow-Origin: [, ]*
X-Content-Duration[53]	Provide the duration of the audio or video in seconds; only supported by Gecko browsers	X-Content-Duration: 42.666
X-Content-Type-Options[54]	The only defined value, “nosniff”, prevents Internet Explorer from MIME-sniffing a response away from the declared content-type. This also applies to Google Chrome, when downloading extensions.[55]	X-Content-Type-Options: nosniff[56]
X-Powered-By[57]	Specifies the technology (e.g. ASP.NET, PHP, JBoss) supporting the web application (version details are often in X-Runtime, X-Version, or X-AspNet-Version)	X-Powered-By: PHP/5.4.0
X-Request-ID,
X-Correlation-ID[34]	Correlates HTTP requests between a client and server.	X-Request-ID: f058ebd6-02f7-4d3f-942e-904344e8cde5
X-UA-Compatible[58]	Recommends the preferred rendering engine (often a backward-compatibility mode) to use to display the content. Also used to activate Chrome Frame in Internet Explorer.	X-UA-Compatible: IE=EmulateIE7
X-UA-Compatible: IE=edge
X-UA-Compatible: Chrome=1
X-XSS-Protection[59]	Cross-site scripting (XSS) filter	X-XSS-Protection: 1; mode=block