List of HTTP header fields（http标头列表）

List of HTTP header fields(http标头列表）

Requests

Field name	Description	Example
Accept	Content-Types that are acceptable	Accept: text/plain
Accept-Charset	Character sets that are acceptable	Accept-Charset: utf-8
Accept-Encoding	Acceptable encodings. See HTTP compression.	Accept-Encoding: gzip, deflate
Accept-Language	Acceptable languages for response	Accept-Language: en-US
Accept-Datetime	Acceptable version in time	Accept-Datetime: Thu, 31 May 2007 20:35:00 GMT
Authorization	Authentication credentials for HTTP authentication	Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==
Cache-Control	Used to specify directives that MUST be obeyed by all caching mechanisms along the request/response chain	Cache-Control: no-cache
Connection	What type of connection the user-agent would prefer	Connection: keep-alive
Cookie	an HTTP cookie previously sent by the server with Set-Cookie (below)	Cookie: $Version=1; Skin=new;
Content-Length	The length of the request body in octets (8-bit bytes)	Content-Length: 348
Content-MD5	A Base64-encoded binary MD5 sum of the content of the request body	Content-MD5: Q2hlY2sgSW50ZWdyaXR5IQ==
Content-Type	The MIME type of the body of the request (used with POST and PUT requests)	Content-Type: application/x-www-form-urlencoded
Date	The date and time that the message was sent	Date: Tue, 15 Nov 1994 08:12:31 GMT
Expect	Indicates that particular server behaviors are required by the client	Expect: 100-continue
From	The email address of the user making the request	From: user@example.com
Host	The domain name of the server (for virtual hosting), and theTCP port number on which the server is listening. The portnumber may be omitted if the port is the standard port for the service requested.[5] Mandatory since HTTP/1.1. Although domain name are specified as case-insensitive,[6][7] it is not specified whether the contents of the Host field should be interpreted in a case-insensitive manner[8] and in practice some implementations of virtual hosting interpret the contents of the Host field in a case-sensitive manner.[citation needed]	Host: en.wikipedia.org:80Host: en.wikipedia.org
If-Match	Only perform the action if the client supplied entity matches the same entity on the server. This is mainly for methods like PUT to only update a resource if it has not been modified since the user last updated it.	If-Match: "737060cd8c284d8af7ad3082f209582d"
If-Modified-Since	Allows a 304 Not Modified to be returned if content is unchanged	If-Modified-Since: Sat, 29 Oct 1994 19:43:31 GMT
If-None-Match	Allows a 304 Not Modified to be returned if content is unchanged, see HTTP ETag	If-None-Match: "737060cd8c284d8af7ad3082f209582d"
If-Range	If the entity is unchanged, send me the part(s) that I am missing; otherwise, send me the entire new entity	If-Range: "737060cd8c284d8af7ad3082f209582d"
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
Max-Forwards	Limit the number of times the message can be forwarded through proxies or gateways.	Max-Forwards: 10
Pragma	Implementation-specific headers that may have various effects anywhere along the request-response chain.	Pragma: no-cache
Proxy-Authorization	Authorization credentials for connecting to a proxy.	Proxy-Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==
Range	Request only part of an entity. Bytes are numbered from 0.	Range: bytes=500-999
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” is misspelled in the RFC as well as in most implementations.)	Referer: http://en.wikipedia.org/wiki/Main_Page
TE	The transfer encodings the user agent is willing to accept: the same values as for the response header Transfer-Encoding can be used, plus the "trailers" value (related to the "chunked" transfer method) to notify the server it expects to receive additional headers (the trailers) after the last, zero-sized, chunk.	TE: trailers, deflate
Upgrade	Ask the server to upgrade to another protocol.	Upgrade: HTTP/2.0, SHTTP/1.3, IRC/6.9, RTA/x11
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
Via	Informs the server of proxies through which the request was sent.	Via: 1.0 fred, 1.1 example.com (Apache/1.1)
Warning	A general warning about possible problems with the entity body.	Warning: 199 Miscellaneous warning

[edit]Common non-standard request headers

Non-standard header fields were conventionally marked by prefixing the field name with X- .^[9] However, this convention became deprecated in June 2012 due to the inconveniences it caused when non-standard headers then became standard.^[10] For example, X-Gzip and Gzip are now both supported headers for compressed HTTP requests and responses.

Field name	Description	Example
X-Requested-With	mainly used to identify Ajax requests. Most JavaScript frameworks send this header with value ofXMLHttpRequest	X-Requested-With: XMLHttpRequest
DNT[11]	Requests a web application to disable their tracking of a user. This is Mozilla's version of the X-Do-Not-Track header (since Firefox 4.0 Beta 11). Safari and IE9 also have support for this header.[12] On March 7, 2011, a draft proposal was submitted to IETF.[13] The W3CTracking Protection Working Group is producing a specification.[14]	DNT: 1 (Do Not Track Enabled)DNT: 0 (Do Not Track Disabled)
X-Forwarded-For[15]	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	X-Forwarded-For: client1, proxy1, proxy2X-Forwarded-For: 129.78.138.66, 129.78.64.103
X-Forwarded-Proto[16]	a de facto standard for identifying the originating protocol of an HTTP request, since a reverse proxy (load balancer) may communicate with a web server using HTTP even if the request to the reverse proxy is HTTPS	X-Forwarded-Proto: https
Front-End-Https[17]	Non-standard header used by Microsoft applications and load-balancers	Front-End-Https: on
X-ATT-DeviceId[18]	Allows easier parsing of the MakeModel/Firmware that is usually found in the User-Agent String of AT&T Devices	x-att-deviceid: MakeModel/Firmware
X-Wap-Profile[19]	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[20]	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 header.	Proxy-Connection: keep-alive

[edit]Responses

Field name	Description	Example
Access-Control-Allow-Origin	Specifying which web sites can participate in cross-origin resource sharing	Access-Control-Allow-Origin: *
Accept-Ranges	What partial content range types this server supports	Accept-Ranges: bytes
Age	The age the object has been in a proxy cache in seconds	Age: 12
Allow	Valid actions for a specified resource. To be used for a 405 Method not allowed	Allow: GET, HEAD
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
Connection	Options that are desired for the connection[21]	Connection: close
Content-Encoding	The type of encoding used on the data. See HTTP compression.	Content-Encoding: gzip
Content-Language	The language the content is in	Content-Language: da
Content-Length	The length of the response body inoctets (8-bit bytes)	Content-Length: 348
Content-Location	An alternate location for the returned data	Content-Location: /index.htm
Content-MD5	A Base64-encoded binary MD5 sum of the content of the response	Content-MD5: Q2hlY2sgSW50ZWdyaXR5IQ==
Content-Disposition[22][23][24]	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"
Content-Range	Where in a full body message this partial message belongs	Content-Range: bytes 21010-47021/47022
Content-Type	The MIME type of this content	Content-Type: text/html; charset=utf-8
Date	The date and time that the message was sent	Date: Tue, 15 Nov 1994 08:12:31 GMT
ETag	An identifier for a specific version of a resource, often a message digest	ETag: "737060cd8c284d8af7ad3082f209582d"
Expires	Gives the date/time after which the response is considered stale	Expires: Thu, 01 Dec 1994 16:00:00 GMT
Last-Modified	The last modified date for the requested object, in RFC 2822format	Last-Modified: Tue, 15 Nov 1994 12:45:26 GMT
Link	Used to express a typed relationship with another resource, where the relation type is defined by RFC 5988	Link: </feed>; rel="alternate"[25]
Location	Used in redirection, or when a new resource has been created.	Location: http://www.w3.org/pub/WWW/People.html
P3P	This header is supposed to set P3Ppolicy, in the form ofP3P:CP="your_compact_policy". However, P3P did not take off,[26]most browsers have never fully implemented it, a lot of websites set this header 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 http://www.google.com/support/accounts/bin/answer.py?hl=en&answer=151657 for more info."
Pragma	Implementation-specific headers that may have various effects anywhere along the request-response chain.	Pragma: no-cache
Proxy-Authenticate	Request authentication to access the proxy.	Proxy-Authenticate: Basic
Refresh	Used in redirection, or when a new resource has been created. This refresh redirects after 5 seconds. This is a proprietary, non-standard header extension introduced by Netscape and supported by most web browsers.	Refresh: 5; url=http://www.w3.org/pub/WWW/People.html
Retry-After	If an entity is temporarily unavailable, this instructs the client to try again after a specified period of time (seconds).	Retry-After: 120
Server	A name for the server	Server: Apache/2.4.1 (Unix)
Set-Cookie	an HTTP cookie	Set-Cookie: UserID=JohnDoe; Max-Age=3600; Version=1
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
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
Transfer-Encoding	The form of encoding used to safely transfer the entity to the user. Currently defined methods are: chunked, compress, deflate, gzip, identity.	Transfer-Encoding: chunked
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.	Vary: *
Via	Informs the client of proxies through which the response was sent.	Via: 1.0 fred, 1.1 example.com (Apache/1.1)
Warning	A general warning about possible problems with the entity body.	Warning: 199 Miscellaneous warning
WWW-Authenticate	Indicates the authentication scheme that should be used to access the requested entity.	WWW-Authenticate: Basic

[edit]Common non-standard response headers

Non-standard header fields are conventionally marked by prefixing the field name with X- .

Field name	Description	Example
X-Frame-Options[27]	Clickjacking protection: "deny" - no rendering within a frame, "sameorigin" - no rendering if origin mismatch	X-Frame-Options: deny
X-XSS-Protection[28]	Cross-site scripting (XSS) filter	X-XSS-Protection: 1; mode=block
X-Content-Type-Options[29]	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.[30]	X-Content-Type-Options: nosniff
X-Powered-By[31]	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-UA-Compatible[32]	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

[edit]Effects of selected HTTP header fields