forHTTPHeaderField

Response Headers(从服务器得到的回复的头)

Field nameDescriptionExampleStatusAccess-Control-Allow-OriginSpecifying which web sites can participate in cross-origin resource sharingAccess-Control-Allow-Origin: *ProvisionalAccept-RangesWhat partial content range types this server supportsAccept-Ranges: bytesPermanentAgeThe age the object has been in a proxy cache in secondsAge: 12PermanentAllowValid actions for a specified resource. To be used for a 405 Method not allowedAllow: GET, HEADPermanentCache-ControlTells all caching mechanisms from server to client whether they may cache this object. It is measured in secondsCache-Control: max-age=3600PermanentConnectionOptions that are desired for the connection^[22]Connection: closePermanentContent-EncodingThe type of encoding used on the data. See HTTP compression.Content-Encoding: gzipPermanentContent-LanguageThe language the content is inContent-Language: daPermanentContent-LengthThe length of the response body in octets (8-bit bytes)Content-Length: 348PermanentContent-LocationAn alternate location for the returned dataContent-Location: /index.htmPermanentContent-MD5A Base64-encoded binary MD5 sum of the content of the responseContent-MD5: Q2hlY2sgSW50ZWdyaXR5IQ==PermanentContent-Disposition^[23][24][25]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"PermanentContent-RangeWhere in a full body message this partial message belongsContent-Range: bytes 21010-47021/47022PermanentContent-TypeThe MIME type of this contentContent-Type: text/html; charset=utf-8PermanentDateThe date and time that the message was sent (in "HTTP-date" format as defined byRFC 2616)Date: Tue, 15 Nov 1994 08:12:31 GMTPermanentETagAn identifier for a specific version of a resource, often a message digestETag: "737060cd8c284d8af7ad3082f209582d"PermanentExpiresGives the date/time after which the response is considered staleExpires: Thu, 01 Dec 1994 16:00:00 GMTPermanent: standardLast-ModifiedThe last modified date for the requested object (in "HTTP-date" format as defined byRFC 2616)Last-Modified: Tue, 15 Nov 1994 12:45:26 GMTPermanentLinkUsed to express a typed relationship with another resource, where the relation type is defined byRFC 5988Link: </feed>; rel="alternate"^[26]PermanentLocationUsed in redirection, or when a new resource has been created.Location: http://www.w3.org/pub/WWW/People.htmlPermanentP3PThis header is supposed to set P3P policy, in the form of P3P:CP="your_compact_policy". However, P3P did not take off,^[27] 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 forthird 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."PermanentPragmaImplementation-specific headers that may have various effects anywhere along the request-response chain.Pragma: no-cachePermanentProxy-AuthenticateRequest authentication to access the proxy.Proxy-Authenticate: BasicPermanentRefreshUsed in redirection, or when a new resource has been created. This refresh redirects after 5 seconds.Refresh: 5; url=http://www.w3.org/pub/WWW/People.htmlProprietary/non-standard: a header extension introduced by Netscape and supported by most web browsers.Retry-AfterIf 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.^[28]

• Example 1: Retry-After: 120
• Example 2: Retry-After: Fri, 07 Nov 2014 23:59:59 GMT

Permanent

ServerA name for the serverServer: Apache/2.4.1 (Unix)PermanentSet-CookieAn HTTP cookieSet-Cookie: UserID=JohnDoe; Max-Age=3600; Version=1Permanent: standardStatusThe HTTP status of the responseStatus: 200 OK ? "Status" is not listed as a registered header. The "Status-Line" of a "Response" is defined by RFC2616^[29] without any explicit "Status:" header name.Strict-Transport-SecurityA 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; includeSubDomainsPermanent: standardTrailerThe Trailer general field value indicates that the given set of header fields is present in the trailer of a message encoded withchunked transfer-coding.Trailer: Max-ForwardsPermanentTransfer-EncodingThe form of encoding used to safely transfer the entity to the user. Currently defined methods are: chunked, compress, deflate, gzip, identity.Transfer-Encoding: chunkedPermanentUpgradeAsk the client to upgrade to another protocol.Upgrade: HTTP/2.0, SHTTP/1.3, IRC/6.9, RTA/x11PermanentVaryTells 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: *PermanentViaInforms the client of proxies through which the response was sent.Via: 1.0 fred, 1.1 example.com (Apache/1.1)PermanentWarningA general warning about possible problems with the entity body.Warning: 199 Miscellaneous warningPermanentWWW-AuthenticateIndicates the authentication scheme that should be used to access the requested entity.WWW-Authenticate: BasicPermanentX-Frame-Options^[30]Clickjacking protection: "deny" - no rendering within a frame, "sameorigin" - no rendering if origin mismatchX-Frame-Options: denyPermanent

Common non-standard response headers(从服务器得到的非标准回复的头)

Field nameDescriptionExamplePublic-Key-Pins^[31]Man-in-the-middle attack mitigation, announces hash of website's authenticTLS certificatePublic-Key-Pins: max-age=2592000; pin-sha256="E9CZ9INDbd+2eRQozYqqbQ2yXLVKB9+xcprMF+44U1g=";X-XSS-Protection^[32]Cross-site scripting (XSS) filterX-XSS-Protection: 1; mode=blockContent-Security-Policy, X-Content-Security-Policy, X-WebKit-CSP^[33]Content Security Policy definition.X-WebKit-CSP: default-src 'self'X-Content-Type-Options^[34]The only defined value, "nosniff", prevents Internet Explorer from MIME-sniffing a response away from the declared content-type. This also applies toGoogle Chrome, when downloading extensions.^[35]X-Content-Type-Options: nosniffX-Powered-By^[36]specifies the technology (e.g. ASP.NET, PHP, JBoss) supporting the web application (version details are often inX-Runtime, X-Version, or X-AspNet-Version)X-Powered-By: PHP/5.4.0X-UA-Compatible^[37]Recommends the preferred rendering engine (often a backward-compatibility mode) to use to display the content. Also used to activateChrome Frame in Internet Explorer.X-UA-Compatible: IE=EmulateIE7
X-UA-Compatible: IE=edge
X-UA-Compatible: Chrome=1

Request Headers(标准请求头)

Header field nameDescriptionExampleStatusAcceptContent-Types that are acceptable for the responseAccept: text/plainPermanentAccept-CharsetCharacter sets that are acceptableAccept-Charset: utf-8PermanentAccept-DatetimeAcceptable version in timeAccept-Datetime: Thu, 31 May 2007 20:35:00 GMTProvisionalAccept-EncodingList of acceptable encodings. See HTTP compression.Accept-Encoding: gzip, deflatePermanentAccept-LanguageList of acceptable human languages for responseAccept-Language: en-USPermanentAuthorizationAuthentication credentials for HTTP authenticationAuthorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==PermanentCache-ControlUsed to specify directives that MUST be obeyed by all caching mechanisms along the request/response chainCache-Control: no-cachePermanentConnectionWhat type of connection the user-agent would preferConnection: keep-alivePermanentContent-LengthThe length of the request body in octets (8-bit bytes)Content-Length: 348PermanentContent-MD5A Base64-encoded binary MD5 sum of the content of the request bodyContent-MD5: Q2hlY2sgSW50ZWdyaXR5IQ==PermanentContent-TypeThe MIME type of the body of the request (used with POST and PUT requests)Content-Type: application/x-www-form-urlencodedPermanentCookiean HTTP cookie previously sent by the server with Set-Cookie (below)Cookie: $Version=1; Skin=new;Permanent: standardDateThe date and time that the message was sent (in "HTTP-date" format as defined byRFC 2616)Date: Tue, 15 Nov 1994 08:12:31 GMTPermanentExpectIndicates that particular server behaviors are required by the clientExpect: 100-continuePermanentFromThe email address of the user making the requestFrom: [e-mail] domain name of the server (for virtual hosting), and the TCP port number on which the server is listening. The port number may be omitted if the port is the standard port for the service requested.^[8] Mandatory since HTTP/1.1. Although domain name are specified as case-insensitive,^[9][10] it is not specified whether the contents of the Host field should be interpreted in a case-insensitive manner^[11] 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:80

Host: en.wikipedia.org

PermanentIf-MatchOnly 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"PermanentIf-Modified-SinceAllows a 304 Not Modified to be returned if content is unchangedIf-Modified-Since: Sat, 29 Oct 1994 19:43:31 GMTPermanentIf-None-MatchAllows a 304 Not Modified to be returned if content is unchanged, seeHTTP ETagIf-None-Match: "737060cd8c284d8af7ad3082f209582d"PermanentIf-RangeIf the entity is unchanged, send me the part(s) that I am missing; otherwise, send me the entire new entityIf-Range: "737060cd8c284d8af7ad3082f209582d"PermanentIf-Unmodified-SinceOnly send the response if the entity has not been modified since a specific time.If-Unmodified-Since: Sat, 29 Oct 1994 19:43:31 GMTPermanentMax-ForwardsLimit the number of times the message can be forwarded through proxies or gateways.Max-Forwards: 10PermanentOriginInitiates a request for cross-origin resource sharing (asks server for an 'Access-Control-Allow-Origin' response header) .Origin: http://www.example-social-network.comPermanent: standardPragmaImplementation-specific headers that may have various effects anywhere along the request-response chain.Pragma: no-cachePermanentProxy-AuthorizationAuthorization credentials for connecting to a proxy.Proxy-Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==PermanentRangeRequest only part of an entity. Bytes are numbered from 0.Range: bytes=500-999PermanentReferer [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_PagePermanentTEThe 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, deflatePermanentUpgradeAsk the server to upgrade to another protocol.Upgrade: HTTP/2.0, SHTTP/1.3, IRC/6.9, RTA/x11PermanentUser-AgentThe user agent string of the user agentUser-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20100101 Firefox/21.0PermanentViaInforms the server of proxies through which the request was sent.Via: 1.0 fred, 1.1 example.com (Apache/1.1)PermanentWarningA general warning about possible problems with the entity body.Warning: 199 Miscellaneous warningPermanent

Common non-standard request headers(非标准请求头)

Field nameDescriptionExampleX-Requested-Withmainly used to identify Ajax requests. Most JavaScript frameworks send this header with value of XMLHttpRequestX-Requested-With: XMLHttpRequestDNT^[12]Requests a web application to disable their tracking of a user. This is Mozilla's version of the X-Do-Not-Track header (sinceFirefox 4.0 Beta 11). Safari and IE9 also have support for this header.^[13] On March 7, 2011, a draft proposal was submitted to IETF.^[14] TheW3C Tracking Protection Working Group is producing a specification.^[15]DNT: 1 (Do Not Track Enabled)

DNT: 0 (Do Not Track Disabled)

X-Forwarded-For^[16]a de facto standard for identifying the originating IP address of a client connecting to a web server through an HTTP proxy or load balancerX-Forwarded-For: client1, proxy1, proxy2

X-Forwarded-For: 129.78.138.66, 129.78.64.103

X-Forwarded-Proto^[17]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 HTTPSX-Forwarded-Proto: httpsFront-End-Https^[18]Non-standard header used by Microsoft applications and load-balancersFront-End-Https: onX-ATT-DeviceId^[19]Allows easier parsing of the MakeModel/Firmware that is usually found in the User-Agent String of AT&T DevicesX-Att-Deviceid: GT-P7320/P7320XXLPGX-Wap-Profile^[20]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.xmlProxy-Connection^[21]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