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HTTP Request Header
Header Description Example
Accept Specifies the content types that the client can accept Accept: text/plain, text/html
Accept-Charset Character encoding sets that the browser can accept. Accept-Charset: iso-8859-5
Accept-Encoding Specifies the content compression encoding types that the browser can support for web server responses. Accept-Encoding: compress, gzip
Accept-Language Languages acceptable to the browser Accept-Language: en,zh
Accept-Ranges Can request one or more sub-range fields of the web entity Accept-Ranges: bytes
Authorization Authorization credentials for HTTP authentication Authorization: credentials
Cache-Control Specifies the caching mechanism that requests and responses follow Cache-Control: no-cache
Connection Indicates whether a persistent connection is needed. (HTTP 1.1 defaults to persistent connections) Connection: close
Cookie When an HTTP request is sent, all cookie values saved under the request domain name are sent to the web server together. Cookie: $Version=1; Skin=new;
Content-Length Length of the request content Content-Length: 348
Content-Type MIME information corresponding to the entity of the request Content-Type: application/x-www-form-urlencoded
Date Date and time the request was sent Date: Tue, 15 Nov 2010 08:12:31 GMT
Expect Specific server behavior requested Expect: 100-continue
From Email of the user making the request From: user@jsons.cn
Host Specifies the domain name and port number of the server for the request Host: www.jsons.cn
If-Match Only valid if the request content matches the entity If-Match: "specific value"
If-Modified-Since Request succeeds if the requested part was modified after the specified time, returns 304 code if not modified If-Modified-Since: Sat, 29 Oct 2010 19:43:31 GMT
If-None-Match Returns 304 code if content hasn't changed, parameter is Etag sent by server previously, compared with Etag回应的 by server to determine change If-None-Match: "specific value"
If-Range If entity hasn't changed, server sends the part missing by client, otherwise sends entire entity. Parameter is also Etag If-Range: "specific value"
If-Unmodified-Since Request succeeds only if entity hasn't been modified after specified time If-Unmodified-Since: Sat, 29 Oct 2010 19:43:31 GMT
Max-Forwards Limits the time information is transmitted through proxies and gateways Max-Forwards: 10
Pragma Used to contain implementation-specific directives Pragma: no-cache
Proxy-Authorization Authorization credentials to connect to proxy Proxy-Authorization: credentials to connect to proxy
Range Requests only a part of the entity, specifies range Range: bytes=500-999
Referer Address of previous webpage, current request webpage follows it, i.e., referrer Referer: http://www.jsons.cn
TE Transport encoding that client is willing to accept, and informs server to accept trailing header information TE: trailers,deflate;q=0.5
Upgrade Specifies a transport protocol to server for conversion if supported Upgrade: HTTP/2.0, SHTTP/1.3, IRC/6.9, RTA/x11
User-Agent Content of User-Agent includes information about the user making the request User-Agent: Mozilla/5.0 (Linux; X11)
Via Informs intermediate gateway or proxy server address, communication protocol Via: 1.0 fred, 1.1 nowhere.com (Apache/1.1)
Warning Warning information about message entity Warn: 199 Miscellaneous warning
HTTP Responses Header
Header Description Example
Accept-Ranges Indicates whether server supports specified range requests and what type of segmented requests Accept-Ranges: bytes
Age Estimated time (in seconds, non-negative) from origin server to proxy cache formation Age: 12
Allow Valid request actions for a network resource, returns 405 if not allowed Allow: GET, HEAD
Cache-Control Tell all the caching mechanism whether it can cache and which type Cache-Control: no-cache
Content-Encoding Content compression encoding types supported by the web server. Content-Encoding: gzip
Content-Language Language of the response body Content-Language: en,zh
Content-Length Length of the response body Content-Length: 348
Content-Location Alternative address for the requested resource Content-Location: /index.htm
Content-MD5 MD5 checksum of the returned resource Content-MD5: MD5 checksum value
Content-Range Byte position of this part in the entire response body Content-Range: bytes 21010-47021/47022
Content-Type MIME type of the returned content Content-Type: text/html; charset=utf-8
Date Time when the origin server sent the message Date: Tue, 15 Nov 2010 08:12:31 GMT
ETag Current value of the entity tag for the requested variable ETag: "current value of requested variable entity tag"
Expires Date and time when the response expires Expires: Thu, 01 Dec 2010 16:00:00 GMT
Last-Modified Last modification time of the requested resource Last-Modified: Tue, 15 Nov 2010 12:45:26 GMT
Location Used to redirect the receiver to a non-request URL location to complete the request or identify a new resource Location: http://www.jsons.cn
Pragma Includes implementation-specific directives that can be applied to any receiver in the response chain Pragma: no-cache
Proxy-Authenticate Indicates the authentication scheme and parameters applicable to the proxy for this URL Proxy-Authenticate: Basic
refresh Applied to redirects or when a new resource is created, redirects after 5 seconds (proposed by Netscape, supported by most browsers)
Refresh: 5; url= http://www.jsons.cn
Retry-After If the entity is temporarily unavailable, notifies the client to try again after the specified time Retry-After: 120
Server Web server software name Server: Apache/1.3.27 (Unix) (Red-Hat/Linux)
Set-Cookie Sets Http Cookie Set-Cookie: UserID=JohnDoe; Max-Age=3600; Version=1
Trailer Indicates that header fields exist at the end of the chunked transfer encoding Trailer: Max-Forwards
Transfer-Encoding File transfer encoding Transfer-Encoding:chunked
Vary Tells downstream proxies whether to use cached responses or request from the origin server Vary: *
Via Informs the proxy client where the response was sent from Via: 1.0 fred, 1.1 nowhere.com (Apache/1.1)
Warning Warns about potential problems with the entity Warning: 199 Miscellaneous warning
WWW-Authenticate Indicates the authorization scheme that the client should use for the requested entity WWW-Authenticate: Basic

Live HTTP Response Headers Reference | Full HTTP Request Headers List

HTTP headers convey metadata about requests, responses, or transmitted entities, categorized into four types: general headers (shared), request headers (client-specific), response headers (server-specific), and entity headers (body-related).

A header field is composed of three components: a field name, a colon (:) delimiter, and a field value.

General headers: These headers are valid for both request and response messages, providing metadata that applies to the entire communication context rather than individual resources or transactions.

Request headers: Enable the client to convey metadata about its identity and preferred response characteristics (e.g., content type, encoding).

Response headers: Allow the server to communicate metadata about its state and capabilities in the response message.

Entity headers: Describe characteristics of the resource being transferred, valid in both request and response messages.

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