HTTP Response and Request Headers Reference Table
The HTTP request headers provide information about the request, response, or other entities being sent. The HTTP headers include four parts: general headers, request headers, response headers, and entity headers. Each header field consists of a domain name, a colon (:), and a domain value.
| Accept-Ranges | Indicate if the server supports specified range requests and what type of segmented requests. | Accept-Ranges: bytes |
| Age | Estimated time from original server to proxy cache formation (in seconds, non-negative) | Age: 12 |
| Allow | Valid request behavior for a certain network resource; return 405 if not allowed. | Allow: GET, HEAD |
| Cache-Control | Inquire about all caching mechanisms to determine which can be cached and what types they are. | Cache-Control: no-cache |
| Content-Encoding | Web server supported return content compression encoding types. | Content-Encoding: gzip |
| Content-Language | Response body language | Content-Language: en,zh |
| Content-Length | Response body length | Content-Length: 348 |
| Content-Location | Another alternative address for the resource requestable. | Content-Location: /index.htm |
| Content-MD5 | Return the MD5 checksum value of the resource. | Content-MD5: Q2hlY2sgSW50ZWdyaXR5IQ== |
| Content-Range | Byte position of this part in the entire return body | Content-Range: bytes 21010-47021/47022 |
| Content-Type | Return the MIME type of the content. | Content-Type: text/html; charset=utf-8 |
| Date | Original server message send time | Date: Tue, 15 Nov 2010 08:12:31 GMT |
| ETag | Current value of the request variable's entity label | ETag: “737060cd8c284d8af7ad3082f209582d” |
| Expires | Expired date and time of response | Expires: Thu, 01 Dec 2010 16:00:00 GMT |
| Last-Modified | Last modified time of the requested resource | Last-Modified: Tue, 15 Nov 2010 12:45:26 GMT |
| Location | Redirect recipient to a non-request URL to fulfill the request or identify a new resource. | Location: https://www.jisuan.mobi/ |
| Pragma | Including executing specific instructions, which can be applied to any recipient in the response chain. | Pragma: no-cache |
| Proxy-Authenticate | It points to the certification scheme and parameters applicable to the URL on the proxy. | Proxy-Authenticate: Basic |
| refresh | Redirected or a new resource is created, redirecting after 5 seconds (proposed by Netscape, supported by most browsers) |
Refresh: 5; url=
https://www.jisuan.mobi/
|
| Retry-After | If the entity is temporarily unavailable, notify 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 | Set Http Cookie | Set-Cookie: UserID=JohnDoe; Max-Age=3600; Version=1 |
| Trailer | Identify the header domain at the end of the block transmission encoding. | Trailer: Max-Forwards |
| Transfer-Encoding | File transfer encoding | Transfer-Encoding:chunked |
| Vary | Instruct the downstream proxy to use cached responses or request from the original server. | Vary: * |
| Via | Inform the proxy client where the response was sent from. | Via: 1.0 fred, 1.1 nowhere.com (Apache/1.1) |
| Warning | Warning: potential issues with entities may exist. | Warning: 199 Miscellaneous warning |
| WWW-Authenticate | Indicate the authorization scheme to be used for the client's request entity. | WWW-Authenticate: Basic |
| Header | Explain. | Example |
|---|---|---|
| Accept | Specified client content type acceptance | Accept: text/plain, text/html |
| Accept-Charset | Browser-supported character encoding set. | Accept-Charset: iso-8859-5 |
| Accept-Encoding | Specify the compression encoding types supported by the browser for web server responses. | Accept-Encoding: compress, gzip |
| Accept-Language | Browser Acceptable Languages | Accept-Language: en,zh |
| Accept-Ranges | You can request one or more child range fields of a web entity. | Accept-Ranges: bytes |
| Authorization | HTTP authorization certificate | Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ== |
| Cache-Control | Specify the caching mechanism for the request and response. | Cache-Control: no-cache |
| Connection | Indicate whether a persistent connection is needed. (HTTP 1.1 defaults to persistent connections.) | Connection: close |
| Cookie | When sending an HTTP request, all cookie values stored under the request domain are sent along to the web server. | Cookie: $Version=1; Skin=new; |
| Content-Length | Content length requested | Content-Length: 348 |
| Content-Type | Requested MIME information corresponding to the entity | Content-Type: application/x-www-form-urlencoded |
| Date | Date and time of request sent | Date: Tue, 15 Nov 2010 08:12:31 GMT |
| Expect | Requested specific server behavior | Expect: 100-continue |
| From | Email of the user initiating the request | From: user@email.com |
| Host | Specify the domain name and port number of the requested server. | Host: www.zcmhi.com |
| If-Match | Only requests that match the entity are valid. | If-Match: “737060cd8c284d8af7ad3082f209582d” |
| If-Modified-Since | If the requested part is modified after the specified time, the request is successful; if not, return a 304 code. | If-Modified-Since: Sat, 29 Oct 2010 19:43:31 GMT |
| If-None-Match | If content hasn't changed, return 304 status code. Compare the Etag parameter (sent previously by the server) with the Etag in the server's response to determine if it has changed. | If-None-Match: “737060cd8c284d8af7ad3082f209582d” |
| If-Range | If the entity hasn't changed, the server sends the missing part to the client; otherwise, it sends the entire entity. The parameter is also called Etag. | If-Range: “737060cd8c284d8af7ad3082f209582d” |
| If-Unmodified-Since | Success only if the entity has not been modified after the specified time. | If-Unmodified-Since: Sat, 29 Oct 2010 19:43:31 GMT |
| Max-Forwards | Limit the time for information transmission via proxies and gateways. | Max-Forwards: 10 |
| Pragma | For containing the implementation of specific instructions. | Pragma: no-cache |
| Proxy-Authorization | Access certificate for connecting to the proxy | Proxy-Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ== |
| Range | Request only a part of an entity, specify the range. | Range: bytes=500-999 |
| Referer | Previous webpage address, followed by the current requested webpage, i.e., the origin. | Referer: http://www.zcmhi.com/archives/71.html |
| TE | Client's acceptable transfer encoding, and notify the server to accept trailing headers. | TE: trailers,deflate;q=0.5 |
| Upgrade | Specify a transmission protocol to the server for conversion (if supported) | Upgrade: HTTP/2.0, SHTTP/1.3, IRC/6.9, RTA/x11 |
| User-Agent | The User-Agent content includes the user information of the request sender. | User-Agent: Mozilla/5.0 (Linux; X11) |
| Via | Notify the intermediate gateway or proxy server address, communication protocol. | Via: 1.0 fred, 1.1 nowhere.com (Apache/1.1) |
| Warning | Warning information about message entities | Warn: 199 Miscellaneous warning |
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