／var／logmarcus chiu

HTTP - Headers

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HTTP headers let the client and the server pass additional information with an HTTP request or response

Header Example

An HTTP header consists of its case-insensitive name followed by a colon (:), then by its value. Whitespace before the value is ignored

GET /tutorials/other/ HTTP/1.1
Host: net.tutsplus.com
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.5) Gecko/20091102 Firefox/3.5.5 (.NET CLR 3.5.30729)
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 300
Connection: keep-alive
Cookie: PHPSESSID=r2t5uvjq435r4q7ib3vtdjq120
Pragma: no-cache
Cache-Control: no-cache

HTTP/1.x 200 OK
Transfer-Encoding: chunked
Date: Sat, 28 Nov 2009 04:36:25 GMT
Server: LiteSpeed
Connection: close
X-Powered-By: W3 Total Cache/0.8
Expires: Sat, 28 Nov 2009 05:36:25 GMT

<!DOCTYPE>
<html>
<head></head><body>EXAMPLE</body>
</html>

Header Types

General Header

Headers applying to both requests and responses but with no relation to the data eventually transmitted in the body

Request Header

Headers containing more information about the resource to be fetched or about the client itself

Response Header

Headers with additional information about the response (e.g. server location, server info, etc)

Entity Header

Headers containing more information about the body of the entity (e.g. content length, MIME-type, etc)

Headers Types (According to How Proxies Handle Them)

End-to-End Headers

These headers must be transmitted to the final recipient of the message; that is, the server for a request or the client for a response. Intermediate proxies must retransmit end-to-end headers unmodified and caches must store them

Hop-by-Hop Headers

These headers are meaningful only for a single transport-level connection and must not be retransmitted by proxies or cached. Such headers are: Connection, Keep-Alive, Proxy-Authenticate, Proxy-Authorization, TE, Trailer, Transfer-Encoding and Upgrade. Note that only hop-by-hop headers may be set using the Connection general header

Header Value Max Size

Header Directives

https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers