HTTP Header Specific explanation

HTTP (hypertexttransferprotocol) is the hypertext transfer protocol, the Universal protocol for the current web page Transmission. The HTTP protocol uses the Request/response model, and the browser or other client makes the Request. The server responds. In terms of the entire network resource transmission, Message-header and Message-body are Included. First pass the Message-header. That HTTP HeaderNews . HTTP header messages are usually divided into 4 sections: general header, request header, Response header, entity Header.

But this kind of division in terms of understanding, the sense of the boundary is not quite clear.

Based on Wikipedia's organization of HTTP header content, It is broadly divided into two parts: request and Response.

Header Explanation Demo sample

Accept-ranges	Indicates whether the server supports the specified range request and what kind of staging request	Accept-ranges:bytes
Age	Estimated Time (in seconds, Non-negative) formed from the original server to the proxy cache	Age:12
Allow	A valid request behavior for a network resource is returned with a 405	allow:get, HEAD
Cache-control	Tell if all caching mechanisms are sufficient to cache and which type	Cache-control:no-cache
Content-encoding	Webserver supports the return content compression encoding Type.	Content-encoding:gzip
Content-language	The language of the response body	Content-language:en,zh
Content-length	The length of the response body	content-length:348
Content-location	There is an alternative to the requested resource, and an address.	Content-location:/index.htm
Content-md5	Returns the MD5 checksum value of a resource	content-md5:q2hly2sgsw50zwdyaxr5iq==
Content-range	The byte position of this section in the entire return body	Content-range:bytes 21010-47021/47022
Content-type	Returns the MIME type of the content	content-type:text/html; Charset=utf-8
Date	The time that the original server message was issued	date:tue, 08:12:31 GMT
ETag	The current value of the entity label of the request variable	ETag: "737060cd8c284d8af7ad3082f209582d"
Expires	Date and time when the response expires	expires:thu, 16:00:00 GMT
Last-modified	Last modified time of request resource	last-modified:tue, 12:45:26 GMT
Location	Used to redirect the receiver to the location of the Non-request URL to complete the request or identify the new resource	Location:http://www.zcmhi.com/archives/94.html
Pragma	Contains implementation-specific instructions that can be applied to whatever receiver on the response chain	Pragma:no-cache
Proxy-authenticate	It indicates the authentication scheme and the number of references on the URL that can be applied to the agent	Proxy-authenticate:basic
Refresh	Applied to redirect or a new resource was created, redirected after 5 seconds (proposed by netscape, supported by most Browsers)	refresh:5; Url=http://www.zcmhi.com/archives/94.html
Retry-after	Suppose the entity is temporarily undesirable. Notifies the client to try again after a specified time	retry-after:120
Server	Webserver software name	server:apache/1.3.27 (Unix) (red-hat/linux)
Set-cookie	Set HTTP Cookies	set-cookie:userid=johndoe; max-age=3600; Version=1
Trailer	Indicates that the header domain is present at the end of the chunked transfer code	Trailer:max-forwards
Transfer-encoding	File transfer encoding	Transfer-encoding:chunked
Vary	Tells the downstream agent whether to use the cache response or the original server request	Vary: *
Via	Tells the proxy client where the response was sent by	via:1.0 fred, 1.1 nowhere.com (apache/1.1)
Warning	Warning about possible issues with the entity	warning:199 Miscellaneous Warning
Www-authenticate	Indicates the authorization scheme that the client request entity should use	Www-authenticate:basic

Many other visit website header Field definitions

Content-type	The requested MIME information corresponding to the entity	content-type:application/x-www-form-urlencoded
Date	Date and time the request was sent	date:tue, 08:12:31 GMT
Expect	The specific server behavior of the request	Expect:100-continue
From	Email from the user who made the request	From: [email protected]
Host	Specify the domain name and port number of the requested server	Host:www.zcmhi.com
If-match	Only the requested content matches the entity to be valid	If-match: "737060cd8c284d8af7ad3082f209582d"
If-modified-since	The request succeeds if the part of the request is altered after the specified time. Return 304 code if not changed	if-modified-since:sat, Oct 19:43:31 GMT
If-none-match	The 304 code is returned if the content has not changed. The number of references to the ETag previously sent by the server is inferred from the etag of the server Response.	If-none-match: "737060cd8c284d8af7ad3082f209582d"
If-range	Assuming that the entity has not changed, the server sends the missing part of the Client. otherwise, the entire entity is Sent. The number of references is also etag	If-range: "737060cd8c284d8af7ad3082f209582d"
If-unmodified-since	Request succeeds only if the entity has not been modified since the specified time	if-unmodified-since:sat, Oct 19:43:31 GMT
Max-forwards	Limit the time that information is transmitted through agents and gateways	Max-forwards:10
Pragma	Used to include implementation-specific instructions	Pragma:no-cache
Proxy-authorization	Connect to an authorization certificate for the agent	Proxy-authorization:basic qwxhzgrpbjpvcgvuihnlc2ftzq==
Range	Just request a part of the entity, specify the scope	range:bytes=500-999
Referer	The address of the previous page, which is immediately followed by the current request page,	Referer:http://www.zcmhi.com/archives/71.html
TE	The transmission encoding that the client is willing to accept. and notifies the server to accept the trailing header information	te:trailers,deflate;q=0.5
Upgrade	Specify a transport protocol to the server for the server to convert (assuming support)	upgrade:http/2.0, shttp/1.3, irc/6.9, rta/x11
User-agent	The content of the user-agent includes the user information that made the request	user-agent:mozilla/5.0 (Linux; X11)
Via	Notify Intermediate gateway or Proxy Server address, communication protocol	via:1.0 fred, 1.1 nowhere.com (apache/1.1)
Warning	About warning messages for message entities	warn:199 Miscellaneous Warning

Requests Partial Header Explanation Demo sample

Accept	Specify what type of content the client can receive	accept:text/plain, text/html
Accept-charset	The set of character encodings that the browser can Accept.	Accept-charset:iso-8859-5
Accept-encoding	Specifies the type of webserver return content compression encoding that the browser can Support.	accept-encoding:compress, gzip
Accept-language	Browser-acceptable language	Accept-language:en,zh
Accept-ranges	Ability to request one or more child range fields for a Web page entity	Accept-ranges:bytes
Authorization	Authorization Certificate for HTTP Authorization	Authorization:basic qwxhzgrpbjpvcgvuihnlc2ftzq==
Cache-control	Specify the caching mechanism that requests and responses follow	Cache-control:no-cache
Connection	Indicates whether a persistent connection is Required. (HTTP 1.1 defaults to persistent Connection)	Connection:close
Cookies	When an HTTP request is Sent. All the cookie values stored under the requested domain name are sent to Webserver.	Cookie: $Version = 1; skin=new;
Content-length	The requested content length	content-length:348

HTTP Header Specific explanation