Minggu, 04 September 2016

HTTP - Hyper Text Transfer Protocol

✔ Dicky Ibrohim Diterbitkan 04.08

HTTP - Hyper Text Transfer Protocol

The Hypertext Transfer Protocol (HTTP) is an application protocol for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web.

Hypertext is structured text that uses logical links (hyperlinks) between nodes containing text. HTTP is the protocol to exchange or transfer hypertext.

Development of HTTP was initiated by Tim Berners-Lee at CERN in 1989. Standards development of HTTP was coordinated by the Internet Engineering Task Force (IETF) and the World Wide Web Consortium (W3C), culminating in the publication of a series of Requests for Comments (RFCs). The first definition of HTTP/1.1, the version of HTTP in common use, occurred in RFC 2068 in 1997, although this was obsoleted by RFC 2616 in 1999.

Transactions between client and server

Client connects
Client makes one or more Requests
Server Responds to Requests
Client drops connection

Http client request has three parts:

1) Method, document URL, HTTP version

Most frequently used methods are:

GET request a document or data
HEAD request document attributes only
POST send data to server

2) Browser type, OS, and acceptable media

3) Optional data

HTTP request example

GET /articles/news/today.asp HTTP/1.1Accept: */*Accept-Language: en-usConnection: Keep-AliveHost: localhostReferer: http://localhost/links.aspUser-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0)Accept-Encoding: gzip, deflate

The header of a request must be followed by a blank line, which is used to separate the header from the body of the request.

HTTP server response

Response has three parts:

1) HTTP version, response code, message

2) Header information

Date and time
Server type
Last modified date and time

Content type and length

3) Body (optional)

Response Phase Form

HTTP response example

žThe header field, Content-type, is required
žAn example of a complete response header:

HTTP/1.1 200 OK

Date: Mon, 27 Jun 2002 17:22:47 GMT

Server: Apache/1.3.22 (Unix) (Red-Hat/Linux)

Last-modified: Wed, 26 Jun 2002 18:12:29 GMT

Accept-ranges: bytes

Content-length: 75

Connection: close

Content-type: text/html

<HTML>

<BODY>