FREE ESSAY ON BASIC HTTP

BASIC HTTP

Status of this memo 
This document is an Internet Draft. Internet Drafts are working documents of the Internet
Engineering Task Force (IETF), its
Areas, and its Working Groups. Note that other groups may also distribute working
documents as Internet Drafts. 
Internet Drafts are working documents valid for a maximum of six months. Internet Drafts
may be updated, replaced, or
obsoleted by other documents at any time. It is not appropriate to use Internet Drafts as
reference material or to cite them other
than as a working draft or work in progress. 
This document is a DRAFT specification of a protocol in use on the internet and to be
proposed as an Internet standard.
Discussion of this protocol takes place on the www-talk@info.cern.ch mailing list -- to
subscribe mail to
www-talk-request@info.cern.ch. Distribution of this memo is unlimited. 
Abstract 
HTTP is a protocol with the lightness and speed necessary for a distributed collaborative
hypermedia information system. It is a
generic stateless object-oriented protocol, which may be used for many similar tasks such
as name servers, and distributed
object-oriented systems, by extending the commands, or methods, used. A feature if HTTP
is the negotiation of data
representation, allowing systems to be built independently of the development of new
advanced representations. 
Note: This specification 
This HTTP protocol is an upgrade on the original protocol as implemented in the earliest
WWW releases. It is
back-compatible with that more limited protocol. 
This specification includes the following parts: 
The Request 
Methods 
A list of headers in the request message 
The response 
Status codes 
Metainformation headers on any object transmitted 
The content of any object content transmitted 
Format negotiation algorithm 
The HTTP Registration Authority 
Security Considerations 
Unresolved points 
References 
The following notes form recommended practice not part of the specification: 
Servers tolerating clients 
Clients tolerating servers 
Purpose 
When many sources of networked information are available to a reader, and when a
discipline of reference between different
sources exists, it is possible to rapidly follow references between units of information
which are provided at different remote
locations. As response times should ideally be of the order of 100ms in, for example, a
hypertext jump, this requires a fast,
stateless, information retrieval protocol. 
Practical information systems require more functionality than simple retrieval, including
search, front-end update and annotation.
This protocol allows an open-ended set of methods to be used. It builds on the discipline
of reference provided by the
Universal Resource Identifier (URI) as a name (URN, RFCxxxx) or address (URL, RFCxxxx)
allows the object of the method
to be specified. 
Reference is made to the Multipurpose Internet Mail Extensions (MIME, RFC1341) which are
used to allow objects to be
transmitted in an open variety of representations. 
Overall operation 
On the internet, the communication takes place over a TCP/IP connection. This does not
preclude this protocol being
implemented over any other protocol on the internet or other networks. In these cases,
the mapping of the HTTP request and
response structures onto the transport data units of the protocol in question is outside
the scope of this specification. It should
not however be at all complicated. 
The protocol is basically stateless, a transaction consisting of 
Connection 
The establishment of a connection by the client to the server - when using TCP/IP port 80
is the well-known port, but
other non-reserverd ports may be specified in the URL; 
Request 
The sending, by the client, of a request message to the server; 
Response 
The sending, by the server, of a response to the client; 
Close 
The closing of the connection by either both parties. 
The format of the request and response parts is defined in this specification. Whilst
header information defined in this
specification is sent in ISO Latin-1 character set in CRLF terminated lines, object
transmission in binary is possible. 
Character sets 
In all cases in HTTP where RFC822 characters are allowed, these may be extended to use
the full ISO Latin 1 character set.
8-bit transmission is always used.