Introduction

Hypertext Transfer Protocol (HTTP) is a very common communications protocol on the Internet which was designed for the transfer of inter-linking documents (hypertext) but which is now used for many different types of transfers and connections.

It is a key component of cloud computing and is the primary protocol used by cush.

Details

HTTP 1.1 (the prevailing version) is defined by a number of RFCs; most notably RFC2616:

   The Hypertext Transfer Protocol (HTTP) is an application-level
   protocol for distributed, collaborative, hypermedia information
   systems. HTTP has been in use by the World-Wide Web global
   information initiative since 1990. The first version of HTTP,
   referred to as HTTP/0.9, was a simple protocol for raw data transfer
   across the Internet. HTTP/1.0, as defined by RFC 1945 [6], improved
   the protocol by allowing messages to be in the format of MIME-like
   messages, containing metainformation about the data transferred and
   modifiers on the request/response semantics. However, HTTP/1.0 does
   not sufficiently take into consideration the effects of hierarchical
   proxies, caching, the need for persistent connections, or virtual
   hosts. In addition, the proliferation of incompletely-implemented
   applications calling themselves "HTTP/1.0" has necessitated a
   protocol version change in order for two communicating applications
   to determine each others true capabilities.

   This specification defines the protocol referred to as "HTTP/1.1".
   This protocol includes more stringent requirements than HTTP/1.0 in
   order to ensure reliable implementation of its features.

   Practical information systems require more functionality than simple
   retrieval, including search, front-end update, and annotation. HTTP
   allows an open-ended set of methods and headers that indicate the
   purpose of a request [47]. It builds on the discipline of reference
   provided by the Uniform Resource Identifier (URI) [3], as a location
   (URL) [4] or name (URN) [20], for indicating the resource to which a
   method is to be applied. Messages are passed in a format similar to
   that used by Internet mail [9] as defined by the Multipurpose
   Internet Mail Extensions (MIME) [7].

   HTTP is also used as a generic protocol for communication between
   user agents and proxies/gateways to other Internet systems, including
   those supported by the SMTP [16], NNTP [13], FTP [18], Gopher [2],
   and WAIS [10] protocols. In this way, HTTP allows basic hypermedia
   access to resources available from diverse applications.