RFC 2774 (rfc2774) - Page 3 of 20

An HTTP Extension Framework

RFC 2774              An HTTP Extension Framework          February 2000


1. Introduction

   This proposal is designed to address the tension between private
   agreement and public specification; and to accommodate dynamic
   extension of HTTP clients and servers by software components. The
   kind of extensions capable of being introduced range from:

      o  extending a single HTTP message;

      o  introducing new encodings;

      o  initiating HTTP-derived protocols for new applications; to...

      o  switching to protocols which, once initiated, run independent
         of the original protocol stack.

   The proposal is intended to be used as follows:

      o  Some party designs and specifies an extension; the party
         assigns the extension a globally unique URI, and makes one or
         more representations of the extension available at that address
         (see section 8).

      o  An HTTP client or server that implements this extension
         mechanism (hereafter called an agent) declares the use of the
         extension by referencing its URI in an extension declaration in
         an HTTP message (see section 3).

      o  The HTTP application which the extension declaration is
         intended for (hereafter called the ultimate recipient) can
         deduce how to properly interpret the extended message based on
         the extension declaration.

   The proposal uses features in HTTP/1.1 but is compatible with
   HTTP/1.0 applications in such a way that extended applications can
   coexist with existing HTTP applications. Applications implementing
   this proposal MUST be based on HTTP/1.1 (or later versions of HTTP).

2. Notational Conventions

   This specification uses the same notational conventions and basic
   parsing constructs as RFC 2068 [5]. In particular the BNF constructs
   "token", "quoted-string", "Request-Line", "field-name", and
   "absoluteURI" in this document are to be interpreted as described in
   RFC 2068 [5].






Nielsen, et al.               Experimental