Network Working Group P. Stickler Internet-Draft Nokia Research Center Expires: July 17, 2002 January 16, 2002 The 'uri:' URI Scheme for URI Reification draft-pstickler-uri-00 Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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 draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http:// www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on July 17, 2002. Copyright Notice Copyright (C) The Internet Society (2002). All Rights Reserved. Abstract This document describes the 'uri:' Uniform Resource Identifier (URI) scheme for the reification of arbitrary Uniform Resource Identifiers. Stickler Expires July 17, 2002 [Page 1] Internet-Draft The 'uri:' URI Scheme January 2002 Table of Contents 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. BNF for the 'uri:' URI Scheme . . . . . . . . . . . . . . . . . 4 3. Security Considerations . . . . . . . . . . . . . . . . . . . . 4 References . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5 Full Copyright Statement . . . . . . . . . . . . . . . . . . . . 6 Stickler Expires July 17, 2002 [Page 2] Internet-Draft The 'uri:' URI Scheme January 2002 1. Overview The 'uri:' URI scheme is intended to provide a simple but consistent means by which URIs (including URI References) may be reified for the sake of communication between web applications about the URIs themselves rather than about the resources they may represent. The ability to differentiate between a particular URI and the web resource which that URI denotes or represents is important in cases where we need to make statements about the history, nature, or other characteristics of the URI itself which are not properties of the resource which it represents -- such as when the URI was minted, by whom, and the class of URI to which it belongs. Examples: uri:http://www.nokia.com uri:mailto:patrick.stickler@nokia.com uri:http://www.abc.com/employees#Bob uri:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6 uri:voc://nokia.com/MARS-2.2/title uri:ftp://ftp.abc.com/pub/apps/free uri:uri:http://www.nokia.com These examples are provided for illustrative purposes only and do not necessarily constitute actual URIs. See the BNF definition below for an explicit definition of 'uri:' URI syntax. Note that this mechanism of reification is infinitely recursive, allowing instances of this URI scheme to themselves be reified by additional encapsulation, as the final example above illustrates. Clearly, the utility of such recursion diminishes greatly with each level of encapsulation, but the absence of a finite boundary ensures that all possible URIs, including instances of this URI scheme, can be reified as needed. The 'uri:' URI scheme belongs to the class of URIs known as Uniform Resource Values (URV) which are themselves a subclass of Uniform Resource Primitives (URP), a class of URI which constitutes a "WYSIWYG" URI, one which is not dereferencible to and does not denote another web resource, but constitutes a self-contained resource where the full realization of that resource is expressed in the URI itself. For a full discussion of the properties of URPs and URVs, please see [1]. Familiarity with the concepts defined therein will facilitate the full understanding of this document. Because a URP is not dereferencible, and hence does not permit the suffixation of a fragment identifier (there is no such thing as a URP Stickler Expires July 17, 2002 [Page 3] Internet-Draft The 'uri:' URI Scheme January 2002 Reference), it is not necessary to escape any hash marks '#' occurring in a URI Reference reified by a 'uri:' URI. 2. BNF for the 'uri:' URI Scheme This is a BNF-like description of the 'uri:' Uniform Resource Identifier syntax, using the conventions of RFC 822[2], except that "|" is used to designate alternatives, and brackets [] are used around optional or repeated elements. Briefly, literals are quoted with "", optional elements are enclosed in [brackets], and elements may be preceded with * to designate n or more repetitions of the following element; n defaults to 0. This BNF description adopts sub-definitions defined in RFC 2396 "Uniform Resource Identifiers (URI): Generic Syntax" [3] which are not repeated here. uri-URI = "uri:" absoluteURI [ "#" fragment ] absoluteURI = fragment = Note that the URI scheme prefix "uri:" is considered to be a valid URI denoting this URI scheme, though it is not itself a valid URI according to this URI scheme. 3. Security Considerations This document raises no known security issues. References [1] Stickler, P., "An Extended Class Taxonomy of Uniform Resource Identifier Schemes", January 2002, . [2] Crocker, D., "STANDARD FOR THE FORMAT OF ARPA INTERNET TEXT MESSAGES", RFC 822, August 1982. [3] Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform Resource Identifiers (URI): Generic Syntax", RFC 2396, August 1998. Stickler Expires July 17, 2002 [Page 4] Internet-Draft The 'uri:' URI Scheme January 2002 Author's Address Patrick Stickler Nokia Research Center Visiokatu 1 Tampere 33720 FI EMail: patrick.stickler@nokia.com Stickler Expires July 17, 2002 [Page 5] Internet-Draft The 'uri:' URI Scheme January 2002 Full Copyright Statement Copyright (C) The Internet Society (2002). All Rights Reserved. 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