The 'acct' URI Scheme
draft-saintandre-acct-uri-00

Network Working Group                                     P. Saint-Andre
Internet-Draft                                       Cisco Systems, Inc.
Intended status: Standards Track                           June 30, 2012
Expires: January 1, 2013

                         The 'acct' URI Scheme
                      draft-saintandre-acct-uri-00

Abstract

   This document defines the 'acct' URI scheme as a way to identify a
   user's account at a service provider, irrespective of the particular
   protocols that can be used to interact with the account.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   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."

   This Internet-Draft will expire on January 1, 2013.

Copyright Notice

   Copyright (c) 2012 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Saint-Andre              Expires January 1, 2013                [Page 1]
Internet-Draft            The 'acct' URI Scheme                June 2012

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Definition  . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 6
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 6
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 6
     7.1.  Normative References  . . . . . . . . . . . . . . . . . . . 6
     7.2.  Informative References  . . . . . . . . . . . . . . . . . . 6
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . . . 7

Saint-Andre              Expires January 1, 2013                [Page 2]
Internet-Draft            The 'acct' URI Scheme                June 2012

1.  Introduction

   Existing URI schemes that enable interaction with, or that identify
   resources associated with, a user's account at a service provider are
   tied to particular services or application protocols.  Two examples
   are the 'mailto' scheme (which enables interaction with a user's
   email account) and the 'http' scheme (which enables retrieval of web
   files controlled by a user or interaction with interfaces providing
   information about a user).  However, there exists no URI scheme that
   generically identifies a user's account at a service provider, in the
   absence of interaction with the account using a particular
   application protocol.  This specification fills that gap.

2.  Rationale

   During formalization of the WebFinger protocol
   [I-D.jones-appsawg-webfinger], much discussion occurred regarding the
   appropriate URI scheme to include when specifying a user's account as
   a web link [RFC5988].  Although both the 'mailto' and 'http' schemes
   were proposed, not all service providers support email services or
   web interfaces on behalf of user accounts (e.g., a microblogging or
   instant messaging provider might not provide email services, or an
   enterprise might not provide HTTP interfaces to information about its
   employees).  Therefore, the discussants recognized that it would be
   helpful to define a URI scheme that could be used to generically
   identify a user's account at a service provider, irrespective of the
   particular services or application protocols that could be used to
   interact with the account.  The result was the 'acct' URI scheme
   defined in this document.

3.  Definition

   The syntax of the 'acct' URI scheme is defined under Section 4 of
   this document.  Although 'acct' URIs take the form
   userpart@domainpart, the scheme is designed for the purpose of
   identification instead of interaction (regarding this distinction,
   see Section 1.2.2 of [RFC3986]).  The "Internet resource" identified
   by an 'acct' URI is a user's account hosted at a service provider,
   where the service provider is associated with a DNS domain name.
   Thus a particular 'acct' URI is formed by setting the userpart
   portion of the URI to the user's account name at the service provider
   and by setting the domainpart portion of the URI to the DNS domain
   name of the service provider.

   An 'acct' URI need not be explicitly assigned by the service
   provider, and can be inferred if the account name and provider domain

Saint-Andre              Expires January 1, 2013                [Page 3]
Internet-Draft            The 'acct' URI Scheme                June 2012

   name are known.  For example, if a user has an account name of
   "foobar" on a microblogging service "status.example.net", it can be
   inferred that the user's 'acct' URI at that provider is
   acct:foobar@status.example.net even if the provider has not
   explicitly assigned such a URI.

   It is not assumed that an entity will necessarily be able to interact
   with a user's account using any particular application protocol, such
   as email; to enable such interaction, an entity would need to use the
   appropriate URI scheme for such a protocol, such as the 'mailto'
   scheme.  While it might be true that the 'acct' URI minus the scheme
   name (e.g., user@example.com derived from acct:user@example.com) can
   be reached via email or some other application protocol, that fact
   would be purely contingent and dependent upon the deployment
   practices of the provider.

   Because an 'acct' URI enables identification only and not
   interaction, it cannot be deferenced directly (as can URIs for most
   application protocols).  Any protocol that uses the 'acct' URI
   scheme, such as the WebFinger protocol, is responsible for specifying
   how an 'acct' URI is to be dereferenced in the context of that
   protocol.

4.  IANA Considerations

   In accordance with the guidelines and registration procedures for new
   URI schemes [RFC4395], this section provides the information needed
   to register the 'acct' URI scheme.

4.1.  URI Scheme Name

   acct

4.2.  Status

   permanent

4.3.  URI Scheme Syntax

   The 'acct' URI syntax is defined here in Augmented Backus-Naur Form
   (ABNF) [RFC5234], borrowing syntax elements from [RFC3986]:

   acctURI      =  "acct:" userpart "@" domainpart
   userpart     =  1*( unreserved / pct-encoded )
   domainpart   =  domainlabel 1*( "." domainlabel)
   domainlabel  =  alphanum / alphanum *( alphanum / "-" ) alphanum
   alphanum     =  ALPHA / DIGIT

Saint-Andre              Expires January 1, 2013                [Page 4]
Internet-Draft            The 'acct' URI Scheme                June 2012

4.4.  URI Scheme Semantics

   The 'acct' URI scheme is used to identify user accounts hosted at
   service providers.  It is used only for identification, not
   interaction.  A protocol that uses the 'acct' URI scheme is
   responsible for specifying how an 'acct' URI is to be dereferenced in
   the context of that protocol.  There is no media type associated with
   the 'acct' URI scheme.

4.5.  Encoding Considerations

   The 'acct' URI scheme allows any character from the Unicode
   repertoire [UNICODE] encoded as a UTF-8 [RFC3629] string that is then
   percent-encoded as necessary into valid ASCII [RFC20].  Note that
   domain labels need to be encoded as A-labels as defined by [RFC5890]
   in order to support internationalized domain names (IDNs).

4.6.  Applications/Protocols That Use This URI Scheme Name

   At present, only the WebFinger protocol uses the 'acct' URI scheme.
   However, use is not restricted to the WebFinger protocol.

4.7.  Interoperability Considerations

   There are no known interoperability concerns related to use of the
   'acct' URI scheme.

4.8.  Security Considerations

   See Section 5 of RFCXXXX.

   [Note to RFC Editor: please replace XXXX with the number issued to
   this document.]

4.9.  Contact

   Peter Saint-Andre, psaintan@cisco.com

4.10.  Author/Change Controller

   This scheme is registered under the IETF tree.  As such, the IETF
   maintains change control.

4.11.  References

   For use of the 'acct' URI scheme with the WebFinger protocol, see
   [I-D.jones-appsawg-webfinger].

Saint-Andre              Expires January 1, 2013                [Page 5]
Internet-Draft            The 'acct' URI Scheme                June 2012

5.  Security Considerations

   Because the 'acct' URI scheme does not directly enable interaction
   with a user's account at a service provider, possible security
   concerns are minimized (aside from the fact that an 'acct' URI
   naturally exposes that a particular account name might exist at the
   provider).  Protocols that make use of 'acct' URIs are responsible
   for defining security considerations related to such usage.

6.  Acknowledgements

   Some text in this document was borrowed from
   [I-D.jones-appsawg-webfinger].

7.  References

7.1.  Normative References

   [RFC20]    Cerf, V., "ASCII format for network interchange", RFC 20,
              October 1969.

   [RFC3629]  Yergeau, F., "UTF-8, a transformation format of ISO
              10646", STD 63, RFC 3629, November 2003.

   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, January 2005.

   [RFC5234]  Crocker, D. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", STD 68, RFC 5234, January 2008.

   [UNICODE]  The Unicode Consortium, "The Unicode Standard, Version
              6.1", 2012,
              <http://www.unicode.org/versions/Unicode6.1.0/>.

7.2.  Informative References

   [I-D.jones-appsawg-webfinger]
              Jones, P., Salgueiro, G., and J. Smarr, "WebFinger",
              draft-jones-appsawg-webfinger-06 (work in progress),
              June 2012.

   [RFC4395]  Hansen, T., Hardie, T., and L. Masinter, "Guidelines and
              Registration Procedures for New URI Schemes", BCP 35,
              RFC 4395, February 2006.

Saint-Andre              Expires January 1, 2013                [Page 6]
Internet-Draft            The 'acct' URI Scheme                June 2012

   [RFC5890]  Klensin, J., "Internationalized Domain Names for
              Applications (IDNA): Definitions and Document Framework",
              RFC 5890, August 2010.

   [RFC5988]  Nottingham, M., "Web Linking", RFC 5988, October 2010.

Author's Address

   Peter Saint-Andre
   Cisco Systems, Inc.
   1899 Wynkoop Street, Suite 600
   Denver, CO  80202
   USA

   Email: stpeter@jabber.org

Saint-Andre              Expires January 1, 2013                [Page 7]