



calext                                                       R. Stepanek
Internet-Draft                                                  Fastmail
Updates: 9553, 9555 (if approved)                           23 July 2025
Intended status: Standards Track                                        
Expires: 24 January 2026


      JSContact Version 2.0: A JSON Representation of Contact Data
                   draft-ietf-calext-jscontact-uid-05

Abstract

   This document defines version "2.0" of JSContact.  It defines the
   "uid" property of a Card object to be optional, rather than mandatory
   as defined in previous version "1.0".  Other than changing the "uid"
   property, all other definitions of JSContact version "1.0" remain as
   defined in RFC 9553.  This document updates RFC 9555 by redefining
   how to convert the now optional "uid" property from and to vCard.

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 https://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 24 January 2026.

Copyright Notice

   Copyright (c) 2025 IETF Trust and the persons identified as the
   document authors.  All rights reserved.











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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://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 Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Notational Conventions  . . . . . . . . . . . . . . . . . . .   2
   2.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  JSContact Version 2.0 . . . . . . . . . . . . . . . . . . . .   3
   4.  Redefined "uid" Property  . . . . . . . . . . . . . . . . . .   4
   5.  Redefined Conversion Rule for the "uid" Property  . . . . . .   4
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
     6.1.  Update to the JSContact Version Registry  . . . . . . . .   4
     6.2.  Update to the JSContact Properties Registry . . . . . . .   5
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Notational Conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   The ABNF definitions in this document use the notations of [RFC5234].
   ABNF rules not defined in this document are defined in either
   [RFC5234] (such as the ABNF for CRLF, WSP, DQUOTE, VCHAR, ALPHA, and
   DIGIT) or [RFC6350].

2.  Introduction

   [RFC9553] defines the "uid" property of a Card object, a mandatory
   property which contains an unique identifier for the entity
   represented by that contact card.  This property being mandatory has
   shown to be applicable for some use cases, but has turned out to be
   an issue in other contexts.

   For example, the CardDAV protocol [RFC6352] requires the UID property
   of a vCard object [RFC6350] to be set.  Accordingly, an internet
   server that implements both CardDAV and JMAP for Contacts [RFC9610]



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   requires the "uid" property of a JSContact Card to be set.  In
   contrast, protocols such as RDAP [RFC9083] have no use for the "uid"
   property, either because they use different identifiers, or they
   prefer to not include any unique identifier in the contact data at
   all.  JSContact should not require them to generate unique
   identifiers that are irrelevant to their use case.

   Also, one of the stated goals of JSContact is to be compatible with
   the semantics of the vCard data format (Section 1 of [RFC9553]).  But
   [RFC6350] defines the UID property of a vCard to be optional, and
   consequently the semantics of JSContact and vCard differ for such a
   crucial common element.

   In case of vCards without a UID property [RFC6350] (Section 6.7.6)
   being converted to JSContact, requiring unique identifiers is
   especially problematic: the Card "uid" property is mandatory and
   accordingly Section 2.1.1 of [RFC9555] requires implementations to
   generate some unique identifier for it during conversion, but it does
   not guarantee it to be the same across implementations or even one
   implementation converting the same Card multiple times.  A recipient
   being unaware that the "uid" property value of such a Card object is
   ephemeral might refer to it in the "members" or "relatedTo"
   properties of another Card object, introducing invalid relations
   between contact cards.

3.  JSContact Version 2.0

   This document redefines the "uid" property of a Card object to become
   optional.  Other than that, the property definition is left
   unchanged.  This change requires the major version of JSContact to
   change, so this document defines the JSContact version to become
   "2.0".

   Implementations MUST create JSContact data that complies with the
   definitions of version "2.0" (or some later registered version) and
   MUST set the "version" property of the JSContact Card object to that
   version.  They MUST NOT reject a Card object without the "uid"
   property as invalid unless specified differently in another document,
   or unless the Card "version" property has value "1.0".  As any valid
   version "1.0" JSContact Card also is valid according to version
   "2.0", there is no need to migrate existing JSContact data.

   If to set the "uid" property is use-case specific.  If an
   implementation is able to consistently generate the exact same unique
   identifier for a JSContact Card representing the same entity and no
   protocol-specific concerns prevail, it is recommended to set the
   "uid" property.




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4.  Redefined "uid" Property

   This document redefines the type signature of the "uid" property,
   originally defined in Section 2.1.9 of [RFC9553].  The new type
   signature is:

   *uid: String (optional).*

   The remaining property definition is left unchanged, with the
   following additional paragraph:

   A Card without a uid property can not be referred to as group member
   in the "members" property [RFC9553] (Section 2.1.6), or put in
   relation to another Card object in the "relatedTo" property [RFC9553]
   (Section 2.1.8).

5.  Redefined Conversion Rule for the "uid" Property

   This document redefines how to convert the Card "uid" property from
   vCard, originally defined in Section 2.1.1 of [RFC9555].  The new
   conversion rule is:

   Implementations that convert a vCard without a UID property [RFC6350]
   (Section 6.7.6) to a Card of version "2.0" or higher MUST NOT
   generate a unique identifier as value for the "uid" property
   [RFC9553] (Section 2.1.9).

   When converting a vCard without UID property to obsoleted JSContact
   version "1.0", implementations MUST generate a value for the "uid"
   property.  Generating unique identifiers is implementation-specific.
   An implementation SHOULD generate the same value when generating the
   same Card multiple times, but MAY generate different values for each
   conversion.  Section 2 describes why this is problematic.
   Consequently, implementations SHOULD NOT convert to version "1.0"
   Card objects.

6.  IANA Considerations

6.1.  Update to the JSContact Version Registry

   IANA will update the "JSContact Version" registry, originally created
   in Section 3.4 of [RFC9553].  It will add the following record:









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         +===============+=======================+===============+
         | Major Version | Highest Minor Version | Reference     |
         +===============+=======================+===============+
         | 2             | 0                     | This document |
         +---------------+-----------------------+---------------+

                    Table 1: JSContact Version Registry

6.2.  Update to the JSContact Properties Registry

   IANA will update the "JSContact Properties" registry, originally
   created in Section 3.5 of [RFC9553]: For the "Reference/Description"
   column of the "uid" property, it will replace the reference to
   [RFC9553] with a reference to Section 4 of this document.

7.  Security Considerations

   This document does not provide new security considerations.  The
   security considerations of Section 4 of [RFC9553] apply.

8.  References

8.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC5234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", STD 68, RFC 5234,
              DOI 10.17487/RFC5234, January 2008,
              <https://www.rfc-editor.org/info/rfc5234>.

   [RFC6350]  Perreault, S., "vCard Format Specification", RFC 6350,
              DOI 10.17487/RFC6350, August 2011,
              <https://www.rfc-editor.org/info/rfc6350>.

   [RFC6352]  Daboo, C., "CardDAV: vCard Extensions to Web Distributed
              Authoring and Versioning (WebDAV)", RFC 6352,
              DOI 10.17487/RFC6352, August 2011,
              <https://www.rfc-editor.org/info/rfc6352>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.





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   [RFC9083]  Hollenbeck, S. and A. Newton, "JSON Responses for the
              Registration Data Access Protocol (RDAP)", STD 95,
              RFC 9083, DOI 10.17487/RFC9083, June 2021,
              <https://www.rfc-editor.org/info/rfc9083>.

   [RFC9553]  Stepanek, R. and M. Loffredo, "JSContact: A JSON
              Representation of Contact Data", RFC 9553,
              DOI 10.17487/RFC9553, May 2024,
              <https://www.rfc-editor.org/info/rfc9553>.

   [RFC9555]  Loffredo, M. and R. Stepanek, "JSContact: Converting from
              and to vCard", RFC 9555, DOI 10.17487/RFC9555, May 2024,
              <https://www.rfc-editor.org/info/rfc9555>.

   [RFC9610]  Jenkins, N., Ed., "JSON Meta Application Protocol (JMAP)
              for Contacts", RFC 9610, DOI 10.17487/RFC9610, December
              2024, <https://www.rfc-editor.org/info/rfc9610>.

Author's Address

   Robert Stepanek
   Fastmail
   PO Box 234
   Collins St. West
   Melbourne VIC 8007
   Australia
   Email: rsto@fastmailteam.com
























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