Protocol-Specific Profiles for JSContact
draft-ietf-calext-jscontact-profiles-11

calext                                                       R. Stepanek
Internet-Draft                                                  Fastmail
Intended status: Standards Track                             M. Loffredo
Expires: 21 June 2026                                            IIT-CNR
                                                        18 December 2025

                Protocol-Specific Profiles for JSContact
                draft-ietf-calext-jscontact-profiles-11

Abstract

   This document defines JSContact profiles, an IANA registry for named
   subsets of JSContact elements.  It aims to facilitate using JSContact
   in context of contact data exchange protocols or other use cases, in
   which supporting all of JSContact semantics might be inappropriate.

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
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   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 21 June 2026.

Copyright Notice

   Copyright (c) 2025 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 (https://trustee.ietf.org/
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   Please review these documents carefully, as they describe your rights
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   provided without warranty as described in the Revised BSD License.

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Table of Contents

   1.  Notational Conventions  . . . . . . . . . . . . . . . . . . .   2
   2.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  JSContact Profiles  . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  Profile Name  . . . . . . . . . . . . . . . . . . . . . .   4
     3.2.  Profile Version . . . . . . . . . . . . . . . . . . . . .   4
     3.3.  Profile Properties  . . . . . . . . . . . . . . . . . . .   5
     3.4.  Supported Properties  . . . . . . . . . . . . . . . . . .   6
   4.  Example Profile . . . . . . . . . . . . . . . . . . . . . . .   7
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  10
     5.1.  Creation of the JSContact Profile Registry  . . . . . . .  10
     5.2.  Initial Contents of the JSContact Profile Registry  . . .  11
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  11
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  11
   Appendix A.  Supported Properties Example . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15

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 [RFC5234]
   (such as the ABNF for DIGIT).

2.  Introduction

   The JSContact [RFC9553] contact card data model and format is
   designed for use in address book applications and directory services.
   Intended as an alternative to the prevalent vCard [RFC6350] data
   format, it covers vCard core semantics and extensions, and provides a
   rich model for personal names, postal addresses and localization.
   All JSContact elements are relevant for some contact card use case
   and, similar to vCard, implementations are expected to support these
   elements when exchanging contact card information using protocols
   such as CardDAV [RFC6352] and JMAP for Contacts [RFC9610].

   In contrast, other protocols and internet standards might require
   exchanging _some_ contact card information, but not all of what
   JSContact provides.  Section 1.7.4 of [RFC9553] outlines how
   JSContact implementations may ignore unknown JSContact elements, but

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   this only applies to future extensions of [RFC9553]; they are still
   expected to implement all elements of the core specification.  Also,
   the extensibility of JSContact and the requirement to preserve
   arbitrary contact elements might not be adequate for some protocols.

   To make use of JSContact under these circumstances, this document
   defines a new IANA registry for JSContact that allows for registering
   named subsets of JSContact elements.  These subsets are referred to
   as "JSContact profiles" and are meant to bring the following
   benefits:

   *  Protocol designers might be encouraged to use JSContact, rather
      than coming up with their own contacts format.  This facilitates
      cross-protocol data exchange and migration.

   *  Different protocols use the same IANA registry to express which
      JSContact elements they support.  This facilitates understanding
      their commonalities and reusing existing profiles.

   *  A central registry provides implementors of JSContact libraries
      with a consistent format documenting which profile supports what
      elements, rather than having to look up that information from
      possibly distinctly organized internet drafts.

   This document is organized as follows: Section 3 defines JSContact
   profiles, Section 4 illustrates JSContact profiles by example,
   Section 5 summarizes the relevant information for IANA to establish
   the JSContact Profiles registry.

3.  JSContact Profiles

   A JSContact profile is a named and versioned set of JSContact
   properties, value types and values.  These JSContact elements MAY be
   further restricted by the profile, but a profile can not loosen
   restrictions.  For example, a profile can define an originally
   optional property to become mandatory, but it can not make a
   mandatory property become optional.

   The JSContact elements MUST be registered in the IANA JSContact
   registry.  A JSContact extension MAY define both a new profile and
   new properties or other elements, as long as they are registered at
   the same time.  A JSContact profile MUST be registered at IANA (see
   Section 5).  Section 3.1 defines how to name a JSContact profile,
   Section 3.2 defines how to version it, Section 3.3 defines how to
   specify the properties supported by that profile.

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   A JSContact object complies with a profile if all its properties are
   in the set of properties defined by that profile and the property
   values comply with the profile restrictions for that property.  A
   JSContact object can comply with multiple profiles, even with
   profiles that weren't defined at the time when the JSContact data was
   created.  Accordingly, this document does not specify any means for
   JSContact data to communicate which profiles it complies with, e.g.
   it does not define a "profile" property for the Card object.

   All properties and values of a JSContact object that complies with a
   profile MUST also be valid (Section 1.7 of [RFC9553]).  Handling
   JSContact data that is valid but that does not comply with the
   expected profile is protocol-specific.  This document deliberately
   does not define such non-compliant data as _invalid_. Profile
   designers decide on their own strategies for handling non-compliant
   data, one of which may be to reject it as invalid.  JSContact data
   that complies with a profile may still not be valid in the context of
   that protocol; the protocol specification MAY define additional
   restrictions that a profile cannot express.

3.1.  Profile Name

   A JSContact profile has a unique name.  The name MUST only contain
   ASCII lowercase alphabetic and numeric characters, optionally
   separated by hyphens.  It MUST start with an alphabetic character and
   it MUST be of at least 1 character and at most 255 characters in
   size.  Formally, it MUST be a valid "profile-name" defined in
   Figure 1.

   profile-name = LALPHA *( ["-"] LALPHA / DIGIT )
                  ; at most 255 octets in size

   LALPHA       = %x61-7A ; a-z

               Figure 1: ABNF Rule for JSContact Profile Name

3.2.  Profile Version

   A JSContact profile has a current version, each profile is versioned
   independently.  The version MUST be a positive integer and it MUST
   increase whenever the profile properties (Section 3.3) change.  The
   inital version value is 1.

   If this versioning scheme is not adequate for protocol designers
   making use of JSContact profiles, then an alternative approach is to
   register a new JSContact profile for each new version.

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3.3.  Profile Properties

   A profile defines a list of property entries that together determine
   the set of properties supported by that profile, as described in
   Section 3.4.  The list MUST NOT be empty.

   Each property entry consists of the following elements:

   Property Name:  This is the name of the JSContact property that this
      entry refers to.  This MUST be a property name registered in the
      "JSContact Properties" registry.  A property name MAY occur
      multiple times in the property entry list if the profile-specific
      restrictions for that property can not be expressed with a single
      entry, but such multiple entries MUST NOT result in conflicting
      restrictions for the same property.  This field MUST NOT be empty.

   Property Context:  This is a comma-separated list of JSContact object
      types that support this property in this profile.  Each of these
      types MUST also be listed in the property contexts for this
      property in the "JSContact Properties" registry, but a profile MAY
      only support the property in a subset of these contexts.  This
      field MUST NOT be empty.

   Restricted Attributes:  This restricts the attributes of the
      property.  This specification only defines how to restrict the
      attributes such that a property becomes mandatory in the listed
      property contexts, despite the property originally being defined
      to be optional in the same contexts.  The verbatim value
      "mandatory" (without quotes) indicates that it is mandatory in
      this profile, the absence of any value indicates that this profile
      does not restrict the property attributes of the original
      definition.

   Restricted Property Type:  This restricts the property value type in
      the listed property contexts, even though the property was
      originally defined with a less restrictive type definition.  If
      set, the original value type MUST contain some type signature in
      form "A|B" and the restricted value type MUST resemble the
      original except that some of the original "A|B" forms now only
      allow a subset of the original choices.  Restricted property types
      can not redefine the "defaultType" attribute [RFC9553]
      (Section 1.3.3), the rules when to set the "@type" property
      [RFC9553] (Section 1.3.4) of the original type definition still
      apply.

      For example, one might want to restrict the "date" property of the
      Anniversary object to only allow partial dates as values.  To do
      so, the original value type "PartialDate|Timestamp" can be

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      restricted to "PartialDate".  Note that the original value type
      need not be exactly in form "A|B".  For example, the type
      signature "Id[A|B|C]" could be restricted to any of "Id[A|B]",
      "Id[A|C]", "Id[B|C]", "Id[A]", "Id[B]", "Id[C]", and the type
      signature "(A|B)[]" to one of "A[]" or "B[]".

   Restricted Enum Values:  This restricts the enumerated values defined
      for this property to a subset of those values.  The values MUST be
      listed in the "JSContact Enum Values" registry for this property
      and context.  Allowed values are separated by comma; the absence
      of any value indicates that all enumerated values are allowed.  A
      profile MAY exclude the default enumerated value of a property, in
      which case all instances of the object MUST have this property set
      to one of the allowed values.

   Restricted PatchObject:  This restricts the PatchObject value of this
      property such that each JSON Pointer key in the PatchObject MUST
      consist of exactly one JSON Pointer reference token [RFC6901]
      (Section 3).  For example, with this restriction the
      "localizations" property of the Card object can only patch
      properties of the Card object by replacing their values entirely.
      The verbatim value "yes" (without quotes) indicates that this
      profile restricts PatchObject keys to a single token; the absence
      of any value indicates that it does not restrict them.  This MUST
      NOT be set to "yes" if the property value type is not a
      PatchObject.

   All profiles MUST support "@type" and "version", and therefore
   profiles MUST NOT include entries for these properties.

3.4.  Supported Properties

   The supported properties of a JSContact profile are determined by the
   profile's property entries and the contents of the IANA "JSContact
   Properties" registry, which is here referred to as "IANA-registered
   properties" for short.  The "version" property of the Card object and
   the "@type" property of any object type are always supported.

   A Card object complies with the profile if all its properties are
   part of the supported properties and all property values are valid
   according to the restrictions defined in the applicable property
   entries.  A PatchObject MUST NOT patch properties that are not
   supported in that profile.

   The following describes the steps to determine the supported
   properties:

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   1.  Initialize the set with all properties of the Card object for
       which a property entry contains "Card" in the Property Context of
       the profile.  If no such entry exists then initialize the set
       with all IANA-registered properties of the Card object.

   2.  For every property in the set having either an object type as
       value type, or a list or map or union of object types, add all
       properties for which a property entry contains those object types
       in the Property Context of the profile.  If no such property
       entry exists then add all IANA-registered properties for the
       object types.

   3.  Repeat the previous step until all object types that are value
       types of properties in the set have been considered.

   Appendix A describes how to determine the supported properties of the
   example profile in Section 4.

4.  Example Profile

   This section provides an example for a JSContact profile and
   illustrates how a JSContact Card complies with that profile.
   Appendix A describes how to determine the supported properties for
   that profile.  The example profile is defined the same as if it would
   be registered in the IANA JSContact Profiles registry.  See Section 5
   for the exact meaning of each registry item.  This profile is just
   for illustration, it is not registered at IANA.

   The following assignments would be registered at IANA if this were a
   real profile:

   Name:
      jscontact-simple

   Version:
      1

   Reference:
      This document, Table 1

   The following table defines the properties of that profile.  This
   profile does not specify any "Restricted Property Type" and the
   according column is omitted.

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    +=============+=============+==========+==============+===========+
    |Property Name|Property     |Restricted|Restricted    |Restricted |
    |             |Context      |Attributes|Enum Values   |PatchObject|
    +=============+=============+==========+==============+===========+
    |addresses    |Card         |          |              |           |
    +-------------+-------------+----------+--------------+-----------+
    |emails       |Card         |          |              |           |
    +-------------+-------------+----------+--------------+-----------+
    |kind         |Card         |          |individual,org|           |
    +-------------+-------------+----------+--------------+-----------+
    |localizations|Card         |          |              |yes        |
    +-------------+-------------+----------+--------------+-----------+
    |name         |Card         |          |              |           |
    +-------------+-------------+----------+--------------+-----------+
    |full         |Address      |mandatory |              |           |
    +-------------+-------------+----------+--------------+-----------+
    |components   |Name         |          |              |           |
    +-------------+-------------+----------+--------------+-----------+
    |full         |Name         |          |              |           |
    +-------------+-------------+----------+--------------+-----------+
    |kind         |NameComponent|          |              |           |
    +-------------+-------------+----------+--------------+-----------+
    |value        |NameComponent|          |              |           |
    +-------------+-------------+----------+--------------+-----------+

           Table 1: Properties of the "jscontact-simple" profile

   This profile describes contact cards that can only contain:

   *  Contact cards for individuals and organizations, but no other
      kinds such as groups or devices.

   *  Full postal address lines, but no address components or any other
      property of the Address object type.

   *  Full names and name components, but no other properties of the
      Name object type.

   *  Email addresses, where all properties of the EmailAddress object
      are supported.

   *  Localizations, with the restriction that the PatchObject must only
      patch properties of the Card object.

   The following Card object complies with the example profile:

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   {
     "@type": "Card",
     "version": "1.0",
     "name": {
        "components": [
         { "kind": "given", "value": "Hayao" },
         { "kind": "surname", "value": "Miyazaki" }
       ]
     },
     "addresses": {
       "a1": {
         "full": "71 Cherry Court, Somewhere, 123SO, UK"
       }
     },
     "emails": {
       "e1": {
         "address": "hayao@example.com"
       }
     },
     "localizations": {
       "jp": {
         "name": {
           "components": [
            { "kind": "surname", "value": "宮崎" },
            { "kind": "given", "value": "駿" }
           ]
         }
       }
     }
   }

   Note that:

   *  The Address, Card, Name, and NameComponent object values only
      contain properties for which a property entry exists in the
      profile.

   *  The EmailAddress object contains the "address" property.  This is
      allowed because the profile contains a property entry for the
      "emails" property of the Card object, but it does not define
      entries for the EmailAddress object properties.  Consequently, all
      properties of the EmailAddress object can be set.

   *  The "full" property of the Address object is set.  It is the only
      property allowed to be set in that profile for Address, and the
      "full" property is mandatory for this profile.

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   *  The "kind" property of the the NameComponent objects is set to
      "surname" and "given", respectively.  Since the profile does not
      restrict the enumerated values of this property, all valid
      NameComponent "kind" property values are supported.

   *  The "kind" property of the Card object is not set.  The profile
      restricts the enumerated values of this property to "individual"
      and "org".  Since "individual" is the default value for this
      property, there is no need to set it.

5.  IANA Considerations

5.1.  Creation of the JSContact Profile Registry

   IANA will add the "JSContact Profile" registry to the "JSContact"
   registry group.  The purpose of this new registry is to register
   profiles for JSContact data.  The registry policy to add a new
   profile to this registry is "Specification Required", while the
   registry policy to update an existing profile is "Expert Review".
   The change controller is IETF.

   Designated experts assert that all proposed assignments are valid
   according to the definitions in this document, e.g. they check that
   the profile name is unique, that the entries in the profile entries
   are syntactically valid, that only known property names are referred
   to, that type restrictions do not incorrectly alter the type of a
   property, and that the version number increases.  On the other hand,
   designated experts do not decide the contents of the profile as long
   as the assignments are valid.

   An entry in this registry consists of the following assignments, all
   of which MUST be set:

   Name:
      This is the name of the profile.  This field is immutable after
      creation.  The name MUST be unique among all registered profiles
      and MUST comply with the definitions in Section 3.1.

   Version:
      This is the version number of the profile.  It MUST comply with
      the definitions in Section 3.2.

   Reference:
      This refers to the specifications of the protocol or use case for
      which this profile applies.  The reference MUST must include the
      section number or name that defines or updates the property
      entries for this profile, as defined in Section 3.3.

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5.2.  Initial Contents of the JSContact Profile Registry

   This document does not define any initial contents for the newly
   created registries.

6.  Security Considerations

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

7.  References

7.1.  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>.

   [RFC6901]  Bryan, P., Ed., Zyp, K., and M. Nottingham, Ed.,
              "JavaScript Object Notation (JSON) Pointer", RFC 6901,
              DOI 10.17487/RFC6901, April 2013,
              <https://www.rfc-editor.org/info/rfc6901>.

   [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>.

   [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>.

7.2.  Informative References

   [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>.

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   [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>.

Appendix A.  Supported Properties Example

   The following illustrates how to determine the supported properties
   of the example profile (Section 4), according to the steps defined in
   Section 3.4:

   1.  We initialize the set of supported properties with all profile
       properties for which the property context includes the "Card"
       object.  The set now includes the properties:

       *  Card.addresses

       *  Card.emails

       *  Card.kind

       *  Card.localizations

       *  Card.name

   2.  Next, we determine which of the properties in the current set
       have an object type as value type.  These are the "Card.address",
       "Card.emails" and "Card.name" properties, so we need to inspect
       the object types "Address", "EmailAddress" and "Name".

   3.  For the "Address" object type, the profile has an entry for the
       "full" property which contains the "Address" object in the
       Property Context, so we add that and only that to the set of
       supported properties.  It now contains:

       *  Address.full

       *  Card.addresses

       *  Card.emails

       *  Card.kind

       *  Card.localizations

       *  Card.name

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       The value type of the "Address.full" property is not an object
       type, so we need not consider a new object type to inspect.  The
       remaining object types to inspect are the "EmailAddress" and
       "Name" objects.

   4.  For the "EmailAddress" object type, the profile does not contain
       any entry where the Property Context contains the "EmailAddress"
       object.  Instead, we add properties of the "JSContact Properties"
       registry where the property context includes the "EmailAddress"
       object.  The set of supported properties now contains:

       *  Address.full

       *  Card.addresses

       *  Card.emails

       *  Card.kind

       *  Card.localizations

       *  Card.name

       *  EmailAddress.address

       *  EmailAddress.contexts

       *  EmailAddress.label

       *  EmailAddress.pref

       None of the newly added properties have object value types.  The
       remaining object type to inspect is the "Name" object.

   5.  For the "Name" object type, the profile explicitly lists the
       "components" and "full" properties, so we add them to the set of
       supported properties.  It now contains:

       *  Address.full

       *  Card.addresses

       *  Card.emails

       *  Card.kind

       *  Card.localizations

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       *  Card.name

       *  EmailAddress.address

       *  EmailAddress.contexts

       *  EmailAddress.label

       *  EmailAddress.pref

       *  Name.full

       *  Name.components

       The newly added Name.components property has object value type
       "NameComponent", so we add that to the list of object types to
       inspect.

   6.  For the "NameComponent" object type, the profile does not
       explicitly list any property.  Instead, we add properties of the
       "JSContact Properties" registry where the property context
       includes the "NameComponent" object.  The set of supported
       properties now contains:

       *  Address.full

       *  Card.addresses

       *  Card.emails

       *  Card.kind

       *  Card.localizations

       *  Card.name

       *  EmailAddress.address

       *  EmailAddress.contexts

       *  EmailAddress.label

       *  EmailAddress.pref

       *  NameComponent.kind

       *  NameComponent.phonetic

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       *  NameComponent.value

       None of the newly added properties have object value types and
       there are no remaining object types to inspect.  This determines
       the set of supported properties by that profile, in addition to
       the "Card.version" and "@type" property that are always
       supported.

Authors' Addresses

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

   Mario Loffredo
   IIT-CNR
   Via Moruzzi, 1
   56124 Pisa
   Italy
   Email: mario.loffredo@iit.cnr.it

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