| RFC draft-ietf-calext-jscontact-uid-05 | JSContact Version 2.0 | July 2025 |
| Stepanek | Expires 24 January 2026 | [Page] |
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.¶
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 (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/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.¶
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].¶
[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] 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.¶
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.¶
This document redefines the type signature of the "uid" property, originally defined in Section 2.1.9 of [RFC9553]. The new type signature is:¶
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).¶
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.¶
IANA will update the "JSContact Version" registry, originally created in Section 3.4 of [RFC9553]. It will add the following record:¶
| Major Version | Highest Minor Version | Reference |
|---|---|---|
| 2 | 0 | This document |
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.¶
This document does not provide new security considerations. The security considerations of Section 4 of [RFC9553] apply.¶