Protocol-Specific Profiles for JSContact

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Table of Contents

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 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, 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 and Section 3.2 define how to name and version a JSContact profile, Section 3.3 defines how to define the properties supported by that profile.¶

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.¶

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

LALPHA       = %x61-7A ; a-z

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.¶

Name:

jscontact-simple¶

Version:

1.0¶

Reference:

This document, Section 4¶

Properties:

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

Property Name	Property Context	Restricted Attributes	Restricted Property Type	Restricted Enum Values	Restricted PatchObject	Since Profile Version
addresses	Card					1.0
emails	Card					1.0
kind	Card			individual,org		1.0
localizations	Card				yes	1.0
name	Card					1.0
full	Address	mandatory				1.0
components	Name					1.0
full	Name					1.0
kind	NameComponent					1.0
value	NameComponent					1.0

¶

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:¶

{
  "@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.¶
• 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

6. Security Considerations

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

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¶

   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¶
   • 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¶
   • 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