NOTICE: This Historical specification provides canonical documentation of a protocol that is in use within the Jabber/XMPP community. This document is not a standards-track specification within the XMPP Standards Foundation's standards process; however, it might be converted to standards-track in the future or might be obsoleted by a more modern protocol.
This specification documents the vCard-XML format currently in use within the Jabber community. A future specification will recommend a standards-track protocol to supersede this informational document.
The basic functionality is for a user to store and retrieve an XML representation of his or her vCard using the data storage capabilities native to all existing Jabber server implementations. This is done by by sending an <iq/> of type "set" (storage) or "get" (retrieval) to one's Jabber server containing a <vCard/> child scoped by the 'vcard-temp' namespace, with the <vCard/> element containing the actual vCard-XML elements as defined by the vCard-XML DTD. Other users may then view one's vCard information.
vCards are an existing and widely-used standard for personal user information storage, somewhat like an electronic business card. The vCard format is defined in RFC 2426 [2].
In 1998 and 1999, Frank Dawson submitted four revisions of an Internet-Draft proposing to represent the standard vCard format in XML. When the jabberd open-source project was originally looking for a method to store personal user information, the most recent revision consulted by the jabberd developers was draft-dawson-vcard-xml-dtd-01 [3]. He also submitted a -02 revision on November 15, 1998 [4] and a -03 revision on June 22, 1999 [5].
Unfortunately, Dawson's proposal did not move forward within the IETF's standards process. For reasons now lost in the mists of time, the Jabber project continued to use the DTD from draft-dawson-vcard-xml-dtd-01, making two small modifications to adapt it for use within the Jabber community (adding the JABBERID and DESC elements) but also specifying element names in all caps rather than lowercase as defined in draft-dawson-vcard-xml-dtd-01. In addition, the Jabber community followed the usage (but not DTD) in that draft regarding version information, including it as an attribute of the vCard element rather than as a child element. This format was implemented within the Jabber community under the 'vcard-temp' namespace.
A user retrieves his or her own vCard by sending an IQ-get with no 'to' address and containing a <vCard/> child element qualified by the 'vcard-temp' namespace.
If a vCard exists for the user, the server MUST return in an IQ-result:
If no vCard exists, the server MUST return a stanza error (which SHOULD be <item-not-found/>) or an IQ-result containing an empty <vCard/> element.
A user may publish or update his or her vCard by sending an IQ of type "set" with no 'to' address, following the format in the previous use case.
The server then returns an IQ-result (or an IQ-error).
Notice that the previous IQ-set included only one changed element (the <DESC/> element). Currently there is no method for partial updates of a vCard, and the entire vCard must be sent to the server in order to update any part of the vCard.
If a user attempts to perform an IQ set on another user's vCard (i.e., by setting a 'to' address to a JID other than the sending user's bare JID), the server MUST return a stanza error, which SHOULD be <forbidden/> or <not-allowed/>.
A user may view another user's vCard by sending an IQ of type "get" to the other user's bare JID.
In accordance with XMPP Core [6], a compliant server MUST respond on behalf of the requestor and not forward the IQ to the requestee's connected resource.
If no vCard exists or the user does not exist, the server MUST return a stanza error. The server MUST return the same error condition in both cases to help prevent directory harvesting attacks. XMPP IM [1] dictates that <service-unavailable/> MUST be used when the user account identified by the 'to' attribute of an IQ stanza does not exist. Hence, <service-unavailable/> MUST be used in both cases.
Note: versions prior to 1.3 of this specification defined that either <service-unavailable/> or <item-not-found/> SHOULD be was used in these cases. For backwards-compatibility, applications SHOULD appropriately handle both errors.
Note: The use of vCards is not limited to accounts associated with human users. For example, an XMPP server could itself have a vCard that defines the server's hosting organization, physical location, and relevant contact addresses.
If an entity supports the vcard-temp protocol, it MUST report that by including a service discovery feature of "vcard-temp" (see Protocol Namespaces regarding issuance of one or more permanent namespaces) in response to a Service Discovery (XEP-0030) [7] information request:
The vCard information published to one's Jabber server is world-readable; therefore, users should exercise due caution when determining what information to include (e.g., street addresses, personal telephone numbers, or email addresses).
The correct capitalization of the wrapper element is <vCard/> (and XML element names are case-sensitive).
All elements within the <vCard/> element MUST be in ALL CAPS (even though this is at odds with draft-dawson-vcard-xml-dtd-01).
The country abbreviation is contained in a <CTRY/> element, not a <COUNTRY/> element (even though this is at odds with draft-dawson-vcard-xml-dtd-01).
Phone numbers MUST be contained in a <NUMBER> element, not included as CDATA within the <TEL/> element.
If no telephone number is included in a <TEL/> element, an empty <NUMBER/> child MUST be included.
Email addresses MUST be contained in a <USERID> element, not included as CDATA within the <EMAIL/> element.
Some Jabber implementations add a 'version' attribute to the <vCard/> element, with the value set at "2.0" or "3.0". The DTD is incorrect, and the examples in draft-dawson-vcard-xml-dtd-01 clearly show that version information is to be included by means of a 'version' attribute, not the <VERSION/> element as defined in the DTD. However, to conform to draft-dawson-vcard-xml-dtd-01, the value should be "3.0", not "2.0".
The following DTD is a slightly modified version of that contained in draft-dawson-vcard-xml-dtd-01. The only modifications were to add the JABBERID and DESC elements.
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The Extensible Messaging and Presence Protocol (XMPP) is defined in the XMPP Core (RFC 6120) and XMPP IM (RFC 6121) specifications contributed by the XMPP Standards Foundation to the Internet Standards Process, which is managed by the Internet Engineering Task Force in accordance with RFC 2026. Any protocol defined in this document has been developed outside the Internet Standards Process and is to be understood as an extension to XMPP rather than as an evolution, development, or modification of XMPP itself.
The following requirements keywords as used in this document are to be interpreted as described in RFC 2119: "MUST", "SHALL", "REQUIRED"; "MUST NOT", "SHALL NOT"; "SHOULD", "RECOMMENDED"; "SHOULD NOT", "NOT RECOMMENDED"; "MAY", "OPTIONAL".
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10. The XMPP Registrar maintains a list of reserved protocol namespaces as well as registries of parameters used in the context of XMPP extension protocols approved by the XMPP Standards Foundation. For further information, see <https://xmpp.org/registrar/>.