Programming Internet Email

Version 3.0 Housekeeping Types

The SOURCE and NAME types provide information relating to the vCard itself and are related. The SOURCE type, if it is included, gives information on the canonical source for the vCard (such as a URL). The NAME type provides human-readable text, suitable for display to a user, that represents the value in the SOURCE type. The SOURCE/NAME types can be used to ensure that a vCard recipient has access to the most recent version of a vCard.

The value of SOURCE type is generally a Universal Resource Indicator (URI) of some form. The CONTEXT subtype is used to show which sort of URI it is. As an example, consider a vCard for which current information is held on a publicly accessible LDAP directory server. The SOURCE and NAME lines might look like this:

SOURCE;CONTEXT=LDAP:  ldap://kernigan.plugged.net.au/cn=David%20Wood,
 %20o=Plugged.net.au,%20c=AU
NAME:                 David Wood's Internet-accessible Contact Details

It should be obvious by now that vCards often contain volatile information that is likely to change frequently. Version 3.0 vCards can use the REV type to specify their creation date (and alternately time). Combined with the SOURCE and NAME types, this allows programs parsing vCards to determine if they have the latest information and to update it as needed. A REV line looks like this:

REV:1999-0l-23T15:30G

The format (defined in ISO 8601) for a date is year-month-day and for a time is hour:minute:secondTIMEZONE. The time may be shortened if such precision isn’t ...