Programming Jabber

Using the JUD and vCards

The two levels in our address book are going to reflect two distinct (but related) mechanisms in Jabber. We’re going to base our address book on the Jabber User Directory (JUD) component and supply further information, in a “drill-down” action, using vCards.

The JUD

Our address book will act as a query frontend for a user directory in the form of a JUD. It doesn’t matter which JUD we use; obviously, that depends on how the application is to be deployed. On one hand, it might be appropriate to point it at your company’s internal JUD, if you have one. On the other hand, it might also be just as appropriate to point it at one of the larger public JUDs, such as the one connected to the Jabber server running on jabber.org (which is users.jabber.org).

vCards

Every Jabber entity—users, components, and servers—has the potential to have a vCard. We saw in Chapter 4 that the Jabber server itself, and many of the components connected to it, had a vCard definition. While the vCard standard is still fluid, the implementation within Jabber, as described in Section 6.5.1 in Chapter 6, is enough to be useful.

The key to the application is that both the Jabber mechanisms that it relies upon—the JUD and vCards—can be accessed independently of the availability of the users that the information stored in those mechanisms represents. The JUD runs as an independent component and manages the directory information using its own data store. With the default JUD and XML Database ...