Chapter 7. Messages, Presence, and Presence Subscription

Table of Contents
CVS notification
Dialup system watch
Presence-sensitive CVS notification

Now that we have a decent grounding in the Jabber protocol and technology, let's put it to work for us. This chapter fits Jabber into solutions for two or three common problems, and shows how the technology and features lend themselves very well to application-to-person (A2P) scenarios.

By way of introduction, we'll have a look at constructing and sending simple Jabber messages, to effect an "in your face" notification mechanism for a version control system. We'll also introduce a usage of the <presence/> element as an availability indicator for connecting systems. Finally we'll combine the two features (<message/> and the concept of availability) to make the notification mechanism "sensitive" to the presence of the person being notified.