Programming Jabber

Subscription Relationships

This method will result in “balanced” subscription relationships between script and recipients. In other words, the script is subscribed to a recipient’s presence, and vice versa.

Of the two presence subscription “directions,” the one where the notification script subscribes to the recipient’s presence (as opposed to the one where the recipient subscribes to the notification script’s presence) is by far the most important. While it’s not critical that the recipients know when the notification script is connected and active, it’s essential that the notification script know about a recipient’s availability at the time it wants to send a message.

So would it be more appropriate to create “unbalanced” subscription relationships?

An unbalanced relationship is one where one party knows about the other party’s availability but not vice versa. The idea for sensitizing the notification script will work as long as the script can know about the availability of the recipients. Whether or not the opposite is true is largely irrelevant.

Nevertheless, it’s worth basing the interaction on balanced, or reciprocal, presence subscriptions, primarily for simplicity’s sake and also for the fact that most Jabber clients (and most users of these clients) tend to cope well and consistently with balanced subscriptions, whereby the representation and interpretation of unbalanced relationships is dealt with and understood in different manners. Some clients use a lurker group ...