First post in a while. I have been busy working on some large application and finishing up my Computing Science Degree. Now that the piece of paper is safely secured above my fireplace, I’ve been trying to find time to do a new post.

I have been building a large application and one of the requirements is to trigger a certain action when an event happens. For example, trigger the sending of an alert email when a database row is updated. Some programmers may be tempted to simply hard-code this functionality into the model class, however this doesn’t give very strict class encapsulation, and can quickly become un-maintainable.

I use the Dojo Javscript toolkit for most of my dynamic front-end functionality. It has implemented a publish/subscribe system using dojo.publish() and dojo.subscribe(). This article will describe the implementation of a similar system using PHP. Read the rest of this entry »