Question

I have an application that lends itself to an event/listener model. Several different kinds of data get published (event), then many different things may or may not need to act on that data (listeners). There’s no specific order the listeners need to happen in and each listener would determine whether or not it needs to act on the event.

What tools for Rails apps are there to accomplish this task? I’m hoping to not have to do this myself (although, I can. It’s not THAT big a deal.)

Edit: Observer pattern might be a better choice for this

Answer 1

Check out EventMachine. It is a very popular event-processing library for Ruby. It looks quite good, and a lot of other libraries seem to take advantage of it (Cramp).

Here is a good introduction: http://rubylearning.com/blog/2010/10/01/an-introduction-to-eventmachine-and-how-to-avoid-callback-spaghetti/