Scala + Play + Akka. Is there a need for Backbone.js?

Question

My backend is in Postgres. I'm using Scala to build APIs of it.

Everytime there is a change in the database, I want my chrome extension to be notified. I've a few questions regarding this:

1. Should I implement websockets here or do long polling?
2. If web-sockets, are there any good examples of how do I do it using scala + play + Akka and javascript?
3. I believe that I've to implement something called as an observer pattern that notifies my chrome extension if there is any change in data. Is there any other pattern that I should follow to get such a thing done with the minimum DB over-head.
4. Should I use Redis or RabbitMQ to deal with this particular notification part of things?

Answer 1

1) I would use http://socket.io/

3) This is interesting question. Observer pattern is commonly used on front end. I would recommend you to check out this article http://addyosmani.com/largescalejavascript/. It helped me to better structure my application. It is basically Pub/Sub pattern with EventBroker/Mediator between. It would be idealy to decouple publisher and subcriber. You can place EventBroker in your application namespace. In this way you have access to message bus from your modules, without needing to pass reference through modules all the time.

4) We have used redis for real/time notifications on website that have similar functionality like pinterest. I am impressed with redis performance.