I develop a browser based game with node.js in back and HTML5 canvas in front-end.
It use WebSockets for communication.
My plan is to generate business events in client side, e.g.: “finishJob”.
Client will store all relevant information up to date.
- client doesn’t have to call server every time it need some data e.g: players money
- to achieve this, client will subscribe to players channel
- every online player has its own channel, like a chat room
- every time something happen with a player, its channel fire an event with players new data
In MVC pattern in here the model is Player, the View is the HTML5 Canvas, but i need 2 type of controllers:
- controller to handle business events
- controller to handle channels and subscribers
My questions: Is this a viable option?
If yes, are there any design pattern similar for this, or any article about this kind of architecture? Are there any naming conventions (“controllers”, “handlers”, “channels”…)?
2
Yes
…see the link below for this pattern…
If you’re writing an application which uses Peers — or any complex app which requires robust Object-Networks I would use an Event-Driven Architecture.
Using a Mediator or EventHub (Event-Aggrigator)
The simplest approach would be to implement the Mediator Pattern designed by Addy Osmoni.
This allows you to write something like:
// core.js
mediator.subscribe('newMemberAdded', function newMemberAddedHandler(id){
this.membersModule.add(id);
});
…
// membersUI.js
$('#addMember').click(function(){
...
mediator.publish('newMemberAdded', 998);
...
});
With this, the only Coupling your modules require is a reference to mediator in order to communicate with other modules.
Using a Mediator is very powerful and will make your modules more Liftable (loose coupling), however, there are some conventions you should consider while developing an EDA:
- Modules only publish interests — not Query+Command events
- e.g: eventHub.fire(‘buttonClicked’) NOT eventHub.fire(‘get:membersList’, function(){ … })
- Query+Command Channels Are reserved for Core/Facade interaction (see Osmoni’s post)
- Work-around those Noun-Verb-Adjective channel-names:
- e.g:
'log','start','change','notice'all can be seen as a command or something that happend. You can add the ing conjugate to obviate this ('starting')
- e.g:
- Listen Before You Speak! — Otherwise you may miss events
- Visit the link above for more
Additionally, you can bind your Mediator to a WebWorker or SharedWorker to share state between browser tabs (etc) and bind your worker to an EventHub on your server for an even cleaner coupling.
I know this post is somewhat ad hoc, but I hope its enough to get you started!
1