Backbone, Faye, and Reaction

I was jealous of what MeteorJS did for NodeJS developers, and decided to steal some of their ideas for Rails. The result is the reaction gem, and a demo app can be downloaded from here.

Transparent Synchronization

Using Reaction, you write your app like a usual Backbone app. However, instead of using Backbone.Collection, use Reaction.Collection to create a synchronized collection.

var collection = new Reaction.Collection({
  controller_name: 'todos',
  model_name: 'todo'
});

The collection provides a custom sync function that routes changes to the conventional CRUD endpoints of the Rails application. For example, when you invoke collection.create({...}, {wait:true}), it makes a POST request to the Rails app.

When updates are pushed from the Rails server to the client, the collection is updated and add, remove, or change events are fired. For example, a view may react to an add event as follows:

collection.bind('add', this.addOne, this);
// ...
addOne: function(obj) {
  $('x').append(new XView(obj).render().el);
}

Local HTML5 Storage

Objects in the collection are cached in the local HTML5 storage. If the client is online, this helps to reduce the initial time required to load the interface; if the client is offline, this allows the collection to be re-created from the cache, showing the user a decent (but outdated) interface.

Separate App Server and Push Server

For scaling purposes, the app server can be separated from the push server. This also allows multiple app servers to share the same push server. When these servers are started, a shared secret must be provided. This secret will be used to sign messages sent from the app servers to the push server.

If you wish to learn more, head to the quickstart.