Backbone.wreqr NPM

A simple infrastructure based on messaging patterns and service bus implementations for decoupling Backbone and Backbone.Marionette applications.

Notice: In the next major release of Marionette, v3, Wreqr will be swapped for an updated library, Radio. If you've already begun using Wreqr, don't worry. This change isn't for quite some time: a few months, at the earliest. Also, we will support easily swapping the two libraries, so you won't run into any problems if you decide to continue using Wreqr.

For an introduction to Radio, check out our blog post. As of Marionette v2.1, you can easily swap in Radio for Wreqr with this shim. We think you'll really like the changes!

Downloads And Source

Grab the source from the src folder above. Grab the most recent builds from the links below.

Standard Builds

Development: backbone.wreqr.js
Production: backbone.wreqr.min.js

Basic Use

Event Aggregator

An event aggregator implementation. It extends from Backbone.Events to provide the core event handling code in an object that can itself be extended and instantiated as needed.

var vent = new Backbone.Wreqr.EventAggregator();

vent.on("foo", function(){
  console.log("foo event");
});

vent.trigger("foo");

Commands And Request / Response

Wreqr can be used by instantiating a Backbone.Wreqr.Commands or Backbone.Wreqr.RequestResponse object. These objects provide a setHandler method to add a handler for a named request or command. Commands can then be executed with the execute method, and request/response can be done through the request method.

Commands

var commands = new Backbone.Wreqr.Commands();

commands.setHandler("foo", function(){
  console.log("the foo command was executed");
});

commands.execute("foo");

Request/Response

var reqres = new Backbone.Wreqr.RequestResponse();

reqres.setHandler("foo", function(){
  return "foo requested. this is the response";
});

var result = reqres.request("foo");
console.log(result);

Radio

Radio is a convenient way for emitting events through channels. Radio can be used to either retrieve a channel, or talk through a channel with either command, reqres, or vent.

// channels
var globalChannel = Backbone.Wreqr.radio.channel('global');
var userChannel = Backbone.Wreqr.radio.channel('user');

// Wreqr events
Backbone.Wreqr.radio.commands.execute( 'global', 'shutdown' );
Backbone.Wreqr.radio.reqres.request(  'global', 'current-user' );
Backbone.Wreqr.radio.vent.trigger(  'global', 'game-over');

Channel

Channel is an object that wraps EventAggregator, Commands, and Reqres. Channels provide a convenient way for the objects in your system to talk to one another without the global channel becoming too noisy.

// global channel
var globalChannel = Backbone.Wreqr.radio.channel('global');
globalChannel.commands.execute('shutdown' );
globalChannel.reqres.request('current-user' );
globalChannel.vent.trigger('game-over');

// user channel
var userChannel = Backbone.Wreqr.radio.channel('user');
userChannel.commands.execute('punnish');
userChannel.reqres.request('user-avatar');
userChannel.vent.trigger('win', {
  level: 2,
  stars: 3
});

Adding Multiple Handlers

Multiple handlers can be set on the Commands and RequestResponse objects in a single call, using the setHandlers method and supplying a {"name": configuration} hash where the configuration is an object literal or a function.

var reqres = new Backbone.Wreqr.RequestResponse();

reqres.setHandlers({
  "foo": function(){ /* ... */ },
  "bar": {
    callback: function(){ /* ... */ },
    context: someObject
  }
});

var result = reqres.request("foo");

The "foo" handler is assigned directly to a function, while the "bar" handler is assigned to a function with a specific context to execute the function within.

This works for all Handlers, Commands and RequestResponse objects.

Removing Handlers

Removing handlers for commands or requests is done the same way, with the removeHandler or removeAllHandlers functions.

reqres.removeHandler("foo");

commands.removeAllHandlers();

Extending Wreqr Objects

The EventAggregator, Commands and RequestResponse objects can all be extended using Backbone's standard extend method.

var MyEventAgg = Backbone.Wreqr.EventAggregator.extend({
  foo: function(){...}
});

var MyCommands = Backbone.Wreqr.Commands.extend({
  foo: function(){...}
});

var MyReqRes = Backbone.Wreqr.RequestResponse.extend({
  foo: function(){...}
});