Active Harmony

What does it do

Active Harmony is a Ruby library for synchronizing Ruby objects with remote REST services.

Synchronizing just objects doesn't make much sense - so Active Harmony expects that you will use some persistance layer for your Ruby objects. For now, we support Mongoid, but you can easily code support for your favorite persistance layer. (Mongoid support is 30 lines - see synchronizable/harmony.rb)

How to use it

Installing

First, add Active Harmony to your Gemfile

gem 'active_harmony', :git => 'git://github.com/vojto/active_harmony.git'

Setting up services

Before you move on to your objects, you need to setup a remote service.

Start by initializing new Service Manager. This will be object that knows about all services. If you're using Rails, you can add this to your initializers:

SERVICE_MANAGER = ActiveHarmony::ServiceManager.new

You will need to access manager in your models later - to setup synchronization with the service. But, customize your service first:

my_service.base_url = 'http://myservice.com/api'
my_service.header['MyServiceKey'] = 'abcdef'

Service allows more customization, like adding authentication, changing paths, and so on. See documentation for ActiveHarmony::Service for more information.

You might want to know, that service supports only XML type of requests/responses for now. XML path for finding entities in XML responses is also one of the things you can customize on Service class.

Now you need to add your newly created service to your manager.

SERVICE_MANAGER.add_service_for_identifier(my_service, :my_service)

Setting up Ruby objects

Setup your Ruby object that will by synced. These lines set up persistence using Mongoid and include two classes from Active Harmony: Core adds basic synchronizable functionality, and Mongoid extends this to Mongoid persistence layer.

class Bacon
  include Mongoid::Document

  include ActiveHarmony::Synchronizable::Core
  include ActiveHarmony::Synchronizable::Mongoid

  field :tastyness
end

Assigning Service to Ruby objects

Now you have added services to your managers, and added synchronization capabilities to your objects. Last step is wiring things up together.

A good place to do this is your model, you'll see why:

class Bacon
  synchronizer.service = \
    SERVICE_MANAGER.service_with_identifier :my_service

  synchronizer.configure do |config|
    config.synchronize :tastyness
  end
end

As you can see, you're using class variable synchronizer. This variable was initialized for you when you included Synchronizable::Core, so you can change Service, or configure synchronizable fields.

Synchronizing objects

Check out documentation of Synchronizable::Core for methods you can use directly on your objects, or check out Synchronizer class that has methods like pulling whole collection from remote server.

Here's a simple example of pushing local changes:

chunky_bacon = Bacon.first
chunky_bacon.push
ActiveHarmony::Queue.instance.run

Please note that using Queue requires Mongoid. If you want to do an instant push, you can pass in true as argument to push:

chunky_bacon.push(true)

License

Copyright (c) 2010 Vojto Rinik

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Credits

  • Vojto Rinik: vojto (at) rinik (dot) net
  • Ryan Smith: ryandotsmith (at) gmail (dot) com