SCAR

SproutCore add-on frameworks such as BulkApi handle the conversion and binding of belongs_to associtions but do not handle the inverse relationships.

For example, BulkApi will map todo.project_id to a Project object but will not create the inverse association, mapping project.todos to an array of IDs (i.e. project.todos #=> [1, 2, 7]).

In order to create this inverse association, we simply need to tell the data source to return the IDs of any associated records. This is what SCAR does.

SCAR extends ActiveRecord's as_json method to tell your model to return these association IDs:

ninja_chores = Project.create :name => "Ninja Chores"

Todo.create(:name => "Wax bo staff", :project => ninja_chores)
Todo.create(:name => "Order Pizza", :project => ninja_chores)

project.as_json #=> { :id => 1, :name => "Ninja Chores", :todo_ids => [1, 2] }

This works just as well for has_one associations:

Owner.create(:name => "Donatello", :project => ninja_chores)

project.as_json #=> { :id => 1, :name => "Ninja Chores", :todo_ids => [1, 2], :owner_id => 9 }

Usage

Currently this is just a simple drop-in lib for Rails 3.

1. Clone and copy scar.rb to #{Rails.root}/lib.
2. You'll need to call require "#{RAILS_ROOT}/lib/scar.rb" in either environment.rb or add this line to an initializer (e.g. #{Rails.root}/config/initializers/scar.rb)

This will eventually become a gem with more flexibility.

Pull requests are certainly welcome.

License

MIT License, of course.