Embedson

Main goal is to implement Mongoids embedded document functionality in ActiveRecord.

Hash representation of class defined by specified method (default to_h) is saved in json/hstore column.

Adds functionality of embeds_one to ActiveRecord.

Adds functionality of embedded_in to any class initialized with Hash.

Installation

Add this line to your application's Gemfile:

gem 'embedson'

And then execute:

$ bundle

Or install it yourself as:

$ gem install embedson

Usage

Example with Searchlight is described in blogpost "Persistent queries in Ruby on Rails with PostgreSQL".

Example with Virtus:

	
	#create_tests.rb - migration
	class CreateTests < ActiveRecord::Migration
	  def change
	    create_table :tests do |t|
	      t.json :data
	    end
	  end
	end
	
	class Test < ActiveRecord::Base

	  embeds_one :virt, class_name: Virt,
                        column_name: :data,
                        inverse_of: :parent,
                        hash_method: :to_h    # default option
	end

	class Virt
	  include Virtus.model
	  extend Embedson::Model

	  attribute :name, String
	  attribute :address, Hash

	  embedded_in :parent, class_name: Test, inverse_of: :virt
	end

	virt = Virt.new(name: 'Sample', address: { street: 'Kind', number: '33' })
	virt.attributes # => {:name=>"Sample", :address=>{:street=>"Kind", :number=>"33"}}

	test = Test.create!
	test.attributes # => {"id"=>1, "data"=>nil}

	test.virt = virt
	test.save
	test.attributes # => {"id"=>1, "data"=>{"name"=>"Sample", "address"=>{"street"=>"Kind", "number"=>"33"}}

	test.reload.virt.attributes # =>  {:name=>"Sample", :address=>{:street=>"Kind", :number=>"33"}}
	test.virt == virt # => true
	test.virt.parent == test # => true

You don't have to use all options to define embeds_one and embedded_in. Just name it with downcased related class name.

	#create_tests.rb - migration
	class CreateTests < ActiveRecord::Migration
	  def change
	    create_table :tests do |t|
	      t.json :virt
	    end
	  end
	end

	class Test < ActiveRecord::Base

	  embeds_one :virt
	end

	class Virt
	  include Virtus.model
	  extend Embedson::Model

	  attribute :name, String
	  attribute :address, Hash

	  embedded_in :test
	end

Additional methods in embedded model:

• ####save Assigns to_h result to parent and saves it with save.

• ####save! Assigns to_h result to parent and saves it with save!.

• ####destroy Assigns nil to parent and saves it with save!

• ####embedson_model_changed! This gem does not provide dirty tracking of embedded model. To register change in parent model use this method in your setter.

	def your_variable=(arg)
	  @your_variable = arg
	  embedson_model_changed!
	end

Known issues

• Placing initialize method after embedded_in and using Emb.new(parent: parent)

These examples will work:

	class Emb
	  extend Embedson::Model

	  def initialize(attributes = {})
	    # do your work here
	  end

	  embedded_in :parent
	end

	class Emb
	  extend Embedson::Model

	  embedded_in :parent

	  def initialize(attributes = {})
	    self.parent = attributes[:parent]
	    # do your work here
	  end
	end

This will not work!

	class Emb
	  extend Embedson::Model
	  embedded_in :parent

	  def initialize(attributes = {})
	    # if you forget about assigning parent
	    # do your work here
	  end
	end

Contributing

1. Fork it ( https://github.com/[my-github-username]/embedson/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

License

Copyright (c) 2014 Szymon Frącczak. See LICENSE.txt for further details.