Simple ActiveRecord diff functionality.

Example usage:

  require 'active_record/diff'

  class User < ActiveRecord::Base
    include ActiveRecord::Diff
  end

  alice = User.create(:name => 'alice', :email_address => 'alice@example.org')

  bob = User.create(:name => 'bob', :email_address => 'bob@example.org')

  alice.diff?(bob)  # => true

  alice.diff(bob)  # => {:name => ['alice', 'bob'], :email_address => ['alice@example.org', 'bob@example.org']}

  alice.diff({:name => 'eve'})  # => {:name => ['alice', 'eve']}
  
Multiple objects can also be compared. Example:

  eve = User.create(:name => 'eve', :email_address => 'bob@example.org')
  
  alice.diff?([bob, eve])  # => true
  
  alice.diff([bob, eve])  # => { :name => ['alice', 'bob', 'eve'], :email_address => ['alice@example.org', 'bob@example.org'] }


By default, ActiveRecord::Base.content_columns is used to decide which attributes
to compare. You can include or exclude attributes from this as follows:

  class User < ActiveRecord::Base
    diff :include => [:id], :exclude => [:password_hash]
  end


Alternatively, you can specify exactly which columns to compare:

  class User < ActiveRecord::Base
    diff :id, :name, :email_address
  end


This is an updated version of the "riff" rails plugin.


To the extent possible under law, Tim Fletcher has waived all copyright and
related or neighboring rights to activerecord-diff. This work is published
from the United Kingdom. http://creativecommons.org/publicdomain/zero/1.0/

Contributions

- Zachary Porter ( zporter )