OnChange

Subscribe to attribute changes events for your active record

Add this line to your application's Gemfile:

gem 'on_change'

And then execute:

$ bundle

Or install it yourself as:

$ gem install on_change

class Book < ActiveRecord::Base
  on_change :title, :lookup_in_google_books
  on_change :title, :price, do |model, attr_name, old_value,new_value|
    model.do_something
  end
  def lookup_in_google_books(attr_name, old_value, new_value)
  end
end

1. Fork it
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 new Pull Request