attribute filter concept for mass assignment

attribute_filter.rb

class User < ActiveRecord::Base
  protection_strategy :whitelist do
    only :first_name, :last_name, :login, :password, :password_confirmation
  end
  protection_strategy :blacklist do
    except :encrypted_password
  end
end

u = User.new({protected_attribute: "blah", first_name: "John"}, filter: :whitelist)

# u.attributes => {first_name: "John"}