ActiveRecord - automatically merging model data as an aggregate - ruby-on-rails

Question

Lets say I have two tables.
class CreateUsers < ActiveRecord::Migration
def self.up
create_table :users do |t|
t.string :type, :default => 'User'
t.string :user_name, :null => false
t.boolean :is_registered, :default => true
# ... many more fields
end
end
end
class CreateContactInfo < ActiveRecord::Migration
def self.up
create_table :contact_info do |t|
t.integer :resource_id
t.string :resource_type
t.string :first_name
t.string :last_name
t.string :middle_initial
t.string :title
end
end
end
class ContactInfo < ActiveRecord::Base
belongs_to :contactable, :polymorphic => true
end
class User < ActiveRecord::Base
has_one :contact_info, :as => :contactable
# composed_of :contact_info # ... It would be nice if magics happened here
end
I would like to have the User's contact_info automatically merged into my User object as attributes of the user object without having to say #user.contact_info.first_name; instead, I would prefer to be able to write #user.first_name.
The reason I am breaking out attributes to the contact_info table is that these are common attributes to multiple models. That is why I am making setting up the contact_info as a polymorphic association.
Does anyone know of a good way to aggregate/merge the attributes of contact_info directly into my user model?

Answer 1

Use delegate:
class User < ActiveRecord::Base
has_one :contact_info, :as => :contactable
delegate :name, :name=, :email, :email=, :to => :contact_info
end

Answer 2

Not necessarily a good way to do it, but I did something similar by overriding the method_missing method and then calling my aggregated object. So, it would look something like:
class User
def method_missing(method_id)
self.contact_info.send(method_id)
end
end
Edit 1: Better implementation (I think this will work):
class User
alias_method :orig_method_missing, :method_missing
def method_missing(method_id)
if (self.contact_info.respond_to?(method_id))
self.contact_info.send(method_id)
else
orig_method_missing(method_id)
end
end
end
The above has the advantage that all other unknown method calls will get passed correctly.

Answer 3

I finally got it! Thank you both amikazmi and Topher Fangio. I had to implement both the delegate and method_missing techniques to get this to work.
Here is the total madness that finally ended up working for me! If anybody has suggestions on how to further improve this, I'd love to hear your suggestions.
class User < ActiveRecord::Base
attr_accessible *([:user_name, :udid, :password, :password_confirmation, :contact_info] + ContactInfo.accessible_attributes.to_a.map {|a| a.to_sym})
has_one :contact_info, :as => :contactable
def method_missing(method_id, *args)
if (!self.respond_to?(method_id) && self.contact_info.respond_to?(method_id))
self.contact_info.send(method_id, *args)
elsif (!self.class.respond_to?(method_id) && ContactInfo.respond_to?(method_id))
ContactInfo.send(method_id, *args)
else
super(method_id, *args)
end
end
# delegating attributes seems redundant with the method_missing above, but this secret sauce works.
ContactInfo.accessible_attributes.to_a.each do |a|
delegate a.to_sym, "#{a}=".to_sym, :to => :contact_info
end
def initialize(*args)
options = args.extract_options!
contact_attrs = ContactInfo.accessible_attributes.to_a.map{|a| a.to_sym}
#ci = ContactInfo.new(options.reject {|k,v| !contact_attrs.include?(k) })
super(*(args << options.reject { |k,v| contact_attrs.include?(k) }.merge(:contact_info => #ci) ) )
self.contact_info = #ci
end
validates_presence_of :user_name
validates_uniqueness_of :user_name
validates_associated :contact_info
def after_save
# automatically save the contact info record for the user after the user has been saved.
self.contact_info.save!
end
end
class ContactInfo < ActiveRecord::Base
set_table_name "contact_info"
belongs_to :contactable, :polymorphic => true
validates_presence_of :email
validates_uniqueness_of :email
attr_accessible :first_name,
:last_name,
:middle_initial,
:title,
:organization_name,
:email,
:email_2,
:twitter_name,
:website_url,
:address_1,
:address_2,
:city,
:state,
:zip,
:phone_work,
:phone_mobile,
:phone_other,
:phone_other_type
def full_name
[self.first_name, self.last_name].compact.join(' ')
end
end