please help - complicated polymorphic association

rubyonrails-talk
1

I am trying to build a shared-appointment system, where users can subscribe to appointments and be updated whenever changes are made to them. I have three objects in this system, appointments, users, and subscribers. Subscribers are a polymorphic object like so: class Subscriber < ActiveRecord::Base   belongs_to :user   belongs_to :subscribable, :polymorphic => true end

The tricky part is that users already own appointments, so I can't create a simple users.appointments association. I can find users by calling appointment.subscribers, but I need help getting the reverse to work (users.subscribers.appointments) I can use named_scope to only grab appointment subscriber objects, but how can I make it automatically link to the appointments, not the subscriber objects?

2

Hi

As subscriber model is polymorphic and as you are referring “subscribers.appointments”

It means, you are having following association in appointment model.

class Appointment < ActiveRecord::Base

has_many :subscribers, :as => : subscribable

end

Here goes solution

class User < ActiveRecord::Base

has_many :subscribers

def appointments

self. subscribers.of_appointment_type.collect { |s| s.subscribable }

end

end

defined “of_appointment_type” as a named_scope in Subscriber model

class Subscriber < ActiveRecord::Base

belongs_to :user belongs_to :subscribable, :polymorphic => true

named_scope :of_appointment_type, :conditions => [ "subscribable_type = ? ", “Appointment”]

end

I am trying to build a shared-appointment system, where users can

subscribe to appointments and be updated whenever changes are made to

them. I have three objects in this system, appointments, users, and

subscribers. Subscribers are a polymorphic object like so:

class Subscriber < ActiveRecord::Base

belongs_to :user

belongs_to :subscribable, :polymorphic => true

It means you have subscribable_id and subscribable_type fields in table

end

The tricky part is that users already own appointments, so I can’t

create a simple users.appointments association. I can find users by

calling appointment.subscribers, but I need help getting the reverse

to work (users.subscribers.appointments) I can use named_scope to

only grab appointment subscriber objects, but how can I make it

automatically link to the appointments, not the subscriber objects?

Sandip