Has a relationship through four models? - ruby-on-rails

Question

I'm having trouble setting up this association between my models.
A User has many Accommodations, and Accommodations have one User.
Accommodations have many Notifications, and Notifications have one Accommodation.
Requests have many Notifications.
How can I make it so that I can get all of the Requests for a given User ( that is, User -> Accommodations (each) -> Notification -> Request)?
Update:
Here's my current controller file:
class PanelController < ApplicationController
before_filter :login_required
def index
#accommodations = current_user.accommodations.all
#requests = Array.new
#accommodations.each do |a|
a.notifications.each do |n|
#requests << Request.where('id' => n.request_id)
end
end
end
end
And models:
models/user.rb
class User < ActiveRecord::Base
[snip]
has_many :accommodations
has_many :notifications,
:through => :accommodations
end
models/accommodation.rb
class Accommodation < ActiveRecord::Base
validates_presence_of :title, :description, :thing, :location, :spaces, :price, :photo
attr_accessible :photo_attributes, :title, :description, :thing, :location, :spaces, :price
has_one :photo
has_many :notifications
belongs_to :user
accepts_nested_attributes_for :photo, :allow_destroy => true
end
models/notification.rb
class Notification < ActiveRecord::Base
attr_accessible :accommodation_id, :request_id
has_one :request
belongs_to :accommodation
end
models/request.rb
class Request < ActiveRecord::Base
belongs_to :notifications
attr_accessible :firstname, :lastname, :email, :phone, :datestart, :dateend, :adults, :children, :location, :status
validates_presence_of :firstname, :lastname, :email, :phone, :datestart, :dateend, :children, :adults, :location
end

Answer 1

Something like this should work:
#reqs = []
#user.accommodations.all.each do |a|
#reqs << a.notification.request
end
Assuming this is correct:
class User
has_many :accommodations
end
class Accommodation
belongs_to :user
has_many :notifications
end
class Notification
belongs_to :accomodation
belongs_to :request
end
class Request
has_many :notifications
end
Using has_many :through will not work for multiple models, as seen here: Ruby-on-Rails: Multiple has_many :through possible?
But you can do something like this in your user model:
class User
has_many :accommodations
has_many :notifications,
:through => :accommodations
def requests
self.notifications.all.collect{|n| n.request }
end
end