I can not read cookie values when I try to access a method from a RoR Application to another RoR Application

I will try to explain as best I can my problem, because it is a lot of
time that I am trying to solve it without success. I hope someone can
really help me, however banal it may seem. So...

I have two RoR 3 applications:

- APP1: www.app1.example.com
- APP2: www.app2.example.com

Notice (if it helps): I do not use www.example.com as a developed RoR
application, for now. At the moment it is only a "nil" project, that
is a RoR basic application simply generated through the command 'rails
new example' in the Terminal.

In APP1 I have a 'APP1/controllers/user_authentications_controller.rb'
with the following code to set user's cookies:

def create
  ...
    cookies.signed[:current_user_id] = { :value => [user.id,
user.make_user_id_salt(user.id)], :expires =>
15.days.from_now, :domain => ".example.com" }
  ...
end

that means (I know) I set cookies accessible from all
'www.subdomain.example.com'. In fact, normally, I can access the value
of the cookie with the code 'cookies[:current_user_id]' both from APP1
and APP2.

The problem happens when I try to access the value of the cookie by
making a request from APP1 to APP2 and vice versa. For example, using
in APP2 the code

Net::HTTP.get( URI.parse( www.app1.example.com/users ) )

and having in ''APP1/controllers/users_controller.rb'' the code

def index
  @check_var = cookies[:current_user_id]
end

the debug of the @check_var in the ''APP1/views/users/index.html.rb''
shows me a blank value. For this reason I can not even use the
conditional constructs and similar!

This is only an example, but it happens also when I use the REST
approach with API, and I think also in other cases when I make an
external request to APPs. It seems that RoR does not follow cookies.

So the question is: is it possible to get/share cookie or session
information between more RoR applications?

I use a Mac with OS "Snow Leopard" v10.6.5, Apache2 and Phusion
Passenger.

that means (I know) I set cookies accessible from all
'www.subdomain.example.com'. In fact, normally, I can access the value
of the cookie with the code 'cookies[:current_user_id]' both from APP1
and APP2.

Always worth double checking in the browser that the cookie got set as you intended

The problem happens when I try to access the value of the cookie by
making a request from APP1 to APP2 and vice versa. For example, using
in APP2 the code

Net::HTTP.get( URI.parse( www.app1.example.com/users ) )

I think you have a misconception of how cookies work. When you set a cookie your http response will have a Set-Cookie. The browsers reads this and then knows that on subsequent requests to appropriate pages it should send that info. It doesn't magically affect http requests made by your app. If you want a request you make via http to send a cookie then you need to craft an appropriate Cookie: header for that request. Similarly, if a cookie is created in response to a request you make using net/http, it will never make it to the user, unless you forward on the set-cookie header.

Fred