Access rails session information by session id

Question

I'm using the default cookie based session store. Basically, I'm using heroku and I need to go from my app: http://test1.myapp.com over to heroku for one page: http://myapp.heroku.com/billing - so I need to access the session when I go to the heroku url. I'd like to access the session[:user_id] on the heroku page, but when is go to the heroku page a new the session is generated.

I was thinking I could pass the session_id on the main url in the querystring, but I don't know how to access it from the heroku url page.

I tried this:

session[params[:sid]][:user_id]

but it's not working. Is it possible to access session information if you know the session id? Or is there another way to read session information from another url (but all in the same rails app)?

Thanks.