Shared authentication between rails and node.js with redis store

I have a rails app and a node.js app and I use Devise to authenticate users. I store the session with Redis. Now I'd like that when a user go to the node app, the app checks through socket.io whether the user is logged in or not. I managed to get the session datas from redis but I don't know how to interpret them to check if the user is logged in.

Here is my code for the node app which checks if the _session_id exists in the database and retrieves the session datas:

io.set('authorization', function (data, accept) {
    if (data.headers.cookie) {
        data.cookie = cookie.parse(data.headers.cookie);
        data.sessionID = data.cookie['_session_id'];
        redis.get(data.sessionID, function (err, session) {
            if (err || !session) {
                accept('Error', false);
            } else {
                data.session = session;
                console.log(session);
                accept(null, true);
            }
        });
    } else {
       return accept('No cookie transmitted.', false);
    }
});

This is what the console.log(session) gives me:

{I"_csrf_token:EFI"1HPglfkCCagvb1LLraU1CEEyx7AtDzztqAEPY5G5lNgY=;FI"warden.user.user.key;TI"    User;F[iI""$2a$10$IHq2WAhwbaqR4WWajRE/Yu;T

How can I check if a user is logged in the rails app with the node app? Thanks

EDIT: It appears that the redis store gem I use calls a Marshalling method before storing the session in database. So I bypassed the problem by overriding the Marshalling method and stored the session datas in JSON format. It's not very elegant so if you find a better way to share sessions between rails and node.js, please let me know.