Access Devise Session in Backbone Marionette? - ruby-on-rails

Question

I'm working on creating a Rails app that uses Devise for user authentication and Backbone Marionette as the front end. I'm having trouble figuring out how to access the session that was created on the backend. I'd like to be able to grab say the username/email to display it in my Marionette app.
Also it might be useful to check to see if the session exists, though for the most part devise authentication in the controller seems to be working fairly well.
Any idea how I can access the current devise session in Backbone?
Thanks in advance!

Answer 1

Rails 3
The session cookies are stored as _app_session. They look obfuscated but they are just base64 encoded. You can use the atob function on the client to decode the session cookie and read any information you put in there. (In Rails 4 you are probably using encrypted session cookies and you will need to do something a little different)
An example cookie might look something like this:
"BAh7CEkiD3Nlc3Npb25faWQGOgZFVEkiJWNlZjFjMDhiNjYyNWEzZDI5YWM5MTJlMDY3MmQ0NTM4BjsAVEkiGXdhcmRlbi51c2VyLnVzZXIua2V5BjsAVFsISSIJVXNlcgY7AEZbBmkHSSIiJDJhJDEwJE5MYlhOWHFUMEtoZmdnNFliZHdyeE8GOwBUSSIQX2NzcmZfdG9rZW4GOwBGSSIxSSt6TnJsZm1FOTZTNWFRWGdSVWtGK2Zmd3BPVUxkQURjWHBqZ2NoZ05nMD0GOwBG"
It would decode into something like this:
atob(cookieStr);
"{I"session_id:ETI"%cef1c08b6625a3d29ac912e0672d4538;�TI"warden.user.user.key;�T[I" User;�F[iI""$2a$10$NLbXNXqT0Khfgg4YbdwrxO;�TI"_csrf_token;�FI"1I+zNrlfmE96S5aQXgRUkF+ffwpOULdADcXpjgchgNg0=;�F"
Rails 3/4
Rather than read from the session cookie I would add a separate cookie or just bootstrap your HTML code with the data you want.
Set your own cookie in your controller or devise hooks:
cookies[:my_data] = {
value: { username: "rocketman", email: "cliff.secord#gmail.com" }.to_json,
domain: "my.sweetapp.com"
}
In your client read that cookie: (use a lib like $.cookie to simplify the reading)
var cookieData, cookies = document.cookie.split('; ');
for (var i = 0, parts; (parts = cookies[i] && cookies[i].split('=')); i++) {
if (decode(parts.shift()) === "my_data") {
cookieData = JSON.parse(decode(parts.join('=')));
}
}
// Do something with cookieData;