Using Cookies.js and jquery.base64.js to parse a signed cookie generated by Rails into an JavaScript Object

application_controller.rb

      
      # ... after succesful login
      def set_current_user_cookie( user )
        client_side_user_obj = { id: user.id, email: user.email }
        cookies.signed[:_application_alt_session] = client_side_user_obj.to_json          
      end
      # ...

cookies.signed_parser.coffee

# Return object as from a signed cookie

Cookies.get_signed_cookie_obj = ( cookie_name ) ->
  return undefined unless cookie = Cookies.get(cookie_name)
  cookie_data_decoded = decodeURIComponent( cookie )
  cookie_data_array = cookie_data_decoded.split('--') # [0]: server data, [1]: server sign
  
  { decoded_data: $.base64.decode(cookie_data_array[0]), sign: cookie_data_array[1] }