How to use Action Cable with Devise

The websocket server is running in a separate process from the Rails application so to authenticate the user we need cookies.

1. Set up cookies in Devise

   # app/config/initializers/warden_hooks.rb
   Warden::Manager.after_set_user do |user,auth,opts|
     scope = opts[:scope]
     auth.cookies.signed["#{scope}.id"] = user.id
     auth.cookies.signed["#{scope}.expires_at"] = 30.minutes.from_now
   end
   
   # app/config/initializers/warden_hooks.rb
   ...
   
   Warden::Manager.before_logout do |user, auth, opts|
     scope = opts[:scope]
     auth.cookies.signed["#{scope}.id"] = nil
     auth.cookies.signed["#{scope}.expires_at"] = nil
   end
   ...

2. Configure AC connection

   # app/channels/application_cable/connection.rb
   module ApplicationCable
     class Connection < ActionCable::Connection::Base
       identified_by :current_user
   
       def connect
         self.current_user = find_verified_user
         logger.add_tags 'ActionCable', current_user.name
       end
   
   protected
     def find_verified_user
       verified_user = User.find_by(id: cookies.signed['user.id'])
       if verified_user && cookies.signed['user.expires_at'] > Time.now
         verified_user
       else
         reject_unauthorized_connection
       end
     end
     end
   end