User's presence in the chat (chat updated by a simple poll)

Question

We implemented a simple chat feature in Rails using simple Ajax updates. Now in each chat room a message belongs to a specific user. We want to show a list of users (something like user presence). Please suggest ways. We do not use Jabber, XMPP, etc.

Chatroom Model:

class ChatRoom < ActiveRecord::Base validates_presence_of :title has_many :messages,:foreign_key=> "chat_room_id" has_many :stories,:foreign_key=>"chat_room_id" has_many :topics,:foreign_key=>"chat_room_id" end 

Messages are chats sent to each user.

Message Model:

 class Message < ActiveRecord::Base belongs_to :user end 

User Model:

 class User < ActiveRecord::Base acts_as_authentic :crypto_provider => Authlogic::CryptoProviders::BCrypt validates_presence_of :nick validates_uniqueness_of :nick has_many :questions end 

Please suggest ways

Answer 1

To keep track of which users are in which room, you can establish a HABTM connection between the ChatRoom and User models. And you can add the last_poll_datetime column to the User model to track the last time the user polled messages (more on this part in a minute).

To list all users in a given room, use the HABTM join table, ChatRooms_Users. You will insert / remove from this table whenever a user joins or leaves the room.

If you want users who close their browsers to close their browsers instead of clicking “leave the room”, set up an outsole task to run every minute, which searches for users with last_poll_datetime older than one minute and removes their rows from the ChatRooms_Users connection table.