Look into the Plezi Ruby framework. I'm the author and it has automatic Redis scalability built in.
(you just setup the ENV['PL_REDIS_URL'] with the Redis URL)
As for the architecture to achieve this, it's fairly simple... I think.
Each server instance "subscribes" to two channels: a global channel for "broadcasting" (messages sent to all users or a large "family" of users) and a unique channel for "unicasting" (messages intended for a specific user connected to the server).
Each server manages it's internal broadcasting system, so that messages are either routed to a specific user, to a family of connections or all users, as par their target audience.
You can find the source code here. The Redis integration is handled using this code together with the websocket object code.
Web socket broadcasts are handled using both the websocket object on_broadcast callback. The Iodine server handles the inner broadcasting within each server instance using the websocket implementation.
I already posted the inner process architecture details as an answer to this question
I think socket.io has cross server support as well.
Edit (some code)
Due to the comment, I thought I'd put in some code... if you edit your question and add more specifications about the feature you're looking for, I can edit the code here.
I'm using the term "room" since this is what you referred to, although I didn't envision Plezi as just a "chat" framework, it is a very simple use case to demonstrate it's real-time abilities.
If you're using Ruby, you can run the following in the irb terminal (make sure to install Plezi first):
require 'plezi'
class MultiRoom
def on_open
return close unless params[:room] && params[:name]
@name = params[:name]
puts "connected to room #{params[:room]}"
# # if you use JSON to get room data,
# # you can use room arrays like so:
# params[:room] = params[:room].split(',') unless params[:room].is_a?(Array)
end
def on_message data
to_room = params[:room]
# # if you use JSON you can try:
# to_room = JSON.parse(data)['room'] rescue nil
# # we can use class `broadcast`, to broadcast also to self
MultiRoom.broadcast :got_msg, to_room, data, @name if to_room
end
protected
def got_msg room, data, from
write ::ERB::Util.html_escape("#{from}: #{data}") if params[:room] == room
# # OR, on JSON, with room arrays, try something like:
# write data if params[:room].include?(room)
end
end
class EchoConnection
def on_message data
write data
MultiRoom.broadcast "myroom", "Echo?", "system" if data == /^test/i
end
end
route '/echo', EchoConnection
route '/:name/(:room)', MultiRoom
# # add Redis auto-scaling with:
# ENV['PL_REDIS_URL'] = "redis://:password@my.host:6389/0"
exit # if running in terminal, using irb
You can test it out by connecting to: ws://localhost:3000/nickname/myroom
to connect to multiple "rooms" (you need to re-write the code for JSON and multi-room), try: ws://localhost:3000/nickname/myroom,your_room
test the echo by connecting to ws://localhost:3000/echo
Notice that the echo acts differently and allows you to have different websockets for different concerns - i.e., having one connection for updates and messages using JSON and another for multiple file uploading using raw binary data over websockets.
