multi rooms kemal websockets server

server.cr

require "kemal"
require "json"

connected_sockets = {} of String => Array(HTTP::WebSocket)
connected_users = {} of String => Hash(String, JSON::Any)

def broadcast(data, sockets)
  sockets.each do |socket|
    socket.send data.to_json
  end
end

def list_of_users(users, sockets)
  broadcast({action: "list", users: users.values.uniq}, sockets)
end

# ws /
# manage multi rooms via the query string
# client sample (create room r1):
# ws = new WebSocket('ws://localhost:3000/?room=r1');
ws "/" do |socket, env|
  room = env.params.query["room"] rescue "global"

  connected_sockets[room] ||= [] of HTTP::WebSocket
  connected_users[room] ||= Hash(String, JSON::Any).new
  connected_sockets[room].push socket

  socket.on_message do |message|
    msg = JSON.parse(message)
    if msg["action"] == "login"
      connected_users[room]["#{socket.object_id}"] = msg["from"]
      list_of_users(connected_users[room], connected_sockets[room])
    end

    if msg["action"] == "message"
      broadcast(
        {action: "message", data: msg},
        connected_sockets[room]
      )
    end
  end

  socket.on_close do |_|
    connected_users[room].reject!(socket.object_id.to_s)
    connected_sockets[room].delete(socket)
  end
end

Kemal.run