require 'socket'

HOST = 'localhost'
PORT = 4505

server = TCPServer.new(HOST, PORT)

# array to store all the active connections
sessions = []
while (session = server.accept)
  # push the current session(socket) in the array
  sessions << session
  # initialize a new thead for each connection
  Thread.new(session) do |local_session|
    # each time a client sends some data send it to all the connections
    while(true)
      data = local_session.gets
      sessions.each do |s| 
        begin
          s.puts data
        rescue Errno::ECONNRESET
          # an exception is raised, that means the connection to the client is broken
          sessions.delete(s)
        end
      end
    end
  end
end