more-complex-client.rb

require 'socket'

host,port = ARGV

begin
    STDOUT.print "Connecting..."
    STDOUT.flush
    s = TCPSocket.open(host,port)
    STDOUT.puts "done"

    local,peer =s.addr,s.peeraddr
    STDOUT.print "Connected to #{peer[2]}:#{peer[1]}"
    STDOUT.puts " using local port #{local[1]}"
    begin
        sleep(0.5)
        msg =s.read_nonblock(4096)
        STDOUT.puts msg.chop
    rescue SystemCallError

    end

    loop do
        STDOUT.print '> '
        STDOUT.flush
        local = STDIN.gets
        break if !local
        s.puts(local)
        s.flush
        response = s.readpartial(4096)
        puts(response.chop)
    end
rescue
    puts $!
ensure
    s.close if s
end

multiplexing-server.rb

require 'socket'
server = TCPServer.open(2000)  # Listen on port 2000
sockets = [server]             # An array of sockets we'll monitor
log = STDOUT                   # Send log messages to standard out
while true                     # Servers loop forever
    ready = select(sockets)      # Wait for a socket to be ready
    readable = ready[0]          # These sockets are readable
    readable.each do |socket|          # Loop through readable sockets
        if socket == server              # If the server socket is ready
            client = server.accept         # Accept a new client
            sockets << client              # Add it to the set of sockets
            # Tell the client what and where it has connected.
            client.puts "Reversal service v0.01 running on #{Socket.gethostname}"
            # And log the fact that the client connected
            log.puts "Accepted connection from #{client.peeraddr[2]}"
        else                             # Otherwise, a client is ready
            input = socket.gets            # Read input from the client
            # If no input, the client has disconnected
            if !input
                log.puts "Client on #{socket.peeraddr[2]} disconnected."
                sockets.delete(socket)       # Stop monitoring this socket
                socket.close                 # Close it
                next                         # And go on to the next
            end
            
            if (input == "quit")           # If the client asks to quit
                socket.puts("Bye!");         # Say goodbye
                log.puts "Closing connection to #{socket.peeraddr[2]}"
                sockets.delete(socket)       # Stop monitoring the socket
                socket.close                 # Terminate the session
            else                           # Otherwise, client is not quitting
                socket.puts(input) # So reverse input and send it back
            end
        end
    end
end