import socket


def main(args=None):
    tcp_s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    tcp_s.bind(('', 1234))

    tcp_s.listen(1)
    client_s, client_addr = tcp_s.accept()

    while True:
        b_data = client_s.recv(4096)
        if not b_data or b_data == "stop":
            break
        client_s.send(b_data.upper())

    client_s.close()
    tcp_s.close()


if __name__ == '__main__':
    main()