import socket

​

MAX_SIZE_BYTES = 65535 # Mazimum size of a UDP datagram

​

# Setting up a socket

s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) 

port = 3000

hostname = '127.0.0.1'

s.bind((hostname, port))

print('Listening at {}'.format(s.getsockname()))

while True:

    data, address = s.recvfrom(MAX_SIZE_BYTES)

    message = data.decode('ascii')

    upperCaseMessage = message.upper()

    print('The client at {} says {!r}'.format(clientAddress, message))

    data = upperCaseMessage.encode('ascii')

    s.sendto(data, clientAddress)