Learning Python Network Programming

Chapter 7

TCP servers

As you understood from the very first client/server interaction diagram, the server
process needs to carry out a bit of extra work. It needs to bind to a socket address
and listen for incoming connections. The following code snippet shows how to
create a TCP server:

import socket

from time import ctime

HOST = 'localhost'

PORT = 12345

BUFSIZ = 1024

ADDR = (HOST, PORT)

if __name__ == '__main__':

server_socket = socket.socket(socket.AF_INET,

socket.SOCK_STREAM)

server_socket.bind(ADDR)

server_socket.listen(5)

server_socket.setsockopt( socket.SOL_SOCKET,

socket.SO_REUSEADDR, 1 )

while True:

print('Server waiting for connection...')

client_sock, addr = server_socket.accept()

print('Client connected from: ', addr)

while True:

data = client_sock.recv(BUFSIZ)

if not data or data.decode('utf-8') == 'END':

break

print("Received from client: %s" % data.decode('utf-

8'))

print("Sending the server time to client: %s"

%ctime())

try:

client_sock.send(bytes(ctime(), 'utf-8'))

except KeyboardInterrupt:

print("Exited by user")

client_sock.close()

server_socket.close()