echo_serv.py

import socket
import sys
import argparse

host = 'localhost'
data_payload = 2048
backlog = 5

def echo_server(port):
  """ A simple echo server """
  # Create a TCP socket. The first arg identifies the 'address family'.
  # AF_INET6 could be used instead for IPv6. The second arg specifies the 
  # socket type. The stream type uses TCP/IP
  sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
  # Enable reuse address/port
  sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
  # Bind the socket to the port
  server_address = (host, port)
  print "Starting up echo server on %s port %s" % server_address
  sock.bind(server_address)
  # Listen to clients, backlog argument specifies the max no. of queued 
  # connections
  sock.listen(backlog)
  while True:
    print "Waiting to receive message from client"
    client, address = sock.accept()
    data = client.recv(data_payload)
    if data:
      print "Data: %s" %data
      client.send(data)
      print "sent %s bytes back to %s" % (data, address)
      client.close()

if __name__ == "__main__":
  parser = argparse.ArgumentParser(description='Socket Server Example')
  parser.add_argument('--port', action="store", dest="port", type=int, required=True)
  given_args = parser.parse_args()
  port = given_args.port
  echo_server(port)