echo_server_threaded.py

#! /usr/bin/env python3

# A simple echo server, with client processing
# handled in a separate thread.

import argparse
import socket
import threading

def handle_connection(conn: socket.socket):
    """ Handler to process client connection """
    while True:
        # TODO Handle connection close error
        data = conn.recv(256).decode('utf-8')
        # getsockname() gets the addr of the local endpoint
        # getpeername() gets the addre of the remote endpoint
        print(f'addr={conn.getpeername()}, data={data}')
        conn.send(data.encode('utf-8'))

def run_server(host, port, backlog=5):
    """ Start the echo server """
    # using the convenience function create_server which internally
    # does the following steps
    #   create a stream socket
    #     sock.bind((host, port))
    #     sock.listen(5)   
    with socket.create_server((host, port), backlog=backlog) as sock:
        print(f'Server listening at {host}:{port}...')
        connid = 0
        while True:
            connection, connaddr = sock.accept()
            connid += 1
            print(f'Connected to addr={connaddr}, conn_id={connid}')
            connthread = threading.Thread(target=handle_connection, args=(connection,))
            connthread.start()

if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("-a", "--addr", help="host address", type=str, default="localhost")
    parser.add_argument("-p", "--port", help="port number", type=int, default=12345)
    args = parser.parse_args()
    run_server(args.addr, args.port)