multiserver.py

from multiprocessing import Process
import selectors
import socket
import time
import random


def read_handler(
        sock: socket.socket,
        sel_: selectors.BaseSelector):
    data = sock.recv(1000)
    if data:
        print(f'echoing: {repr(data)} | '
              f'{sock.getpeername()}')
        time.sleep(random.randrange(1, 10) / 10)
        sock.send(data)
    else:
        print('closing...')
        sel_.unregister(sock)
        sock.close()


def accept_handler(
        sock: socket.socket,
        sel_: selectors.BaseSelector):

    conn: socket.socket
    addr: str
    conn, addr = sock.accept()
    print(f'accepted: {conn.getpeername()} from {addr}')
    conn.setblocking(False)
    sel_.register(conn, selectors.EVENT_READ, read_handler)


def start_server(port=5577):
    sel = selectors.DefaultSelector()
    sock = socket.socket()
    sock.bind(('localhost', port))
    sock.setblocking(False)
    sock.listen(100)
    sel.register(sock, selectors.EVENT_READ, accept_handler)

    while True:
        events = sel.select()
        for key, mask in events:
            callback = key.data
            callback(key.fileobj, sel)


def start_client(word: str, port=5577):
    sock = socket.socket()
    sock.connect(('localhost', port))
    sock.sendall(word.encode())
    time.sleep(random.randrange(1, 5) / 10)
    data = sock.recv(1024)
    print(data.decode())
    sock.close()


def main():
    srv = Process(target=start_server)
    srv.start()
    words = 'apple hello mango world banana organe'.split()
    for i in range(10):
        Process(target=start_client,
                args=(f'[{i+1}] ' + random.choice(words),))\
            .start()
    srv.join(9)
    srv.kill()


if __name__ == '__main__':
    main()