server_class.py

import socket
import os
import threading
import argparse

class Server(threading.Thread):
    def __init__(self, host, port):
        super().__init__()
        self.connections = []
        self.host = host
        self.port = port

    def run(self):
        
        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        sock.bind((self.host, self.port))

        sock.listen(1)
        print('Listening at:', sock.getsockopt(1, socket.SOL_SOCKET))

        while True:
            # Accept new connection
            sc, sockname = sock.accept()
            print('Accepted a new connection from {} to {}'.format(sc.getpeername(), sc.getsockname()))

            # Create new thread
            server_socket = ServerSocket(sc, sockname, self)

            # Start new thread
            server_socket.start()

            # Add thread to active connections
            self.connections.append(server_socket)
            print('Ready to receive messages from', sc.getpeername())
    
    def broadcast(self, message, source):

        for connection in self.connections:
            connection.send(message)

class ServerSocket(threading.Thread):
    def __init__(self, sc, sockname, server):
        super().__init__()
        self.sc = sc
        self.sockname = sockname
        self.server = server

    def run(self):
        while True:
            message = self.sc.recv(1024).decode('ascii')
            if message:
                print('{} says {!r}'.format(self.sockname, message))
                self.server.broadcast(message, self.sockname)
            else:
                # Client has closed the socket, exit the thread
                print('{} has closed the connection'.format(self.sockname))
                self.sc.close()
                server.remove_connection(self)
                return

    def send(self, message):
        self.sc.sendall(message.encode('ascii'))

def exit(server):

    while True:
        ipt = input('')
        if ipt == 'q':
            print('Closing all connections...')
            for connection in server.connections:
                connection.sc.close()
            print('Shutting down the server...')
            os._exit(0)

if __name__ == '__main__':
    
    parser = argparse.ArgumentParser(description='Chatroom Server')
    parser.add_argument('-p', metavar='PORT', type=int, default=1060,
                        help='TCP port (default 1060)')
    args = parser.parse_args()    # Create and start server thread
    server = Server('127.0.0.1', args.p)
    server.start()    
    exit = threading.Thread(target = exit, args = (server,))
    exit.start()