server.py

from socket import socket, AF_INET, SOCK_STREAM, SOL_SOCKET, SO_REUSEADDR
from threading import Thread
from datetime import datetime
from select import select

class Server():
    def __init__(self):
        self.HEADER_LENGTH = 10
        self.server = ('localhost', 1234)
        self.server_socket = socket(AF_INET, SOCK_STREAM)
        self.server_socket.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
        self.sockets_list = [self.server_socket]
        self.clients = {}

    def run(self):
        try:
            self.server_socket.bind((self.server[0], self.server[1]))
            self.server_socket.listen()
            print(f'Listening for connections on {self.server[0]}:{self.server[1]}...\n\n')
            while True:
                read_sockets, _, exception_sockets = select(self.sockets_list, [], self.sockets_list)
                for notified_socket in read_sockets:
                    if notified_socket == self.server_socket:
                        client_socket, client_address = self.server_socket.accept()
                        user = self.receive_message(client_socket)
                        if user is False:
                            continue
                        self.sockets_list.append(client_socket)
                        self.clients[client_socket] = user
                        print(f'Accepted new connection from {client_address[0]}:{client_address[1]}, username: {user["data"].decode("utf-8")}')
                    else:
                        message = self.receive_message(notified_socket)
                        if message is False:
                            print('Closed connection from: {}'.format(self.clients[notified_socket]['data'].decode('utf-8')))
                            self.sockets_list.remove(notified_socket)
                            del self.clients[notified_socket]
                            continue
                        user = self.clients[notified_socket]
                        print(f'Received message from {user["data"].decode("utf-8")}: {message["data"].decode("utf-8")}')
                        for client_socket in self.clients:
                            if client_socket != notified_socket:
                                client_socket.send(user['header'] + user['data'] + message['header'] + message['data'])
                for notified_socket in exception_sockets:
                    self.sockets_list.remove(notified_socket)
                    del self.clients[notified_socket]
        except:
            pass

    def receive_message(self, client_socket):
        try:
            message_header = client_socket.recv(self.HEADER_LENGTH)
            if not len(message_header):
                return False
            message_length = int(message_header.decode('utf-8').strip())
            return {'header': message_header, 'data': client_socket.recv(message_length)}
        except:
            return False


s = Server().run()