server.py

import socket
import threading

HOST = socket.gethostbyname(socket.gethostname())
PORT = 5050
ADDR = (HOST, PORT)

server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind(ADDR)
server.listen()

clients = []
nicknames = []

#sends a massage
def broadcast(massage):
    for client in clients:
        client.send(massage)

#handle each client
def handle(client):
    while True:
        try:
            massage = client.recv(1024)
            broadcast(massage)
        except:
            index = clients.index(client)
            clients.remove(client)
            client.close()
            nickname = nicknames[index]
            broadcast(f'{nickname} left the chat!'.encode('ascii'))
            nicknames.remove(nickname)
            break

#receive from each client
def receive():
    while True:
        client, address = server.accept()
        print(f'connected with {str(address)}')

        client.send('NICK'.encode('ascii'))
        nickname = client.recv(1024).decode('ascii')
        nicknames.append(nickname)
        clients.append(client)

        print(f'nickname of the client is {nickname}')
        broadcast(f'{nickname} joined the chat'.encode('ascii'))
        client.send('connected to the server'.encode('ascii'))

        thread = threading.Thread(target=handle, args=(client,))
        thread.start()

print('server is listening...')
receive()