chat_client.py

from socket import AF_INET, socket, SOCK_STREAM
from threading import Thread


def receive():
    while True:
        try:
            msg = client_socket.recv(BUFFSIZE).decode("utf8")
            print(msg)
        except OSError:
            break


def send(msg):
    client_socket.send(bytes(msg, "utf8"))

    if msg == "{quit}":
        client_socket.close()
        exit(0)


HOST = input('Enter host: ')
PORT = input('Enter port: ')

if not PORT:
    PORT = 9000
else:
    PORT = int(PORT)

BUFFSIZE = 1024
ADDR = (HOST, PORT)

client_socket = socket(AF_INET, SOCK_STREAM)
client_socket.connect(ADDR)

receive_thread = Thread(target=receive)
receive_thread.start()

while True:
    message = input()

    if message:
       send(message)

chat_server.py

from socket import AF_INET, socket, SOCK_STREAM
from threading import Thread


def accept_connections():
    while True:
        client, client_address = SERVER.accept()
        print("%s:%s esá conectado." % (client, client_address))
        client.send(bytes("Olá! entre com seu nome: ", "utf8"))
        print('stop !')
        addresses[client] = client_address
        Thread(target=handle_client, args=(client,)).start()


def handle_client(client):  # Takes client socket as argument.
    name = client.recv(BUFFSIZE).decode("utf8")
    welcome = 'Bem vindo %s! Para sair do chat você precisa digitar "{quit}".' % name
    client.send(bytes(welcome, "utf8"))
    msg = "%s entrou no chat!" % name
    broadcast(bytes(msg, "utf8"))
    clients[client] = name

    while True:
        msg = client.recv(BUFFSIZE)
        if msg != bytes("{quit}", "utf8"):
            broadcast(msg, name + ": ")
        else:
            client.send(bytes("{quit}", "utf8"))
            client.close()
            del clients[client]
            broadcast(bytes("%s saiu do chat." % name, "utf8"))
            break


def broadcast(msg, prefix=""):
    for sock in clients:
        sock.send(bytes(prefix, "utf8") + msg)


clients = {}
addresses = {}

HOST = input('Enter host: ')
PORT = input('Enter port: ')

if not PORT:
    PORT = 9000
else:
    PORT = int(PORT)

BUFFSIZE = 1024
ADDR = (HOST, PORT)

SERVER = socket(AF_INET, SOCK_STREAM)
SERVER.bind(ADDR)

if __name__ == "__main__":
    SERVER.listen(5)
    print("Esperando por conexão...")
    ACCEPT_THREAD = Thread(target=accept_connections)
    ACCEPT_THREAD.start()
    ACCEPT_THREAD.join()
    SERVER.close()