chatprogramm_tutorial_10.py

def receive(client_socket):
    message_size = client_socket.recv(LENGTH_HEADER_SIZE)
    if len(message_size):
        return None
    message_size = message_size.decode('utf-8')
    size_as_int = int(message_size.strip())

    user_header = client_socket.recv(USER_HEADER_SIZE).decode('utf-8')
    user = user_header.strip()        
    message = client_socket.recv(message_length).decode('utf-8')
    print (f'{user} > {message}')    
    return f'{size_header}{user_header}{message}'