web-app-from-scratch-1-03.py

RESPONSE = b"""\
HTTP/1.1 200 OK
Content-type: text/html
Content-length: 15

<h1>Hello!</h1>""".replace(b"\n", b"\r\n")

with socket.socket() as server_sock:
    server_sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    server_sock.bind((HOST, PORT))
    server_sock.listen(0)
    print(f"Listening on {HOST}:{PORT}...")

    client_sock, client_addr = server_sock.accept()
    print(f"New connection from {client_addr}.")
    with client_sock:
        client_sock.sendall(RESPONSE)