server.py

import socket
import threading

PORT = 5050
SERVER = "0.0.0.0"
ADDR = (SERVER, PORT)
HEADER = 64
FORMAT = "utf-8"
CLOSE_WORD = "DISCONNECT"

server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
server.bind(ADDR)


def recv_exactly(conn, n):
    data = b""
    while len(data) < n:
        chunk = conn.recv(n - len(data))
        if not chunk:
            return None
        data += chunk
    return data


def handle_connection(conn, addr):
    print(f"[NEW CONNECTION] {addr} connected.")
    while True:
        raw_len = recv_exactly(conn, HEADER)
        if not raw_len:
            break
        length = int(raw_len.decode(FORMAT).strip())
        msg = recv_exactly(conn, length)
        if msg is None:
            break
        msg = msg.decode(FORMAT)
        if msg == CLOSE_WORD:
            break
        print(f"[{addr}] {msg}")
    conn.close()
    print(f"[DISCONNECTED] {addr}")


def start():
    server.listen()
    print(f"[LISTENING] on {SERVER}:{PORT}")
    while True:
        conn, addr = server.accept()
        thread = threading.Thread(target=handle_connection, args=(conn, addr))
        thread.start()


start()