server.py

import threading 
import socket

PORT = 5050
SERVER = "localhost" 
# socket.gethostbyname(socket.gethostname()) this will give the local ip address of the machine which is running the code 
ADDR  = (SERVER,PORT)
FORMAT = "utf-8"
DISCONNECT_MESSAGE = "[!] DISCONNECTED!"

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

clients = set()

clients_lock  = threading.Lock()

def handleClient(conn, addr):
    print(f"[+]NEW CONNECTION \n {addr} CONNECTED !")

    try:
        connected = True
        while connected:
             msg = conn.recv(1024).decode(FORMAT)
             if not msg:
                break
             if msg==DISCONNECT_MESSAGE :
                connected=False
             print(f"[$] {addr} : {msg}")
             with clients_lock:
                 for c in clients:
                     c.sendall(f"[$$] {addr} {msg}".encode(FORMAT ))
    finally:
        with clients_lock:
            clients.remove(conn)
        conn.close()



def start():
    print("[+] SERVER STARTED ...")
    server.listen()
    while True:
        conn, addr = server.accept()
        with clients_lock:
            clients.add(conn)
        thread = threading.Thread(target=handleClient,args=(conn, addr))
        thread.start()

start()