Socket Server-Client Programming.....

Server Side 

#===========================================================================================

import socket

import threading

import sys

#===========================================================================================

DISCONNECTED_MSG = "!close"

SIZE = 1024

IP = socket.gethostbyname(socket.gethostname()) # getting IP address it is str type

PORT = 9999

ADDR = (IP, PORT) #tuple type

FORMAT = 'utf-8'

#===========================================================================================

#creating socket and binding and listening

def fn_socketBindListening(nIP=IP, nPort=PORT):

    #print("main display" +IP)

    print("[Starting] Server is starting")

    global server

    try:

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

        server.bind(ADDR)

        server.listen(1)

        print(f"[Server Assigned Port to Listening Client:....{nIP}:{nPort}]")

    except socket.error as msg :

        print("Error while Socket creation,Binding and Listening "+str(msg))

        sys.exit()

#===========================================================================================

#Accepting request from clint and creating thread for each client and handed over to client handler fun

def fn_accepting():

    print("accepting")

    try:

            while True:

                conn, addr = server.accept() #addr[0] is ip and str type and addr[1] is port int type..

                #print("addr",addr[0],"....port"+str(addr[1]))

                thread = threading.Thread(target= fn_clientHandler, args=(conn,addr))

                thread.daemon = True #free the server resources while closeing of theread

                thread.start()

                print(f"ACTIVE Client  {threading.active_count()-1}")

    except threading.ThreadError as msg :

        print("Error while Thread creation "+str(msg))

        sys.exit()

    except socket.error as msg:

        print("Error while Thread creation " + str(msg))

        sys.exit()

#===========================================================================================

#fun to handle each client from server side

def fn_clientHandler(conn, addr):

    connected = True

    while connected:

        msg = conn.recv(SIZE).decode(FORMAT)

        if msg == DISCONNECTED_MSG:

            connected = False

        print(f"At Server[{addr}]--{msg}")

        msg=f"Received Msg: {msg}"

        conn.send(msg.encode(FORMAT))

    conn.close()

    

#===========================================================================================

def main(nIP=IP, nPort=PORT):

    fn_socketBindListening(nIP, nPort)

    fn_accepting()

#===========================================================================================

if __name__== "__main__":

    main(IP, PORT)

#===========================================================================================