Simple example of socket programming using Python and threading module

client.c

#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <arpa/inet.h>

int main(int argc, char *argv[]) {
    struct sockaddr_in server;
    int sock;
    char msg[] = "12";

    /* Server info */
    server.sin_family = AF_INET;
    server.sin_addr.s_addr = inet_addr("127.0.0.1");
    server.sin_port = htons(8000);

    /* Socket */
    sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock == -1) {
        printf("Failed to create socket\n");
        return 1;
    }

    if (connect(sock, (struct sockaddr *)&server, sizeof(server)) < 0) {
        perror("Connect failed");
        return 1;
    }

    send(sock, msg, strlen(msg), 0);

    return 0;
}

pyclient.py

#!/usr/bin/python

import socket

if __name__ == '__main__':
    host = "127.0.0.1"
    port = 8000

    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.connect((host, port))
    s.send(b"10")
    s.close()

server.py

#!/usr/bin/python
import socket
import traceback
import threading

def ledBlink():
    print ("Python Client Connected")

def ledKelip():
    print("Java Client Connected")

def ledKelap():
    print("C Client Connected")

def handle_conn(sock, addr):
    print("Got Connection from {} and handled by {}".format(addr, threading.currentThread().getName()))
    msg = ''    # message buffer
    while True:
        data = sock.recv(1024)
        if not len(data):
            break
        msg += str(data, 'utf-8')

    if msg == '10':
        ledBlink()
    elif msg == '11':
        ledKelib()
    elif msg == '12':
        ledKelap()
    else:
        print('Unknown command from {}'.format(addr))
    sock.close()

if __name__ == '__main__':
    host = "127.0.0.1"
    port = 8000
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    s.bind((host, port))
    s.listen(5)
    print("Server Running..... Listening to Clients Now")
    print("Press Ctrl-C to quit")

    while True:
        try:
            clientsock, clientaddr = s.accept()
        except KeyboardInterrupt:
            break
        except:
            print('are we having error')
            traceback.print_exc()
            continue

        t = threading.Thread(target=handle_conn, args=[clientsock, clientaddr])
        t.start()

    s.close()
    print('Server terminating')