tcp_echo_server.py

import socket
import select

MAX_MSG_LENGTH = 1024
SERVER_PORT = 5555
SERVER_IP = '0.0.0.0'

messages_to_send = []

"""
This script sets up a server that listens for incoming client connections on IP address '0.0.0.0' and port 5555.
When a new client joins, the server prints a message with the client's address and adds the client socket to a list of connected clients.
The server then continuously listens for data from clients, and if data is received, it prints the data and adds the client socket and data to a list of messages to be sent.
If the data received is empty, the server closes the connection with the client.
Finally, the server sends any messages in the messages_to_send list to the corresponding client sockets.
"""

def print_client_sockets(client_sockets):
     for c in client_sockets:
         print("\t", c.getpeername())

def main():
    print("Setting up server..." )
    server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    server_socket.bind((SERVER_IP, SERVER_PORT))
    server_socket.listen()
    print("Listening for clients..." )
    client_sockets = []
    while True:
        ready_to_read, ready_to_write, in_error = select.select([server_socket] + client_sockets, client_sockets, [])
        for current_socket in ready_to_read:
            if current_socket is server_socket:
                (client_socket, client_address) = current_socket.accept()
                print( "New client joined!" ,client_address)
                client_sockets.append(client_socket)
                print_client_sockets(client_sockets)
            else:
                try:
                    data = current_socket.recv(MAX_MSG_LENGTH).decode()
                    print("New data from client")
                    if data == "":
                        print("\tConnection closed from", current_socket.getpeername())
                        client_sockets.remove(current_socket)
                        current_socket.close()
                        print_client_sockets(client_sockets)
                    else:
                        print(data)
                        messages_to_send.append((current_socket, data))
                except:
                    print("\t", current_socket.getpeername(), "cloesed the connection")
                    client_sockets.remove(current_socket)
                    current_socket.close()
                    print_client_sockets(client_sockets)

        for message in messages_to_send:
            current_socket, data = message
            if current_socket in ready_to_write:
                current_socket.send(data.encode())
                messages_to_send.remove(message)

main()