TCP sockets

As you will see in a moment, we will create socket objects using the socket.socket() function and specify the socket type as socket.SOCK_STREAM. When we do this, the default protocol that it uses is the TCP.

For network programming in Python, we need to create a socket object and then use this to call other functions of the module. The following code will start a web server using the sockets library. The script waits for a connection to be made; if it is received, it will show the received bytes.

You can find the following code in the tcp_server.py file:

#!/usr/bin/env python3

import socket

host = '127.0.0.1'
port = 12345
BUFFER_SIZE = 1024

#The socket objects support the context manager type
#so we can use it with a with statement, there's no need to call socket_close ()
#We create a TCP type socket object
with socket.socket(socket.AF_INET,socket.SOCK_STREAM) as socket_tcp:
    socket_tcp.bind((host, port))
    # We wait for the client connection
    socket_tcp.listen(5)
    # We establish the connection with the client
    connection, addr = socket_tcp.accept()
    with connection:
        print('[*] Established connection')
            while True:
                # We receive bytes, we convert into str
                data = connection.recv(BUFFER_SIZE)
                # We verify that we have received data
                if not data:
                    break
                else:
                    print('[*] Data received: {}'.format(data.decode('utf-8')))
                connection.send(data)

Let's see what this script does in detail: