Question

I am new to socket programming and I wish to know what these lines of code do. I know they are creating UDP sockets, but it would help if someone explained what the code means. Thank you.

Python Code:

import socket

testingSocket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
testingSocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR,
testingSocket.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
testingSocket.bind(('0.0.0.0', 50000))
send_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
send_socket.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
receiving_thread = Thread(target=self.receivingFunction)
send_thread = Thread(target=self.sendMessage)
broadcast_online_status_thread = Thread(target=onlineStatus)

Answer 1

Explanation is given with # before every code line.

CODE:

# this module can give access to low-level socket functionalities.

# in this module some of the functions are platform dependant

import socket

# The AF_INET is in reference to th family or domain, it means ipv4, as opposed to ipv6 with AF_INET6. The SOCK_DGRAM means it will be a UDP socket. UDP means it will be connectionless.

testingSocket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

# configuring the socket with the available options here, setsockopt function used to set the socket options. When retrieving a socket option, or setting it, you specify the option name as well as the level. When level = SOL_SOCKET, the item will be searched for in the socket itself. SO_REUSEADDR is set to 1 means that the validated addresses supplied to bind() should allow reuse of local addresses.

testingSocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR,1)

# SO_BROADCAST this option is used check the reports whether transmission of broadcast messages is set to 1 here means allowed.

testingSocket.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)

# bind the socket with the provided < ip address and the port number >

testingSocket.bind(('0.0.0.0', 50000))

#creating another socket by name send socket

send_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

#configures the send socket and checking the whether broadcast is set to True

send_socket.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)

# This constructor should always be called with keyword arguments. Arguments target is the callable object to be invoked by the run() method. Defaults is None means nothing is called.

#receiving function is called

receiving_thread = Thread(target=self.receivingFunction)

# send Message is called

send_thread = Thread(target=self.sendMessage)

#onlineStatus is called

broadcast_online_status_thread = Thread(target=onlineStatus)