socket

The socket module is Python's standard interface for the transport layer. Sockets can be classified by family

• AF_INET Internet
• AF_UNIX for UNIX sockets

and type: - SOCK_STREAM TCP - SOCK_DGRAM UDP

These enum values are required upon initialization of a socket object: ^{[Ortega][Ortega]: 25}

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

Sources:

• Sockets tutorial

TCP serverTCP ClientUDP serverUDP client

import socket


with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    s.bind((HOST,PORT))

import socket


with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    s.connect((HOST,PORT))

import socket


with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as s:
    s.bind((HOST,PORT))

import socket

msg = "Hello, world!"
with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as s:
    s.sendto(msg.encode(), (HOST,PORT))

Define port on which to listen for connections.

serversocket.bind(('localhost',80))

Connect to a remote socket in one direction

client_socket.connect(('www.packtpub.com',80))

Convert a domain name into IPv4 address

socket.gethostbyname('packtpub.com') # '83.166.169.231'

Defaults to localhost with no arguments

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((socket.gethostname(),1234))

Get protocol name from port number

socket.getservbyport(80) # 'http'

Listen to a maximum of 10 connections

serversocket.listen(10)

Receive bytestream from server

msg = s.recv(1024)
print(msg.decode('utf-8'))