Python Notes

some of this is taken from Learning Python Networking (2nd edition) by Jose Manual Ortega , Dr. M.O. Faruque Sarker, and Sam Washington

Table of Contents

places where python install touches

Remove it automatically on the settings page. Under Apps and Features, there are application execution aliases.

Disable the ones that are relevant.
C:\Users\Username\AppData\Local\Microsoft\WindowsApps\ (aliases/directories - delete those that you don't want)
echo %PATH% ... remove entries that you don't want

pdb

l - list file and place and breakpoints
n - Step over next line in code
step - step into next line in code
print(a) - print a (or any other variable )
dir(a) - (built-in Python function) Without arguments, return the list of names in the current local scope. With an argument, attempt to return a list of valid attributes for that object.

dragonfly related

window titles

using methods in dragonfly's Window class. E.g. Window.get_foreground() or Window.get_all_windows().
window.classname should give the app name and
window.title for the title.

PIP

sudo apt-get install python-pip
pip install <to install>
pip install virtualenv

virtualenv Python37

virtualenv (choose env variables including version of Python)
documentation

python networking

a lot of these notes were taken from Learning Python Networking

Socket types

https://docs.python.org/3/library/socket.html

Currently, there are several types of sockets, and each one is usually associated with a type of protocol, for example:

SOCK_STREAM - TCP
SOCK_DGRAM - UDP datagram/async communication.

Sockets can also be classified according to their family.

socket.AF_UNIX - Unix sockets - created before the concept of networks and are based on files
socket.AF_INET - IPv4
socket.AF_INET6 - IPv6
socket.AF_BLUETOOTH - bluetooth
socket.AF_VSOCK - virt machines to hosts, Availability: Linux >= 4.8 QEMU >= 2.8 ESX >= 4.0 ESX Workstation >= 6.5.
socket.AF_PACKET - low-level interface directly to net devices. Packets represented by the tuple (ifname, proto[, pkttype[, hatype[, addr]]]) :

ifname - device name.
ifname - String specifying the device name.
proto - An in network-byte-order integer specifying Ethernet protocol number.
pkttype - Optional integer specifying packet type:

PACKET_HOST (the default) - Packet addressed to the local host.
PACKET_BROADCAST - Physical-layer broadcast packet.
PACKET_MULTIHOST - sent to a phys-layer multicast addr
PACKET_OTHERHOST - Packet to other host that has been caught by device driver in promiscuous mode.
PACKET_OUTGOING - Packet originating from the local host that is looped back to a packet socket.

hatype - Optional integer specifying the ARP hardware address type.
addr - Optional bytes-like object specifying the hardware physical address, whose interpretation depends on the device.

Server socket methods

https://docs.python.org/3/library/socket.html

The following are some server socket methods

bind(): With this method, we can define in which port our server will be listening to connections
listen(backlog): This method makes the socket accept connections and accept to start listening to connections
accept(): This method is used for accepting the following connection:

other socket flags

import socket
serversocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
#bind the socket to localhost on port 80
serversocket.bind((‘localhost', 80))
#become a server socket and listen a maximum of 10 connections
serversocket.listen(10)

Getting information about ports, protocols, and domains

#!/usr/bin/env python3

import socket

def find_service_name():
    protocolname = 'tcp'
    for port in [80, 25]:
        print ("Port: %s => service name: %s" %(port, socket.getservbyport(port, protocolname)))
    
    print ("Port: %s => service name: %s" %(53, socket.getservbyport(53, 'udp')))
    
if __name__ == '__main__':
    find_service_name()

#!/usr/bin/env python3
import socket
try:
	infolist = socket.getaddrinfo('www.packtpub.com', 'www', 0,	socket.SOCK_STREAM, 0, socket.AI_ADDRCONFIG | socket.AI_V4MAPPED | socket.AI_CANONNAME,)
except socket.gaierror as e:
	print('Name service failure:', e.args[1])
	sys.exit(1)

info = infolist[0]
print(infolist)
socket_args = info[0:3]
address = info[4]
s = socket.socket(*socket_args)
try:
	s.connect(address)
except socket.error as e:
	print('Network failure:', e.args[1])
else:
	print('Success: host', info[3], 'is listening on port 80')

#!/usr/bin/env python3
import socket
try:
    infolist = socket.getaddrinfo('www.packtpub.com', 'www', 0, socket.SOCK_STREAM, 0, socket.AI_ADDRCONFIG | socket.AI_V4MAPPED | socket.AI_CANONNAME,)
except socket.gaierror as e:
    print('Name service failure:', e.args[1])
    sys.exit(1)

info = infolist[0]
print(infolist)
socket_args = info[0:3]
address = info[4]
s = socket.socket(*socket_args)
try:
    s.connect(address)
except socket.error as e:
    print('Network failure:', e.args[1])
else:
    print('Success: host', info[3], 'is listening on port 80')

TCP sockets

#!/usr/bin/env python3

import socket

def get_remote_info():
    remote_host = 'www.packtpub.com'
    try:
        print ("IP address of %s: %s" %(remote_host, socket.gethostbyname(remote_host)))
    except socket.error as err_msg:
        print ("%s: %s" %(remote_host, err_msg))
    
if __name__ == '__main__':
    get_remote_info()

TCP client template

#!/usr/bin/env python3

import socket

# The client must have the same server specifications
host = '127.0.0.1'
port = 12345
BUFFER_SIZE = 1024

MESSAGE = 'Hello world,this is my first message' 

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as socket_tcp:
    socket_tcp.connect((host, port))
    # We convert str to bytes
    socket_tcp.send(MESSAGE.encode('utf-8'))
    data = socket_tcp.recv(BUFFER_SIZE)

TCP server template

#!/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)