knowledge_base:programming:python:python3

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knowledge_base:programming:python:python3 [2024/12/26 23:12] – removed - external edit (Unknown date) 127.0.0.1knowledge_base:programming:python:python3 [2024/12/26 23:12] (current) – ↷ Page moved from knowledge_base:programming:python3 to knowledge_base:programming:python:python3 George Wayne
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 +====== Python Programming ======
 +
 +===== Python Virtual Environments =====
 +
 +==== Create virtual environment inside the project folder ====
 +
 +<code>
 +python -m venv .venv
 +</code>
 +
 +==== Activate It ====
 +
 +<code>
 +.\.venv\Scripts\activate
 +</code>
 +
 +==== Install Packages ====
 +
 +<code>
 +pip install <package-name>
 +</code>
 +
 +==== Create Requirements.txt ====
 +
 +<code>
 +pip freeze > requirements.txt
 +</code>
 +
 +==== Install Packages All at Once ====
 +
 +<code>
 +pip install -r requirements.txt
 +</code>
 +
 +==== Deactivate ====
 +
 +<code>
 +deactivate
 +</code>
 +
 +
 +
 +===== Distribute Standalone EXE using Pyinstaller =====
 +
 +**Note: It is highly recommended to download the Python program from python.org directly. Python installed from Microsoft Store may have issues (speaking from my personal experience when wxPython was used)**
 +  - Install pyinstaller package ''pip install -U pyinstaller''
 +  - Execute ''pyinstaller --noconsole --onefile --windowed your_application.py''
 +
 +===== Regular Expression =====
 +
 +https://developers.google.com/edu/python/regular-expressions
 +
 +===== Threading =====
 +
 +https://christopherdavis.me/blog/threading-basics.html
 +
 +===== Pandas Dataframe Multiindexing =====
 +
 +https://towardsdatascience.com/accessing-data-in-a-multiindex-dataframe-in-pandas-569e8767201d
 +
 +===== My NTAG, I2C, Wifi, Subprocess, Timeout, Argparsing Example =====
 +**tested on Raspbian Jessie**
 +<code>
 +#!/usr/bin/env python3
 +import smbus
 +import math
 +import re
 +import subprocess
 +import shlex
 +import os
 +import time
 +import signal
 +import functools
 +import argparse
 +
 +# common i2c functions are:
 +# read_byte(addr)
 +# write_byte(addr, val)
 +# read_byte_data(addr, cmd)
 +# write_byte_data(addr, cmd, val)
 +# read_word_data(addr, cmd)
 +# write_word_data(addr, cmd, val)
 +# read_i2c_block_data(addr, cmd, count)
 +# write_i2c_block_data(addr, cmd, vals)
 +
 +class TimedOut(Exception):
 + pass
 +
 +def call_with_timeout(timeout, f, *args, **kwargs):
 + """Call f with the given arguments, but if timeout seconds pass before
 + f returns, raise TimedOut. The exception is raised asynchronously,
 + so data structures being updated by f may be in an inconsistent state.
 + """
 + def handler(signum, frame):
 + raise TimedOut("Timed out after {} seconds.".format(timeout))
 +
 + old = signal.signal(signal.SIGALRM, handler)
 + try:
 + signal.alarm(timeout)
 + try:
 + return f(*args, **kwargs)
 + finally:
 + signal.alarm(0)
 + finally:
 + signal.signal(signal.SIGALRM, old)
 +
 +def with_timeout(timeout):
 + """Decorator for a function that causes it to timeout after the given
 + number of seconds.
 + """
 + def decorator(f):
 + @functools.wraps(f)
 + def wrapped(*args, **kwargs):
 + return call_with_timeout(timeout, f, *args, **kwargs)
 + return wrapped
 + return decorator
 +
 +# def run_program(rcmd):
 +# Runs a program, and it's parameters (e.g. rcmd = 'ls -lh /var/www')
 +# Returns output if sucessful, or None and logs error if not.
 +@with_timeout(50)
 +def run_program(rcmd, wpacli=False):
 + cmd = shlex.split(rcmd)
 + try:
 + proc = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
 + if (wpacli):
 + for line in iter(proc.stdout.readline, ''):
 + line = line.decode('utf-8')
 + if (re.search(r'Trying to associate with', line)) :
 + print(line, end='')
 + scanned = re.search(r"Trying to associate with\s*(..:..:..:..:..:..).*?SSID='(.*?)'", line)
 + if (scanned): print('SSID = "{}", bssid = "{}"'.format(scanned.group(2), scanned.group(1)))
 + elif (re.search(r'CTRL-EVENT-CONNECTED - Connection to', line)): # connected
 + print(line, end='')
 + break
 + elif (re.search(r'CTRL-EVENT-REGDOM-CHANGE', line)):
 + print(line, end='')
 +# break # not connected but could be another ssid to try
 + elif (re.search(r'CTRL-EVENT', line) or re.search(r'WPA: 4-Way Handshake failed', line) or
 + re.search(r'WPS-AP-AVAILABLE', line) or re.search(r'Associated with', line) or
 + re.search(r'WPA: Key negotiation completed with', line)): print(line, end='')
 + elif (re.search(r'<\d>', line)): print(line, end='')
 + resp = proc.communicate(input=b'quit\n')
 + else:
 + resp = proc.communicate()
 + except TimedOut:
 + print('timed out')
 + proc.terminate()
 + resp = proc.communicate()
 + finally:
 + return resp
 +
 +# Function to put credentials to /etc/wpa_supplicant/wpa_supplicant.conf
 +# Returns True if updated or added, False if nothing to do
 +def addwpa(ssid, psk):
 + if (not ssid or not psk): return
 + try:
 + f = open('/etc/wpa_supplicant/wpa_supplicant.conf', 'r')
 + wpafile = f.read()
 + pattern = r'(network\s*=\s*{.*?ssid\s*=\s*"' + ssid + r'".*?psk\s*=\s*")(.*?)(".*?})'
 +# print('Search pattern: {}'.format(pattern))
 + network = re.search(pattern, wpafile, re.DOTALL)
 + if (network): # update exiting network
 + oldpsk = network.group(2)
 + if (psk != oldpsk): # only do work if needed
 + substr = r'\g<1>' + psk + r'\g<3>'
 + newfile = re.subn(pattern, substr, wpafile, flags=re.DOTALL) # flags are important
 + f = open('/etc/wpa_supplicant/wpa_supplicant.conf', 'w')
 + f.write(newfile[0])
 + f.close()
 + print('Existing Wifi network "{}" has been updated.'.format(ssid))
 + return True
 + else:
 + print('Existing Wifi network "{}" was up to date.'.format(ssid))
 + return False
 + else: # add new network
 + newnet = 'network={\n\tssid="' + ssid + '"\n\tmode=0\n\tpsk="' + psk + '"\n}\n'
 + f = open('/etc/wpa_supplicant/wpa_supplicant.conf', 'a')
 + f.write(newnet)
 + f.close()
 + print('New Wifi network "{}" has been added.'.format(ssid))
 + return True
 + except (OSError, IOError) as err:
 + print(err)
 +
 +def read_ntag():
 + bus = smbus.SMBus(1)
 + addr = 0x55
 + block1 = bus.read_i2c_block_data(addr, 0x01, 16) # read the first user block and check validity
 + try:
 + if (block1[1] == 0xFF and block[2] != 0xD1):
 + raise ValueError('Message has more than 248 characters are not supported')
 + if (block1[2] != 0xD1): raise ValueError('It is not a well-known type that I can understand.')
 + if (block1[5] != 0x54): raise ValueError('It is not a text NDEF record that I can interpret.')
 + recordlen = block1[4]
 + payload = block1[9:16]
 + i = 0x2
 + while i <= 0x2 + math.floor((recordlen-9)/16): # read entire payload record
 + block = bus.read_i2c_block_data(addr, i, 16)
 + payload = payload + block
 + i = i+1
 + # print(' '.join(format(x, '02X') for x in payload))
 + del payload[recordlen-2:] # trim the extras
 + if (payload[recordlen-3] != 0xFE):
 + raise ValueError('Expecting EOF marking 0xFE. Record length incorrect.')
 + del payload[recordlen-3:]
 + payload = ''.join(chr(x) for x in payload)
 + value = re.findall(r'(["\'])(.*?)\1', payload)
 + if (len(value)<2): raise ValueError('Please put two values in " " or \' \'.')
 + return value[0][1], value[1][1] # return ssid, psk
 + except ValueError as err:
 + print(err)
 + finally:
 + bus.close()
 +
 +
 +
 +# main function
 +def main():
 + parser = argparse.ArgumentParser()
 + parser.add_argument('-f', '--force', help='force wifi reconnect', action='store_true')
 + args = parser.parse_args()
 +
 + username, password = read_ntag()
 + if (args.force or addwpa(username, password)):
 + # re-start wpa_supplicant
 + print('Connecting Wifi ...')
 + if (not os.path.isfile('/run/wpa_supplicant.wlan0.pid')):
 + print('wpa_supplicant not running')
 + resp = run_program('wpa_cli status')
 + for x in list(map(lambda x: x.decode('utf-8'), resp)): print(x, end='')
 +# run_program('/sbin/wpa_supplicant -s -B -P /run/wpa_supplicant.wlan0.pid -i wlan0 -D nl80211,wext -c /etc/wpa_supplicant/wpa_supplicant.conf')
 + else:
 + print('ifdown wlan0')
 + resp = run_program('ifdown wlan0')
 + for x in list(map(lambda x: x.decode('utf-8'), resp)): print(x, end='')
 + time.sleep(3)
 + print('ifup wlan0')
 + resp = run_program('ifup wlan0')
 + for x in list(map(lambda x: x.decode('utf-8'), resp)): print(x, end='')
 + resp = run_program('wpa_cli', True) # run wpa_cli in interactive mode to get wpa_supplicant output
 + for x in list(map(lambda x: x.decode('utf-8'), resp)): print(x, end='')
 + resp = run_program('wpa_cli status')
 + for x in list(map(lambda x: x.decode('utf-8'), resp)): print(x, end='')
 + print('Getting IP address...')
 + time.sleep(10)
 + ipaddr = subprocess.check_output(['hostname', '-I'])
 + print('IP Address: {}'.format(ipaddr))
 + else: print('Nothing to do')
 + print('Type "sudo startx" to enter graphic mode.')
 +
 +if __name__ == '__main__':
 + main()
 +</code>
 +
 +===== Subprocess and Wifi =====
 +
 +<code>
 +#!/usr/bin/env python
 +# -*- coding: utf-8 -*-
 +# [email protected] / @glennzw
 +# Handle wireless networking from Python
 +# The name (evil.py) is a play on 'wicd'
 +from subprocess import Popen, call, PIPE
 +import errno
 +from types import *
 +import logging
 +import sys
 +import logging
 +import time
 +import argparse
 +import re
 +import shlex
 +
 +SUPPLICANT_LOG_FILE = "wpa_supplicant.log"
 +
 +"""
 +This bit of code allows you to control wireless networking
 +via Python. I chose to encapsualte wpa_supplicant because
 +it has the most consistent output with greatest functionality.
 +
 +Currently supports OPEN, WPA[2], and WEP.
 +
 +#e.g:
 +
 +>>> iface = get_wnics()[0]
 +>>> start_wpa(iface)
 +>>> networks = get_networks(iface)
 +>>> connect_to_network(iface, "myHomeNetwork", "WPA", "singehackshackscomounaniña")
 +>>> is_associated(iface)
 +True
 +>>> do_dhcp(iface)
 +>>> has_ip(iface)
 +True
 +
 +"""
 +
 +logging.basicConfig(level=logging.DEBUG,
 +                    format='%(asctime)s %(levelname)s %(filename)s: %(message)s',
 +                    datefmt='%Y-%m-%d %H:%M:%S',
 +                    filename='evil.log',
 +                    filemode='w')
 +
 +
 +def run_program(rcmd):
 +    """
 +    Runs a program, and it's paramters (e.g. rcmd="ls -lh /var/www")
 +    Returns output if successful, or None and logs error if not.
 +    """
 +
 +    cmd = shlex.split(rcmd)
 +    executable = cmd[0]
 +    executable_options=cmd[1:]    
 +
 +    try:
 +        proc  = Popen(([executable] + executable_options), stdout=PIPE, stderr=PIPE)
 +        response = proc.communicate()
 +        response_stdout, response_stderr = response[0], response[1]
 +    except OSError, e:
 +        if e.errno == errno.ENOENT:
 +            logging.debug( "Unable to locate '%s' program. Is it in your path?" % executable )
 +        else:
 +            logging.error( "O/S error occured when trying to run '%s': \"%s\"" % (executable, str(e)) )
 +    except ValueError, e:
 +        logging.debug( "Value error occured. Check your parameters." )
 +    else:
 +        if proc.wait() != 0:
 +            logging.debug( "Executable '%s' returned with the error: \"%s\"" %(executable,response_stderr) )
 +            return response
 +        else:
 +            logging.debug( "Executable '%s' returned successfully. First line of response was \"%s\"" %(executable, response_stdout.split('\n')[0] ))
 +            return response_stdout
 +
 +
 +def start_wpa(_iface):
 +    """
 +    Terminates any running wpa_supplicant process, and then starts a new one.
 +    """
 +    run_program("wpa_cli terminate")
 +    time.sleep(1)
 +    run_program("wpa_supplicant -B -Dwext -i %s -C /var/run/wpa_supplicant -f %s" %(_iface, SUPPLICANT_LOG_FILE))
 +
 +def get_wnics():
 +    """
 +    Kludgey way to get wireless NICs, not sure if cross platform.
 +    """
 +    r = run_program("iwconfig")
 +    ifaces=[]
 +    for line in r.split("\n"):
 +        if "IEEE" in line:
 +            ifaces.append( line.split()[0] )
 +    return ifaces
 +
 +
 +
 +def get_networks(iface, retry=10):
 +    """
 +    Grab a list of wireless networks within range, and return a list of dicts describing them.
 +    """
 +    while retry > 0:
 +        if "OK" in run_program("wpa_cli -i %s scan" % iface):
 +            networks=[]
 +            r = run_program("wpa_cli -i %s scan_result" % iface).strip()
 +            if "bssid" in r and len ( r.split("\n") ) >1 :
 +                for line in r.split("\n")[1:]:
 +                    b, fr, s, f = line.split()[:4]
 +                    ss = " ".join(line.split()[4:]) #Hmm, dirty
 +                    networks.append( {"bssid":b, "freq":fr, "sig":s, "ssid":ss, "flag":f} )
 +                return networks
 +        retry-=1
 +        logging.debug("Couldn't retrieve networks, retrying")
 +        time.sleep(0.5)
 +    logging.error("Failed to list networks")
 +
 +
 +def _disconnect_all(_iface):
 +    """
 +    Disconnect all wireless networks.
 +    """
 +    lines = run_program("wpa_cli -i %s list_networks" % _iface).split("\n")
 +    if lines:
 +        for line in lines[1:-1]:
 +            run_program("wpa_cli -i %s remove_network %s" % (_iface, line.split()[0]))  
 +
 +
 +def connect_to_network(_iface, _ssid, _type, _pass=None):
 +    """
 +    Associate to a wireless network. Support _type options:
 +    *WPA[2], WEP, OPEN
 +    """
 +    _disconnect_all(_iface)
 +    time.sleep(1)
 +    if run_program("wpa_cli -i %s add_network" % _iface) == "0\n":
 +        if run_program('wpa_cli -i %s set_network 0 ssid \'"%s"\'' % (_iface,_ssid)) == "OK\n":
 +            if _type == "OPEN":
 +                run_program("wpa_cli -i %s set_network 0 auth_alg OPEN" % _iface)
 +                run_program("wpa_cli -i %s set_network 0 key_mgmt NONE" % _iface)
 +            elif _type == "WPA" or _type == "WPA2":
 +                run_program('wpa_cli -i %s set_network 0 psk "%s"' % (_iface,_pass))
 +            elif _type == "WEP":
 +                run_program("wpa_cli -i %s set_network 0 wep_key %s" % (_iface,_pass))
 +            else:
 +                logging.error("Unsupported type")
 +            
 +            run_program("wpa_cli -i %s select_network 0" % _iface)
 +            
 +def is_associated(_iface):
 +    """
 +    Check if we're associated to a network.
 +    """
 +    if "wpa_state=COMPLETED" in run_program("wpa_cli -i %s status" % _iface):
 +        return True
 +    return False
 +
 +def has_ip(_iface):
 +    """
 +    Check if we have an IP address assigned
 +    """
 +    status = run_program("wpa_cli -i %s status" % _iface)
 +    r = re.search("ip_address=(.*)", status)
 +    if r:
 +        return r.group(1)
 +    return False
 +
 +def do_dhcp(_iface):
 +    """
 +    Request a DHCP lease.
 +    """
 +    run_program("dhclient %s" % _iface)
 +
 +
 +def main():
 +    print "[--- EViL. Python wireless network manager. ---]"
 +    print "[        [email protected] / @glennzw\n"
 +    parser = argparse.ArgumentParser()
 +    parser.add_argument("-n","--nics", help="List wireless network interfaces.", action="store_true")
 +    parser.add_argument("-l","--list", help="List wireless networks (specify adapter).", action="store_true")
 +    parser.add_argument("-i","--iface", help="Specify interface.")
 +    parser.add_argument("-c","--connect", help="Connect to network.", action="store_true")
 +    parser.add_argument("-s","--ssid", help="Specify SSID")
 +    parser.add_argument("-t","--type", help="Specify network type (OPEN, WEP, WPA, WPA2)")
 +    parser.add_argument("-p","--passw", help="Specify password or key.")
 +    args = parser.parse_args()
 +
 +    if len(sys.argv) < 2:
 +        print "[!] No options supplied. Try --help."
 +        sys.exit(-1)
 +
 +    if args.nics:
 +        nics = get_wnics()
 +        if nics:
 +            print "[+] Available NICs:"
 +            for nic in get_wnics():
 +                print nic
 +        else:
 +            print "[W] No wireless interfaces found :-("
 +    elif args.list:
 +        if not args.iface:
 +            print "[!] Please specify interface. Use --help for help."
 +            sys.exit(-1)
 +        else:
 +            if args.iface not in get_wnics():
 +                print "[E] Bad interface! - '%s'" % args.iface
 +                sys.exit(-1)
 +            print "[+] Searching for available networks..."
 +            start_wpa(args.iface)
 +            networks = get_networks(args.iface)
 +            if networks:
 +                networks = sorted(networks, key=lambda k: k['sig']) 
 +                print "[+] Networks in range:"
 +                for network in networks:
 +                    print " SSID:\t%s" % network['ssid']
 +                    print " Sig:\t%s" % network['sig']
 +                    print " BSSID:\t%s" % network['bssid']
 +                    print " Flags:\t%s" % network['flag']
 +                    print " Freq:\t%s\n" % network['freq']
 +            else:
 +                print "[W] No wireless networks detected :-("
 +    elif args.connect:
 +        if not args.iface or not args.ssid or not args.type or (args.type != "OPEN" and not args.passw):
 +            print "[E] Missing options for --connect. Check --help for assistance."
 +            sys.exit(-1)
 +        else:
 +            sys.stdout.write( "[+] Associating to '%s' on '%s' (may take some time)... " % (args.ssid, args.iface))
 +            sys.stdout.flush()
 +            if args.iface not in get_wnics():
 +                print "[E] No such wireless interface! - '%s'" % args.iface
 +                sys.exit(-1)
 +            start_wpa(args.iface)
 +            connect_to_network(args.iface, args.ssid, args.type, args.passw)
 +            while not is_associated(args.iface):
 +                time.sleep(1)
 +            print "Success."
 +            sys.stdout.write("[+] Requesting DHCP lease... ")
 +            sys.stdout.flush()
 +            do_dhcp(args.iface)
 +            while not has_ip(args.iface):
 +                time.sleep(1)
 +            print "Success. (%s)" % has_ip(args.iface)
 +            print "[+] Associated and got lease. Hoorah."
 +
 +if __name__ == "__main__":
 +    main()
 +</code>
 +
 +===== Resources =====
 +
 +==== Plotly & Dash ====
 +
 +  - https://python-graph-gallery.com/plotly/
 +  - https://stackoverflow.com/questions/40471026/subplots-with-two-y-axes-each-plotly-and-python-pandas
 +  - https://medium.com/@yahyasghiouri1998/dockerize-your-dash-app-f502275475fa
 +  - https://devopscube.com/build-docker-image/
 +  - https://stackoverflow.com/questions/76004602/how-do-we-access-the-value-of-dcc-store-in-plotly
 +  - https://stackoverflow.com/questions/63225707/plotly-dash-refreshing-global-data-on-reload
 +
 +