WLAN-Autoconnect-Hack

#!/usr/bin/env python3

import time
from subprocess import Popen, PIPE, call

def scan_wlan(dev, ap):
    proc = Popen(['/sbin/iwlist', dev, 'scanning'], stdout=PIPE, stderr=PIPE)
    out, _ = proc.communicate()
    out = out.decode()
    for line in out.splitlines():
        if "ESSID:" in line:
            _, essid = line.split(':')
            essid = essid.replace('"', '')
            if essid == ap:
                return True
    else:
        return False

def ping(ip):
    cmd = ['ping', '-c1', '-W1', ip]
    returncode = Popen(cmd, stdout=PIPE, stderr=PIPE).wait()
    if returncode == 0:
        return True
    else:
        return False

def reconnect(dev):
    call(['/sbin/ifdown', dev], stdout=PIPE, stderr=PIPE)
    time.sleep(1)
    call(['/sbin/ifup', dev], stdout=PIPE, stderr=PIPE)


def main(dev, ap, ip):
    while True:
        if not ping(ip):
            if scan_wlan(dev, ap):
                reconnect(dev)
        time.sleep(5)

if __name__ == '__main__':
    main('wlan0', 'Mikrowelle 3', '192.168.43.1')