Connect to a WiFi networks using a QR code

connect-qr-code.py

import re
import cv2
import subprocess
pat = re.compile(r'^WIFI:S:([^;]+);T:WPA;P:([^;]+);;')

detect = cv2.QRCodeDetector()
cv2.namedWindow("preview")
vc = cv2.VideoCapture(0)
rval, frame = vc.read()

while rval:
    cv2.imshow("preview", frame)
    rval, frame = vc.read()
    value, points, straight_qrcode = detect.detectAndDecode(frame)
    if value:
        print(value)
        if mat := pat.match(value):
            ap, pwd = mat.groups()
            print(f'Connecting to {ap} (password: {pwd})')
            subprocess.check_call(
                    ['nmcli', 'd', 'wifi',
                        'connect', ap,
                        'password', pwd])
            break
    key = cv2.waitKey(20)
    if key == 27: # exit on ESC
        break