My experience using python to manipulate Wi-Fi hardware is very limited.

my script below works fine on a raspberry pi model 3 B+ connecting to Wi-Fi ‘tiphone’ (iPhone hotspot) but when it goes to connect back to the other Wi-Fi (gooberbest) it presents a dialog box for the user to enter passphrase. Why is this?

this a a small function I’m working on for a portable data collection device. In the office it connects to gooberbest, when it leaves it tethers to iPhone hot spot via Wi-Fi, upon return it reconnects to gooberbest.

my understanding is the iPhone hotspot does not constantly broadcast, so my thought is to loop thru reading active SSIDs until i find the iPhone SSID. The iPhone is set to maximum compatibility. The results I had tethering via USB led me to believe that was not a reliable connection method.

this is my code:

# -*- coding:UTF-8 -*-

import os, time, re, sys
from wireless import Wireless

#### empty list for ESSIDs
active_wireless_networks = []

#### SSID and Password for target WiFi network
goal_ssid="tiphone"
goal_pw="---------"

#### Boolean to use if target WiFi found
target_wifi_found=False

#### loop to run scanning WiFi until target SSID found
while target_wifi_found==False:
    wifi_count=0 # for number of SSID's found
    unique_wifi_count=0 # to count unique SSID's found

    #### scan wlan0
    lines = os.popen("sudo iwlist wlan0 scan").read().split("n")

    for line in lines: #iterate through each line returned by previous command
      line = line.rstrip() #remove spaces a end of each line
      if line.find("SSID:") >= 0: #filter to just lines that contain 'SSID:'
        line=line.lstrip() #remove spaces a beginning of each line
        wifi_count =wifi_count+1 # increment the number of SSID's found

        ssid=line[7:-1] # remove the first seven (ESSID:")  and the last character (") from the current line
        if ssid=="tiphone": # check if this is the target SSID
            target_wifi_found=True # if yes set boolean to True
        active_wireless_networks.append(ssid) # add the current SSID to the list of active_wireless_networks list
    print (wifi_count, " SSID's have been found, ", len(set(active_wireless_networks)), "are unique")


    if  target_wifi_found==False: #checking if target SSID is found
        print ("tiphone NOT one of them, sleeping 5 seconds then rescanningn")

### loop starts over if tiphone SSID not found ###

print ("Wi-Fi tiphone FOUND,going to connect")
    wire = Wireless() # define wire
    wire.connect(ssid=goal_ssid,password=goal_pw) #connect to target wifi
    time.sleep(20) #pause program to allow wifi to connect

### computer connecting to target wifi now ###

print ("going to confirm which wifi now connected to")

if 'tiphone' in str(subprocess.check_output(['iwgetid -r'], shell=True)).split(''')[1][:-2]:
    print("Connected to target wifi,tiphonenn")
    wifi="tiphone"

if 'gooberbest' in str(subprocess.check_output(['iwgetid -r'], shell=True)).split(''')[1][:-2]:
    print('I am connected to gooberbest Wi-Fi!')


time.sleep(60) # pause profram to allow thigs to settle

### for testing purposes reconnect to other WiFi - gooberbest
print("reconnecting to gooberbestnn")
wire.connect(ssid="gooberbest",password="--------")
time.sleep(60)

print ("going to check which wifi now connected to")

if 'tiphone' in str(subprocess.check_output(['iwgetid -r'], shell=True)).split(''')[1][:-2]:
    print('I am connect to iphone Wi-Fi!')
    wifi="tiphone"

if 'gooberbest' in str(subprocess.check_output(['iwgetid -r'], shell=True)).split(''')[1][:-2]:
    print('I am connected to gooberbest Wi-Fi!')

there’s no error message, just when it tries to reconnect to the Wi-Fi it was originally connected to, one of my saved Wi-Fi connections the Raspberry OS opens a dialog box for the user to enter the passphrase. This is undesirable.

Lastly, the results the script produces are not always consistent, sometimes it fails to connect to either Wi-Fi. I am I using the best method to establish a WIFI connection?