Check status if Raspberry Pi is connected to any WiFi network (Not Internet necessarily) using Python

Question

I don't want to check if it has Internet connectivity! I just want to check if it's connected to the WiFi network (I'd have already given its SSID in the WPA_supplicant file).. This network won't have Internet access.

Solution 1

Problem

iwconfig didn't work for me, but iwgetid did.

How do I solve this issue?

Code

import subprocess
ps = subprocess.Popen(['iwgetid'], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
try:
    output = subprocess.check_output(('grep', 'ESSID'), stdin=ps.stdout)
    print(output)
except subprocess.CalledProcessError:
    # grep did not match any lines
    print("No wireless networks connected")

Solution 2

Assuming you are running some kind of linux (like raspbian), you don't need to use Python for this, the easiest way would be:

iwconfig 2>&1 | grep ESSID

from the command line or a shell script. There will be output if you are connected to a wireless network, and no output if not. You could wrap this in subprocess if you want to run it from Python:

import subprocess
ps = subprocess.Popen(['iwconfig'], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
try:
    output = subprocess.check_output(('grep', 'ESSID'), stdin=ps.stdout)
    print(output)
except subprocess.CalledProcessError:
    # grep did not match any lines
    print("No wireless networks connected")

Comments

[Dan Ionescu]

Do you want to check it from the inside of the py or from the outside?

[Krishnakumar M]

Using the Pi, I'll be running the Python script in the Raspberry Pi only.

[Dan Ionescu]

You could consider pinging a few big websites, and consider the internet down if all are down

[Krishnakumar M]

@DanIonescu I don't want to check if it has Internet connectivity! I just want to check if it's connected to the WiFi network (I'd have already given its SSID in the WPA_supplicant file).. This network won't have Internet access. Do you get it?

[Krishnakumar M]

Works fine! Thank you so much.

[Austin]

Careful with this solution. If your wifi adapter is attempting to connect to a network (even if it will be rejected due to something like an incorrect password), this command will still show the SSID as connected during the attempts.