Python subrocess wsgi. How to correctly read the value from the file?

Question

Python

Hello! The problem is this: It is
necessary to read the gpio value from the file.
The result of executing the command "cat /sys/devices/virtual/gpio/gpio27/value" is "0", as it should be
WSGI is connected to the Apache server, the script is written:

import os
import glob
import subprocess
result = subprocess.call("cat /sys/devices/virtual/gpio/gpio27/value", shell = True)
if result == 0:
  state = "ON"
else:
  state = "OFF"	
def application(environ, start_response):
    status = '200 OK'
    output = state

    response_headers = [('Content-type', 'text/plain'), ('Content-Length', str(len(output)))]
    start_response(status, response_headers)

    return [output]

The result of its execution is always "OFF", i.e. "one". Regardless of the contents of the file "value"
What could be the problem?

Answer 1

RTFM carefully, gentlemen.
subprocess.call() returns an exit code. cat successfully reads the value from the file, that is, the exit code is always 0 (yes, exactly int).
And all because you initially chose a transrectal solution. Why call cat from a Python program when you can just open a file and read from it?

with open('/sys/devices/virtual/gpio/gpio27/value') as f:
    result = f.read()

In this case, by the way, it will be a string unit.