This is probably a Linux question, but concerns specific Pi code. I am using the DHT11 class from http://abyz.me.uk/rpi/pigpio/download.html and have written a program which uses this.

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from __future__ import absolute_import, division, print_function, unicode_literals

import time
import pigpio
from dht11 import  DHT11

pi = pigpio.pi()
sensor = DHT11(pi, 4)
d = sensor.next()
print("temperature: {}°C".format(d['temperature']))
print("humidity: {}%".format(d['humidity']))

The pigpiod daemon runs on boot. The code is installed in /usr/local/bin/

-rwsr-sr-x 1 root staff 9284 2018-05-13 16:34 dht*
-rwxr-xr-x 1 root staff  440 2018-11-08 10:13 dht11_once.py*
-rw-r--r-- 1 root staff 4674 2018-11-08 10:13 dht11.py

The program can be run by any user (even unprivileged users) but I cannot seem to get it to work from php using the following:-

<?php $cpu_temp = (float) file_get_contents('/sys/class/thermal/thermal_zone0/temp'); ?>
<?php $hostname = shell_exec('/bin/hostname'); ?>
<?php $hostIP = shell_exec('/bin/hostname -I'); ?>
<?php $temperature = shell_exec('/usr/local/bin/dht11_once.py'); ?>
<html><head><title>RPi PHP Test</title></head>
 <h1>Hello from the Raspberry Pi - <?php echo $hostname ?></h1>
 <div>Your IP address is: <?php echo $_SERVER['REMOTE_ADDR']; ?></div>
 <div>Pi IP address is: <?php echo $hostIP ?></div>
 <div><?php echo $temperature ?></div>
 <div><h3>The CPU temperature is: <?php echo $cpu_temp/1000 ?>°C</h3></div>

This is probably a permission problem, but what would be needed eludes me. Is it even possible to get a python program to run GPIO access code this way? (The dht program is compiled c code, which does run, but has other issues.)

Update The code above does run and does call '/usr/local/bin/dht11_once.py' but does not appear to call the code that interfaces with the GPIO.

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