To Access the gpios from webpage by executing python code

Question

I'm a student in electronics department doing a project on home automation using Raspberry Pi (for bulbs, fan, temperature and camera).

I want to access the GPIO pins from a web interface to execute a Python script to control the devices on the server (RPi).

I installed WiringPi but I can't move forward to control them.

See the example below of a webpage to control a simple led (on & off): https://i.sstatic.net/SLNyx.jpg

I have installed apache2 server.
I have paced the code in cgi-bin and pointed the button on to that link It says "permission denied" in error log file, it shows to try as root.

led.py in cgi-bin folder:

#!/usr/bin/python2.7

import RPi.GPIO as GPIO 
GPIO.setmode(GPIO.BOARD) 
GPIO.setup(7, GPIO.OUT) 
GPIO.output(7,True)

Answer 1

WebIOPi may be the best solution for you. https://code.google.com/p/webiopi/ You can modify the software to your needs, but that will control all GPIO pins through a web interface. Try it out and see if it works for you.

Answer 2

Check out this project built for this exact reason: https://github.com/newbrute/pi-ui

The UI is not pre-configured and offers more flexibility than other options out there

Edit: To be clear, this is an alternative solution and not a fix for WiringPi.

Relevant code

<!-- Setup a pin. Since no direction is specified, it will be an output -->
<div ng-init="run('gpio.setup').with({channel: 18})" />
<!-- Write to the pin when buttons are clicked -->
<button ng-click="run('gpio.write').with({channel: 18, value: true})">
    Red On
</button>

NodeJS's child_process.exec function will allow you to run a python script in conjunction with this option

Answer 3

Write a php script for your website. This is the page you will see when you access your pi.

Send the button values via POST method to the script.

Extract the message and call a python script which will do the actual change on the GPIO.

$command = escapeshellcmd(sudo python /home/pi/path/to/script.py led 1); exec("$command > /dev/null &");

The first line would call the python script located in /home/pi/path/to/ and execute it. The > /dev/null will tell it to put all output into an non-existing file and the & will run it in the background. The last 2 are not really necessary but without it your website will load as long as it takes to execute the python script.

At the moment php could not start python because of the sudo command. It is nessesary because we need the privileges to work with the GPIO Pins. So we need to do: sudo nano /etc/sudoers and at the end add www-data ALL=(ALL) NOPASSWD: ALL

Write a Python Script that takes the input variables from php and performs the task.