Sudo through webserver (Pan tilt hat)

Question

I have bought https://shop.pimoroni.com/products/pan-tilt-hat , it works fine, but I want to control it through a php webserver, but every time I try, it requires sudo but when I use sudo I get an error in /var/log/apache2/error.log

We trust you have received the usual lecture from the local System
Administrator. It usually boils down to these three things:

    #1) Respect the privacy of others.
    #2) Think before you type.
    #3) With great power comes great responsibility.

sudo: no tty present and no askpass program specified

Another question could be: How do I avoid having to use sudo with the pan tilt hat library

Answer 1

Give the apache user permissions to run sudo commands without password. Assuming the user in question is called www-data, add the following line to your sudoers file:

www-data ALL=(ALL) NOPASSWD:ALL

Once you get that working, you can restrict commands which could be run without password to hat-related only, so if your web server gets hacked, the attacker will not be able to run random commands as root.

Answer 2

the PanTiltHAT library doesn't require sudo. It requires membership of the i2c group, so all I needed to do to achieve a similar end result (control of PanTiltHAT mounted camera from a web UI) was to add the www-data user to the i2c group in the OS. A Linux command for that is

sudo gpasswd -a www-data i2c

Although, I was using a flask (not PHP) based web application, so I could very easily integrate calls through the python interface library.