For those whom may be interested by the problem...
The problem I was facing was two-fold: initializing the USB webcam via a php script called from the client and starting an application from this php script that could write images to disk in the folder /var/www/images
.
- To enable the USB camera, I just had to add the user www-data (Apache) to the group video. I found it by looking at my own account: I saw that I was a member of this group so it seemed natural to add Apache to it too!
- To allows the application (that captures images from the camera) to store them in the folder
/var/www/images
I observed that the subfolderimages
belonged to user root and was a member of group root. Since it was Apache that ran the php script that called my application, I switched the owner ofimages
to www-data.
As we say in French... Voilà!
Thanks to all of you who gave me some hints!