Sure Tom, I can't run with browser your script "find-path.php" outside public_html so, how can I discover the path of "products" folder since the moment it is below the public_html but not the "find-path.php" ?

Suppose you put "find-path.php" in the pulbic_html folder and it reports

/var/www/silvio/public_html/find-path.php

Then the physical path of public_html is

/var/www/silvio/public_html/