PHP can't find path while HTML can-CodePudding

I'm still a bit new to PHP and stumbled across a weird error I can't fix. I have different util PHP files for different purposes, such as getting user data or basic util functions.

But I can't figure out why PHP does sometimes not find the path when using the require function.
In particular this example:

print '<a href="/api/connection.php">Huh</a>';

ob_start();
require "/api/connection.php";
ob_end_clean();

HTML shows a working link redirecting to the page, but PHP still can't find the connection file.

Here is my file tree:

So why is that and how can I fix it? Does PHP have another way of linking files or is it something else?

Thanks in Advance

CodePudding user response：

PHP paths are relative to the root of the filesystem, not the document root. Use $_SERVER['DOCUMENT_ROOT'] to get the latter.

require $_SERVER['DOCUMENT_ROOT'] . "/api/connection.php";