Different behavior when using relative paths

Question

As I have learned so far, using the ./ reference to the current folder, while the ../ references one level up the current folder, and using / references the root directory. So when adding the relative path inside an image source's attribute in all three conditions it works fine, but when trying to use the three ways with Include, Both ./ and / references the current folder. Is there any misunderstanding? because I am confused. the code I use :

<?php

echo '<strong>This is the child using ./ </strong><br><br><img src="./image.jpg"><br><br>';
echo '<strong>This is the parent using ../ </strong><br><br><img src="../image.png"><br><br>';
echo '<strong>This is the root using / <br><br><img src="/image.png"></strong><br>';
include('./file.php');
include('../file.php');
include('/file.php');

?>

Answer 1

You can tweak the Php environment, here is an example:

<?php    
chroot(__DIR__);
include '/tmp/foo.txt';

Rather than including the absolute path /tmp/foo.txt, from the system root /. The root is changed to the current directory and it references the folder tmp in there.

The example above will work as a CLI script run as root. But there may be other ways to chroot the Php environment.

Public references to assets that begin with a forward slash are relative to the document root. Suppose we have a file system like the following, where /foo is the document root.

/foo
|-- bar.png
|-- baz
|   |-- bat.html
|   `-- man.ogg
`-- home.html

Using absolute paths: if we want to reference man.ogg from home.html, we would use a path /baz/man.ogg, if we were to reference bar.png from bat.html, we would use the path /bar.png. I hope you can see that starting with a slash is not the same as referencing the current directory.