PHP Url相对和绝对

Question

I have this class:

class PageBuilder {
    public function GetHeader() {
        include(dirname(dirname(__FILE__)) . '/template/header.php');
    }
}

Which when called will insert the header file into my page. All is good.

$page_builder->GetHeader();

In the header.php is the top of the HTML file which includes a menu. My problem is, depending on where the PageBuilder gets called from changes the menu link URLs.

How do I make sure they are always relative to the root folder.

dirname(__FILE__) doesn't work because it turns the URL into file:///, also I really don't want to append the entire http://www.blahblah.com/blah because if it is relative to the root it doesn't matter about any of that.

EDIT

So as someone posted you can use $_SERVER[''] but which one is reliable, no doubt PHP will have put in some blinding caveats.

See I was thinking $_SERVER['SERVER_ADDR'] or $_SERVER['SERVER_NAME'] or $_SERVER['HTTP_HOST'] .....

Going $_SERVER['HTTP_HOST'] for now .. result is fail.

Just prefixing with / resolves to the localhost root so my links are localhost/admin/profile.php rather than localhost/TestApp/admin/profile.php, Do I have to actually specify that it sits in folder named TestApp?

Answer 1

After trial and error with the help of @deceze I simply pass my URL through a routing class which prefixes the URL with '/TestApp/' this can be change easily if the project gets moved because the use of classes.

So I do:

<a href="<?php $url_routing->ParseUrl('admin/account/logout.php') ?>">Log Out </a>

Gets passed through:

public function ParseUrl($url) {
    return '/TestApp/' . $url;
}

It is hardly best practice, but there can't be best practices with a language that doesn't follow any itself.

Looking at @Anthony answer of using $_SERVER['PHP_SELF']; it does always give the TestApp folder. Needs more looking into but I will take that. I assume its relative to the server address.