How do file references within a PHP Objects work?

Question

I'm trying to create an PHP object that can load objects in other files on demand when needed. My problem is that when I reference the files based on file location for the class definition, it can not find the files. So file structure:

/Test.php

/os/os.php (extends kernel)

/os/kernel.php

/os/libraries/lib1.php

/os/libraries/lib2.php

/os/libraries/lib3.php

In kernel.php, the libraries are referenced as 'libraries/lib1.php'. If I create an "os" object in Test.php. The lib files are not found.

Answer 1

I think if you specify any sort of relative path (rather than just a filename or absolute path), PHP will try to include it relative to $_SERVER['SCRIPT_FILENAME'] (the main script which was run), and therefore you get inconsistent results.

You could define an absolute path somewhere in a file that you know will be always included , e.g.:

<?php
//e.g. this could be file os/kernel.php
//define absolute path to libraries dir
define('LIBRARY_PATH', dirname(__FILE__) . '/libraries');

And then elsewhere (in kernel.php and others) use this when you are including another file:

<?php
include LIBRARY_PATH . '/lib1.php';

Answer 2

Use a good naming convention for your classes, include_path and use spl_autoload.

For exemple:

Name your classes like this: class Os class Kernel class Libraries_Lib1 ...

Register your include path

set_include_path(implode(PATH_SEPARATOR, array(
    realpath('os/'),
    get_include_path(),
)));
spl_autoload_register("autoload");

And use an autoload:

function autoload($className) {
   $name = implode("/", explode("_", $className));
   require_once(strtolower($name) . ".php");
}