spl_autoload_register() 在不同目录中

Question

I have a file that auto loads each of my classes. This is what it contains:

spl_autoload_register(function($class){
    require_once 'classes/' . $class . '.php';
});
require_once 'functions/sanitize.php';
require_once 'functions/hash.php';

But when I require_once this file from another php file that is inside my ajax folder, it will try looking for the classes , the function will look from my classes with the path: main_folder/ajax/classes instead of just main_folder/classes .

Does anyone know how to fix this ?

FIX :

spl_autoload_register(function($class){
    if (file_exists('classes/' . $class . '.php')) {
       require_once 'classes/' . $class . '.php';
    }
    elseif (file_exists('../classes/' . $class . '.php')) {
       require_once '../classes/' . $class . '.php';
    }
    elseif (file_exists('../../classes/' . $class . '.php')) {
       require_once '../../classes/' . $class . '.php';
    }

Answer 1

You should simple use this function just once - in the main file (usually index.php) and not in another files.

However if it's not possible (but I don't see any reason when could it be not possible) you can change it for example that way:

spl_autoload_register(function($class){
    if (file_exists('classes/' . $class . '.php')) {
       require_once 'classes/' . $class . '.php';
    }
    elseif (file_exists( $class . '.php')) {
       require_once $class . '.php';
    }
});

Answer 2

You need to know the absolute path to the classes directory, then just use a full qualified path to get there.

Make sure your document root is correctly configured with your http server. Furthermore this is usually solved by routing all requests to index.php and deriving the base path (document root) from there. Here is your code modified:

spl_autoload_register(function($class) {
    $resolved = $_SERVER['DOCUMENT_ROOT'] . DIRECTORY_SEPARATOR . 'classes' . DIRECTORY_SEPARATOR . $class . '.php';
    if(file_exists($resolved)) {
      require_once $resolved;
    } else {
      // make it known to your that a class failed to load somehow
      return;
    }
})

Here is another implementation that I use for simple projects

Answer 3

Here is a proper way, It should universally work.

spl_autoload_register(function ($classname) {
    $classpath = sprintf('%s' . DIRECTORY_SEPARATOR . '%s.php', dirname(realpath(__FILE__)), basename($classname, '.{php,PHP}'));

    if (file_exists($classpath)) {
        echo "Loading <b>$classpath</b>...<br>";
        require($classpath);
    }
});