Am I not understanding plugins?

Question

So I am trying to make it so that you can load a class from a child theme, theme or plugin using the following:

class AisisCore_Loader_AutoLoader{

    protected static $_instance;

    protected static $_directories;

    public function get_instance(){
        if(null == self::$_instance){
            self::$_instance = new self();
        }

        self::$_directories = array(
            get_template_directory(),
            get_stylesheet_directory(),
            plugin_dir_path(__FILE__),
        );

        return self::$_instance;
    }

    public function reset_instance(){
        self::$_instance = null;
    }

    public function register_auto_loader(){
        spl_autoload_register(array($this, 'load_class'));
    }

    public function load_class($class){
        $path = str_replace('_', '/', $class);
        foreach(self::$_directories as $directories){
            if(file_exists($directories . '/' . $path . '.php')){
                require_once($directories . '/' . $path . '.php');
            }
        }
    }   
}

But I don't think I am understanding how the plugin_dir_path function is working. the problem is that, once this class is instantiated, no class can be loaded in the plugin's directory. that is /plugin/myplugin/ How ever if I have a theme using the framework I am developing, and the theme is activated, and I instantiate this class in the plugin's main php file via:

//require_once(plugin_dir_path(__FILE__) . 'AisisCore/Loader/AutoLoader.php');
require_once(get_template_directory() . '/AisisCore/Loader/AutoLoader.php');

// Setup the autoloader.
$auto_loader = AisisCore_Loader_AutoLoader::get_instance();
$auto_loader->register_auto_loader();

$obj = new AisisCore_Http_Http();

Then everything works, it sees the AisisCore_Http_http class and and so on, but if I do:

require_once(plugin_dir_path(__FILE__) . 'AisisCore/Loader/AutoLoader.php');
//require_once(get_template_directory() . '/AisisCore/Loader/AutoLoader.php');

// Setup the autoloader.
$auto_loader = AisisCore_Loader_AutoLoader::get_instance();
$auto_loader->register_auto_loader();

$obj = new AisisCore_Http_Http();

it freaks out and cannot find the class.

Ideas?

Answer 1

when faced something similar I found a solution that works if your framework resides inside a plugin (so it seems).

If your main plugin file (one that is recognized by WordPress as the plugin file) is in, e.g. /plugin/Aisis/ you can put this path in a constant, eg.

define('AISISPATH', dirname(__FILE__));
require ( trailingslashit (AISISPATH) . 'AisisCore/Loader/AutoLoader.php' );
if ( ! class_exists('AisisCore_Loader_AutoLoader') ) die('Something strange happened.');
AisisCore_Loader_AutoLoader::get_instance();

In your get_instance() method of AisisCore_Loader_AutoLoader class put:

    self::$_directories = array(
        get_template_directory(),
        get_stylesheet_directory(),
        trailingslashit( AISISPATH )
    );

Doing like so, AisisCore_Loader_AutoLoader::$_directories[2] will be {wp_path_here}/plugin/Aisis so when you call $obj = new AisisCore_Http_Http(); your autoloader method will search in {wp_path_here}/plugin/Aisis/AisisCore/Http/Http.php.

Everything works, of course, if the plugin is activated from WP dashboard.

If you follow this process, is a good idea start the get_instance() method with: if ( ! defined('AISISPATH ') ) die('Framework not initilized.');

Your logic probably doesn't work because plugin_dir_path($file), is just a wrapper for trailingslashit( dirname( $file ) ) (see the Codex) so if you use this function passing __FILE__ as param it will return the folder in which the file that call the function is (in your case 'AisisCore/Loader/') and not your framework root.

Hope this helps you.