Is autoloader different for framework vs. normal library

Question

According to the PCR-0 proposal, all the autoloader needs is autoload() function. Zend has a few autoloading classes

Zend_Loader()
Zend_Loader_Autoloader()
Zend_Loader_Autoloader_Resource()
Zend_Loader_Autoloader_Interface()

I'm guessing it has all these classes because it's a framework, so it needs to load its own classes, as well as library classes for any libraries that the developer may add and which don't have their own autoloader.

I have a library (normal library, not a framework). Right now it doesn't have an autoloader so I use Zend's Zend_Loader_Autoloader_Resource ->addResourceType(). If I write an autoloader for it, which autoloader will be used: Zend's or the library? and do I have to implement an autoloader as complex as Zend's or a simple one like the PCR-0 example.

What happens in these cases

both framework and library have their own autoloader
framework has autoloader, but the library doesn't
framework has NO autoloader, and library has

Tomáš Fejfar Tomáš Fejfar · Accepted Answer · 2011-06-05T23:51:23

I'd suggest sticking to direct path->class mapping and implementing your own autoloader like this:

class MyLib_Autoloader
{
    public function __construct() {
        spl_autoload_register(array($this, 'autoload'));
    }
    public function autoload($className)
    {
        if (substr($className, 0, 6) == 'MyLib_') {
            include dirname(__FILE__) . DIRECTORY_SEPARATOR . '..' . DIRECTORY_SEPARATOR strtr($className, '_', DIRECTORY_SEPARATOR) . '.php';
            return true;
        } 
        return false;
    }
}

This will check if the class is from your namespace and load the file. Assumes your autoloader is in /some/path/MyLib/ -> the include path will be /some/path/MyLib/../MyLib/ClassName.php. You can also add more logic to strip the initial MyLib from the class name and get rid of that '..'.

Make sure to use only require. It's faster and the autoload function is not called more than once for each classname! :) No need to include_once/require_once/etc. Go with the fastest.

Usage is as simple as:

include '/some/path/MyLib/Autploader.php';
$loader = new MyLib_Autoloader();

Is autoloader different for framework vs. normal library

2 Answers