In a new post to his blog Rob Allen introduces you to the autoloader that comes with the Zend Framework 2 and shows how to use it to load your own classes.

Autoloading is the process in PHP whereby the system attempts to load a class when it is first encountered (via new or via class_exists) if it hasn't already been loaded via a require or include. Autoload works by looking for a method called __autoload or walking through any method registered with spl_autoload_register. Zend Framework 2 provides the ZendLoaderAutoloader component for autoloading of Zend Framework and your own classes.

The PSR-0-standard tool allows you to load files, set up class mapping and allows for multiple autoloading methods to work side-by-side. He shows how to use the standard autoloading functionality to define paths to locate files (with prefixes and namespaces) in both a constructor-based setup and a more programatic approach. He also shows how to use the ClassMapAutoloader to load from a mapping of class name to class file. Wrapping it up, he shows how to combine the two methods into a single ZendLoaderAutoloaderFactory instance.

In his latest post Volker looks at something he sees more and more projected implementing as a simple way to not have to manually define paths all over their applications - creating autoloaders. His post shows how to create one such autoloader for a legacy, non-framework type of project.

The first argument usually is "ease of use". It can get pretty annoying when you have to clutter your whole application with "require this file here and that file over there" statements. [...] The main motivation for autoloading usually is "getting rid of all the require statements and the problems resulting from forgetting one at one point where you don't notice it because on your machine it worked.

In some projects you're lucky enough to have class name to file name mapping to make it simpler. His project didn't have that, so he needed a way around it. His answer came in the PHP Autoload Builder tool - a handy command line script that works through your code and builds an index of sorts you can refer to for the correct class-to-file map.

Matthew Weier O'Phinney has a new post to his blog (following this post on directory iteration for autoloading) with some of the benchmarks of different methods he tried for automatically loading the libraries his scripts needed on demand.

During the past week, I've been looking at different strategies for autoloading in Zend Framework. I've suspected for some time that our class loading strategy might be one source of performance degradation, and wanted to research some different approaches, and compare performance. In this post, I'll outline the approaches I've tried, the benchmarking strategy I applied, and the results of benchmarking each approach.

His testing included a baseline of the Zend Framework 1.x series loading, a naming/class standard following the PEAR standards and class mapping with file/class name pairs. He includes his benchmarking strategy and the scripts he used to run the tests (on github here). He ran them both with and without opcode caching to give a better overall performance view.