Backported ZF2 Autoloaders

In the past six weeks, I've delivered both a webinar and a tutorial on Zend Framework 2 development patterns. The first pattern I've explored is our new suite of autoloaders, which are aimed at both performance and rapid application development -- the latter has always been true, as we've followed PEAR standards, but the former has been elusive within the 1.X series.

Interestingly, I've had quite some number of folks ask if they can use the new autoloaders in their Zend Framework 1 development. The short answer is "yes," assuming you're running PHP 5.3 already. If not, however, until today, the answer has been "no."

I've recently backported the ZF2 autoloaders to PHP 5.2, and posted them on GitHub:

https://github.com/weierophinney/zf-examples/tree/feature%2Fzf1-classmap/zf1-classmap

I'm also posting a tarball here:

http://weierophinney.net/uploads/zf1-classmap.tgz

The functionality includes:

  • A class map generation tool
  • A PSR-0-compliant autoloader, with include_path fallback capabilities
  • A class-map autoloader
  • An autoloader factory for loading many autoloading strategies at once

I've included a README file that details most use cases:

https://github.com/weierophinney/zf-examples/blob/feature%2Fzf1-classmap/zf1-classmap/README.md

The most interesting use case, I find, is combining a class-map autoloader with a PSR-0 autoloader configured with one or more paths and set as a fallback. This allows the benefits of performance when the class-map is seeded well, and developer performance when in active development. For it to work, you need to create at least an empty class-map. I will do the following immediately after generating a project in order to pre-seed it:


prompt> cd application/
prompt> php /path/to/zf/bin/classmap_generator.php -w
  Creating class file map for library in '/var/www/project/application'...
  Wrote classmap file to '/var/www/project/application/.classmap.php'
prompt> cd ../library/
prompt> php /path/to/zf/bin/classmap_generator.php -w
  Creating class file map for library in '/var/www/project/library'...
  Wrote classmap file to '/var/www/project/library/.classmap.php'

(The "-w" switch tells the generator to overwrite any classmap files already present.)

From there, I do the following in public/index.php:


require_once __DIR__ . '/../library/ZendX/Loader/AutoloaderFactory.php';
ZendX_Loader_AutoloaderFactory::factory(array(
    'ZendX_Loader_ClassMapAutoloader' => array(
        __DIR__ . '/../library/.classmap.php',
        __DIR__ . '/../application/.classmap.php',
    ),
    'ZendX_Loader_StandardAutoloader' => array(
        'prefixes' => array(
            'My' => __DIR__ . '/../library/My',
        ),
        'fallback_autoloader' => true,
    ),
));

The above examples do the following:

  • Create classmaps from the classes available in each of my "application" and "library" directories of my project.
  • Instantiates a class-map autoloader from those classmaps, and registers them with the SPL autoloader.
  • Creates a StandardAutoloader instance that's aware of the "My" vendor prefix, pointing to the "My" subdirectory in my library; as I add class files here, they will automatically be found.
  • Sets a fallback autoloader aware of my include_path.

This setup takes a minute or so to create, but ensures that I'm immediately productive. I then periodically update my classmap, by rerunning the classmap_generator.php script on my application and library directories and checking this in under version control.

This library is an excellent way to start boosting your ZF1 application performance (particularly if you strip your require_once calls), while simultaneously starting to make your code forward-compatible with ZF2.

Updates

2011-05-11 11:00 CDT
Updated classmap_generator.php in the repository to remove a closure and thus make it truly PHP 5.2 compliant. Additionally, updated the zf1-classmap.tgz tarball with this change.
2011-05-11 16:00 CDT
Updated ClassFileLocator to define PHP 5.3-specific tokenizer constants when in earlier PHP versions.
2011-05-23 10:25 CDT
Updated generate_classmap.php to (a) use DIRECTORY_SEPARATOR in paths to ensure portability from Windows to *nix environments, and (b) cache the results of dirname(__FILE__) to improve performance. Thanks to Tomas Fejfar for reporting these issues.
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