Complete and simple to install Composer autoloader or Magento

1. Other Composer autoloader integrations aren't complete. The most common issues with other implementations:

• They allow both Magento and Composer to register autoloaders. This causes problems when using libraries that expect class_exists to work properly—Magento's will always attempt to include the file.
• They allow Magento's autoload to register itself, then manually de-register it. This is wholly unnecessary overhead.
• They require manual configuration of composer.json for Magento autoloading.

2. With more and more need to integrate namespaced systems with Magento, a require-able, redistributable, easy to set up module is needed

Until it's listed in packagist or firegento, add the repository to your composer.json:

{
    "type": "vcs",
    "url": "https://github.com/mattwellss/magento-composer-autoloader"
}

Add the library to your require section:

"require": {
    "mattwellss/magento-composer-autoloader": "~1.0"
}

Post install, the new Varien_Autoload class needs to know where vendor/autoload.php is hiding. This must be configured.

Regardless of how the vendor dir is defined, it must not end with a trailing slash.

The two methods of describing the vendor root directory are:

• VENDOR_ROOT constant. Must be defined in all entry points.
• MAGE_VENDOR_ROOT env variable. Be sure it's defined for all PHP environments (cli and fpm/mod_php).

Normally, composer dump -o is all one does to optimize a composer autoloader. However, running php shell/classmap_generator.php when deploying new code to production is recommended. The script generates a classmap file to be used by composer to speed autoloading of files in Magento's code pools.

To enable use of the generated classmap, include define('OPTIMIZED_COMPOSER', true) in includes/config.php.