OnAppInit.php

<?php
/**
 * OnApp API wrapper bootstrap
 *
 * @category    API wrapper
 * @package     OnApp
 * @author      Lev Bartashevsky
 * @copyright   © 2011 OnApp
 * @link        http://www.onapp.com/
 */
if( ! defined( 'ONAPP_WRAPPER_ROOT_DIR' ) ) {
    /**
     * Check PHP version
     * PHP 5.3+ is required
     */
    if( ( PHP_MAJOR_VERSION < 5 ) || ( PHP_MAJOR_VERSION == 5 && PHP_MINOR_VERSION < 3 ) ) {
        exit( 'OnApp wrapper error: PHP 5.3+ is required. You have PHP ' . PHP_VERSION . PHP_EOL );
    }

    /**
     * Specify the wrapper root dir
     */
    define( 'ONAPP_WRAPPER_ROOT_DIR', dirname( __FILE__ ) . DIRECTORY_SEPARATOR );

    /**
     * Automatically load requested class
     *
     * @param string $className requested class' name
     *
     * @return bool
     */
    function OnAppAutoLoad( $className ) {
        // compatibility with legacy code
        $className = str_replace( 'ONAPP', 'OnApp', $className );

        $path = str_replace( 'OnApp_', '', $className );
        $path = explode( '_', $path );
        $path = ONAPP_WRAPPER_ROOT_DIR . implode( DIRECTORY_SEPARATOR, $path ) . '.php';

        if( file_exists( $path ) ) {
            require $path;

            if( class_exists( $className ) ) {
                return true;
            }
            //todo add loging instead of printing
        }

        return false;
    }

    /**
     * Register autoload handler
     */
    spl_autoload_register( 'OnAppAutoLoad' );

    /**
     * Detect if the code run in CLI for testing purposes
     */
    if( defined( 'STDIN' ) ) {
        define( 'IS_CLI', true );
    }
    else {
        define( 'IS_CLI', false );
    }
}