PHPExcel class not found in Zend Autoloader

Create an autoloader for PHPExcel and add it to the Zend autoloader stack.

In library/My/Loader/Autoloader/PHPExcel.php:

class My_Loader_Autoloader_PHPExcel implements Zend_Loader_Autoloader_Interface
{
    public function autoload($class)
    {
        if ('PHPExcel' != $class){
            return false;
        }
        require_once 'PHPExcel.php';
        return $class;
    }
}

And in application/configs/application.ini:

autoloadernamespaces[] = "My_"

Then, in application/Bootstrap.php:

protected function _initAutoloading()
{
    $autoloader = Zend_Loader_Autoloader::getInstance();
    $autoloader->pushAutoloader(new My_Loader_Autoloader_PHPExcel());
}

Then you should be able to instantiate PHPExcel - say, in a controller - with a simple:

$excel = new PHPExcel();

The only sticky part is all of this is how PHPExcel handles loading all its dependencies within its own folder. If that is done intelligently - either with calls like require_once basename(__FILE__) . '/someFile.php' or with its own autoloader that somehow doesn't get in the way of the Zend autoloader - then all should be cool. #famouslastwords

Nowadays composer is a frequently used tool that wasn't so popular back in 2012. Even older projects built in ZF1 can make use of composer and its autoloader.

How to get all your libraries to work without having to add custom autoloaders to your application.ini each time?

Make use of composer's autoloader

First, start with setting up composer.json. Once created, run composer install to gather all required packages and create composer's autoloader.

Now, let's update your project's public/index.php. From now on all requirements that are loaded via composer will be autoloaded.

<?php

// Define path to application directory
defined('APPLICATION_PATH')
    || define('APPLICATION_PATH', realpath(dirname(__FILE__) . '/../application'));

// Define application environment
defined('APPLICATION_ENV')
    || define('APPLICATION_ENV', (getenv('APPLICATION_ENV') ? getenv('APPLICATION_ENV') : 'development'));

// Include composer autoloader
require_once __DIR__ . '/../vendor/autoload.php';

/** Zend_Application */
require_once 'Zend/Application.php';

// Create application, bootstrap, and run
$application = new Zend_Application(
    APPLICATION_ENV,
    array( 'config' => APPLICATION_PATH . '/configs/application.ini' )
);

$application->bootstrap();
$application->run();