Zend Framework 2 - Cache-conform service factories

Question

The zend file application.config.php offers some way to cache the config, which I find very nice for a production system:

return array(
        'modules' => array(
                'Application',
        ),
        'module_listener_options' => array(
                'module_paths' => array(
                        './module',
                        './vendor'
                ),
                'config_glob_paths' => array('config/autoload/{,*.}{global,local}.php'),
                'config_cache_enabled' => true,
                'config_cache_key' => md5('config'),
                'module_map_cache_enabled' => true,
                'module_map_cache_key' => md5('module_map'),
                'cache_dir' => './data/cache',
        ),
);

However, activating that leads immediately to errors like

Fatal error: Call to undefined method Closure::__set_state()

This has to do with factories written as closures, like these:

'service_manager' => array(
    'factories' => array(
        'auth.service' => function($sm) {
            /* hic sunt ponies */
        },
    ),
),

Unfortunately, the issues only tell me why this error happens, but not how to resolve it.

How can I rework this and similar factories so the cache will work with them?

Answer 1

Rework your factory closures to factory classes.

Config

'service_manager' => array(
    'factories' => array(
        'auth.service' => \Fully\Qualified\NS\AuthFactory::class,
    ),
),

Factory

namespace Fully\Qualified\NS;

use Zend\ServiceManager\FactoryInterface;
use Zend\ServiceManager\ServiceLocatorInterface;

class AuthFactory implements FactoryInterface
{
    public function createService(ServiceLocatorInterface $serviceLocator) {
        // create your object and set dependencies
        return $object
    }
}

Besides this approach making caching possible, another advantage is that PHP will parse your config faster since it doesn't have to create a Closure class on each request for each anonymous function.