Integrating Doctrine 2 ORM and Migrations into Zend Expressive

I've started a new project in which we're looking at using Doctrine 2 ORM, but we're in a Zend Expressive project. As of yet, Expressive is in it's infancy, which means there are still things undocumented and missing. So I'm putting my two cents into how we got the ORM working in our project.

First up, we're going to use DoctrineORMModule -
we're mostly using ZF components (such as Zend\Form) so it makes sense to use something that already integrates with this later down the line, so start with

$ composer require doctrine/doctrine-orm-module
$ composer require doctrine/migrations

If you don't want to use the ORM, ignore the instructions for ORM, and the same for Migrations.

Next up, you want your configuration to be included. This would be easy if it were not for the fact Zend Expressive looks for the dependencies config key, but Doctrine has this all in service_manager. So we need to make a shim which reads the config of both DoctrineModule and DoctrineORMModule and merge them into the final config:

<?php

use Zend\Stdlib\ArrayUtils;

$vendorPath = __DIR__ . '/../../vendor'; // You may need to adjust this depending on your structure...

$doctrineModuleConfig = require_once $vendorPath . '/doctrine/doctrine-module/config/module.config.php';
$doctrineModuleConfig['dependencies'] = $doctrineModuleConfig['service_manager'];
unset($doctrineModuleConfig['service_manager']);

$doctrineOrmModuleConfig = require_once $vendorPath . '/doctrine/doctrine-orm-module/config/module.config.php';
$doctrineOrmModuleConfig['dependencies'] = $doctrineOrmModuleConfig['service_manager'];
unset($doctrineOrmModuleConfig['service_manager']);

return ArrayUtils::merge($doctrineModuleConfig, $doctrineOrmModuleConfig);

Once this is done, there's a couple more things to do. First we need to provide our own Doctrine connection / driver / migrations configurations. This is the normal setup, so check out the DoctrineORMModule docs for this. We simply placed our config into doctrine.global.php with the default configuration, and then specify platform-specific config into a Git-ignored local.php.

Finally, because we're using the ORM with annotations, we need to register the annotation loader:

\Doctrine\Common\Annotations\AnnotationRegistry::registerLoader(
    function ($className) {
        return class_exists($className);
    }
);

This code can actually live anywhere, but we added a Bootstrap middleware which has a function that calls this. This could be seen as synonymous with a Module.php in ZF2's bootstrap sequence.

If anyone has any feedback, or simpler ways of doing this, I'd love to hear :)

EDIT There was one more thing, in your dependencies.global.php you need to alias configuration to config, because it looks for configuration:

<?php

return [
    'dependencies' => [
        'aliases' => [
            'configuration' => 'config',
        ],
    ],
];