Using AbstractPluginManager with Zend Expressive 3 - php

Question

I'd like to inject an array of objects that implement a common interface into one of my services. I am using zend servicemanager as the DI container. I have been reading the docs for quite a bit now and it seems to me that AbstractPluginManager is the way to go. I haven't been able to make it work though.
Is there an example using an AbstractPluginManager + Zend Expressive 3 that I can take a look at?
My ultimate goal is to dynamically inject all registered classes that implement a common interface into my service.
Example:
interface I{}
class A implements I{}
class B implements I{}
class C{}
MyService
__construct(array Iimplementations){...}
$service = $container->get('myservice')
$service has Iimplementations
Thanks in advance

Answer 1

The AbstractPluginManager is mostly for validation and filter plugins. You can create classes and while validating, you can pass specific configuration which makes the filter or validator re-usable.
What you are looking for is probably an abstract factory. You register the factory once and it can create a service for you. In your case with a specific set of dependencies.
interface I{}
class A implements I{}
class B implements I{}
class MyAbstractFactory implements AbstractFactoryInterface
{
public function canCreate(ContainerInterface $container, $requestedName)
{
return in_array('I', class_implements($requestedName), true);
}
public function __invoke(ContainerInterface $container, $requestedName, array $options = null)
{
return new $requestedName(
$container->get(DependencyFoo::class),
$container->get(DependencyBar::class)
);
}
}
// config/autoload/dependencies.global.php
return [
'dependencies' => [
'factories' => [
// ...
],
'abstract_factories' => [
MyAbstractFactory::class,
],
],
];
You can also go crazy and use reflection to detect dependencies if they are different for each class, however that adds a lot of overhead. I think it's easier and more maintainable to create separate factories. And then there is zend-expressive-tooling which is a cli tool that can create factories, handlers and middleware.

Answer 2

/*Getting I concrete implementations via the plugin manager will ensure the implementation of the I interface*/
class IPluginManager extends AbstractPluginManager
{
protected $instanceOf = I::class;
public function getIConcreteImplementations()
{
$concreteImpl = [];
foreach(array_keys($this->factories) as $key)
{
$concreteImpl[] = $this->get($key);
}
return $concreteImpl;
}
}
/*IPluginManagerFactory*/
class TransactionSourcePluginManagerFactory
{
const CONFIG_KEY = 'i-implementations-config-key';
public function __invoke(ContainerInterface $container, $name, array $options = null)
{
$pluginManager = new IPluginManager($container, $options ?: []);
// If this is in a zend-mvc application, the ServiceListener will inject
// merged configuration during bootstrap.
if ($container->has('ServiceListener')) {
return $pluginManager;
}
// If we do not have a config service, nothing more to do
if (! $container->has('config')) {
return $pluginManager;
}
$config = $container->get('config');
// If we do not have validators configuration, nothing more to do
if (! isset($config[self::CONFIG_KEY]) || !
is_array($config[self::CONFIG_KEY])) {
return $pluginManager;
}
// Wire service configuration for validators
(new Config($config[self::CONFIG_KEY]))->configureServiceManager($pluginManager);
return $pluginManager;
}
}
/*In the ConfigProvider of the module or global config*/
class ConfigProvider
{
/**
* Returns the configuration array
*
* To add a bit of a structure, each section is defined in a separate
* method which returns an array with its configuration.
*
*/
public function __invoke() : array
{
return [
'dependencies' => $this->getDependencies(),
'routes' => $this->getRoutes(),
'i-implementations-config-key' => $this->getIConcreteImplementations(),
];
}
public function getIConcreteImplementations() : array
{
return [
'factories' => [
A::class => AFactory::class,
B::class => InvokableFactory::class,
],
];
}
}
/*I can now be sure that I am injecting an array of I implementations into my Service*/
class ServiceFactory
{
public function __invoke(ContainerInterface $container) : Service
{
$pluginManager = $container->get(IPluginManager::class);
$impl = $pluginManager->getIConcreteImplementations();
return new Service($impl);
}
}