[5.3] [RFC] CMSPlugin: Lazy subscriber interface and decorator

libraries/src/Event/LazyServiceSubscriber.php

@@ -0,0 +1,154 @@
+<?php
+
+/**
+ * Joomla! Content Management System
+ *
+ * @copyright  (C) 2024 Open Source Matters, Inc. <https://www.joomla.org>
+ * @license    GNU General Public License version 2 or later; see LICENSE.txt
+ */
+
+namespace Joomla\CMS\Event;
+
+use Joomla\CMS\Extension\PluginInterface;
+use Joomla\Event\DispatcherInterface;
+use Joomla\Event\SubscriberInterface;
+use Psr\Container\ContainerInterface;
+
+// phpcs:disable PSR1.Files.SideEffects
+\defined('_JEXEC') or die;
+// phpcs:enable PSR1.Files.SideEffects
+
+/**
+ * Decorator for lazy subscribers be pulled from the service container when subscribed event dispatched.
+ *
+ * @since  __DEPLOY_VERSION__
+ */
+final class LazyServiceSubscriber implements LazySubscriberInterface, PluginInterface
+{
+    /**
+     * The service container
+     *
+     * @var    ContainerInterface
+     * @since  __DEPLOY_VERSION__
+     */
+    private $container;
+
+    /**
+     * Subscriber class name, and id in the container
+     *
+     * @var    string
+     * @since  __DEPLOY_VERSION__
+     */
+    private $class;
+
+    /**
+     * List of events, and listeners.
+     *
+     * @var array
+     * @since  __DEPLOY_VERSION__
+     */
+    private $eventsAndListeners = [];
+
+    /**
+     * Subscriber instance.
+     *
+     * @var object
+     * @since  __DEPLOY_VERSION__
+     */
+    private $instance;
+
+    /**
+     * Constructor.
+     *
+     * @param \Psr\Container\ContainerInterface $container  Container
+     * @param string                            $class      Subscriber class name, and id in the container
+     *
+     * @since  __DEPLOY_VERSION__
+     */
+    public function __construct(ContainerInterface $container, string $class)
+    {
+        $this->container = $container;
+        $this->class     = $class;
+
+        if (!is_subclass_of($class, SubscriberInterface::class)) {
+            throw new \InvalidArgumentException(sprintf('Class %s does not implement %s', $class, SubscriberInterface::class));
+        }
+
+        $this->eventsAndListeners = $class::getSubscribedEvents();
+    }
+
+    /**
+     * Retrieve the instance of Subscriber.
+     *
+     * @return object
+     *
+     * @throws \Throwable
+     *
+     * @since  __DEPLOY_VERSION__
+     */
+    public function getSubscriberInstance(): object
+    {
+        if (!$this->instance) {
+            $this->instance = $this->container->get($this->class);
+        }
+
+        return $this->instance;
+    }
+
+    /**
+     * Returns an array of events and the listeners, the subscriber will listen to.
+     *
+     * @return array
+     *
+     * @since  __DEPLOY_VERSION__
+     */
+    public function getEventsAndListeners(): array
+    {
+        return $this->eventsAndListeners;
+    }
+
+    /**
+     * Method to call the event listeners.
+     *
+     * @param string $eventName
+     * @param array  $arguments
+     *
+     * @return mixed
+     *
+     * @throws \InvalidArgumentException
+     *
+     * @since  __DEPLOY_VERSION__
+     */
+    public function __call(string $eventName, array $arguments): mixed
+    {
+        $instance = $this->instance ?: $this->getSubscriberInstance();
+
+        if (!\is_callable([$instance, $eventName])) {
+            throw new \InvalidArgumentException(sprintf('Event "%s" not supported by %s.', $eventName, $this->class));
+        }
+
+        return \call_user_func_array([$instance, $eventName], $arguments);
+    }
+
+    /**
+     * A dummy to complete the interface.
+     *
+     * @return  void
+     *
+     * @since   __DEPLOY_VERSION__
+     */
+    public function registerListeners()
+    {
+    }
+
+    /**
+     * A dummy to complete the interface.
+     *
+     * @return  void
+     *
+     * @since   __DEPLOY_VERSION__
+     */
+    public function setDispatcher(DispatcherInterface $dispatcher)
+    {
+    }
+}

libraries/src/Event/LazySubscriberInterface.php

@@ -0,0 +1,56 @@
+<?php
+
+/**
+ * Joomla! Content Management System
+ *
+ * @copyright  (C) 2024 Open Source Matters, Inc. <https://www.joomla.org>
+ * @license    GNU General Public License version 2 or later; see LICENSE.txt
+ */
+
+namespace Joomla\CMS\Event;
+
+// phpcs:disable PSR1.Files.SideEffects
+\defined('_JEXEC') or die;
+// phpcs:enable PSR1.Files.SideEffects
+
+/**
+ * Decorator for lazy subscribers be pulled from the service container when subscribed event dispatched.
+ *
+ * @since  __DEPLOY_VERSION__
+ */
+interface LazySubscriberInterface
+{
+    /**
+     * Retrieve the instance of Subscriber.
+     *
+     * @return object
+     *
+     * @throws \Throwable
+     *
+     * @since  __DEPLOY_VERSION__
+     */
+    public function getSubscriberInstance(): object;
+
+    /**
+     * Returns an array of events and the listeners, the subscriber will listen to.
+     *
+     * The array keys are event names and the value can be:
+     *
+     *   - The method name (of the subscriber instance) to call (priority defaults to 0)
+     *   - An array composed of the method name (of the subscriber instance) to call and the priority
+     *   - A callable instance to call
+     *   - An array composed of the callable instance to call and the priority
+     *
+     *  For instance:
+     *
+     *   ['eventName' => 'methodName']
+     *   ['eventName' => ['methodName', $priority]]
+     *   ['eventName' => $callable]
+     *   ['eventName' => [$callable, $priority]]
+     *
+     * @return array
+     *
+     * @since  __DEPLOY_VERSION__
+     */
+    public function getEventsAndListeners(): array;
+}

libraries/src/Plugin/PluginHelper.php

@@ -10,9 +10,11 @@
 namespace Joomla\CMS\Plugin;
 
 use Joomla\CMS\Cache\Exception\CacheExceptionInterface;
+use Joomla\CMS\Event\LazySubscriberInterface;
 use Joomla\CMS\Factory;
 use Joomla\Event\DispatcherAwareInterface;
 use Joomla\Event\DispatcherInterface;
+use Joomla\Event\Priority;
 
 // phpcs:disable PSR1.Files.SideEffects
 \defined('_JEXEC') or die;
@@ -239,7 +241,19 @@ protected static function import($plugin, $autocreate = true, DispatcherInterfac
             return;
         }
 
-        $plugin->registerListeners();
+        if ($plugin instanceof LazySubscriberInterface) {
+            foreach ($plugin->getEventsAndListeners() as $eventName => $params) {
+                if (\is_array($params) && !\is_callable($params)) {
+                    $callback = !\is_string($params[0]) && \is_callable($params[0]) ? $params[0] : [$plugin, $params[0]];
+                    $dispatcher->addListener($eventName, $callback, $params[1] ?? Priority::NORMAL);
+                } else {
+                    $callback = !\is_string($params) && \is_callable($params) ? $params : [$plugin, $params];
+                    $dispatcher->addListener($eventName, $callback);
+                }
+            }
+        } else {
+            $plugin->registerListeners();
+        }
     }
 
     /**

plugins/system/schedulerunner/services/provider.php

@@ -10,6 +10,7 @@
 
 \defined('_JEXEC') or die;
 
+use Joomla\CMS\Event\LazyServiceSubscriber;
 use Joomla\CMS\Extension\PluginInterface;
 use Joomla\CMS\Factory;
 use Joomla\CMS\Plugin\PluginHelper;
@@ -31,7 +32,7 @@
     public function register(Container $container): void
     {
         $container->set(
-            PluginInterface::class,
+            ScheduleRunner::class,
             function (Container $container) {
                 $plugin     = new ScheduleRunner(
                     $container->get(DispatcherInterface::class),
@@ -41,6 +42,11 @@ function (Container $container) {
 
                 return $plugin;
             }
+        )->set(
+            PluginInterface::class,
+            function (Container $container) {
+                return new LazyServiceSubscriber($container, ScheduleRunner::class);
+            }
         );
     }
 };

plugins/system/tasknotification/services/provider.php

@@ -10,6 +10,7 @@
 
 \defined('_JEXEC') or die;
 
+use Joomla\CMS\Event\LazyServiceSubscriber;
 use Joomla\CMS\Extension\PluginInterface;
 use Joomla\CMS\Factory;
 use Joomla\CMS\Plugin\PluginHelper;
@@ -33,7 +34,7 @@
     public function register(Container $container): void
     {
         $container->set(
-            PluginInterface::class,
+            TaskNotification::class,
             function (Container $container) {
                 $plugin     = new TaskNotification(
                     $container->get(DispatcherInterface::class),
@@ -45,6 +46,11 @@ function (Container $container) {
 
                 return $plugin;
             }
+        )->set(
+            PluginInterface::class,
+            function (Container $container) {
+                return new LazyServiceSubscriber($container, TaskNotification::class);
+            }
         );
     }
 };

plugins/system/webauthn/services/provider.php

@@ -12,6 +12,7 @@
 
 use Joomla\Application\ApplicationInterface;
 use Joomla\Application\SessionAwareWebApplicationInterface;
+use Joomla\CMS\Event\LazyServiceSubscriber;
 use Joomla\CMS\Extension\PluginInterface;
 use Joomla\CMS\Factory;
 use Joomla\CMS\Plugin\PluginHelper;
@@ -40,7 +41,7 @@
     public function register(Container $container)
     {
         $container->set(
-            PluginInterface::class,
+            Webauthn::class,
             function (Container $container) {
                 $app     = Factory::getApplication();
                 $session = $container->has('session') ? $container->get('session') : $this->getSession($app);
@@ -72,6 +73,11 @@ function (Container $container) {
 
                 return $plugin;
             }
+        )->set(
+            PluginInterface::class,
+            function (Container $container) {
+                return new LazyServiceSubscriber($container, Webauthn::class);
+            }
         );
     }