Make it possible to broadcast events to (web) clients

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>

core/Command/Broadcast/Test.php

@@ -0,0 +1,100 @@
+<?php declare(strict_types=1);
+
+/**
+ * @copyright 2019 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2019 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OC\Core\Command\Broadcast;
+
+use OCP\EventDispatcher\ABroadcastedEvent;
+use OCP\EventDispatcher\IEventDispatcher;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+class Test extends Command {
+
+	/** @var IEventDispatcher */
+	private $eventDispatcher;
+
+	public function __construct(IEventDispatcher $eventDispatcher) {
+		parent::__construct();
+		$this->eventDispatcher = $eventDispatcher;
+	}
+
+	protected function configure(): void {
+		$this
+			->setName('broadcast:test')
+			->setDescription('test the SSE broadcaster')
+			->addArgument(
+				'uid',
+				InputArgument::REQUIRED,
+				'the UID of the users to receive the event'
+			)
+			->addArgument(
+				'name',
+				InputArgument::OPTIONAL,
+				'the event name',
+				'test'
+			);
+	}
+
+	protected function execute(InputInterface $input, OutputInterface $output) {
+		$name = $input->getArgument('name');
+		$uid = $input->getArgument('uid');
+
+		$event = new class($name, $uid) extends ABroadcastedEvent {
+			/** @var string */
+			private $name;
+			/** @var string */
+			private $uid;
+
+			public function __construct(string $name,
+										string $uid) {
+				parent::__construct();
+				$this->name = $name;
+				$this->uid = $uid;
+			}
+
+			public function broadcastAs(): string {
+				return $this->name;
+			}
+
+			public function getUids(): array {
+				return [
+					$this->uid,
+				];
+			}
+
+			public function serialize(): array {
+				return [
+					'description' => 'this is a test event',
+				];
+			}
+		};
+
+		$this->eventDispatcher->dispatch('broadcasttest', $event);
+
+		return 0;
+	}
+
+}

core/register_command.php

@@ -78,6 +78,8 @@
 	$application->add(new OC\Core\Command\Background\WebCron(\OC::$server->getConfig()));
 	$application->add(new OC\Core\Command\Background\Ajax(\OC::$server->getConfig()));
 
+	$application->add(\OC::$server->query(\OC\Core\Command\Broadcast\Test::class));
+
 	$application->add(new OC\Core\Command\Config\App\DeleteConfig(\OC::$server->getConfig()));
 	$application->add(new OC\Core\Command\Config\App\GetConfig(\OC::$server->getConfig()));
 	$application->add(new OC\Core\Command\Config\App\SetConfig(\OC::$server->getConfig()));

lib/private/Broadcast/Events/BroadcastEvent.php

@@ -0,0 +1,37 @@
+<?php declare(strict_types=1);
+
+namespace OC\Broadcast\Events;
+
+use JsonSerializable;
+use OCP\Broadcast\Events\IBroadcastEvent;
+use OCP\EventDispatcher\ABroadcastedEvent;
+use OCP\EventDispatcher\Event;
+
+class BroadcastEvent extends Event implements IBroadcastEvent {
+
+	/** @var ABroadcastedEvent */
+	private $event;
+
+	public function __construct(ABroadcastedEvent $event) {
+		parent::__construct();
+
+		$this->event = $event;
+	}
+
+	public function getName(): string {
+		return $this->event->broadcastAs();
+	}
+
+	public function getUids(): array {
+		return $this->event->getUids();
+	}
+
+	public function getPayload(): JsonSerializable {
+		return $this->event;
+	}
+
+	public function setBroadcasted(): void {
+		$this->event->setBroadcasted();
+	}
+
+}

lib/private/EventDispatcher/EventDispatcher.php

@@ -25,7 +25,10 @@
 
 namespace OC\EventDispatcher;
 
+use OC\Broadcast\Events\BroadcastEvent;
+use OCP\Broadcast\Events\IBroadcastEvent;
 use OCP\EventDispatcher\Event;
+use OCP\EventDispatcher\ABroadcastedEvent;
 use OCP\EventDispatcher\IEventDispatcher;
 use OCP\IContainer;
 use OCP\ILogger;
@@ -73,6 +76,14 @@ public function addServiceListener(string $eventName,
 	public function dispatch(string $eventName,
 							 Event $event): void {
 		$this->dispatcher->dispatch($event, $eventName);
+
+		if ($event instanceof ABroadcastedEvent && !$event->isPropagationStopped()) {
+			// Propagate broadcast
+			$this->dispatch(
+				IBroadcastEvent::class,
+				new BroadcastEvent($event)
+			);
+		}
 	}
 
 	public function dispatchTyped(Event $event): void {

lib/public/Broadcast/Events/IBroadcastEvent.php

@@ -0,0 +1,35 @@
+<?php declare(strict_types=1);
+
+namespace OCP\Broadcast\Events;
+
+use JsonSerializable;
+
+/**
+ * @since 18.0.0
+ */
+interface IBroadcastEvent {
+
+	/**
+	 * @return string the name of the event
+	 * @since 18.0.0
+	 */
+	public function getName(): string;
+
+	/**
+	 * @return string[]
+	 * @since 18.0.0
+	 */
+	public function getUids(): array;
+
+	/**
+	 * @return JsonSerializable the data to be sent to the client
+	 * @since 18.0.0
+	 */
+	public function getPayload(): JsonSerializable;
+
+	/**
+	 * @since 18.0.0
+	 */
+	public function setBroadcasted(): void;
+
+}

lib/public/EventDispatcher/ABroadcastedEvent.php

@@ -0,0 +1,57 @@
+<?php declare(strict_types=1);
+
+namespace OCP\EventDispatcher;
+
+use JsonSerializable;
+
+/**
+ * @since 18.0.0
+ */
+abstract class ABroadcastedEvent extends Event implements JsonSerializable {
+
+	private $broadcasted = false;
+
+	/**
+	 * Get the name of the event, as received on the client-side
+	 *
+	 * Uses the fully qualified event class name by default
+	 *
+	 * @return string
+	 * @since 18.0.0
+	 */
+	public function broadcastAs(): string {
+		return get_class($this);
+	}
+
+	/**
+	 * @return string[]
+	 * @since 18.0.0
+	 */
+	abstract public function getUids(): array;
+
+	/**
+	 * @since 18.0.0
+	 */
+	public function setBroadcasted(): void {
+		$this->broadcasted = true;
+	}
+
+	/**
+	 * @since 18.0.0
+	 */
+	public function isBroadcasted(): bool {
+		return $this->broadcasted;
+	}
+
+	abstract public function serialize(): array;
+
+	public final function jsonSerialize() {
+		return array_merge(
+			$this->serialize(),
+			[
+				'name' => $this->broadcastAs(),
+			]
+		);
+	}
+
+}