feat: subscription events (WIP)

src/Hub/Controller/SubscribeController.php

@@ -56,9 +56,10 @@ public function __invoke(
     ): ResponseInterface {
         $subscribedTopics = $this->extractSubscribedTopics($request);
         $allowedTopics = $this->extractAllowedTopics($request);
+        $payload = $this->extractPayload($request);
         $lastEventId = extract_last_event_id($request);
 
-        $subscriber = new Subscriber($subscribedTopics);
+        $subscriber = new Subscriber($subscribedTopics, $payload);
 
         if (null !== $lastEventId) {
             async(
@@ -138,4 +139,15 @@ private function extractAllowedTopics(ServerRequestInterface $request): ?array
 
         return $jwt->claims()->get('mercure')['subscribe'] ?? null;
     }
+
+    private function extractPayload(ServerRequestInterface $request): mixed
+    {
+        /** @var UnencryptedToken|null $jwt */
+        $jwt = $request->getAttribute('token');
+        if (null === $jwt) {
+            return null;
+        }
+
+        return $jwt->claims()->get('mercure')['payload'] ?? null;
+    }
 }

src/Hub/Hub.php

@@ -8,6 +8,7 @@
 use Freddie\Hub\Middleware\HttpExceptionConverterMiddleware;
 use Freddie\Hub\Transport\PHP\PHPTransport;
 use Freddie\Hub\Transport\TransportInterface;
+use Freddie\Message\Message;
 use Freddie\Message\Update;
 use Freddie\Subscription\Subscriber;
 use Generator;
@@ -17,12 +18,14 @@
 use Symfony\Component\OptionsResolver\OptionsResolver;
 
 use function array_key_exists;
+use function json_encode;
 use function sprintf;
 
 final class Hub implements HubInterface
 {
     public const DEFAULT_OPTIONS = [
         'allow_anonymous' => true,
+        'enable_subscription_events' => true,
     ];
 
     /**
@@ -46,6 +49,7 @@ public function __construct(
         $resolver = new OptionsResolver();
         $resolver->setDefaults(self::DEFAULT_OPTIONS);
         $resolver->setAllowedTypes('allow_anonymous', 'bool');
+        $resolver->setAllowedTypes('enable_subscription_events', 'bool');
         $this->options = $resolver->resolve($options);
         foreach ($controllers as $controller) {
             $controller->setHub($this);
@@ -79,11 +83,30 @@ public function publish(Update $update): PromiseInterface
     public function subscribe(Subscriber $subscriber): void
     {
         $this->transport->subscribe($subscriber);
+        if (true === $this->getOption('enable_subscription_events')) {
+            foreach ($subscriber->subscriptions as $subscription) {
+                $update = new Update(
+                    $subscription->id,
+                    new Message(data: (string) json_encode($subscription), private: true)
+                );
+                Loop::futureTick(fn () => $this->publish($update));
+            }
+        }
     }
 
     public function unsubscribe(Subscriber $subscriber): void
     {
         $this->transport->unsubscribe($subscriber);
+        if (true === $this->getOption('enable_subscription_events')) {
+            $subscriber->active = false;
+            foreach ($subscriber->subscriptions as $subscription) {
+                $update = new Update(
+                    $subscription->id,
+                    new Message(data: (string) json_encode($subscription), private: true)
+                );
+                Loop::futureTick(fn () => $this->publish($update));
+            }
+        }
     }
 
     public function reconciliate(string $lastEventID): Generator

src/Subscription/Subscription.php

@@ -4,11 +4,43 @@
 
 namespace Freddie\Subscription;
 
-final class Subscription
+use JsonSerializable;
+
+use function sprintf;
+use function urlencode;
+
+final class Subscription implements JsonSerializable
 {
+    public readonly string $id;
+
     public function __construct(
         public Subscriber $subscriber,
         public string $topic,
     ) {
+        $this->id = sprintf(
+            '/.well-known/mercure/subscriptions/%s/%s',
+            urlencode($this->topic),
+            urlencode((string) $subscriber->id)
+        );
+    }
+
+    /**
+     * @return array<string, mixed>
+     */
+    public function jsonSerialize(): array
+    {
+        $output = [
+            'id' => $this->id,
+            'type' => 'Subscription',
+            'subscriber' => (string) $this->subscriber->id,
+            'topic' => $this->topic,
+            'active' => $this->subscriber->active,
+        ];
+
+        if (null !== $this->subscriber->payload) {
+            $output['payload'] = $this->subscriber->payload;
+        }
+
+        return $output;
     }
 }