Subscription send only to others (#2298)

Co-authored-by: Benedikt Franke <[email protected]>

CHANGELOG.md

@@ -18,6 +18,7 @@ You can find and compare releases at the [GitHub release page](https://github.co
 - Require implementations of `BatchedEntityResolver` to maintain the keys given in `array $representations` https://github.com/nuwave/lighthouse/pull/2286
 - Use the strongest possible native types over PHPDocs
 - Require filter directives such as `@whereKey` in `@delete`, `@forceDelete` and `@restore` https://github.com/nuwave/lighthouse/pull/2289
+- Subscriptions can now be filtered via `$subscriber->socket_id` and `request()->header('X-Socket-ID')` https://github.com/nuwave/lighthouse/pull/2298
 
 ### Fixed
 

docs/master/subscriptions/filtering-subscriptions.md

@@ -40,3 +40,38 @@ class PostUpdatedSubscription extends GraphQLSubscription
     }
 }
 ```
+
+## Only To Others
+
+When building an application that utilizes event broadcasting, you may occasionally need to broadcast an event to all subscribers of a channel except for the current user.
+You may accomplish this using the filter function, this following snippet is equivalent to [the `toOthers()` method from Laravel's broadcast helper](https://laravel.com/docs/9.x/broadcasting#only-to-others).
+
+```php
+namespace App\GraphQL\Subscriptions;
+
+use Nuwave\Lighthouse\Subscriptions\Subscriber;
+use Nuwave\Lighthouse\Schema\Types\GraphQLSubscription;
+
+final class PostUpdatedSubscription extends GraphQLSubscription
+{
+    /**
+     * Filter which subscribers should receive the subscription.
+     */
+    public function filter(Subscriber $subscriber, mixed $root): bool
+    {
+        // Filter out the sender
+        return $subscriber->socket_id !== request()->header('X-Socket-ID');
+    }
+}
+```
+
+When you initialize a Laravel Echo instance, a socket ID is assigned to the connection.
+If you are using a global [Axios](https://github.com/mzabriskie/axios) instance to make HTTP requests from your JavaScript application, the socket ID will automatically be attached to every outgoing request in the `X-Socket-ID` header.
+Then, you can access that in your filter function.
+
+If you are not using a global Axios instance, you will need to manually configure your JavaScript application to send the `X-Socket-ID` header with all outgoing requests.
+You may retrieve the socket ID using the `Echo.socketId()` method:
+
+```js
+const socketId = Echo.socketId();
+```

src/Subscriptions/Subscriber.php

@@ -24,6 +24,11 @@ class Subscriber
      */
     public $channel;
 
+    /**
+     * X-Socket-ID header passed on the subscription query.
+     */
+    public ?string $socket_id;
+
     /**
      * The topic subscribed to.
      *
@@ -91,6 +96,13 @@ public function __construct(
         $this->variables = $resolveInfo->variableValues;
         $this->context = $context;
 
+        $xSocketID = request()->header('X-Socket-ID');
+        // @phpstan-ignore-next-line
+        if (is_array($xSocketID)) {
+            throw new \Exception('X-Socket-ID must be a string or null.');
+        }
+        $this->socket_id = $xSocketID;
+
         $operation = $resolveInfo->operation;
         assert($operation instanceof OperationDefinitionNode, 'Must be here, since webonyx/graphql-php validated the subscription.');
 
@@ -108,6 +120,7 @@ public function __construct(
     public function __serialize(): array
     {
         return [
+            'socket_id' => $this->socket_id,
             'channel' => $this->channel,
             'topic' => $this->topic,
             'query' => serialize(
@@ -133,6 +146,7 @@ public function __unserialize(array $data): void
         );
         assert($documentNode instanceof DocumentNode, 'We know the type since it is set during construction and serialized.');
 
+        $this->socket_id = $data['socket_id'];
         $this->query = $documentNode;
         $this->fieldName = $data['field_name'];
         $this->args = $data['args'];

tests/Integration/Subscriptions/Storage/RedisStorageManagerTest.php

@@ -77,8 +77,8 @@ public function testDeleteSubscriber(): void
 
     public function testSubscribersByTopic(): void
     {
-        /** @var RedisStorageManager $storage */
         $storage = $this->app->make(RedisStorageManager::class);
+        assert($storage instanceof RedisStorageManager);
 
         $this->querySubscription();
         $this->querySubscription();
@@ -97,10 +97,26 @@ public function testSubscribersByTopic(): void
         $this->assertContainsOnlyInstancesOf(Subscriber::class, $createdSubscribers);
     }
 
+    public function testSocketIDStoredOnSubscribe(): void
+    {
+        $storage = $this->app->make(RedisStorageManager::class);
+        assert($storage instanceof RedisStorageManager);
+
+        $this->querySubscription('taskCreated', [
+            'X-Socket-ID' => '1234.1234',
+        ]);
+
+        $createdSubscriber = $storage->subscribersByTopic('TASK_CREATED')->first();
+
+        $this->assertSame('1234.1234', $createdSubscriber->socket_id);
+    }
+
     /**
+     * @param array<string, mixed> $headers
+     *
      * @return \Illuminate\Testing\TestResponse
      */
-    protected function querySubscription(string $topic = /** @lang GraphQL */ 'taskUpdated(id: 123)')
+    protected function querySubscription(string $topic = /** @lang GraphQL */ 'taskUpdated(id: 123)', array $headers = [])
     {
         return $this->graphQL(/** @lang GraphQL */ "
         subscription {
@@ -109,6 +125,6 @@ protected function querySubscription(string $topic = /** @lang GraphQL */ 'taskU
                 name
             }
         }
-        ");
+        ", [], [], $headers);
     }
 }