Subscription send only to others

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 $representations` https://github.com/nuwave/lighthouse/pull/2286
 - Use the strongest possible property types over PHPDocs
 - Require filter directives such as `@whereKey` in `@delete`, `@forceDelete` and `@restore` https://github.com/nuwave/lighthouse/pull/2289
+- Subscriptions can now be filtered via `$subscriber->socket_id` and `request()->header('X-Socket-ID')` https://github.com/nuwave/lighthouse/pull/2298
 
 ### Fixed
 

docs/5/subscriptions/filtering-subscriptions.md

@@ -4,11 +4,11 @@ There are times when you'll need to filter out specific events based on the argu
 
 ```graphql
 subscription onPostUpdated($post_id: ID!) {
-  postUpdated(post_id: $post_id) {
-    id
-    title
-    content
-  }
+    postUpdated(post_id: $post_id) {
+        id
+        title
+        content
+    }
 }
 ```
 

docs/master/subscriptions/filtering-subscriptions.md

@@ -4,11 +4,11 @@ There are times when you'll need to filter out specific events based on the argu
 
 ```graphql
 subscription onPostUpdated($post_id: ID!) {
-  postUpdated(post_id: $post_id) {
-    id
-    title
-    content
-  }
+    postUpdated(post_id: $post_id) {
+        id
+        title
+        content
+    }
 }
 ```
 
@@ -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.
      *
@@ -90,6 +95,7 @@ public function __construct(
         $this->args = $args;
         $this->variables = $resolveInfo->variableValues;
         $this->context = $context;
+        $this->socket_id = request()->header('X-Socket-ID');
 
         $operation = $resolveInfo->operation;
         assert($operation instanceof OperationDefinitionNode, 'Must be here, since webonyx/graphql-php validated the subscription.');
@@ -108,6 +114,7 @@ public function __construct(
     public function __serialize(): array
     {
         return [
+            'socket_id' => $this->socket_id,
             'channel' => $this->channel,
             'topic' => $this->topic,
             'query' => serialize(
@@ -133,6 +140,7 @@ 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'];