Allow using callbacks with load relations extender

src/Api/Controller/AbstractSerializeController.php

@@ -88,10 +88,15 @@ abstract class AbstractSerializeController implements RequestHandlerInterface
     protected static $beforeSerializationCallbacks = [];
 
     /**
-     * @var array
+     * @var string[]
      */
     protected static $loadRelations = [];
 
+    /**
+     * @var array<string, callable>
+     */
+    protected static $loadRelationCallables = [];
+
     /**
      * {@inheritdoc}
      */
@@ -149,6 +154,8 @@ abstract protected function createElement($data, SerializerInterface $serializer
 
     /**
      * Returns the relations to load added by extenders.
+     *
+     * @return string[]
      */
     protected function getRelationsToLoad(): array
     {
@@ -164,15 +171,34 @@ protected function getRelationsToLoad(): array
     }
 
     /**
-     * Eager loads the required relationships.
+     * Returns the relation callables to load added by extenders.
      *
-     * @param Collection $models
-     * @param array $relations
-     * @return void
+     * @return array<string, callable>
+     */
+    protected function getRelationCallablesToLoad(): array
+    {
+        $addedRelationCallables = [];
+
+        foreach (array_reverse(array_merge([static::class], class_parents($this))) as $class) {
+            if (isset(static::$loadRelationCallables[$class])) {
+                $addedRelationCallables = array_merge($addedRelationCallables, static::$loadRelationCallables[$class]);
+            }
+        }
+
+        return $addedRelationCallables;
+    }
+
+    /**
+     * Eager loads the required relationships.
      */
-    protected function loadRelations(Collection $models, array $relations): void
+    protected function loadRelations(Collection $models, array $relations, ServerRequestInterface $request = null): void
     {
         $addedRelations = $this->getRelationsToLoad();
+        $addedRelationCallables = $this->getRelationCallablesToLoad();
+
+        foreach ($addedRelationCallables as $name => $relation) {
+            $addedRelations[] = $name;
+        }
 
         if (! empty($addedRelations)) {
             usort($addedRelations, function ($a, $b) {
@@ -194,7 +220,29 @@ protected function loadRelations(Collection $models, array $relations): void
 
         if (! empty($relations)) {
             $relations = array_unique($relations);
-            $models->loadMissing($relations);
+        }
+
+        $callableRelations = [];
+        $nonCallableRelations = [];
+
+        foreach ($relations as $relation) {
+            if (isset($addedRelationCallables[$relation])) {
+                $load = $addedRelationCallables[$relation];
+
+                $callableRelations[$relation] = function ($query) use ($load, $request, $relations) {
+                    $load($query, $request, $relations);
+                };
+            } else {
+                $nonCallableRelations[] = $relation;
+            }
+        }
+
+        if (! empty($callableRelations)) {
+            $models->loadMissing($callableRelations);
+        }
+
+        if (! empty($nonCallableRelations)) {
+            $models->loadMissing($nonCallableRelations);
         }
     }
 
@@ -430,4 +478,16 @@ public static function setLoadRelations(string $controllerClass, array $relation
 
         static::$loadRelations[$controllerClass] = array_merge(static::$loadRelations[$controllerClass], $relations);
     }
+
+    /**
+     * @internal
+     */
+    public static function setLoadRelationCallables(string $controllerClass, array $relations)
+    {
+        if (! isset(static::$loadRelationCallables[$controllerClass])) {
+            static::$loadRelationCallables[$controllerClass] = [];
+        }
+
+        static::$loadRelationCallables[$controllerClass] = array_merge(static::$loadRelationCallables[$controllerClass], $relations);
+    }
 }

src/Api/Controller/ListDiscussionsController.php

@@ -125,7 +125,7 @@ protected function data(ServerRequestInterface $request, Document $document)
 
         $results = $results->getResults();
 
-        $this->loadRelations($results, $include);
+        $this->loadRelations($results, $include, $request);
 
         if ($relations = array_intersect($include, ['firstPost', 'lastPost', 'mostRelevantPost'])) {
             foreach ($results as $discussion) {

src/Api/Controller/ListGroupsController.php

@@ -82,6 +82,10 @@ protected function data(ServerRequestInterface $request, Document $document)
             $queryResults->areMoreResults() ? null : 0
         );
 
-        return $queryResults->getResults();
+        $results = $queryResults->getResults();
+
+        $this->loadRelations($results, [], $request);
+
+        return $results;
     }
 }

src/Api/Controller/ListNotificationsController.php

@@ -79,7 +79,7 @@ protected function data(ServerRequestInterface $request, Document $document)
 
         $notifications = $this->notifications->findByUser($actor, $limit + 1, $offset);
 
-        $this->loadRelations($notifications, array_diff($include, ['subject.discussion']));
+        $this->loadRelations($notifications, array_diff($include, ['subject.discussion']), $request);
 
         $notifications = $notifications->all();
 

src/Api/Controller/ListPostsController.php

@@ -108,7 +108,7 @@ protected function data(ServerRequestInterface $request, Document $document)
 
         $results = $results->getResults();
 
-        $this->loadRelations($results, $include);
+        $this->loadRelations($results, $include, $request);
 
         return $results;
     }

src/Api/Controller/ListUsersController.php

@@ -109,7 +109,7 @@ protected function data(ServerRequestInterface $request, Document $document)
 
         $results = $results->getResults();
 
-        $this->loadRelations($results, $include);
+        $this->loadRelations($results, $include, $request);
 
         return $results;
     }

src/Extend/ApiController.php

@@ -30,6 +30,7 @@ class ApiController implements ExtenderInterface
     private $removeSortFields = [];
     private $sort;
     private $load = [];
+    private $loadCallables = [];
 
     /**
      * @param string $controllerClass: The ::class attribute of the controller you are modifying.
@@ -303,7 +304,27 @@ public function setSort(array $sort, $callback = null): self
      */
     public function load($relations): self
     {
-        $this->load = array_merge($this->load, (array) $relations);
+        $this->load = array_merge($this->load, array_map('strval', (array) $relations));
+
+        return $this;
+    }
+
+    /**
+     * Allows loading a relationship with additional query modification.
+     *
+     * @param string $relation: Relationship name, see load method description.
+     * @param callable(\Illuminate\Database\Query\Builder|\Illuminate\Database\Eloquent\Relations\Relation, \Psr\Http\Message\ServerRequestInterface|null, array): void $callback
+     *
+     * The callback to modify the query, should accept:
+     * - \Illuminate\Database\Query\Builder|\Illuminate\Database\Eloquent\Relations\Relation $query: A query object.
+     * - \Psr\Http\Message\ServerRequestInterface|null $request: An instance of the request.
+     * - array $relations: An array of relations that are to be loaded.
+     *
+     * @return self
+     */
+    public function loadWhere(string $relation, callable $callback): self
+    {
+        $this->loadCallables = array_merge($this->loadCallables, [$relation => $callback]);
 
         return $this;
     }
@@ -375,6 +396,7 @@ public function extend(Container $container, Extension $extension = null)
         }
 
         AbstractSerializeController::setLoadRelations($this->controllerClass, $this->load);
+        AbstractSerializeController::setLoadRelationCallables($this->controllerClass, $this->loadCallables);
     }
 
     /**

tests/integration/extenders/ApiControllerTest.php

@@ -803,6 +803,126 @@ public function custom_second_level_relation_is_not_loaded_when_first_level_is_n
 
         $this->assertTrue($users->pluck('firstLevelRelation')->filter->relationLoaded('secondLevelRelation')->isEmpty());
     }
+
+    /**
+     * @test
+     */
+    public function custom_callable_first_level_relation_is_loaded_if_added()
+    {
+        $users = null;
+
+        $this->extend(
+            (new Extend\Model(User::class))
+                ->hasOne('firstLevelRelation', Post::class, 'user_id'),
+            (new Extend\ApiController(ListUsersController::class))
+                ->loadWhere('firstLevelRelation', function ($query, $request) {})
+                ->prepareDataForSerialization(function ($controller, $data) use (&$users) {
+                    $users = $data;
+
+                    return [];
+                })
+        );
+
+        $this->send(
+            $this->request('GET', '/api/users', [
+                'authenticatedAs' => 1,
+            ])
+        );
+
+        $this->assertFalse($users->filter->relationLoaded('firstLevelRelation')->isEmpty());
+    }
+
+    /**
+     * @test
+     */
+    public function custom_callable_second_level_relation_is_loaded_if_added()
+    {
+        $users = null;
+
+        $this->extend(
+            (new Extend\Model(User::class))
+                ->hasOne('firstLevelRelation', Post::class, 'user_id'),
+            (new Extend\Model(Post::class))
+                ->belongsTo('secondLevelRelation', Discussion::class),
+            (new Extend\ApiController(ListUsersController::class))
+                ->load('firstLevelRelation')
+                ->loadWhere('firstLevelRelation.secondLevelRelation', function ($query, $request) {})
+                ->prepareDataForSerialization(function ($controller, $data) use (&$users) {
+                    $users = $data;
+
+                    return [];
+                })
+        );
+
+        $this->send(
+            $this->request('GET', '/api/users', [
+                'authenticatedAs' => 1,
+            ])
+        );
+
+        $this->assertFalse($users->pluck('firstLevelRelation')->filter->relationLoaded('secondLevelRelation')->isEmpty());
+    }
+
+    /**
+     * @test
+     */
+    public function custom_callable_second_level_relation_is_not_loaded_when_first_level_is_not()
+    {
+        $users = null;
+
+        $this->extend(
+            (new Extend\Model(User::class))
+                ->hasOne('firstLevelRelation', Post::class, 'user_id'),
+            (new Extend\Model(Post::class))
+                ->belongsTo('secondLevelRelation', Discussion::class),
+            (new Extend\ApiController(ListUsersController::class))
+                ->loadWhere('firstLevelRelation.secondLevelRelation', function ($query, $request) {})
+                ->prepareDataForSerialization(function ($controller, $data) use (&$users) {
+                    $users = $data;
+
+                    return [];
+                })
+        );
+
+        $this->send(
+            $this->request('GET', '/api/users', [
+                'authenticatedAs' => 1,
+            ])
+        );
+
+        $this->assertTrue($users->pluck('firstLevelRelation')->filter->relationLoaded('secondLevelRelation')->isEmpty());
+    }
+
+    /**
+     * @test
+     */
+    public function custom_callable_second_level_relation_is_loaded_when_first_level_is()
+    {
+        $users = null;
+
+        $this->extend(
+            (new Extend\Model(User::class))
+                ->hasOne('firstLevelRelation', Post::class, 'user_id'),
+            (new Extend\Model(Post::class))
+                ->belongsTo('secondLevelRelation', Discussion::class),
+            (new Extend\ApiController(ListUsersController::class))
+                ->loadWhere('firstLevelRelation', function ($query, $request) {})
+                ->loadWhere('firstLevelRelation.secondLevelRelation', function ($query, $request) {})
+                ->prepareDataForSerialization(function ($controller, $data) use (&$users) {
+                    $users = $data;
+
+                    return [];
+                })
+        );
+
+        $this->send(
+            $this->request('GET', '/api/users', [
+                'authenticatedAs' => 1,
+            ])
+        );
+
+        $this->assertTrue($users->pluck('firstLevelRelation')->filter->relationLoaded('secondLevelRelation')->isNotEmpty());
+    }
 }
 
 class CustomDiscussionSerializer extends DiscussionSerializer