Allow relationships to specify adapter-specific scope logic

src/Adapter/AdapterInterface.php

@@ -2,6 +2,7 @@
 
 namespace Tobyz\JsonApiServer\Adapter;
 
+use Closure;
 use Tobyz\JsonApiServer\Schema\Attribute;
 use Tobyz\JsonApiServer\Schema\HasMany;
 use Tobyz\JsonApiServer\Schema\HasOne;
@@ -216,9 +217,11 @@ interface AdapterInterface
      *
      * @param array $models
      * @param array $relationships
+     * @param Closure $scope Should be called to give the deepest relationship
+     *   an opportunity to scope the query that will fetch related resources
      * @return mixed
      */
-    public function load(array $models, array $relationships): void;
+    public function load(array $models, array $relationships, Closure $scope): void;
 
     /**
      * Load information about the IDs of related resources onto a collection

src/Adapter/EloquentAdapter.php

@@ -2,6 +2,7 @@
 
 namespace Tobyz\JsonApiServer\Adapter;
 
+use Closure;
 use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
@@ -188,9 +189,13 @@ class EloquentAdapter implements AdapterInterface
         $query->take($limit)->skip($offset);
     }
 
-    public function load(array $models, array $relationships): void
+    public function load(array $models, array $relationships, Closure $scope): void
     {
-        (new Collection($models))->loadMissing($this->getRelationshipPath($relationships));
+        $relationship = end($relationships);
+
+        (new Collection($models))->loadMissing([
+            $this->getRelationshipPath($relationships) => $scope
+        ]);
     }
 
     public function loadIds(array $models, Relationship $relationship): void

src/Handler/Concerns/IncludesData.php

@@ -8,6 +8,7 @@ use function Tobyz\JsonApiServer\evaluate;
 use Tobyz\JsonApiServer\Exception\BadRequestException;
 use Tobyz\JsonApiServer\ResourceType;
 use Tobyz\JsonApiServer\Schema\Relationship;
+use function Tobyz\JsonApiServer\run_callbacks;
 
 trait IncludesData
 {
@@ -103,9 +104,27 @@ trait IncludesData
         $adapter = $this->resource->getAdapter();
         $fields = $this->resource->getSchema()->getFields();
 
-        // TODO: don't load IDs for relationships which are included below
+        $trails = $this->buildRelationshipTrails($this->resource, $include);
+        $loaded = [];
+
+        foreach ($trails as $relationships) {
+            $relationship = end($relationships);
+
+            if (($load = $relationship->getLoadable()) instanceof Closure) {
+                $load($models, $relationships, false, $request);
+            } else {
+                $scope = function ($query) use ($request, $relationship) {
+                    run_callbacks($relationship->getScopes(), [$query, $request]);
+                };
+
+                $adapter->load($models, $relationships, $scope);
+            }
+
+            $loaded[] = $relationships[0];
+        }
+
         foreach ($fields as $name => $field) {
-            if (! $field instanceof Relationship || ! evaluate($field->getLinkage(), [$request]) || ! $field->getLoadable()) {
+            if (! $field instanceof Relationship || ! evaluate($field->getLinkage(), [$request]) || ! $field->getLoadable() || in_array($field, $loaded)) {
                 continue;
             }
 
@@ -115,16 +134,5 @@ trait IncludesData
                 $adapter->loadIds($models, $field);
             }
         }
-
-        $trails = $this->buildRelationshipTrails($this->resource, $include);
-
-        foreach ($trails as $relationships) {
-            if (($load = end($relationships)->getLoadable()) instanceof Closure) {
-                // TODO: probably need to loop through relationships here
-                $load($models, false);
-            } else {
-                $adapter->load($models, $relationships);
-            }
-        }
     }
 }

src/Schema/Relationship.php

@@ -13,6 +13,7 @@ abstract class Relationship extends Field
     private $links = true;
     private $loadable = true;
     private $includable = false;
+    private $scopes = [];
 
     public function type($type)
     {
@@ -122,4 +123,14 @@ abstract class Relationship extends Field
     {
         return 'relationships';
     }
+
+    public function scope(Closure $callback)
+    {
+        $this->scopes[] = $callback;
+    }
+
+    public function getScopes(): array
+    {
+        return $this->scopes;
+    }
 }