Relationship Resolvers (#132)

* wip

* Apply fixes from StyleCI

[ci skip] [skip ci]

* Ignore phpunit cache

* Tests

* Apply fixes from StyleCI

[ci skip] [skip ci]

.gitignore

@@ -3,3 +3,4 @@ composer.lock
 .DS_Store
 .idea/
 .vscode/
+.phpunit.result.cache

src/Eloquent/ModelSchema.php

@@ -350,6 +350,10 @@ public function getRelations(): Collection
 
             return $field;
         })->map(function (Field $field) {
+            if ($field instanceof EloquentField) {
+                return $field->getRelation($this->getModel());
+            }
+
             $accessor = $field->getAccessor();
 
             Utils::invariant(

src/Field.php

@@ -43,12 +43,12 @@ public static function float(): Fields\Field
         return self::getRegistry()->field(self::getRegistry()->float());
     }
 
-    public static function model(string $class): Fields\Field
+    public static function model(string $class): Fields\EloquentField
     {
         return self::getRegistry()->eloquent($class);
     }
 
-    public static function collection(string $class): Fields\Field
+    public static function collection(string $class): Fields\EloquentField
     {
         return self::model($class)->list();
     }

src/Fields/EloquentField.php

@@ -2,9 +2,12 @@
 
 namespace Bakery\Fields;
 
+use Bakery\Utils\Utils;
 use Bakery\Eloquent\ModelSchema;
 use Bakery\Support\TypeRegistry;
 use Bakery\Types\Definitions\RootType;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\Relation;
 
 class EloquentField extends Field
 {
@@ -18,6 +21,16 @@ class EloquentField extends Field
      */
     protected $inverseRelationName;
 
+    /**
+     * @var callable|null
+     */
+    protected $relationResolver;
+
+    /**
+     * @var callable|null
+     */
+    protected $collectionResolver;
+
     /**
      * EloquentField constructor.
      *
@@ -79,4 +92,53 @@ public function name(): string
     {
         return $this->getModelClass()->getTypename();
     }
+
+    /**
+     * Set a custom relation resolver.
+     */
+    public function relation(callable $resolver): self
+    {
+        $this->relationResolver = $resolver;
+
+        return $this;
+    }
+
+    /**
+     * Return the Eloquent relation.
+     */
+    public function getRelation(Model $model): Relation
+    {
+        if ($resolver = $this->relationResolver) {
+            return $resolver($model);
+        }
+
+        $accessor = $this->getAccessor();
+
+        Utils::invariant(
+            method_exists($model, $accessor),
+            'Relation "'.$accessor.'" is not defined on "'.get_class($model).'".'
+        );
+
+        return $model->{$accessor}();
+    }
+
+    /**
+     * Determine if the field has a relation resolver.
+     */
+    public function hasRelationResolver(): bool
+    {
+        return isset($this->relationResolver);
+    }
+
+    /**
+     * Get the result of the field.
+     */
+    public function getResult(Model $model)
+    {
+        if ($resolver = $this->relationResolver) {
+            return $resolver($model)->get();
+        }
+
+        return $model->{$this->getAccessor()};
+    }
 }

src/Fields/Field.php

@@ -221,7 +221,7 @@ public function description(string $description): self
     }
 
     /**
-     * Return the name of the database column associated with this field.
+     * Return the name of the database column or method associated with this field.
      *
      * @return string|null
      */
@@ -524,6 +524,14 @@ public function resolve(callable $resolver): self
         return $this;
     }
 
+    /**
+     * Get the resolver.
+     */
+    public function getResolver(): ?callable
+    {
+        return $this->resolver;
+    }
+
     /**
      * Resolve the field.
      *

src/Queries/Concerns/EagerLoadRelationships.php

@@ -3,8 +3,8 @@
 namespace Bakery\Queries\Concerns;
 
 use Bakery\Eloquent\ModelSchema;
+use Bakery\Fields\EloquentField;
 use Bakery\Support\TypeRegistry;
-use Bakery\Fields\PolymorphicField;
 use Illuminate\Database\Eloquent\Builder;
 
 trait EagerLoadRelationships
@@ -32,15 +32,20 @@ protected function eagerLoadRelations(Builder $query, array $fields, ModelSchema
                 continue;
             }
 
+            // If a custom relation resolver is provided we cannot eager load.
+            if ($field instanceof EloquentField && $field->hasRelationResolver()) {
+                continue;
+            }
+
             $with = array_map(function ($with) use ($path) {
                 return $path ? "{$path}.{$with}" : $with;
             }, $field->getWith() ?? []);
 
             $query->with($with);
 
-            if ($field->isRelationship() && ! $field instanceof PolymorphicField) {
+            if ($field instanceof EloquentField) {
                 $accessor = $field->getAccessor();
-                $related = $schema->getModel()->{$accessor}()->getRelated();
+                $related = $field->getRelation($schema->getModel())->getRelated();
                 $relatedSchema = $this->registry->getSchemaForModel($related);
                 $this->eagerLoadRelations($query, $subFields, $relatedSchema, $path ? "{$path}.{$accessor}" : $accessor);
             }

src/Queries/SingleEntityQuery.php

@@ -15,8 +15,6 @@ class SingleEntityQuery extends EloquentQuery
 {
     /**
      * Get the name of the query.
-     *
-     * @return string
      */
     public function name(): string
     {
@@ -29,8 +27,6 @@ public function name(): string
 
     /**
      * The return type of the query.
-     *
-     * @return \Bakery\Types\Definitions\RootType
      */
     public function type(): RootType
     {
@@ -39,8 +35,6 @@ public function type(): RootType
 
     /**
      * The arguments for the Query.
-     *
-     * @return array
      */
     public function args(): array
     {
@@ -49,12 +43,6 @@ public function args(): array
 
     /**
      * Resolve the EloquentQuery.
-     *
-     * @param Arguments $args
-     * @param mixed $root
-     * @param mixed $context
-     * @param \GraphQL\Type\Definition\ResolveInfo $info
-     * @return \Illuminate\Database\Eloquent\Model|null ?Model
      */
     public function resolve(Arguments $args, $root, $context, ResolveInfo $info): ?Model
     {
@@ -83,10 +71,6 @@ public function resolve(Arguments $args, $root, $context, ResolveInfo $info): ?M
 
     /**
      * Query by the arguments supplied to the query.
-     *
-     * @param Builder $query
-     * @param Arguments $args
-     * @return Builder
      */
     protected function queryByArgs(Builder $query, Arguments $args): Builder
     {

src/Types/EloquentMutationInputType.php

@@ -66,7 +66,7 @@ protected function getFieldsForRelation(string $relation, EloquentField $root):
         $fields = collect();
         $root->setRegistry($this->registry);
         $inputType = 'Create'.$root->getName().'Input';
-        $relationship = $this->model->{$root->getAccessor()}();
+        $relationship = $root->getRelation($this->model);
 
         if ($root->isList()) {
             $name = Str::singular($relation).'Ids';

src/Types/EntityType.php

@@ -95,7 +95,7 @@ protected function getRelationFields(): Collection
     protected function getFieldsForRelation(string $key, EloquentField $field): Collection
     {
         $fields = collect();
-        $relationship = $this->model->{$field->getAccessor()}();
+        $relationship = $field->getRelation($this->model);
 
         if ($field->isList()) {
             $fields = $fields->merge($this->getPluralRelationFields($key, $field));
@@ -126,12 +126,10 @@ protected function getPluralRelationFields(string $key, EloquentField $field): C
 
         $field = $field->args([
             'filter' => $this->registry->type($field->getName().'Filter')->nullable(),
-        ])->resolve(function (Model $model, string $accessor, Arguments $args) {
-            $relation = $model->{$accessor}();
+        ])->resolve(function (Model $model, string $accessor, Arguments $args) use ($field) {
+            $relation = $field->getRelation($model);
 
-            $result = $args->isEmpty() ? $model->{$accessor} : $this->getRelationQuery($relation, $args)->get();
-
-            return $result;
+            return $args->isEmpty() ? $field->getResult($model) : $this->getRelationQuery($relation, $args)->get();
         });
 
         $fields->put($key, $field);
@@ -142,10 +140,10 @@ protected function getPluralRelationFields(string $key, EloquentField $field): C
             ->args($field->getArgs())
             ->nullable($field->isNullable())
             ->viewPolicy($field->getViewPolicy())
-            ->resolve(function (Model $model, string $accessor, Arguments $args) {
-                $relation = $model->{$accessor}();
+            ->resolve(function (Model $model, string $accessor, Arguments $args) use ($field) {
+                $relation = $field->getRelation($model);
 
-                $result = $args->isEmpty() ? $model->{$accessor} : $this->getRelationQuery($relation, $args)->get();
+                $result = $args->isEmpty() ? $field->getResult($model) : $this->getRelationQuery($relation, $args)->get();
 
                 return $result->pluck($relation->getRelated()->getKeyName());
             })
@@ -155,10 +153,10 @@ protected function getPluralRelationFields(string $key, EloquentField $field): C
             ->accessor($field->getAccessor())
             ->nullable($field->isNullable())
             ->viewPolicy($field->getViewPolicy())
-            ->resolve(function (Model $model, string $accessor, Arguments $args) {
-                $relation = $model->{$accessor};
+            ->resolve(function (Model $model, string $accessor, Arguments $args) use ($field) {
+                $relation = $field->getRelation($model);
 
-                $result = $args->isEmpty() ? $model->{$accessor} : $this->getRelationQuery($relation, $args);
+                $result = $args->isEmpty() ? $field->getResult($model) : $this->getRelationQuery($relation, $args)->get();
 
                 return $result->count();
             })

tests/Feature/EntityQueryTest.php

@@ -130,6 +130,34 @@ public function it_can_filter_a_relation()
         $response->assertJsonFragment(['body' => 'Cool story'])->assertJsonMissing(['body' => 'Boo!']);
     }
 
+    /** @test */
+    public function it_uses_custom_resolver_for_relationships()
+    {
+        $user = factory(User::class)->create();
+        $article = factory(Article::class)->create(['user_id' => $user->id]);
+
+        factory(Comment::class)->create(['commentable_id' => $article->id, 'author_id' => $user->id, 'body' => 'This is my comment.']);
+        factory(Comment::class)->create(['commentable_id' => $article->id, 'body' => 'This is a comment from someone else.']);
+
+        $query = '
+            query {
+                article {
+                    id
+                    myComments {
+                        id
+                        body
+                    }
+                    myCommentsCount
+                    myCommentIds
+                }
+            }
+        ';
+
+        $this->graphql($query)
+            ->assertJsonFragment(['body' => 'This is my comment.'])
+            ->assertJsonMissing(['body' => 'This is a comment from someone else.']);
+    }
+
     /** @test */
     public function it_shows_the_count_for_many_relationships()
     {

tests/Fixtures/Schemas/ArticleSchema.php

@@ -32,6 +32,9 @@ public function relations(): array
             'tags' => Field::collection(TagSchema::class),
             'comments' => Field::collection(CommentSchema::class),
             'remarks' => Field::collection(CommentSchema::class)->accessor('comments'),
+            'myComments' => Field::collection(CommentSchema::class)->relation(function (Article $article) {
+                return $article->comments()->where('author_id', optional(auth()->user())->getAuthIdentifier());
+            }),
         ];
     }
 }