fix(metadata): implement MappedObjectPaginator for fixing pagination on mapped data

src/State/Pagination/MappedObjectPaginator.php

@@ -0,0 +1,62 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\State\Pagination;
+
+use Symfony\Component\ObjectMapper\ObjectMapperInterface;
+
+final class MappedObjectPaginator implements \IteratorAggregate, PaginatorInterface
+{
+    public function __construct(
+        private readonly iterable $entities,
+        private readonly ObjectMapperInterface $mapper,
+        private readonly string $resourceClass,
+        private readonly float $totalItems = 0.0,
+        private readonly float $currentPage = 1.0,
+        private readonly float $lastPage = 1.0,
+        private readonly float $itemsPerPage = 30.0,
+    ) {
+    }
+
+    public function count(): int
+    {
+        return (int) $this->totalItems;
+    }
+
+    public function getLastPage(): float
+    {
+        return $this->lastPage;
+    }
+
+    public function getTotalItems(): float
+    {
+        return $this->totalItems;
+    }
+
+    public function getCurrentPage(): float
+    {
+        return $this->currentPage;
+    }
+
+    public function getItemsPerPage(): float
+    {
+        return $this->itemsPerPage;
+    }
+
+    public function getIterator(): \Traversable
+    {
+        foreach ($this->entities as $entity) {
+            yield $this->mapper->map($entity, $this->resourceClass);
+        }
+    }
+}

src/State/Provider/ObjectMapperProvider.php

@@ -15,7 +15,7 @@
 
 use ApiPlatform\Metadata\Operation;
 use ApiPlatform\Metadata\Util\CloneTrait;
-use ApiPlatform\State\Pagination\ArrayPaginator;
+use ApiPlatform\State\Pagination\MappedObjectPaginator;
 use ApiPlatform\State\Pagination\PaginatorInterface;
 use ApiPlatform\State\ProviderInterface;
 use Symfony\Component\ObjectMapper\ObjectMapperInterface;
@@ -52,7 +52,15 @@ public function provide(Operation $operation, array $uriVariables = [], array $c
         $request?->attributes->set('mapped_data', $data);
 
         if ($data instanceof PaginatorInterface) {
-            $data = new ArrayPaginator(array_map(fn ($v) => $this->objectMapper->map($v, $operation->getClass()), iterator_to_array($data)), 0, \count($data));
+            $data = new MappedObjectPaginator(
+                iterator_to_array($data),
+                $this->objectMapper,
+                $operation->getClass(),
+                $data->getTotalItems(),
+                $data->getCurrentPage(),
+                $data->getLastPage(),
+                $data->getItemsPerPage(),
+            );
         } elseif (\is_array($data)) {
             foreach ($data as &$v) {
                 if (\is_object($v)) {

tests/State/Provider/ObjectMapperProviderTest.php

@@ -15,6 +15,7 @@
 
 use ApiPlatform\Metadata\Get;
 use ApiPlatform\State\Pagination\ArrayPaginator;
+use ApiPlatform\State\Pagination\MappedObjectPaginator;
 use ApiPlatform\State\Provider\ObjectMapperProvider;
 use ApiPlatform\State\ProviderInterface;
 use PHPUnit\Framework\TestCase;
@@ -160,7 +161,7 @@ public function testProvideMapsPaginator(): void
         $provider = new ObjectMapperProvider($objectMapper, $decorated);
 
         $result = $provider->provide($operation);
-        $this->assertInstanceOf(ArrayPaginator::class, $result);
+        $this->assertInstanceOf(MappedObjectPaginator::class, $result);
         $items = iterator_to_array($result);
         $this->assertCount(2, $items);
         $this->assertSame($targetResource1, $items[0]);
@@ -192,7 +193,7 @@ public function testProvideMapsEmptyPaginator(): void
         $provider = new ObjectMapperProvider($objectMapper, $decorated);
 
         $result = $provider->provide($operation);
-        $this->assertInstanceOf(ArrayPaginator::class, $result);
+        $this->assertInstanceOf(MappedObjectPaginator::class, $result);
         $this->assertCount(0, iterator_to_array($result));
     }
 }