Total count cache

docs/helpers/relay-paginator.md

@@ -244,6 +244,26 @@ class Greetings implements QueryInterface
 }
 ````
 
+#### Total count caching
+
+You may want to cache your total count for paginator result 
+
+````php
+<?php
+
+use Overblog\GraphQLBundle\Relay\Connection\Paginator;
+use Overblog\GraphQLBundle\Relay\Connection\TotalCountCache;
+
+/** @var Paginator $paginator */     
+return $paginator->auto(
+    $args,
+    new TotalCountCache (
+        fn () => $backend->countAll(),
+    ),
+);
+````
+
+
 #### Promise handling
 
 Paginator also supports promises if you [use that feature](https://github.com/webonyx/graphql-php/pull/67)

src/Relay/Connection/Paginator.php

@@ -20,7 +20,6 @@ class Paginator
     public const MODE_PROMISE = true;
 
     private bool $promise;
-    private int $totalCount;
     private ConnectionBuilder $connectionBuilder;
 
     /** @var callable */
@@ -127,16 +126,10 @@ private function handleEntities($entities, callable $callback)
     /**
      * @param int|callable $total
      *
-     * @return int|mixed
+     * @return int
      */
-    private function computeTotalCount($total, array $callableArgs = [])
+    private function computeTotalCount($total, array $callableArgs = []): int
     {
-        if (isset($this->totalCount)) {
-            return $this->totalCount;
-        }
-
-        $this->totalCount = is_callable($total) ? call_user_func_array($total, $callableArgs) : $total;
-
-        return $this->totalCount;
+        return is_callable($total) ? call_user_func_array($total, $callableArgs) : $total;
     }
 }

src/Relay/Connection/TotalCountCache.php

@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Overblog\GraphQLBundle\Relay\Connection;
+
+use Symfony\Contracts\Service\ResetInterface;
+
+class TotalCountCache implements ResetInterface
+{
+    /**
+     * @var int|callable
+     */
+    private $total;
+    private int $totalCount;
+
+    /**
+     * @param int|callable $total
+     */
+    public function __construct($total)
+    {
+        $this->total = $total;
+    }
+
+    public function __invoke(array $callableArgs = []): int
+    {
+        if (isset($this->totalCount)) {
+            return $this->totalCount;
+        }
+
+        $this->totalCount = is_callable($this->total) ? call_user_func_array($this->total, $callableArgs) : $this->total;
+
+        return $this->totalCount;
+    }
+
+    public function reset(): void
+    {
+        unset($this->totalCount);
+    }
+}

tests/Relay/Connection/PaginatorTest.php

@@ -9,6 +9,7 @@
 use Overblog\GraphQLBundle\Relay\Connection\ConnectionInterface;
 use Overblog\GraphQLBundle\Relay\Connection\Output\Connection;
 use Overblog\GraphQLBundle\Relay\Connection\Paginator;
+use Overblog\GraphQLBundle\Relay\Connection\TotalCountCache;
 use PHPUnit\Framework\TestCase;
 use function array_slice;
 use function base64_encode;
@@ -259,6 +260,30 @@ public function testAutoBackwardWithCallable(): void
         $this->assertTrue($result->getPageInfo()->getHasPreviousPage());
     }
 
+    public function testAutoBackwardWithCachedCallable(): void
+    {
+        $paginator = new Paginator(function ($offset, $limit) {
+            $this->assertSame(1, $offset);
+            $this->assertSame(4, $limit);
+
+            return $this->getData($offset);
+        });
+
+        $countCalled = false;
+
+        /** @var Connection $result */
+        $result = $paginator->auto(new Argument(['last' => 4]), new TotalCountCache(function () use (&$countCalled) {
+            $countCalled = true;
+
+            return 5;
+        }));
+
+        $this->assertTrue($countCalled);
+        $this->assertCount(4, $result->getEdges());
+        $this->assertSameEdgeNodeValue(['B', 'C', 'D', 'E'], $result);
+        $this->assertTrue($result->getPageInfo()->getHasPreviousPage());
+    }
+
     public function testTotalCallableWithArguments(): void
     {
         $paginatorBackend = new PaginatorBackend();

tests/Relay/Connection/TotalCountCacheTest.php

@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Overblog\GraphQLBundle\Tests\Relay\Connection;
+
+use Overblog\GraphQLBundle\Relay\Connection\TotalCountCache;
+use PHPUnit\Framework\TestCase;
+
+class TotalCountCacheTest extends TestCase
+{
+    public function testCacheCallable(): void
+    {
+        $total = $this->createMock(TotalCountCache::class);
+        $total
+            ->expects($this->once())
+            ->method('__invoke')
+            ->willReturn(7);
+
+        $cache = new TotalCountCache($total);
+
+        $this->assertEquals(7, $cache());
+        $this->assertEquals(7, $cache());
+    }
+
+    public function testCacheInt(): void
+    {
+        $cache = new TotalCountCache(12);
+
+        $this->assertEquals(12, $cache());
+    }
+
+    public function testReset(): void
+    {
+        $total = $this->createMock(TotalCountCache::class);
+        $total
+            ->expects($this->exactly(2))
+            ->method('__invoke')
+            ->willReturn(7);
+
+        $cache = new TotalCountCache($total);
+
+        $this->assertEquals(7, $cache());
+        $cache->reset();
+        $this->assertEquals(7, $cache());
+    }
+}