Use custom serializer for PlatformSubscriber

Author: VincentLanglet

fixtures/StructuredOutput/MathReasoningWithAttributes.php

@@ -0,0 +1,30 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\AI\Fixtures\StructuredOutput;
+
+use Symfony\Component\Serializer\Attribute\Ignore;
+use Symfony\Component\Serializer\Attribute\SerializedName;
+
+final class MathReasoningWithAttributes
+{
+    /**
+     * @param Step[] $steps
+     */
+    public function __construct(
+        public array $steps,
+        #[SerializedName('foo')]
+        public string $finalAnswer,
+        #[Ignore]
+        public float $result,
+    ) {
+    }
+}

src/ai-bundle/config/services.php

@@ -62,6 +62,7 @@
 use Symfony\AI\Platform\Contract;
 use Symfony\AI\Platform\Contract\JsonSchema\DescriptionParser;
 use Symfony\AI\Platform\Contract\JsonSchema\Factory as SchemaFactory;
+use Symfony\AI\Platform\Serializer\StructuredOutputSerializer;
 use Symfony\AI\Platform\StructuredOutput\PlatformSubscriber;
 use Symfony\AI\Platform\StructuredOutput\ResponseFormatFactory;
 use Symfony\AI\Platform\StructuredOutput\ResponseFormatFactoryInterface;
@@ -122,10 +123,11 @@
                 service('type_info.resolver')->nullOnInvalid(),
             ])
         ->alias(ResponseFormatFactoryInterface::class, 'ai.platform.response_format_factory')
+        ->set('ai.platform.structured_output_serializer', StructuredOutputSerializer::class)
         ->set('ai.platform.structured_output_subscriber', PlatformSubscriber::class)
             ->args([
                 service('ai.agent.response_format_factory'),
-                service('serializer'),
+                service('ai.platform.structured_output_serializer'),
             ])
             ->tag('kernel.event_subscriber')
 

src/platform/src/Contract/JsonSchema/Factory.php

@@ -300,7 +300,6 @@ private function findDiscriminatorMapping(string $className): ?array
          * @see https://github.com/symfony/ai/pull/585#issuecomment-3303631346
          */
         $reflectionProperty = new \ReflectionProperty($result, 'mapping');
-        $reflectionProperty->setAccessible(true);
 
         return $reflectionProperty->getValue($result);
     }

src/platform/src/Serializer/StructuredOutputSerializer.php

@@ -0,0 +1,52 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\AI\Platform\Serializer;
+
+use Symfony\Component\PropertyInfo\Extractor\PhpDocExtractor;
+use Symfony\Component\PropertyInfo\Extractor\ReflectionExtractor;
+use Symfony\Component\PropertyInfo\PropertyInfoExtractor;
+use Symfony\Component\Serializer\Encoder\JsonEncoder;
+use Symfony\Component\Serializer\Mapping\ClassDiscriminatorFromClassMetadata;
+use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactory;
+use Symfony\Component\Serializer\Mapping\Loader\AttributeLoader;
+use Symfony\Component\Serializer\Normalizer\ArrayDenormalizer;
+use Symfony\Component\Serializer\Normalizer\BackedEnumNormalizer;
+use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
+use Symfony\Component\Serializer\Serializer;
+
+class StructuredOutputSerializer extends Serializer
+{
+    /*
+     * Custom serializer made to deserialize StructuredOutput.
+     *
+     * Since field name are generated by the `Symfony\AI\Platform\Contract\JsonSchema\Factory`
+     * without using the serializer (and the serializer metadata/attributes), we have to ignore them
+     * again when deserializing the data by not passing `classMetadataFactory` to ObjectNormalizer.
+     */
+    public function __construct()
+    {
+        $classMetadataFactory = new ClassMetadataFactory(new AttributeLoader());
+        $discriminator = new ClassDiscriminatorFromClassMetadata($classMetadataFactory);
+        $propertyInfo = new PropertyInfoExtractor([], [new PhpDocExtractor(), new ReflectionExtractor()]);
+
+        $normalizers = [
+            new BackedEnumNormalizer(),
+            new ObjectNormalizer(
+                propertyTypeExtractor: $propertyInfo,
+                classDiscriminatorResolver: $discriminator,
+            ),
+            new ArrayDenormalizer(),
+        ];
+
+        parent::__construct($normalizers, [new JsonEncoder()]);
+    }
+}

src/platform/src/StructuredOutput/PlatformSubscriber.php

@@ -17,18 +17,8 @@
 use Symfony\AI\Platform\Exception\InvalidArgumentException;
 use Symfony\AI\Platform\Exception\MissingModelSupportException;
 use Symfony\AI\Platform\Result\DeferredResult;
+use Symfony\AI\Platform\Serializer\StructuredOutputSerializer;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
-use Symfony\Component\PropertyInfo\Extractor\PhpDocExtractor;
-use Symfony\Component\PropertyInfo\Extractor\ReflectionExtractor;
-use Symfony\Component\PropertyInfo\PropertyInfoExtractor;
-use Symfony\Component\Serializer\Encoder\JsonEncoder;
-use Symfony\Component\Serializer\Mapping\ClassDiscriminatorFromClassMetadata;
-use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactory;
-use Symfony\Component\Serializer\Mapping\Loader\AttributeLoader;
-use Symfony\Component\Serializer\Normalizer\ArrayDenormalizer;
-use Symfony\Component\Serializer\Normalizer\BackedEnumNormalizer;
-use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
-use Symfony\Component\Serializer\Serializer;
 use Symfony\Component\Serializer\SerializerInterface;
 
 /**
@@ -40,29 +30,13 @@ final class PlatformSubscriber implements EventSubscriberInterface
 
     private string $outputType;
 
+    private SerializerInterface $serializer;
+
     public function __construct(
         private readonly ResponseFormatFactoryInterface $responseFormatFactory = new ResponseFormatFactory(),
-        private ?SerializerInterface $serializer = null,
+        ?SerializerInterface $serializer = null,
     ) {
-        if (null !== $this->serializer) {
-            return;
-        }
-
-        $classMetadataFactory = new ClassMetadataFactory(new AttributeLoader());
-        $discriminator = new ClassDiscriminatorFromClassMetadata($classMetadataFactory);
-        $propertyInfo = new PropertyInfoExtractor([], [new PhpDocExtractor(), new ReflectionExtractor()]);
-
-        $normalizers = [
-            new BackedEnumNormalizer(),
-            new ObjectNormalizer(
-                classMetadataFactory: $classMetadataFactory,
-                propertyTypeExtractor: $propertyInfo,
-                classDiscriminatorResolver: $discriminator,
-            ),
-            new ArrayDenormalizer(),
-        ];
-
-        $this->serializer = new Serializer($normalizers, [new JsonEncoder()]);
+        $this->serializer = $serializer ?? new StructuredOutputSerializer();
     }
 
     public static function getSubscribedEvents(): array

src/platform/tests/StructuredOutput/PlatformSubscriberTest.php

@@ -15,6 +15,7 @@
 use PHPUnit\Framework\TestCase;
 use Symfony\AI\Fixtures\SomeStructure;
 use Symfony\AI\Fixtures\StructuredOutput\MathReasoning;
+use Symfony\AI\Fixtures\StructuredOutput\MathReasoningWithAttributes;
 use Symfony\AI\Fixtures\StructuredOutput\PolymorphicType\ListItemAge;
 use Symfony\AI\Fixtures\StructuredOutput\PolymorphicType\ListItemName;
 use Symfony\AI\Fixtures\StructuredOutput\PolymorphicType\ListOfPolymorphicTypesDto;
@@ -35,7 +36,6 @@
 use Symfony\AI\Platform\Result\TextResult;
 use Symfony\AI\Platform\StructuredOutput\PlatformSubscriber;
 use Symfony\AI\Platform\Test\PlainConverter;
-use Symfony\Component\Serializer\SerializerInterface;
 
 final class PlatformSubscriberTest extends TestCase
 {
@@ -95,12 +95,16 @@ public function testProcessOutputWithResponseFormat()
         $this->assertSame('data', $deferredResult->asObject()->some);
     }
 
-    public function testProcessOutputWithComplexResponseFormat()
+    /**
+     * @param class-string $class
+     */
+    #[DataProvider('complexFormatDataProvider')]
+    public function testProcessOutputWithComplexResponseFormat(string $class)
     {
         $processor = new PlatformSubscriber(new ConfigurableResponseFormatFactory(['some' => 'format']));
 
         $model = new Model('gpt-4', [Capability::OUTPUT_STRUCTURED]);
-        $options = ['response_format' => MathReasoning::class];
+        $options = ['response_format' => $class];
         $invocationEvent = new InvocationEvent($model, new MessageBag(), $options);
         $processor->processInput($invocationEvent);
 
@@ -139,7 +143,7 @@ public function testProcessOutputWithComplexResponseFormat()
 
         $deferredResult = $resultEvent->getDeferredResult();
         $this->assertInstanceOf(ObjectResult::class, $result = $deferredResult->getResult());
-        $this->assertInstanceOf(MathReasoning::class, $structure = $deferredResult->asObject());
+        $this->assertInstanceOf($class, $structure = $deferredResult->asObject());
         $this->assertInstanceOf(Metadata::class, $result->getMetadata());
         $this->assertCount(5, $structure->steps);
         $this->assertInstanceOf(Step::class, $structure->steps[0]);
@@ -151,6 +155,14 @@ public function testProcessOutputWithComplexResponseFormat()
         $this->assertSame(-3.75, $structure->result);
     }
 
+    public static function complexFormatDataProvider(): iterable
+    {
+        return [
+            [MathReasoning::class],
+            [MathReasoningWithAttributes::class],
+        ];
+    }
+
     /**
      * @param class-string $expectedTimeStructure
      */
@@ -254,8 +266,7 @@ public function testProcessOutputWithCorrectPolymorphicTypesResponseFormat()
     public function testProcessOutputWithoutResponseFormat()
     {
         $resultFormatFactory = new ConfigurableResponseFormatFactory();
-        $serializer = self::createMock(SerializerInterface::class);
-        $processor = new PlatformSubscriber($resultFormatFactory, $serializer);
+        $processor = new PlatformSubscriber($resultFormatFactory);
 
         $converter = new PlainConverter($result = new TextResult('{"some": "data"}'));
         $deferred = new DeferredResult($converter, new InMemoryRawResult());