Exception during normalization of embedded entities where not all are ApiResources

[backbone87]

I have a problem with normalization.

Datamodel: Fall (Case) <- 1:n -> Tag <- n:1 -> Tagdefinition

All 3 models are doctrine entities, but only Fall and Tagdefinition are ApiResources. Tags should be serialized within the Fall output, something like this:

{
  "@context": "/contexts/Fall",
  "@id": "/faelle",
  "@type": "hydra:Collection",
  "hydra:member": [
    {
      "@id": "/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1",
      "@type": "Fall",
      "id": "691bcf98-5c41-11e7-b7d5-046d49573cb1",
      "tags": [
        {
          "erstellungsdatum": "2017-06-30T15:09:47+00:00",
          "beschriftung": "Test"
        }
      ]
    }
  ],
  "hydra:totalItems": 1
}

This works fine up until now. I have a getTags on the Fall entity and the beschriftung (label) and erstellungsdatum (created date) are within the normalization group and get printed. however i dont know which tag it is. i want to serialize the Tagdefinition too (IRI and/or embedded within each tag). if i add the serialization group to the foreignkey "tagdefinition" in the Tag entity, i get the following error:

ApiPlatform\Core\Exception\InvalidArgumentException:
No resource class found for object of type "App\Entity\Tagdefinition".

  at vendor/api-platform/core/src/Api/ResourceClassResolver.php:58
  at ApiPlatform\Core\Api\ResourceClassResolver->getResourceClass(object(Tagdefinition), 'App\\Entity\\Fall', true)
     (vendor/api-platform/core/src/JsonLd/Serializer/ItemNormalizer.php:65)
  at ApiPlatform\Core\JsonLd\Serializer\ItemNormalizer->normalize(object(Tagdefinition), 'jsonld', array('groups' => array('fall_collection_output'), 'collection_operation_name' => 'get', 'operation_type' => 'collection', 'resource_class' => 'App\\Entity\\Fall', 'request_uri' => '/faelle', 'resources' => array('/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1'), 'jsonld_has_context' => true, 'api_sub_level' => true, 'iri' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1', 'api_normalize' => true, 'cache_key' => '7b899eea53ad666095cf9ad460b4ba97', 'circular_reference_limit' => array('00000000762694b10000000031e3a665' => 1, '000000007626940c0000000031e3a665' => 1)))
     (vendor/symfony/symfony/src/Symfony/Component/Serializer/Serializer.php:142)
  at Symfony\Component\Serializer\Serializer->normalize(object(Tagdefinition), 'jsonld', array('groups' => array('fall_collection_output'), 'collection_operation_name' => 'get', 'operation_type' => 'collection', 'resource_class' => 'App\\Entity\\Fall', 'request_uri' => '/faelle', 'resources' => array('/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1'), 'jsonld_has_context' => true, 'api_sub_level' => true, 'iri' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1', 'api_normalize' => true, 'cache_key' => '7b899eea53ad666095cf9ad460b4ba97', 'circular_reference_limit' => array('00000000762694b10000000031e3a665' => 1, '000000007626940c0000000031e3a665' => 1)))
     (vendor/symfony/symfony/src/Symfony/Component/Serializer/Normalizer/AbstractObjectNormalizer.php:99)
  at Symfony\Component\Serializer\Normalizer\AbstractObjectNormalizer->normalize(object(Tag), 'jsonld', array('groups' => array('fall_collection_output'), 'collection_operation_name' => 'get', 'operation_type' => 'collection', 'resource_class' => 'App\\Entity\\Fall', 'request_uri' => '/faelle', 'resources' => array('/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1'), 'jsonld_has_context' => true, 'api_sub_level' => true, 'iri' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1', 'api_normalize' => true, 'cache_key' => '7b899eea53ad666095cf9ad460b4ba97', 'circular_reference_limit' => array('00000000762694b10000000031e3a665' => 1, '000000007626940c0000000031e3a665' => 1)))
     (vendor/symfony/symfony/src/Symfony/Component/Serializer/Serializer.php:142)
  at Symfony\Component\Serializer\Serializer->normalize(object(Tag), 'jsonld', array('groups' => array('fall_collection_output'), 'collection_operation_name' => 'get', 'operation_type' => 'collection', 'resource_class' => 'App\\Entity\\Fall', 'request_uri' => '/faelle', 'resources' => array('/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1'), 'jsonld_has_context' => true, 'api_sub_level' => true, 'iri' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1', 'api_normalize' => true, 'cache_key' => '7b899eea53ad666095cf9ad460b4ba97', 'circular_reference_limit' => array('00000000762694b10000000031e3a665' => 1)))
     (vendor/api-platform/core/src/Hydra/Serializer/CollectionNormalizer.php:68)
  at ApiPlatform\Core\Hydra\Serializer\CollectionNormalizer->normalize(array(object(Tag)), 'jsonld', array('groups' => array('fall_collection_output'), 'collection_operation_name' => 'get', 'operation_type' => 'collection', 'resource_class' => 'App\\Entity\\Fall', 'request_uri' => '/faelle', 'resources' => array('/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1'), 'jsonld_has_context' => true, 'api_sub_level' => true, 'iri' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1', 'api_normalize' => true, 'cache_key' => '7b899eea53ad666095cf9ad460b4ba97', 'circular_reference_limit' => array('00000000762694b10000000031e3a665' => 1)))
     (vendor/api-platform/core/src/Hydra/Serializer/PartialCollectionViewNormalizer.php:48)
  at ApiPlatform\Core\Hydra\Serializer\PartialCollectionViewNormalizer->normalize(array(object(Tag)), 'jsonld', array('groups' => array('fall_collection_output'), 'collection_operation_name' => 'get', 'operation_type' => 'collection', 'resource_class' => 'App\\Entity\\Fall', 'request_uri' => '/faelle', 'resources' => array('/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1'), 'jsonld_has_context' => true, 'api_sub_level' => true, 'iri' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1', 'api_normalize' => true, 'cache_key' => '7b899eea53ad666095cf9ad460b4ba97', 'circular_reference_limit' => array('00000000762694b10000000031e3a665' => 1)))
     (vendor/api-platform/core/src/Hydra/Serializer/CollectionFiltersNormalizer.php:65)
  at ApiPlatform\Core\Hydra\Serializer\CollectionFiltersNormalizer->normalize(array(object(Tag)), 'jsonld', array('groups' => array('fall_collection_output'), 'collection_operation_name' => 'get', 'operation_type' => 'collection', 'resource_class' => 'App\\Entity\\Fall', 'request_uri' => '/faelle', 'resources' => array('/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1'), 'jsonld_has_context' => true, 'api_sub_level' => true, 'iri' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1', 'api_normalize' => true, 'cache_key' => '7b899eea53ad666095cf9ad460b4ba97', 'circular_reference_limit' => array('00000000762694b10000000031e3a665' => 1)))
     (vendor/symfony/symfony/src/Symfony/Component/Serializer/Serializer.php:142)
  at Symfony\Component\Serializer\Serializer->normalize(array(object(Tag)), 'jsonld', array('groups' => array('fall_collection_output'), 'collection_operation_name' => 'get', 'operation_type' => 'collection', 'resource_class' => 'App\\Entity\\Fall', 'request_uri' => '/faelle', 'resources' => array('/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1'), 'jsonld_has_context' => true, 'api_sub_level' => true, 'iri' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1', 'api_normalize' => true, 'cache_key' => '7b899eea53ad666095cf9ad460b4ba97', 'circular_reference_limit' => array('00000000762694b10000000031e3a665' => 1)))
     (vendor/api-platform/core/src/Serializer/AbstractItemNormalizer.php:420)
  at ApiPlatform\Core\Serializer\AbstractItemNormalizer->getAttributeValue(object(Fall), 'tags', 'jsonld', array('groups' => array('fall_collection_output'), 'collection_operation_name' => 'get', 'operation_type' => 'collection', 'resource_class' => 'App\\Entity\\Fall', 'request_uri' => '/faelle', 'resources' => array('/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1'), 'jsonld_has_context' => true, 'api_sub_level' => true, 'iri' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1', 'api_normalize' => true, 'cache_key' => '7b899eea53ad666095cf9ad460b4ba97', 'circular_reference_limit' => array('00000000762694b10000000031e3a665' => 1)))
     (vendor/symfony/symfony/src/Symfony/Component/Serializer/Normalizer/AbstractObjectNormalizer.php:81)
  at Symfony\Component\Serializer\Normalizer\AbstractObjectNormalizer->normalize(object(Fall), 'jsonld', array('groups' => array('fall_collection_output'), 'collection_operation_name' => 'get', 'operation_type' => 'collection', 'resource_class' => 'App\\Entity\\Fall', 'request_uri' => '/faelle', 'resources' => array('/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1'), 'jsonld_has_context' => true, 'api_sub_level' => true, 'iri' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1', 'api_normalize' => true, 'cache_key' => '7b899eea53ad666095cf9ad460b4ba97', 'circular_reference_limit' => array('00000000762694b10000000031e3a665' => 1)))
     (vendor/api-platform/core/src/Serializer/AbstractItemNormalizer.php:94)
  at ApiPlatform\Core\Serializer\AbstractItemNormalizer->normalize(object(Fall), 'jsonld', array('groups' => array('fall_collection_output'), 'collection_operation_name' => 'get', 'operation_type' => 'collection', 'resource_class' => 'App\\Entity\\Fall', 'request_uri' => '/faelle', 'resources' => array('/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1'), 'jsonld_has_context' => true, 'api_sub_level' => true, 'iri' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1', 'api_normalize' => true))
     (vendor/api-platform/core/src/JsonLd/Serializer/ItemNormalizer.php:73)
  at ApiPlatform\Core\JsonLd\Serializer\ItemNormalizer->normalize(object(Fall), 'jsonld', array('groups' => array('fall_collection_output'), 'collection_operation_name' => 'get', 'operation_type' => 'collection', 'resource_class' => 'App\\Entity\\Fall', 'request_uri' => '/faelle', 'resources' => array('/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1'), 'jsonld_has_context' => true, 'api_sub_level' => true, 'iri' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1'))
     (vendor/symfony/symfony/src/Symfony/Component/Serializer/Serializer.php:142)
  at Symfony\Component\Serializer\Serializer->normalize(object(Fall), 'jsonld', array('groups' => array('fall_collection_output'), 'collection_operation_name' => 'get', 'operation_type' => 'collection', 'resource_class' => 'App\\Entity\\Fall', 'request_uri' => '/faelle', 'resources' => array('/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1'), 'jsonld_has_context' => true, 'api_sub_level' => true))
     (vendor/api-platform/core/src/Hydra/Serializer/CollectionNormalizer.php:88)
  at ApiPlatform\Core\Hydra\Serializer\CollectionNormalizer->normalize(object(Paginator), 'jsonld', array('groups' => array('fall_collection_output'), 'collection_operation_name' => 'get', 'operation_type' => 'collection', 'resource_class' => 'App\\Entity\\Fall', 'request_uri' => '/faelle', 'resources' => array('/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1'), 'jsonld_has_context' => true, 'api_sub_level' => true))
     (vendor/api-platform/core/src/Hydra/Serializer/PartialCollectionViewNormalizer.php:48)
  at ApiPlatform\Core\Hydra\Serializer\PartialCollectionViewNormalizer->normalize(object(Paginator), 'jsonld', array('groups' => array('fall_collection_output'), 'collection_operation_name' => 'get', 'operation_type' => 'collection', 'resource_class' => 'App\\Entity\\Fall', 'request_uri' => '/faelle', 'resources' => array('/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1')))
     (vendor/api-platform/core/src/Hydra/Serializer/CollectionFiltersNormalizer.php:65)
  at ApiPlatform\Core\Hydra\Serializer\CollectionFiltersNormalizer->normalize(object(Paginator), 'jsonld', array('groups' => array('fall_collection_output'), 'collection_operation_name' => 'get', 'operation_type' => 'collection', 'resource_class' => 'App\\Entity\\Fall', 'request_uri' => '/faelle', 'resources' => array('/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1')))
     (vendor/symfony/symfony/src/Symfony/Component/Serializer/Serializer.php:142)
  at Symfony\Component\Serializer\Serializer->normalize(object(Paginator), 'jsonld', array('groups' => array('fall_collection_output'), 'collection_operation_name' => 'get', 'operation_type' => 'collection', 'resource_class' => 'App\\Entity\\Fall', 'request_uri' => '/faelle', 'resources' => array('/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1')))
     (vendor/symfony/symfony/src/Symfony/Component/Serializer/Serializer.php:115)
  at Symfony\Component\Serializer\Serializer->serialize(object(Paginator), 'jsonld', array('groups' => array('fall_collection_output'), 'collection_operation_name' => 'get', 'operation_type' => 'collection', 'resource_class' => 'App\\Entity\\Fall', 'request_uri' => '/faelle', 'resources' => array('/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1' => '/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1')))
     (vendor/api-platform/core/src/EventListener/SerializeListener.php:65)
  at ApiPlatform\Core\EventListener\SerializeListener->onKernelView(object(GetResponseForControllerResultEvent), 'kernel.view', object(TraceableEventDispatcher))
  at call_user_func(array(object(SerializeListener), 'onKernelView'), object(GetResponseForControllerResultEvent), 'kernel.view', object(TraceableEventDispatcher))
     (vendor/symfony/symfony/src/Symfony/Component/EventDispatcher/Debug/WrappedListener.php:106)
  at Symfony\Component\EventDispatcher\Debug\WrappedListener->__invoke(object(GetResponseForControllerResultEvent), 'kernel.view', object(ContainerAwareEventDispatcher))
  at call_user_func(object(WrappedListener), object(GetResponseForControllerResultEvent), 'kernel.view', object(ContainerAwareEventDispatcher))
     (vendor/symfony/symfony/src/Symfony/Component/EventDispatcher/EventDispatcher.php:212)
  at Symfony\Component\EventDispatcher\EventDispatcher->doDispatch(array(object(WrappedListener), object(WrappedListener), object(WrappedListener), object(WrappedListener), object(WrappedListener)), 'kernel.view', object(GetResponseForControllerResultEvent))
     (vendor/symfony/symfony/src/Symfony/Component/EventDispatcher/EventDispatcher.php:44)
  at Symfony\Component\EventDispatcher\EventDispatcher->dispatch('kernel.view', object(GetResponseForControllerResultEvent))
     (vendor/symfony/symfony/src/Symfony/Component/EventDispatcher/Debug/TraceableEventDispatcher.php:146)
  at Symfony\Component\EventDispatcher\Debug\TraceableEventDispatcher->dispatch('kernel.view', object(GetResponseForControllerResultEvent))
     (vendor/symfony/symfony/src/Symfony/Component/HttpKernel/HttpKernel.php:158)
  at Symfony\Component\HttpKernel\HttpKernel->handleRaw(object(Request), 1)
     (vendor/symfony/symfony/src/Symfony/Component/HttpKernel/HttpKernel.php:68)
  at Symfony\Component\HttpKernel\HttpKernel->handle(object(Request), 1, true)
     (vendor/symfony/symfony/src/Symfony/Component/HttpKernel/Kernel.php:171)
  at Symfony\Component\HttpKernel\Kernel->handle(object(Request))
     (src/Resources/bin/app.php:21)

it happens on both jsonld and json normalizers.

basically this check "fails" https://github.com/api-platform/core/blob/master/src/Api/ResourceClassResolver.php#L53 but i dont even know why the check is there (especially the first "strict" part)

in terms of jsonld Fall::tags are a container of blank nodes (Tag) that contain a label, a created date and a reference to the Tagdefinition (maybe more in the future).

[backbone87]

some more context:

at ApiPlatform\Core\Api\ResourceClassResolver->getResourceClass(object(Tagdefinition), 'App\\Entity\\Fall', true)
     (vendor/api-platform/core/src/JsonLd/Serializer/ItemNormalizer.php:65)

This happens when the normalizer tries to serialize the Tag::definition single valued association that is embedded into the Fall output. Thats why the first argument is an object of type Tagdefinition (which is the value of Tag::definition property) and the resource class is App\Entity\Fall.

Is my assumption correct, that when normalizing embedded objects that are not ApiResources the serialization context property "resourceClass" should be dropped?

[backbone87]

If i add unset($context['resource_class']); before https://github.com/api-platform/core/blob/master/src/Serializer/AbstractItemNormalizer.php#L420 then i get:

{
  "@context": "/contexts/Fall",
  "@id": "/faelle",
  "@type": "hydra:Collection",
  "hydra:member": [
    {
      "@id": "/faelle/691bcf98-5c41-11e7-b7d5-046d49573cb1",
      "@type": "Fall",
      "id": "691bcf98-5c41-11e7-b7d5-046d49573cb1",
      "tags": [
        {
          "definition": {
            "@id": "/tagdefinitionen/c72fba28-5da3-11e7-96da-8559e375ccf0",
            "@type": "Tagdefinition",
            "name": "Test"
          },
          "erstellungsdatum": "2017-06-30T15:09:47+00:00",
          "beschriftung": "Dies ist eine Testbeschriftung"
        }
      ]
    }
  ],
  "hydra:totalItems": 1
}

which is close, but missing entries in the context. In general i noticed that the jsonld context is only embedded in the root entity (and also only root entity props are contained in the context, which leads to a wrong jsonld graph). however its perfectly legal to embed a context in subobject: https://json-ld.org/spec/latest/json-ld/#advanced-context-usage - alternatively you should be able to pass up nested contexts.

[backbone87]

Ok additionally to the change mentioned above, the following needs to be commented out:
https://github.com/api-platform/core/blob/master/src/Serializer/ContextTrait.php#L33-L35

this is to make sure, when serializing intermediate non-resource object A and then hitting a resource object B again within A, the correct resource class is set into the context.

@dunglas @soyuka can i have your opinion on these changes? i would love to provide a PR, since this is a blocker on my current project.

[backbone87]

@dunglas is it possible to get some feedback on this?

[dunglas]

Can you provide a PR (or at least a failing test), it will ease the review process.

[backbone87]

The referenced PR contains the changes i currently use that solve (?) the problem.

The serialization context is carried through to "normal" object serialization for nested objects. This PR prevents it, but i dont know which implications this change has on other aspects.

[teohhanhui]

I'm still waiting for a major refactoring of the normalizer. Lol...

I made a quick hack for using blank nodes in #956 but it needs work, at least to make sure the JSON-LD document root is correctly set when serializing a collection.

[backbone87]

I need this fixed for my project.
I try to describe the problem again:
You have 3 Objects where 2 of them are API resources and the 1 in the middle is a normal entity. If you start serializing one of the API resources and want to nest the non-resource entity and within it the other API resource, the following serializers are used:

1. Object a of type A (is API resource) uses JSON-LD Serializer
2. Property x of a contains related object b of type B (is not an API resource) uses standard symfony object serializer
3. Property y of b contains related object c of type C (is API resource) uses JSON-LD Serializer

The problem is, that when serializing an inner API resource object, the outer serializer call sets up the context for the inner serializer (see https://github.com/api-platform/core/blob/master/src/Serializer/AbstractItemNormalizer.php#L437 the call to createRelationSerializationContext). But when serializing b, the standard object serializer is used, which knows nothing about preparing the context for a nested relation.

I hope i got this clear now.

I rly need some feedback on this, especially if the PR #1253 fixes this properly.

[soyuka]

I'm confirming this issue (I added a test in your PR).

Though if b is a ResourceClass everything is fine :P.