Access to subressource results in error 500: Can't get a way to read the property "id" in class "Doctrine\ORM\PersistentCollection".

[xalopp]

API Platform version(s) affected: 4.0.11 and later

Description

Accessing a defined subresource (https://localhost/tags/5/color/1) on doctrine entities results in error 500:
Can't get a way to read the property "id" in class "Doctrine\ORM\PersistentCollection".

How to reproduce

• Start a new API-Platform Project from API platform template
• Create the entities Tag and TagColor with docker compose exec -ti php bin/console make:entity
• Add Subresource related Attributes as described in the documentation.
• Add some some tag colors and tag in the database via the admin interface
• Accessing the TagColor collection works curl -k https://localhost/tags/1/color

  {
    "@context": "/contexts/TagColor",
    "@id": "/tags/1/color",
    "@type": "Collection",
    "totalItems": 1,
    "member": [
      {
        "@id": "/tag_colors/1",
        "@type": "TagColor",
        "id": 1,
        "color": "red",
        "tags": [
          "/tags/1",
          "/tags/5"
        ]
      }
    ]
  }
  

• When accessing a non existing subresource, curl -k https://localhost/tags/5/color/99999, a 404 is returned as expected
• When accessing a existing resource, curl -k https://localhost/tags/1/color/1, a error 500 is returned with this stack trace:

{
  "@context": "/contexts/Error",
  "@id": "/errors/500",
  "@type": "Error",
  "title": "An error occurred",
  "detail": "Can't get a way to read the property \"id\" in class \"Doctrine\\ORM\\PersistentCollection\".",
  "status": 500,
  "type": "/errors/500",
  "trace": [
    {
      "file": "/app/vendor/symfony/property-access/PropertyAccessor.php",
      "line": 334,
      "function": "readProperty",
      "class": "Symfony\\Component\\PropertyAccess\\PropertyAccessor",
      "type": "->"
    },
    {
      "file": "/app/vendor/symfony/property-access/PropertyAccessor.php",
      "line": 104,
      "function": "readPropertiesUntil",
      "class": "Symfony\\Component\\PropertyAccess\\PropertyAccessor",
      "type": "->"
    },
    {
      "file": "/app/vendor/api-platform/metadata/IdentifiersExtractor.php",
      "line": 106,
      "function": "getValue",
      "class": "Symfony\\Component\\PropertyAccess\\PropertyAccessor",
      "type": "->"
    },
    {
      "file": "/app/vendor/api-platform/metadata/IdentifiersExtractor.php",
      "line": 86,
      "function": "getIdentifierValue",
      "class": "ApiPlatform\\Metadata\\IdentifiersExtractor",
      "type": "->"
    },
    {
      "file": "/app/vendor/api-platform/metadata/IdentifiersExtractor.php",
      "line": 56,
      "function": "getIdentifiersFromOperation",
      "class": "ApiPlatform\\Metadata\\IdentifiersExtractor",
      "type": "->"
    },
    {
      "file": "/app/vendor/api-platform/symfony/Routing/IriConverter.php",
      "line": 187,
      "function": "getIdentifiersFromItem",
      "class": "ApiPlatform\\Metadata\\IdentifiersExtractor",
      "type": "->"
    },
    {
      "file": "/app/vendor/api-platform/symfony/Routing/IriConverter.php",
      "line": 168,
      "function": "generateSymfonyRoute",
      "class": "ApiPlatform\\Symfony\\Routing\\IriConverter",
      "type": "->"
    },
    {
      "file": "/app/vendor/api-platform/jsonld/Serializer/ItemNormalizer.php",
      "line": 127,
      "function": "getIriFromResource",
      "class": "ApiPlatform\\Symfony\\Routing\\IriConverter",
      "type": "->"
    },
    {
      "file": "/app/vendor/symfony/serializer/Debug/TraceableNormalizer.php",
      "line": 58,
      "function": "normalize",
      "class": "ApiPlatform\\JsonLd\\Serializer\\ItemNormalizer",
      "type": "->"
    },
    {
      "file": "/app/vendor/symfony/serializer/Serializer.php",
      "line": 159,
      "function": "normalize",
      "class": "Symfony\\Component\\Serializer\\Debug\\TraceableNormalizer",
      "type": "->"
    },
    {
      "file": "/app/vendor/symfony/serializer/Serializer.php",
      "line": 138,
      "function": "normalize",
      "class": "Symfony\\Component\\Serializer\\Serializer",
      "type": "->"
    },
    {
      "file": "/app/vendor/symfony/serializer/Debug/TraceableSerializer.php",
      "line": 47,
      "function": "serialize",
      "class": "Symfony\\Component\\Serializer\\Serializer",
      "type": "->"
    },
    {
      "file": "/app/vendor/api-platform/state/Processor/SerializeProcessor.php",
      "line": 74,
      "function": "serialize",
      "class": "Symfony\\Component\\Serializer\\Debug\\TraceableSerializer",
      "type": "->"
    },
    {
      "file": "/app/vendor/api-platform/state/Processor/WriteProcessor.php",
      "line": 51,
      "function": "process",
      "class": "ApiPlatform\\State\\Processor\\SerializeProcessor",
      "type": "->"
    },
    {
      "file": "/app/vendor/api-platform/symfony/Controller/MainController.php",
      "line": 112,
      "function": "process",
      "class": "ApiPlatform\\State\\Processor\\WriteProcessor",
      "type": "->"
    },
    {
      "file": "/app/vendor/symfony/http-kernel/HttpKernel.php",
      "line": 181,
      "function": "__invoke",
      "class": "ApiPlatform\\Symfony\\Controller\\MainController",
      "type": "->"
    },
    {
      "file": "/app/vendor/symfony/http-kernel/HttpKernel.php",
      "line": 76,
      "function": "handleRaw",
      "class": "Symfony\\Component\\HttpKernel\\HttpKernel",
      "type": "->"
    },
    {
      "file": "/app/vendor/symfony/http-kernel/Kernel.php",
      "line": 197,
      "function": "handle",
      "class": "Symfony\\Component\\HttpKernel\\HttpKernel",
      "type": "->"
    },
    {
      "file": "/app/vendor/symfony/runtime/Runner/Symfony/HttpKernelRunner.php",
      "line": 35,
      "function": "handle",
      "class": "Symfony\\Component\\HttpKernel\\Kernel",
      "type": "->"
    },
    {
      "file": "/app/vendor/autoload_runtime.php",
      "line": 29,
      "function": "run",
      "class": "Symfony\\Component\\Runtime\\Runner\\Symfony\\HttpKernelRunner",
      "type": "->"
    },
    {
      "file": "/app/public/index.php",
      "line": 5,
      "function": "require_once"
    }
  ],
  "description": "Can't get a way to read the property \"id\" in class \"Doctrine\\ORM\\PersistentCollection\"."
}

My entities looks like this:

Tag.php

<?php

namespace App\Entity;

use ApiPlatform\Metadata\ApiResource;
use App\Repository\TagRepository;
use Doctrine\ORM\Mapping as ORM;

#[ORM\Entity(repositoryClass: TagRepository::class)]
#[ApiResource]
class Tag
{
    #[ORM\Id]
    #[ORM\GeneratedValue]
    #[ORM\Column]
    private ?int $id = null;

    #[ORM\Column(length: 32)]
    private ?string $text = null;

    #[ORM\ManyToOne(inversedBy: 'tags')]
    #[ORM\JoinColumn(nullable: false)]
    #[Link(fromProperty: 'tags')]
    private ?TagColor $tagColor = null;

    public function getId(): ?int
    {
        return $this->id;
    }

    public function getText(): ?string
    {
        return $this->text;
    }

    public function setText(string $text): static
    {
        $this->text = $text;

        return $this;
    }

    public function getTagColor(): ?TagColor
    {
        return $this->tagColor;
    }

    public function setTagColor(?TagColor $tagColor): static
    {
        $this->tagColor = $tagColor;

        return $this;
    }
}

TagColor.php

<?php

namespace App\Entity;

use ApiPlatform\Metadata\ApiResource;
use ApiPlatform\Metadata\Get;
use ApiPlatform\Metadata\GetCollection;
use ApiPlatform\Metadata\Link;
use App\Repository\TagColorRepository;
use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Collections\Collection;
use Doctrine\ORM\Mapping as ORM;

#[ORM\Entity(repositoryClass: TagColorRepository::class)]
#[ApiResource]
#[ApiResource(
    uriTemplate: '/tags/{tagId}/color/{id}',
    uriVariables: [
        'tagId' => new Link(fromClass: Tag::class, toProperty: 'tags'),
        'id' => new Link(fromClass: TagColor::class),
    ],
    operations: [ new Get() ]
)]
#[ApiResource(
    uriTemplate: '/tags/{tagId}/color',
    uriVariables: [
        'tagId' => new Link(fromClass: Tag::class, toProperty: 'tags'),
    ],
    operations: [ new GetCollection() ]
)]
class TagColor
{
    #[ORM\Id]
    #[ORM\GeneratedValue]
    #[ORM\Column]
    private ?int $id = null;

    #[ORM\Column(length: 16)]
    private ?string $color = null;

    /**
     * @var Collection<int, Tag>
     */
    #[ORM\OneToMany(mappedBy: 'tagColor', targetEntity: Tag::class, orphanRemoval: true)]
    private Collection $tags;

    public function __construct()
    {
        $this->tags = new ArrayCollection();
    }

    public function getId(): ?int
    {
        return $this->id;
    }

    public function getColor(): ?string
    {
        return $this->color;
    }

    public function setColor(string $color): static
    {
        $this->color = $color;

        return $this;
    }

    /**
     * @return Collection<int, Tag>
     */
    public function getTags(): Collection
    {
        return $this->tags;
    }

    public function addTag(Tag $tag): static
    {
        if (!$this->tags->contains($tag)) {
            $this->tags->add($tag);
            $tag->setTagColor($this);
        }

        return $this;
    }

    public function removeTag(Tag $tag): static
    {
        if ($this->tags->removeElement($tag)) {
            // set the owning side to null (unless already changed)
            if ($tag->getTagColor() === $this) {
                $tag->setTagColor(null);
            }
        }

        return $this;
    }
}

[vinceAmstoutz]

@xalopp Your current configuration for the subresource uses toProperty: tags, which references the tags collection in TagColor. However, tags is a collection, and API Platform treats it as if it's a single entity.

Updates the uriVariables configuration for your subresource with something like this:

 #[ApiResource(
     uriTemplate: '/tags/{tagId}/color/{id}',
     uriVariables: [
-        'tagId' => new Link(fromClass: Tag::class, toProperty: 'tags'),
+        'tagId' => new Link(fromClass: Tag::class, toProperty: 'tagColor'), // Adjusted to reference `tagColor`
         'id' => new Link(fromClass: TagColor::class),
     ],
     operations: [ new Get() ]
 )]
 #[ApiResource(
     uriTemplate: '/tags/{tagId}/color',
     uriVariables: [
-        'tagId' => new Link(fromClass: Tag::class, toProperty: 'tags'),
+        'tagId' => new Link(fromClass: Tag::class, toProperty: 'tagColor'), // Adjusted to reference `tagColor`
     ],
     operations: [ new GetCollection() ]
 )]

ℹ️ Important: It is recommended to define a single ApiResource with one or multiple operations (e.g., GET, POST, or GET_COLLECTION) rather than creating separate #[ApiResource] definitions for each operation. Alternatively, you can use method-specific attributes such as #[GetCollection() or #Get() for individual actions within the same resource without defining any #[ApiResource]. This approach ensures better maintainability, reduces potential conflicts and avoids unexpected behaviors in your API configuration.

[xalopp]

@vinceAmstoutz thanks for your response. Applying your changes, results in

{
  "@context": "/contexts/Error",
  "@id": "/errors/500",
  "@type": "Error",
  "title": "An error occurred",
  "detail": "Association name expected, 'tagColor' is not an association.",
  "status": 500,
  "type": "/errors/500",
  "trace": [
  ....
  }

This inspired me to change it to

'tagId' => new Link(toProperty: 'tags'),

which solved my issue. Without really understanding why 🙃

The Link attribute for $tagColor attribute of Tag seems to have no impact, because it still working when it's omitted.

Since I used this documentation page https://api-platform.com/docs/core/subresources/#company-employees to configure the entities, it might need some clarifications / updates. Happy to provide a PR for that.

[vinceAmstoutz]

@xalopp Perfect, I thought it was a relationship problem. I invite you to read additional resources on the subject to better understand it, such as Declare a subresource Guide and a SymfonyCast about subsresources.

If you think the https://api-platform.com/docs/core/subresources/#company-employees documentation needs clarification, please feel free to contribute, visit our CONTRIBUTING.md and submit your suggestions. Thanks!

[ytilotti]

@xalopp are you sure is working? The tagId is not transform to Tag object.