如何让API平台加载相关（如多个）资源/实体？

Question

根据文档，默认情况下，api平台将加载相关资源。

但是在默认配置中，我对具有关系的资源的所有查询（主要是典型的Many2One关系）都用对象IRI而不是序列化对象填充这些属性。

例如，对于该实体：

/**
 * @ORM\Entity(repositoryClass="App\Repository\BoostLeadContactActionRepository")
 * @ORM\Table(name="BoostLeadContactActions")
 */
class BoostLeadContactAction {

    /**
     * @ORM\Id()
     * @ORM\GeneratedValue()
     * @ORM\Column(type="integer")
     */
    private $id;

    /**
     * @ORM\ManyToOne(targetEntity="App\Entity\BoostLead", inversedBy="contacts")
     * @ORM\JoinColumn(nullable=false)
     */
    private $boostLead;

    /**
     * @ORM\ManyToOne(targetEntity="App\Entity\ContactChannel", fetch="EAGER")
     * @ORM\JoinColumn(nullable=false, referencedColumnName="Id")
     */
    private $channel;

    // getters/setters/extra properties removed for brevity
}

然后我们就有了相应的联系人频道：

/**
 * ContactChannel
 *
 * @ORM\Table(name="ContactChannels")
 * @ORM\Entity
 */
class ContactChannel {

    /**
     * @var int
     *
     * @ORM\Column(name="Id", type="smallint", nullable=false, options={"unsigned"=true})
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="IDENTITY")
     */
    private $id;

    /**
     * @var string
     *
     * @ORM\Column(name="Name", type="string", length=64, nullable=false)
     */
    private $name = '';
}

我已经在关系上设置了finch="EAGER"，即使理论上不需要。我的配置是默认的，但是以防万一我真的在我的api_platform.yaml中写了这个：

    eager_loading:
        # To enable or disable eager loading.
        enabled: true

        # Fetch only partial data according to serialization groups.
        # If enabled, Doctrine ORM entities will not work as expected if any of the other fields are used.
        fetch_partial: false

        # Max number of joined relations before EagerLoading throws a RuntimeException.
        max_joins: 30

        # Force join on every relation.
        # If disabled, it will only join relations having the EAGER fetch mode.
        force_eager: true

debug:config api_platform的结果确认应用了正确的配置：

Current configuration for extension with alias "api_platform"
=============================================================

api_platform:
    title: FooBar API
    description: 'FooBar API, only for authenticated use'
    version: 0.8.0
    name_converter: null
    path_segment_name_generator: api_platform.path_segment_name_generator.underscore
    eager_loading:
        enabled: true
        fetch_partial: false
        max_joins: 30
        force_eager: true

然而结果会是这样的：

{
  "@context": "/api/contexts/BoostLeadContactAction",
  "@id": "/api/boost_lead_contact_actions/9",
  "@type": "BoostLeadContactAction",
  "id": 9,
  "boostLead": "/api/boost_leads/30",
  "channel": "/api/contact_channels/1",
  "direction": "outgoing",
  "successful": true,
  "type": "/api/lead_contact_attempt_reasons/1",
  "notes": "2",
  "createdAt": "2019-05-16T10:27:33+00:00",
  "updatedAt": "2019-05-16T10:27:33+00:00"
}

“boostLead”、“channel”和“type”应该是实际的实体，急切地加载，但只返回IRIs。我确认所执行的SQL查询不包括任何类型的连接。

有趣的是，这似乎是另一个用户遇到的相反的麻烦。我希望我有他们的问题。

是什么阻止了这些关系被急切地加载？这些关系以其他方式工作（我可以使用Doctrine进行其他查询，或者创建自定义序列化组，相关属性将被包括在内）。




Answer 1

默认情况下，可取消引用的IRI用于显示相关关联。查看执行的语句时，您不应该看到显式的JOIN查询，而是看到相关关联的附加SELECT语句。

如果您想要关联对象的JSON表示。您需要为相关关联中所需的属性指定序列化@Groups。这将导致SELECT语句添加到JOIN中，以检索要序列化的相关数据。

更多详情见https://api-platform.com/docs/core/serialization/#embedding-relations

namespace App\Entity;

use ApiPlatform\Core\Annotation\ApiResource;
use Symfony\Component\Serializer\Annotation\Groups;

/**
 * @ApiResource(normalizationContext={ "groups": {"boost"} })
 * @ORM\Entity()
 * @ORM\Table(name="BoostLeadContactActions")
 */
class BoostLeadContactAction {

    /**
     * @ORM\Id()
     * @ORM\GeneratedValue()
     * @ORM\Column(type="integer")
     * @Groups({"boost"})
     */
    private $id;

    /**
     * @ORM\ManyToOne(targetEntity="App\Entity\BoostLead", inversedBy="contacts")
     * @ORM\JoinColumn(nullable=false)
     * @Groups({"boost"})
     */
    private $boostLead;

    /**
     * @ORM\ManyToOne(targetEntity="App\Entity\ContactChannel", fetch="EAGER")
     * @ORM\JoinColumn(nullable=false, referencedColumnName="Id")
     * @Groups({"boost"})
     */
    private $channel;

    // getters/setters/extra properties removed for brevity
}

namespace App\Entity;

use ApiPlatform\Core\Annotation\ApiResource;
use Symfony\Component\Serializer\Annotation\Groups;

/**
 * @ApiResource()
 * @ORM\Table(name="ContactChannels")
 * @ORM\Entity
 */
class ContactChannel {

    /**
     * @var int
     * @ORM\Column(name="Id", type="smallint", nullable=false, options={"unsigned"=true})
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="IDENTITY")
     * @Groups({"boost"})
     */
    private $id;

    /**
     * @var string
     * @ORM\Column(name="Name", type="string", length=64, nullable=false)
     * @Groups({"boost"})
     */
    private $name = '';
}

这将导致检索标准化值

{
  "@context": "/api/contexts/BoostLeadContactAction",
  "@id": "/api/boost_lead_contact_actions/9",
  "@type": "BoostLeadContactAction",
  "id": 9,
  "boostLead": "/api/boost_leads/30",
  "channel": {
      "@id": "/api/contact_channels/1",
      "@type": "ContactChannel",
      "id": "1",
      "name": "Test"
   },
  "direction": "outgoing",
  "successful": true,
  "type": "/api/lead_contact_attempt_reasons/1",
  "notes": "2",
  "createdAt": "2019-05-16T10:27:33+00:00",
  "updatedAt": "2019-05-16T10:27:33+00:00"
}