如何让 API 平台加载相关（例如 Many2One）资源/实体？

Question

根据文档，api-platform默认会立即加载相关资源。

但在默认配置上，我对具有关系的资源（主要是典型Many2One关系）的所有查询都会使用对象 IRI 而不是序列化对象来填充这些属性。

例如，对于这个实体：

/**
 * @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
}

那么我们就有了对应的ContactChannel：

/**
 * 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 = '';
}

fetch="EAGER"即使理论上不需要，我也已经建立了 这种关系。我的配置是默认的，但以防万一我实际上在我的api_platform.yaml：

    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

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

    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

但结果会是这样的：

{
  "@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 IRI。我确认执行的 SQL 查询不包含任何类型的join.

有趣的是，这似乎与其他用户遇到的问题相反。我希望我有他们的问题。

是什么阻止了这些关系的急切加载？否则关系会起作用（我可以使用 Doctrine 执行其他查询，或者创建自定义序列化组，并且将包含相关属性）。

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，您不应该看到显式JOIN查询，而是看到SELECT相关关联的附加语句。

如果您想要关联对象的 JSON 表示形式。您需要Serialization @Groups在相关关联中指定所需的属性。这会导致SELECT语句中添加aJOIN来检索要序列化的相关数据。

有关更多详细信息，请参阅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 = '';
}

这应该会导致检索到标准化值

{
  "@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"
}