如何使用 JMS Serializer EventSubscriberInterface（php，symfony）将对象序列化为其自己的属性（数组）答案

【问题标题】：How to serialize object as its own property (array) using JMS Serializer EventSubscriberInterface (php, symfony)如何使用 JMS Serializer EventSubscriberInterface（php，symfony）将对象序列化为其自己的属性（数组）
【发布时间】：2021-06-10 17:07:49
【问题描述】：

我需要将一个对象序列化为它自己的属性（它的类型是数组），我的意思是这个对象有一个数组属性books，转换之后我想跳过books这个键，所以结构会更平坦[book1, book2]（不是[books => [book1, book2]]。我有以下课程：

<?php

class Store
{
    private ?BooksCollection $booksCollection = null;

    public function __construct(?BooksCollection $booksCollection = null)
    {
        $this->booksCollection = $booksCollection;
    }

    public function getBooksCollection(): ?BooksCollection
    {
        return $this->booksCollection;
    }
}

class BooksCollection
{
    /** @var Book[] */
    private array $books;

    public function __construct(Book ...$books)
    {
        $this->books = $books;
    }

    public function getBooks(): array
    {
        return $this->books;
    }
}

class Book
{
    private string $title;

    public function __construct(string $title)
    {
        $this->title = $title;
    }

    public function getTitle(): string
    {
        return $this->title;
    }
}

和序列化配置：

Store:
  exclusion_policy: ALL
  properties:
    booksCollection:
      type: BooksCollection

BooksCollection:
  exclusion_policy: ALL
  properties:
    books:
      type: array<int, Book>

Book:
  exclusion_policy: ALL
  properties:
    title:
      type: string

我想通过的测试：

<?php

use JMS\Serializer\ArrayTransformerInterface;
use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;

class StoreSerializeTest extends KernelTestCase
{
    /** @var ArrayTransformerInterface */
    private $serializer;

    protected function setUp(): void
    {
        self::bootKernel();
        $this->serializer = self::$kernel->getContainer()->get('jms_serializer');
    }

    public function testSerialization(): void
    {
        $store = new Store(new BooksCollection(new Book('Birdy'), new Book('Lotr')));

        $serializedStore = $this->serializer->toArray($store);
        $storeUnserialized = $this->serializer->fromArray($serializedStore, Store::class);

        self::assertSame(
            [
                'books_collection' => [
                    ['title' => 'Birdy'],
                    ['title' => 'Lotr']
                ]
            ],
            $serializedStore
        );
        self::assertEquals($store, $storeUnserialized);
    }
}

正如您在下面看到的，测试失败了。我怎样才能摆脱一个嵌套的“书”？

我的主要想法是使用EventSubscriberInterface 和onPreSerialize 事件，但我真的不知道如何将对象BooksCollection 替换为由其自身属性books 组成的数组。有没有人已经知道怎么做？

【问题讨论】：

为什么不使用扩展 IterratorAggregate 并序列化他的书项的类 BookCollection ？ Insteed JMS Serializer，你应该使用 Symfony Serializer 组件:)
我已经尝试过使用虚拟财产public function getIterator(): Iterator { return new ArrayIterator($this->books); }，但是商店序列化的结果仍然有关键的“书籍”

标签： php symfony serialization jmsserializerbundle jms-serializer

【解决方案1】：

最后，我想通了。我实现了SubscribingHandlerInterface

<?php

use JMS\Serializer\Context;
use JMS\Serializer\GraphNavigatorInterface;
use JMS\Serializer\Handler\SubscribingHandlerInterface;
use JMS\Serializer\JsonDeserializationVisitor;
use JMS\Serializer\JsonSerializationVisitor;
use Book;
use BooksCollection;

class BooksCollectionHandler implements SubscribingHandlerInterface
{
    public static function getSubscribingMethods(): array
    {
        return [
            [
                'type' => BooksCollection::class,
                'format' => 'json',
                'method' => 'serialize',
                'direction' => GraphNavigatorInterface::DIRECTION_SERIALIZATION,
            ],
            [
                'type' => BooksCollection::class,
                'format' => 'json',
                'method' => 'deserialize',
                'direction' => GraphNavigatorInterface::DIRECTION_DESERIALIZATION,
            ]
        ];
    }

    public function serialize(
        JsonSerializationVisitor $visitor,
        BooksCollection $booksCollection,
        array $type,
        Context $context
    ) {
        return $visitor->visitArray($booksCollection->getBooks(), ['name' => 'array'], $context);
    }

    public function deserialize(
        JsonDeserializationVisitor $visitor,
        array $data,
        array $type,
        Context $context
    ): BooksCollection {
        $collection = [];

        foreach ($data as $book) {
            $collection[] =
                $visitor->getNavigator()->accept($book, ['name' => Book::class], $context);
        }

        return new BooksCollection(...$collection);
    }
}

服务配置：

    books_handler:
        class: BooksCollectionHandler
        tags:
            - { name: jms_serializer.subscribing_handler }

【讨论】：