如何将JSON数组传递给API方法？

Question

我正在创建一个API方法，我希望将自定义JSON项目的数组发送到该方法。 我不想在我的JSON对象后面有一个数据库模型。 JSON只是将瞬态数据发送到我的API方法的一种方式，它不是由任何数据库表直接支持的。

这是我发布的JSON数据：

{
   "stockItems": [
      {
        "sku": "SKU-1234",
        "qty": 15
      },
      {
        "sku": "SKU-5678",
        "qty": 25
      }
   ]
}

这是我的自定义模型和界面：

StockItemInterface.php

namespace MyCompany\CatalogInventory\Api\Data;

/**
 * @api
 */
interface StockItemInterface
{
    /**
     * @return float
     */
    public function getQty();

    /**
     * @return string
     */
    public function getSku();

    /**
     * @param float $qty
     * @return $this
     */
    public function setQty($qty);

    /**
     * @param string $sku
     * @return $this
     */
    public function setSku($sku);
}

Item.php

namespace MyCompany\CatalogInventory\Model\Stock;

use MyCompany\CatalogInventory\Api\Data\StockItemInterface;

class Item implements StockItemInterface
{
    protected $sku;

    protected $qty;

    /**
     * @param array $data
     */
    public function __construct(array $data = [])
    {
    }

    /**
     * @return float
     */
    public function getQty()
    {
        return $this->qty;
    }

    /**
     * @return string
     */
    public function getSku()
    {
        return $this->sku;
    }

    /**
     * @param float $qty
     * @return $this
     */
    public function setQty($qty)
    {
        $this->qty = $qty;
    }

    /**
     * @param string $sku
     * @return $this
     */
    public function setSku($sku)
    {
        $this->sku = $sku;
    }
}

这是我的API方法

StockRegistryInterface.php

namespace MyCompany\CatalogInventory\Api;

/**
 * Interface StockRegistryInterface
 * @api
 */
interface StockRegistryInterface
{
    /**
    * @param \MyCompany\CatalogInventory\Api\Data\StockItemInterface[] $stockItems
    * @return int
    */
    public function updateStockItems(array $stockItems);
}

StockRegistry

namespace MyCompany\CatalogInventory\Model;

use Magento\Catalog\Model\ProductFactory;
use Magento\CatalogInventory\Api\Data\StockItemInterface;
use Magento\CatalogInventory\Api\StockConfigurationInterface;
use Magento\CatalogInventory\Api\StockItemCriteriaInterfaceFactory;
use Magento\CatalogInventory\Api\StockItemRepositoryInterface;
use Magento\CatalogInventory\Model\Spi\StockRegistryProviderInterface;
use MyCompany\CatalogInventory\Api\StockRegistryInterface;

/**
 * Class StockRegistry
 *
 * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
 */
class StockRegistry extends \Magento\CatalogInventory\Model\StockRegistry implements StockRegistryInterface
{
    /**
     * @param StockConfigurationInterface $stockConfiguration
     * @param StockRegistryProviderInterface $stockRegistryProvider
     * @param StockItemRepositoryInterface $stockItemRepository
     * @param StockItemCriteriaInterfaceFactory $criteriaFactory
     * @param ProductFactory $productFactory
     */
    public function __construct(
        StockConfigurationInterface $stockConfiguration,
        StockRegistryProviderInterface $stockRegistryProvider,
        StockItemRepositoryInterface $stockItemRepository,
        StockItemCriteriaInterfaceFactory $criteriaFactory,
        ProductFactory $productFactory
    ) {
        parent::__construct($stockConfiguration, $stockRegistryProvider, $stockItemRepository, $criteriaFactory, $productFactory);
    }

    /**
     * @inheritdoc
     */
    public function updateStockItems(array $stockItems)
    {
        // do stuff
    }
}

当我发布到API方法时，出现此错误

"Fatal Error: 'Uncaught Error: Cannot instantiate interface MyCompany\\CatalogInventory\\Api\\Data\\StockItemInterface in 
\/var\/www\/magento2\/lib\/internal\/Magento\/Framework\/ObjectManager\/Factory\/AbstractFactory.php:111    
Stack trace:
#0 \/var\/www\/magento2\/lib\/internal\/Magento\/Framework\/ObjectManager\/Factory\/Compiled.php(108): 
Magento\\Framework\\ObjectManager\\Factory\\AbstractFactory->createObject('MyCompany\\\\CatalogI...', Array)
#1 \/var\/www\/magento2\/lib\/internal\/Magento\/Framework\/ObjectManager\/ObjectManager.php(56): 
Magento\\Framework\\ObjectManager\\Factory\\Compiled->create('MyCompany\\\\CatalogI...', Array)
#2 \/var\/www\/magento2\/lib\/internal\/Magento\/Framework\/Webapi\/ServiceInputProcessor.php(166): 
Magento\\Framework\\ObjectManager\\ObjectManager->create('\\\\MyCompany\\\\Catalog...')
#3 \/var\/www\/magento2\/lib\/internal\/Magento\/Framework\/Webapi\/ServiceInputProcessor.php(399): 
Magento\\Framework\\Webapi\\ServiceInputProcessor->_createFromArray('\\\\MyCompany\\\\Catalog...', Array)
#4 \/var\/www\/magento2\/lib\/internal\/Magento\/Framework\/Webapi\/ServiceInputProcessor.php(332): 
' in '\/var\/www\/magento2\/lib\/internal\/Magento\/Framework\/ObjectManager\/Factory\/AbstractFactory.php' on line 111"

AbstractFactory.createObject发生异常：

protected function createObject($type, $args)
{
    return new $type(...array_values($args));
}

问题在于$args是一个空数组，因此array_values引发异常。

如何编写我的Item类，以便Magento可以成功构建它，并且没有支持数据库模型？