How to add custom data with Category "getList" API?

Question

I need to add product count with my category listing API response. I tried using Magento's default API rest/V1/categories/list with my searchCriteria

I am getting category data below format.

{
    "items": [
        {
            "id": 8379,
            "parent_id": 2,
            "name": "Sanitarije, grijanje, vodoinstalacije, klima (SGK)",
            "is_active": true,
            "position": 1,
            "level": 2,
            "children": "8380,8602,8965,8980",
            "created_at": "2021-09-28 20:28:39",
            "updated_at": "2022-05-19 08:37:01",
            "path": "1/2/8379",
            "available_sort_by": [],
            "include_in_menu": true,
            "custom_attributes": [...]
        }
    ]
}

I need to add product count with each category response data.

Answer 1

I got the solution. I have to use the extension_attributes to share the custom data in the category API.

-Create an extension_attributes file in the below path Vendor/Module/etc/extension_attributes.xml

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Api/etc/extension_attributes.xsd">
        <extension_attributes for="Magento\Catalog\Api\Data\CategoryInterface">
            <attribute code="category_product_collection_count" type="Vendor\Module\Api\Data\CategoryCustomDataInterface[]" />
        </extension_attributes>
 </config>

Then after crate a Data interface Vendor\Module\Api\Data\CategoryCustomDataInterface

<?php
    /**
     * Copyright ©  All rights reserved.
     * See COPYING.txt for license details.
     */
    declare(strict_types=1);
    
    namespace Vendor\Moduel\Api\Data;
    
    interface CategoryCustomDataInterface
    {
    
        const CODE = 'code';
        const VALUE = 'value';
    
        /**
         * Get id
         * @return string|null
         */
        public function getCode();
    
        /**
         * @param $code
         * @return mixed
         */
        public function setCode($code);
    
        /**
         * Get content
         * @return string|null
         */
        public function getValue();
    
        /**
         * Set value
         * @param string $value
         * @return \Vendor\Module\Api\Data\CategoryCustomDataInterface
         */
        public function setValue($value);
    }

Define the Data interface to its actual implementation in the model

Vendor\Module\Model\Api\Data\CategoryCustomData

<?php
/**
 * Copyright ©  All rights reserved.
 * See COPYING.txt for license details.
 */
declare (strict_types = 1);

namespace Wcb\ApiConnect\Model\Api\Data;

use Magento\Framework\Model\AbstractModel;
use Vendor\Module\Api\Data\CategoryCustomDataInterface;

class CategoryCustomData extends AbstractModel implements CategoryCustomDataInterface
{

    /**
     * @inheritDoc
     */
    public function getCode()
    {
        return $this->_get(self::CODE);
    }
    /**
     * @inheritDoc
     */
    public function setCode($code)
    {
        return $this->setData(self::CODE, $code);
    }

    /**
     * @return string|null
     */
    public function getValue()
    {
        return $this->_get(self::VALUE);
    }

    /**
     * @param string $value
     * @return \Vendor\Module\Api\Data\CategoryCustomDataInterface
     */
    public function setValue($value)
    {
        return $this->setData(self::VALUE, $value);
    }
}

-Need to set the dependencies through di.xml and the path will be etc/webapi_rest/di.xml

  <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
  <preference for="Vendor\Module\Api\Data\CategoryCustomDataInterface" type="Vendor\Module\Model\Api\Data\CategoryCustomData"/>
        
   <type name="Magento\Catalog\Model\CategoryRepository">
           <plugin name="category_product_collection_count" type="Vendor\Module\Plugin\CategoryProductCollectionCountAfterGet"/>
    </type>
       

-And finally, we need to Pass our custom data in the extension_attribute code. Vendor/Module/Plugin/CategoryProductCollectionCountAfterGet.php

 <?php
    namespace Vendor\Module\Plugin;
    
    /**
     * Copyright © Magento, Inc. All rights reserved.
     * See COPYING.txt for license details.
     */
    use Magento\Catalog\Api\Data\CategoryInterface;
    use Magento\Catalog\Api\CategoryRepositoryInterface;
    
    class CategoryProductCollectionCountAfterGet
    {
    
        const PRODUCT_COUNT ='product_count';
    
    
        /**
         * @param CategoryExtensionFactory $extensionFactory
         */
        public function __construct(
        ) {
        }
        public function afterGet(
            CategoryRepositoryInterface $subject,
            CategoryInterface $entity
        ) {
    
    
            $data[$entity->getEntityId()] = ['id'=>$entity->getEntityId(),'product_count'=>$entity->getProductCount(),'product_count_inc_child'=>count($entity->getProductCollection())];
            $extensionAttributes = $entity->getExtensionAttributes(); /** get current extension attributes from entity **/
            $extensionAttributes->setData('category_product_collection_count', $data);
    
    
            $entity->setExtensionAttributes($extensionAttributes);
    
            return $entity;
        }
    
    }

• Output

  "extension_attributes": { "category_product_collection_count": [ { "id": "8379", "product_count": 6, "product_count_inc_child": 617 } ] },