How to set notify me when back in stock for Magento 2 through REST API?

Question

In Magento2 customers can subscribe to the out-of-stock products and get notifications when back in stock. I would like to know how can a customer subscribe to out-of-stock products through REST API.

Answer 1

You need to create a custom API.For Implement Custom API, We need to create a custom Module.

Description: We have define our API end point in etc/webapi.xml file. For Add product we have /V1/productalertstock/add/:productId and for delete /V1/productalertstock/delete/:productId. The complete URL will be http://{Magento2Root}/rest/V1/productalertstock/add/123

For Accessing above API You need Customer token, which can be get by http://{Magento2Root}/rest/V1/integration/customer/token

Where:

• 123 is the product ID
• {Magento2Root} is root folder/Url of magento 2

Create folowing File OR module can be downloaded from GitHub

app/code/Pawan/ProductAlertApi/registration.php

<?php
\Magento\Framework\Component\ComponentRegistrar::register(
    \Magento\Framework\Component\ComponentRegistrar::MODULE,
    'Pawan_ProductAlertApi',
    __DIR__
);

/var/www/html/magento237/app/code/Pawan/ProductAlertApi/etc/module.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
    <module name="Pawan_ProductAlertApi" setup_version="1.0.2" />
</config>

app/code/Pawan/ProductAlertApi/etc/di.xml

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <preference for="Pawan\ProductAlertApi\Api\ProductAlertManagementInterface" type="Pawan\ProductAlertApi\Model\ProductAlert"/>
</config>

app/code/Pawan/ProductAlertApi/etc/webapi.xml

<?xml version="1.0" ?>
<routes xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Webapi:etc/webapi.xsd">
    <!-- Add product stock alert start-->
   <route url="/V1/productalertstock/add/:productId" method="POST">
        <service class="Pawan\ProductAlertApi\Api\ProductAlertManagementInterface" method="addProductAlertStock"/>
        <resources>
            <resource ref="self" />
        </resources>
        <data>
            <parameter name="customerId" force="true">%customer_id%</parameter>
        </data>
    </route>
    <!-- Add product stock alert ends-->
    <!-- Delete product stock alert start-->
   <route url="/V1/productalertstock/delete/:productId" method="POST">
        <service class="Pawan\ProductAlertApi\Api\ProductAlertManagementInterface" method="deleteProductAlertStock"/>
        <resources>
            <resource ref="self" />
        </resources>
        <data>
            <parameter name="customerId" force="true">%customer_id%</parameter>
        </data>
    </route>
    <!-- Delete product stock alert ends-->
</routes>

app/code/Pawan/ProductAlertApi/Api/ProductAlertManagementInterface.php

<?php
namespace Pawan\ProductAlertApi\Api;
use Exception;

/**
 * Interface ProductAlertManagementInterface
 * @api
 */
interface ProductAlertManagementInterface
{
    /**
     * Return true if product Added to Alert.
     *
     * @param int $customerId
     * @param int $productId
     * @return bool true on success
     * @throws \Magento\Framework\Exception\LocalizedException
     * @throws \Magento\Framework\Exception\NoSuchEntityException
     */
    public function addProductAlertStock($customerId, $productId);
    /**
     * Return true if product Added to Alert.
     *
     * @param int $customerId
     * @param int $productId
     * @return bool true on success
     * @throws \Magento\Framework\Exception\LocalizedException
     * @throws \Magento\Framework\Exception\NoSuchEntityException
     */
    public function deleteProductAlertStock($customerId, $productId);
}

app/code/Pawan/ProductAlertApi/Model/ProductAlert.php

<?php

namespace Pawan\ProductAlertApi\Model;

use Magento\Catalog\Api\ProductRepositoryInterface;
use Magento\Framework\Exception\NoSuchEntityException;
use Magento\Store\Model\StoreManagerInterface;
use Magento\ProductAlert\Model\StockFactory;

use Pawan\ProductAlertApi\Api\ProductAlertManagementInterface;

class ProductAlert implements ProductAlertManagementInterface
{
    protected $productRepository;
    private $storeManager;
    protected $stockFactory;

    public function __construct(
        ProductRepositoryInterface $productRepository,
        StoreManagerInterface $storeManager,
        StockFactory $stockFactory
    ) {
        $this->productRepository = $productRepository;
        $this->storeManager = $storeManager;
        $this->stockFactory = $stockFactory;
    }
    
    public function addProductAlertStock($customerId, $productId)
    {
        try {
        
            /* @var $product \Magento\Catalog\Model\Product */
            $product = $this->productRepository->getById($productId);
            $store = $this->storeManager->getStore();
            /** @var \Magento\ProductAlert\Model\Stock $model */
            $model = $this->stockFactory->create()
                ->setCustomerId($customerId)
                ->setProductId($product->getId())
                ->setWebsiteId($store->getWebsiteId())
                ->setStoreId($store->getId());
            $model->save();
            return true;
        } catch (NoSuchEntityException $noEntityException) {
            return false;
        }
    } 
    public function deleteProductAlertStock ($customerId, $productId)
    {
        try {
        /* @var $product \Magento\Catalog\Model\Product */
            $product = $this->productRepository->getById($productId);
            $model = $this->stockFactory->create()
                ->setCustomerId($customerId)
                ->setProductId($product->getId())
                ->setWebsiteId(
                    $this->storeManager
                        ->getStore()
                        ->getWebsiteId()
                )->setStoreId(
                    $this->storeManager
                        ->getStore()
                        ->getId()
                )
                ->loadByParam();
            if ($model->getId()) {
                $model->delete();
            }
            return true;
        } catch (NoSuchEntityException $noEntityException) {
            return false;
        }
    }
    
}

Answer 2

check mageplaza product Alerts for magento2 module. they do provide REST API.