I’m receiving this message “Error 400 Invalid “products[1].productId” property. This collection should contain only elements with unique value in “productId” property.”

From this plugin: https://wordpress.org/plugins/kinguin/ on: https://github.com/kinguinltdhk/Kinguin-eCommerce-API/issues/46

Someone else is having a similar issue. How should I go about fixing it?

I was looking at this code, but I don’t know if I’m looking in the right place:

<?php
/**
 * Product WebHook class.
 *
 * @package WPDeskILKinguin
 */

namespace WPDeskILKinguinCommon;

use WPDeskILKinguinAdminConfiguration;
use WPDeskILKinguinAdminExceptionsKinguinWebHookIncorrectSecret;
use WPDeskILKinguinAdminKinguinAPI;
use WPDeskILKinguinAdminProductInsertUpdate;

defined( 'ABSPATH' ) || exit;

class ProductWebHook {
    use Configuration;



    /**
     * Register product update route.
     */
    public function register_route() {
        register_rest_route(
            'kinguin/v1',
            '/products/update',
            array(
                'methods'             => WP_REST_Server::CREATABLE,
                'callback'            => array( $this, 'update_product' ),
                'args'                => array(),
                'permission_callback' => function() {
                    return true;
                }
            )
        );
    }



    /**
     * Validate response and send Rest API response
     *
     * @param WP_REST_Request $request Incoming request with order status update.
     *
     * @see https://github.com/kinguinltdhk/Kinguin-eCommerce-API/blob/master/features/Webhooks.md#product-updated-webhook
     */
    public function update_product( WP_REST_Request $request ) {

        if ( $request->is_json_content_type() ) {
            try {
                if ( $this->check_secret( $request->get_header( 'X-Event-Secret' ) ) ) {
                    $body     = json_decode( $request->get_body(), true );
                    $response = $this->event_handler( $body );
                }
            } catch ( Exception $e ) {
                $response = array(
                    'status'        => $e->getCode(),
                    'response'      => $e->getMessage(),
                );
                //wc_get_logger()->debug( 'Error for webhook: ', array( 'source' => 'kinguin-debug-log' ) );
                //wc_get_logger()->debug( print_r( $e->getCode(), true), array( 'source' => 'kinguin-debug-log' ) );
                //wc_get_logger()->debug( print_r( $e->getMessage(), true), array( 'source' => 'kinguin-debug-log' ) );
            }

        } else {
            $response = array(
                'status'        => 406,
                'response'      => 'Not Acceptable',
            );
        }

        return new WP_REST_Response( $response ? $response : null, 204 );
    }



    /**
     * Check and validate X-Event-Secret value from request header.
     *
     * @param string|null $secret X-Event-Secret value.
     *
     * @return bool
     *
     * @throws WPDeskILKinguinAdminExceptionsKinguinWebHookIncorrectSecret Incorrect X-Event-Secret value.
     */
    private function check_secret( $secret ) : bool {
        if ( $secret === $this->get_products_webhook_secret() ) {
            return true;
        } else {
            throw new KinguinWebHookIncorrectSecret( 401, 'Incorrect X-Event-Secret' );
        }
    }



    /**
     * Event switcher
     *
     * @param string $event Available int this method: order.complete, order.status.
     * @param array $body Response body.
     *
     * @return array
     *
     * @throws WPDeskILKinguinAdminExceptionsKinguinMissingApiKeyException No Api Key provided.
     * @throws WPDeskILKinguinAdminExceptionsKinguinNoConnectionException  No connection.
     * @throws WPDeskILKinguinAdminExceptionsKinguinStatusCodeException    Exception for any other status code than 200.
     */
    private function event_handler( array $body ) {
        $product = $this->request_product( $body['productId'] );
        $post = new InsertUpdate();
        $post->set_currency_rate();
        if ( $post->manage_webhook( $product ) ) {
            return array(
                'status'   => 200,
                'response' => 'Product updated'
            );
        } else {
            return array(
                'status'   => 404,
                'response' => 'Product not found'
            );
        }
    }



    /**
     * Request product object from Kinguin API
     *
     * @param string $product_id Kinguin productId.
     *
     * @return array Kinguin product.
     *
     * @throws WPDeskILKinguinAdminExceptionsKinguinMissingApiKeyException
     * @throws WPDeskILKinguinAdminExceptionsKinguinNoConnectionException
     * @throws WPDeskILKinguinAdminExceptionsKinguinStatusCodeException
     *
     * @see https://github.com/kinguinltdhk/Kinguin-eCommerce-API/tree/master/api/products/v2#get-product
     */
    private function request_product( $product_id ) {
        try {
            $product = ( new KinguinAPI() )->get( $this->get_api_url() . '/v2/products/' . $product_id );
            $product = json_decode( json_encode( $product ), true, 512, JSON_OBJECT_AS_ARRAY );
            return $product;
        } catch ( Exception $error ) {
            wc_get_logger()->debug( 'Kinguin request_product error: ', array( 'source' => 'kinguin-debug-log' ) );
            wc_get_logger()->debug( print_r( $error->getMessage(), true), array( 'source' => 'kinguin-debug-log' ) );
            throw $error;
        }
    }

}