How to add additional options in order admin side in Magento 2.3?

Question

I am sending additional custom options in the cart when add to cart a product.

I have used this link . Using this link I have added custom options in the cart as well on checkout page and minicart. But custom options are not showing in admin.

I have tried link2, Link3, link4 but still getting error on checkout page: {"message":"An error occurred on the server. Please try to place the order again."}

How can I show additional custom options on the order page in admin?

Answer 1

I found the issue reason and fixed the error in Magento 2.3

I changed the below code from the original code.

if (count($additionalOptions) > 0) { to if ($additionalOptions) {

and unserialize to $this->serializer->unserialize

Please check my code carefully.

in events.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Event/etc/events.xsd">
    <event name="sales_model_service_quote_submit_before">
        <observer name="unique_name" instance="Vendor\ModuleName\Observer\OrderItemAdditionalOptions" />
    </event>
</config>

in Observer Class.

<?php
namespace Vendor\ModuleName\Observer;
 
use Magento\Framework\Event\ObserverInterface;
 
class OrderItemAdditionalOptions implements ObserverInterface
{

    public function __construct(
        \Magento\Store\Model\StoreManagerInterface $storeManager,
        \Magento\Framework\View\LayoutInterface $layout,
        \Magento\Framework\App\RequestInterface $request,
        \Psr\Log\LoggerInterface $logger,
        Json $serializer = null
    )
    {
        $this->_layout = $layout;
        $this->_storeManager = $storeManager;
        $this->_request = $request;
        $this->logger = $logger;
        $this->serializer = $serializer ?: \Magento\Framework\App\ObjectManager::getInstance()
            ->get(\Magento\Framework\Serialize\Serializer\Json::class);
    }
    /**
     * @param \Magento\Framework\Event\Observer $observer
     */
    public function execute(\Magento\Framework\Event\Observer $observer)
    {
        try {
            $quote = $observer->getQuote();
            $order = $observer->getOrder();
            $quoteItems = [];

            // Map Quote Item with Quote Item Id
            foreach ($quote->getAllVisibleItems() as $quoteItem) {
                $quoteItems[$quoteItem->getId()] = $quoteItem;
            }

            foreach ($order->getAllVisibleItems() as $orderItem) {
                $quoteItemId = $orderItem->getQuoteItemId();
                $quoteItem = $quoteItems[$quoteItemId];
                $additionalOptions = $quoteItem->getOptionByCode('additional_options');

                
                if ($additionalOptions) {
                    // Get Order Item's other options
                    $options = $orderItem->getProductOptions();
                    // Set additional options to Order Item
                    $options['additional_options'] = $this->serializer->unserialize($additionalOptions->getValue());
                    $orderItem->setProductOptions($options);
                }
            }
        } catch (\Exception $e) {
            // catch error if any
        }
    }
}

This code works fine in my project.

You can find the additional option result in sales_order_item table.