Mrthdrb

I used this to Add Additional Options In Magento 2 Cart

https://livesubwpcache.cloudways.com/blog/add-additional-options-in-magento-2/

But this is working only with Simple product.

For configurable products, I did the following change

$item->addOption(array(
 'product_id' => $item->getProductId(),
 'code' => 'additional_options',
 'value' => serialize($additionalOptions)
));

After that, the additional_options going to the cart. But it is not getting saved when complete the order.

seems because of this ….

//filter out config/bundle etc product
if(!$item->getParentItemId() && $item->getProductType() == MagentoCatalogModelProductType::TYPE_SIMPLE)

 $this->quoteItems[$item->getId()] = $item;

How can I fix it ? I need this functionality for configurable products.

Step 1: Create registration.php and module.xml file the for custom module.

Step 2: Assign Observers to Events

/app/code/Namespace/Mymodule/etc/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="catalog_product_load_after">
 <observer name="set_additional_options" instance="NamespaceMymoduleObserverSetAdditionalOptions"/>
 </event>
</config>

Step 3: Create the Observers

app/code/Namespace/Mymodule/Observer/SetAdditionalOptions.php

<?php
namespace NamespaceMymoduleObserver;

use MagentoFrameworkEventObserverInterface;
use MagentoFrameworkAppRequestInterface;

class SetAdditionalOptions implements ObserverInterface

 /**
 * @var RequestInterface
 */
 protected $_request;

 /**
 * @param RequestInterface $request
 */
 public function __construct(
 RequestInterface $request
 ) 
 $this->_request = $request;
 

 /**
 * @param MagentoFrameworkEventObserver $observer
 */
 public function execute(MagentoFrameworkEventObserver $observer)
 
 // Check and set information according to your need
 if ($this->_request->getFullActionName() == 'checkout_cart_add') //checking when product is adding to cart
 $product = $observer->getProduct();
 $additionalOptions = [];
 $additionalOptions[] = array(
 'label' => "Some Label",
 'value' => "Your Information",
 );
 $observer->getProduct()->addCustomOption('additional_options', serialize($additionalOptions));
 
 

run below command after

rm -rf var/di var/generation var/cache/* var/log/* var/page_cache/*

php bin/magento setup:upgrade

php bin/magento setup:di:compile

php bin/magento cache:clean

php bin/magento cache:flush

php bin/magento indexer:reindex

reference links

https://www.cloudways.com/blog/add-additional-options-in-magento-2/

https://webkul.com/blog/additional-options-cart-item-magento2/

After add additional options to cart You need to create another observer for save additional attributes order item from quote item.

Please add this event observer code in Module's etc/events.xml

<event name="sales_model_service_quote_submit_before">
 <observer instance="VendorModuleObserverSalesOrderItemAdditionalOptions" name="vendor_module_observer_sales_model_service_quote_submit_before"/>
</event>

Please create observer file in your module

VendorModuleObserverSalesOrderItemAdditionalOptions.php

And here is Observer code for save Additional Options to Order Item.

<?php
namespace VendorModuleObserverSales;
use MagentoFrameworkEventObserverInterface;
use MagentoFrameworkAppObjectManager;
use MagentoFrameworkSerializeSerializerJson;
class OrderItemAdditionalOptions implements ObserverInterface

public function __construct(
Json $serializer = null
) 
 $this->serializer = $serializer ?: ObjectManager::getInstance()->get(Json::class);

/**
 * @param MagentoFrameworkEventObserver $observer
 */
public function execute(MagentoFrameworkEventObserver $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 (count($additionalOptions) > 0) 
 // 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
 

Please check this I think it will help you.

after $item->addOption(...) try calling $item->saveItemOptions().

Also a side note, don't add the options as serialized using serialize($additionalOptions), use json_encode or better yet the method MagentoFrameworkSerializeSerializerJson::serialize.