How do I get the product item author id from the order object?

Question

I have a website, where users can add their products. After a user purchases a product and pays for it, I want to create some custom logic. I need to know the authors of the individual items purchased. After following this guide I have the below EventSubscriber code

public function orderCompleteHandler(WorkflowTransitionEvent $event) {
  $order = $event->getEntity();
  $items = $order->getItems();

  foreach($items as $item){
    error_log($item->getTotalPrice()->getNumber());
    // Here I want to get the item's author 
  }
}

(Please disregard the error_log function as it is only for developing purposes)

It works as expected and lists the prices (one-by-one) of the items purchased. Now I want to list the authors of the items as well. Unfortunately there is no built in method to get the authors. I was thinking to go in the direction of getting the order item as an entity and then getting the entity author that way. Any suggestions how to do this? or any other suggested approaches?

Answer 1

The point is, the order items (purchased entities) are not products, but product variations. You need first to get product object as the parent of a variation and then you can call the getOwner() method as suggested by @Jaypan to get user object.

You can do all this stuff by one simple line inside your loop as below

foreach($items as $item) {
    $userObj = $item->getPurchasedEntity()->getProduct()->getOwner();
}

Answer 2

As per the discussion above with @Jaypan Commerce order doesn't implement the EntityOwnerInterface so I made a pretty ugly workaround, that I'm posting, so it might help others, but please only use this if you know what you are doing.

public function orderCompleteHandler(WorkflowTransitionEvent $event) {
$order = $event->getEntity();
$items = $order->getItems();

foreach ($items as $item) {
  $item_id = $item->getPurchasedEntityId();
  $database = \Drupal::database();
  $query = $database->query("SELECT * FROM commerce_product_field_data WHERE product_id = :product_id", [
    ':product_id' => $item_id,
  ]);
  $result = $query->fetchAssoc();
  $author_id = $result['uid'];
}