How to clear a specific user cart items without session

Question

Here is how the cart is cleared for the current session user:

$cart = Mage::getSingleton('checkout/cart'); 
$quoteItems = Mage::getSingleton('checkout/session')
                  ->getQuote()
                  ->getItemsCollection();

foreach( $quoteItems as $item ){
    $cart->removeItem( $item->getId() );    
}
$cart->save();

My question is how can i clear cart by user id, not by session?

Answer 1

Take a look in app/code/core/Mage/Sales/Model/Quote.php. On line :354 you find the method loadByCustomer(). You can call it like:

$quote = Mage::getModel('sales/quote')->loadByCustomer($customer);
$quoteItems = $quote->getAllItems();

$customer could be the customer Model or the customer Id

Answer 2

You can remove specific customer cart by customer id or email address

$customer = Mage::getModel('customer/customer')->setWebsiteId(Mage::app()->getWebsite()->getId());

$customerId = $customerEmail = '';
       if ( isset($_REQUEST['customerId']) ) {
        $customerId = $_REQUEST['customerId'];
       }

       if ( isset($_REQUEST['customerEmail']) ) {
        $customerEmail = $_REQUEST['customerEmail'];
       }

if (isset($customerId) and $customerId != '') {  
    $customer = $customer->load($customerId);
} elseif (isset($customerEmail) and $customerEmail != '' ) {
    $customer = $customer->loadByEmail($customerEmail);
} else {
               echo "customerId or customerEmail parameter required";
               exit;
       }

if ($customer->getId()) {

       $storeIds = Mage::app()->getWebsite(Mage::app()->getWebsite()->getId())->getStoreIds();

      $quote = Mage::getModel('sales/quote')->setSharedStoreIds($storeIds)->loadByCustomer($customer);

    if ($quote) {
        $collection = $quote->getItemsCollection(false);

        if ($collection->count() > 0) {
            foreach( $collection as $item ) {
                if ($item && $item->getId()) {
                    $quote->removeItem($item->getId());
                    $quote->collectTotals()->save();
                }
            }
        }
    }
}