Magento: Checkout - controller - CartController.php

<?php
//Path : app\code\local\ABC\Checkout\controllers\CartController.php
//http://magento.stackexchange.com/questions/45132/adding-a-product-to-the-cart-via-querystring-using-sku
require_once(Mage::getModuleDir('controllers','Mage_Checkout').DS.'CartController.php');
class ABC_Checkout_CartController extends Mage_Checkout_CartController
{

    protected function _initProduct()
    {
        $sku = $this->getRequest()->getParam('sku');
        $productId = (int) $this->getRequest()->getParam('product');

        if($sku){
            $params = $this->getRequest()->getParams();
            $productId = Mage::helper('checkout/cart')->getProductIdByParams($params, false);
            if(! $productId){
                return false;
            }
        }

        if ($productId) {
            $product = Mage::getModel('catalog/product')
                ->setStoreId(Mage::app()->getStore()->getId())
                ->load($productId);
            if ($product->getId()) {
                return $product;
            }
        }
        return false;
    }

    /**
     * Shopping cart display action
     */
    public function indexAction()
    {
        //remove last order id to prevent update order/status API again
        Mage::getModel('checkout/session')->unsLastOrderId();

        parent::indexAction();
    }

    /**
     * Custom Add product to shopping cart action
     */
    public function addAction()
    {
        $cart = $this->_getCart();
        $params = $this->getRequest()->getParams();

        if ($params["isAjax"] == 1) {
            $response = array();
            try {
                if (isset($params['qty'])) {
                    $filter = new Zend_Filter_LocalizedToNormalized(
                        array('locale' => Mage::app()->getLocale()->getLocaleCode())
                    );
                    $params['qty'] = $filter->filter($params['qty']);
                }

                $product = $this->_initProduct();
                $related = $this->getRequest()->getParam('related_product');

                /**
                 * Check product availability
                 */
                if (!$product) {
                    $this->_goBack();
                    return;
                }

                $cart->addProduct($product, $params);
                if (!empty($related)) {
                    $cart->addProductsByIds(explode(',', $related));
                }

                $cart->save();

                $this->_getSession()->setCartWasUpdated(true);

                /**
                 * @todo remove wishlist observer processAddToCart
                 */
                Mage::dispatchEvent('checkout_cart_add_product_complete',
                    array('product' => $product, 'request' => $this->getRequest(), 'response' => $this->getResponse())
                );

                if (!$this->_getSession()->getNoCartRedirect(true)) {
                    if (!$cart->getQuote()->getHasError()) {
                        $message = $this->__('%s was added to your shopping cart.', Mage::helper('core')->escapeHtml($product->getName()));
                        $this->loadLayout();
                        $response["message"] = $message;
                        if(Mage::getSingleton('core/session')->getSwitchView() == "desktop") {
                            $response["right_slide"] = $this->getLayout()->getBlock('sp_help_rightslide')->toHtml();
                            $response["sidebar"] = $this->getLayout()->getBlock('cart_sidebar')->toHtml();
                        }else{
                            $this->_getSession()->addSuccess($message);
                        }
                    }
                }
            } catch (Mage_Core_Exception $e) {
                if ($this->_getSession()->getUseNotice(true)) {
                    $this->_getSession()->addNotice(Mage::helper('core')->escapeHtml($e->getMessage()));
                } else {
                    $messages = array_unique(explode("\n", $e->getMessage()));
                    foreach ($messages as $message) {
                        $this->_getSession()->addError(Mage::helper('core')->escapeHtml($message));
                    }
                }

                $url = $this->_getSession()->getRedirectUrl(true);
                if ($url) {
                    $this->getResponse()->setRedirect($url);
                } else {
                    $this->_redirectReferer(Mage::helper('checkout/cart')->getCartUrl());
                }
            } catch (Exception $e) {
                $this->_getSession()->addException($e, $this->__('Cannot add the item to shopping cart.'));
                Mage::logException($e);
            }
            $this->getResponse()->setBody(Mage::helper('core')->jsonEncode($response));
            return;
        } else {
            return parent::addAction();
        }
    }


    /**
     * Delete shoping cart item action
     */
    public function deleteAction()
    {
        $id = (int) $this->getRequest()->getParam('id');
        if ($id) {
            try {
                $productName = "";
                foreach ($this->_getCart()->getItems() as $item) {
                    if ($item->getId() == $id) {
                        $productName = $item->getName();
                        break;
                    }
                }
                $this->_getCart()->removeItem($id)
                  ->save();
                $message = $this->__('%s has already removed from your cart.', Mage::helper('core')->escapeHtml($productName));
                $this->_getSession()->addSuccess($message);
            } catch (Exception $e) {
                $this->_getSession()->addError($this->__('Cannot remove the item.'));
                Mage::logException($e);
            }
        }
        $this->_redirectReferer(Mage::getUrl('*/*'));
    }


    /**
     * Update shopping cart data action
     */
    public function updatePostAction()
    {
        $updateAction = (string)$this->getRequest()->getParam('update_cart_action');
        $redirect_url = (string)$this->getRequest()->getParam('redirect_url');

        switch ($updateAction) {
            case 'empty_cart':
                $this->_emptyShoppingCart();
                break;

            case 'update_qty': // back to shopping cart
                //refresh stock - call connector api - get stock qty real time
                Mage::getModel('abc_stock/data')->refreshStockOnepage();

                $this->_updateShoppingCart();
                break;

            case 'continue_shopping': // go to product page

                $this->_updateShoppingCart();
                break;

            default: // go to checkout page
                //refresh stock - call connector api - get stock qty real time
                Mage::getModel('abc_stock/data')->refreshStockOnepage();
                list($stock_status, $total_items_has_stock, $total_items) = Mage::getModel('abc_stock/data')->checkStockOnepage();

                if($total_items_has_stock != $total_items){
                    Mage::getSingleton('customer/session')->setIsAllStockAvailable(FALSE);
                    Mage::getSingleton('checkout/session')->addError($this->__('Sorry, you can not place an order at this time. Please try again later.'));
                    $this->_redirectUrl(Mage::getUrl('checkout/cart'));

                    return;
                }else{
                    $this->_updateShoppingCart();
                }
        }


        if($redirect_url){
            $this->_redirectUrl($redirect_url);
        }else{
            $this->_goBack();
        }

    }

    public function addMassAction() {
        $product_list = $this->getRequest()->getPost("product_list");
        $products = explode(",", $product_list);
        $cart = Mage::getModel('checkout/cart');
        $cart->init();
        /* @var $pModel Mage_Catalog_Model_Product */
        foreach ($products as $product_id) {
            if ($product_id == '') {
                continue;
            }
            $pModel = Mage::getModel('catalog/product')->load($product_id);
                try {
                    $cart->addProduct($pModel, array('qty' => '1'));
                } catch (Exception $e) {
                    continue;
                }
        }
        $cart->save();
        if ($this->getRequest()->isXmlHttpRequest()) {
            exit('1');
        }
        $this->_redirect('checkout/cart');

    }

}

?>