related products not getting in a quote items

Question

When I add a product to cart then its related products will be added automatically with it and it's working. But, I want to make the price zero on the cart page for related products only, as they will be free. I have added event as below :

<events>
<sales_quote_add_item>
        <observers>
            <priceupdate_observer>
                <type>singleton</type>
                <class>Inchoo_CustomLinkedProducts_Model_Observer</class>
                <method>modifyPrice</method>
            </priceupdate_observer>
        </observers>
        </sales_quote_add_item>
        </events>

Method in the observer is as below:

public function modifyPrice(Varien_Event_Observer $obs)
    {
        $free_product = $obs->getQuoteItem()->getProduct();
        // Get all custom products
        $custom_products = $free_product->getCustomProductCollection();
        // get all custom product id and save in array
        $custom_product_ids = array();
        foreach($custom_products as $product){
          $custom_product_ids[] = $product->getId(); // double check to make sure this product_id 
        }
        //$collection = Mage::getModel('sales/quote_item')->getCollection();

        // $items = Mage::getModel(‘checkout/cart’)->getQuote()->getAllItems();

       $items = Mage::getSingleton('checkout/session')->getQuote()->getAllItems();
         foreach($items as $item )
         { 
             if(in_array($item->getProductId(), $custom_product_ids))
              {
                $price = $this->_getPriceByItem($item);
                $item->setCustomPrice($price);
                $item->setOriginalCustomPrice($price);
              }
         }

       }

it is not working and i don't get related/custom product ids in the session , only 1 id gets printed.

Answer 1

Use below code:

You can use an observer class to listen to checkout_cart_product_add_after, and use a product’s “Super Mode” to set custom prices against the quote item.

In your /app/code/local/{namespace}/{yourmodule}/etc/config.xml:

   <config>
    ...
    <frontend>
        ...
        <events>
            <checkout_cart_product_add_after>
                <observers>
                    <unique_event_name>
                        <class>{{modulename}}/observer</class>
                        <method>modifyPrice</method>
                    </unique_event_name>
                </observers>
            </checkout_cart_product_add_after>
        </events>
        ...
    </frontend>
    ...
</config>

/app/code/local/{namespace}/{yourmodule}/Model/Observer.php

 class <namespace>_<modulename>_Model_Observer
{
    public function modifyPrice(Varien_Event_Observer $obs)
    {
        // Get the quote item
        $item = $obs->getQuoteItem();
        // Ensure we have the parent item, if it has one
        $item = ( $item->getParentItem() ? $item->getParentItem() : $item );
        // Load the custom price
        $price = "your custom price logic";
        // Set the custom price
        $item->setCustomPrice($price);
        $item->setOriginalCustomPrice($price);
        // Enable super mode on the product.
        $item->getProduct()->setIsSuperMode(true);
    }

}

may be helpful to you