Magento add custom options to cart

Question

I'm trying to add product's custom option to cart programmatically using event

controller_action_predispatch_checkout_cart_add

In my observer function I'm not able to to get product object using following methods

$observer->getProduct()->getId();

or

$observer->getEvent()->getProduct()->getId();

Though I'm getting product Id using

$obsPId = Mage::app()->getRequest()->getParam('product')

Check Details here.

Now I've created product object using

$product = Mage::getSingleton('catalog/product')->load($obsPId);

I've created product's additional custom option in array

$additionalOptions = array(
                        'label' => $sareeLabel,
                        'value' => $sareeOptionId,
                    );

Now issue is here: Code being used to add additional option to product

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

Error: Fatal error: Call to a member function getId() on a non-object in Magento's core model Product.php.

I've also tried using observer $observer->getProduct() ->addCustomOption('additional_options', serialize($additionalOptions));

but it gives Fatal error: Call to a member function addCustomOption() on a non-object in my observer's function.

Questions:

1. Is it normal in Magento that below observer functions won't work on controller_action_predispatch_checkout_cart_add event? $observer->getProduct()->getId(); $observer->getEvent()->getProduct()->getId();
2. In my above code, how I can add custom options to cart?

Answer 1

The event is called before the action Mage_Checkout_CartController::addAction() which calls $this->_initProduct() that does the load of the product.

Better set the request parameters with your custom options with ... ->getRequest()->setParam(name, value) in your observer function. See the parameters by adding a product in cart, log all ...->getRequest()->getParams() in logs and see the key names of the array with custom options.

But you'll need ids of the custom options which implies at most a product load in your observer. A better implementation would be to fetch only the custom option ids and labels, not the entire prouduct (+100 SQL queries).