Prevent fatal error of non object ($o->getShippingAddress()) - only sometimes not available

Question

I want to prevent a fatal error if object is not available.

Background: I wrote an observer to catch data from the shipping object.

$o = Mage::getModel('sales/order')->load($observer->getOrderIds());
    if (is_object($o->getShippingAddress()->getPostcode()))
        $zip = $o->getShippingAddress()->getPostcode()

But I get an fatal error if the Shipping Address object will not be loaded (i.e. for downloadable products).

Fatal error: Call to a member function getPostcode() on a non-object in /var/www/app/code/local/MyModule/Model/Observer.php on line 22

How can I get rid of it?

Thank you so much

Answer 1

Try it like this.

$o = Mage::getModel('sales/order')->load($observer->getOrderIds());
if ($o->getShippingAddress() && $o->getShippingAddress()->getPostcode()) {
    $zip = $o->getShippingAddress()->getPostcode();
}