Can’t Get Value from Attribute ‘eancode’

To answer the question:

Thanks to some handy built-in methods you don't have to do any loading on your own:

• Mage_Sales_Model_Order_Shipment_Item provides getOrderItem
• Mage_Sales_Model_Order_Item provides getProduct

So, all you should have to do is this:

$product = $shipmentItem->getOrderItem()->getProduct();

If size is persisted to the order item, you can do:

$item = $shipmentItem->getOrderItem();
echo $item->getAttributeText('size');

Or, if you need to load the ID value from the product itself, you can get all of the product's selected ID values:

$size = $shipmentItem->getOrderItem()->getProduct()->getSize();

Like all of Magento, the answer's in the source — all you need to do is go digging (or hop to then end of this post).

First, find the class for the attribute source

$source = Mage::getResourceModel('catalog/product')
->getAttribute('color')
->getSource();        
var_dump(get_class($source));
exit;

In modern versions of Magento, this should point to the class Mage_Eav_Model_Entity_Attribute_Source_Table, which is located at

#File: app/code/core/Mage/Eav/Model/Entity/Attribute/Source/Table.php
class Mage_Eav_Model_Entity_Attribute_Source_Table extends Mage_Eav_Model_Entity_Attribute_Source_Abstract
{
    //...
}

Next, we'll look for the definition of the getOptionId method on this class and/or it's parent classes. We'll find it in the Mage_Eav_Model_Entity_Attribute_Source_Abstract class

#File: app/code/core/Mage/Eav/Model/Entity/Attribute/Source/Abstract.php
public function getOptionId($value)
{
    foreach ($this->getAllOptions() as $option) {
        if (strcasecmp($option['label'], $value)==0 || $option['value'] == $value) {
            return $option['value'];
        }
    }
    return null;
}

Examining this method, we can see if works by foreaching over a list of options from the getAllOptions method. So let's look at this method's definition.

#File: app/code/core/Mage/Eav/Model/Entity/Attribute/Source/Table.php
public function getAllOptions($withEmpty = true, $defaultValues = false)
{
    $storeId = $this->getAttribute()->getStoreId();
    if (!is_array($this->_options)) {
        $this->_options = array();
    }
    if (!is_array($this->_optionsDefault)) {
        $this->_optionsDefault = array();
    }
    if (!isset($this->_options[$storeId])) {
        $collection = Mage::getResourceModel('eav/entity_attribute_option_collection')
            ->setPositionOrder('asc')
            ->setAttributeFilter($this->getAttribute()->getId())
            ->setStoreFilter($this->getAttribute()->getStoreId())
            ->load();
        $this->_options[$storeId]        = $collection->toOptionArray();
        $this->_optionsDefault[$storeId] = $collection->toOptionArray('default_value');
    }
    $options = ($defaultValues ? $this->_optionsDefault[$storeId] : $this->_options[$storeId]);
    if ($withEmpty) {
        array_unshift($options, array('label' => '', 'value' => ''));
    }

    return $options;
}

Ah ha! Now we're on to something. This appears to be the method that loads all the option information. Specifically, we're interested in

$storeId = $this->getAttribute()->getStoreId();

So, Magento gets the store ID for the options to load from the attribute. This means you should be able to do something like the following (replacing color and red with your own variables, of course)

    //get the attribute
    $attribute = Mage::getResourceModel('catalog/product')
    ->getAttribute('color');

    //set the store id on the attribute
    $attribute->setStoreId(Mage_Core_Model_App::ADMIN_STORE_ID);

    //get the source
    $source = $attribute->getSource();

    //get the id
    $id = $source->getOptionId('red');