Get product changes

Question

Situation is:

Admin logs in to system and he changes product somehow.

For example:

Sets qty to 10 Adds 2 images Changes description

Is there any

Answer 1

just in case some people still coming up to this one: @clockworkgeek's answer is not correct, as soon as you turn on developer mode and displaying errors (php>=5.4) you will get exceptions and warnings:

Array to string conversion in...

as solution for recursive comparison:

public function onCatalogProductSaveBefore($observer)
{
  $product = $observer->getProduct();
  if ($product->hasDataChanges()) {
    $newValues = $this->_compareArrayAssocRecursive($product->getData(), $product->getOrigData());
    $oldValues = $this->_compareArrayAssocRecursive($product->getOrigData(), $product->getData());
  }
}

protected function _compareArrayAssocRecursive($array1, $array2) 
{
    $diff = array();
    foreach ($array1 as $key => $value) {
        if (is_array($value)) {
            if (!isset($array2[$key]) || !is_array($array2[$key])) {
                $diff[$key] = $value;
            } else {
                $newDiff = $this->_compareArrayAssocRecursive($value, $array2[$key]);
                if (!empty($newDiff)) {
                    $diff[$key] = $newDiff;
                }
            }
        } elseif (!array_key_exists($key,$array2) || $array2[$key] !== $value) {
            $diff[$key] = $value;
        }
    }
    return $diff;
}

Hope that helps Personally i would recommend to put that function into a helper class and make it public :)

UPDATE: according to problems with numeric values was float and decimal the better solution would be:

/**
 * return diff according to product changes 
 * 
 * @param Mage_Catalog_Model_Product $product
 * @return array
 */
protected function _compareArrayAssocRecursive($product)
{
    $diff = array();
    $attributes = $product->getTypeInstance(true)->getEditableAttributes($product);

    foreach ($attributes as $key => $value) {
        if ($product->dataHasChangedFor($key)) {
            $diff[$key] = $product->getData($key);
        }
    }
    return $diff;
}