Checking for attribute value existence. What does this do?

Question

I got this code from here, and it works. There's a section of it that I don't quite get, however. Please see lines [A] and [B].

public function attributeValueExists($attCode, $attributeValue)
{
    $attributeModel = Mage::getModel('eav/entity_attribute');
    $attributeOptionModel = Mage::getModel('eav/entity_attribute_source_table') ;

    $attributeId = $attributeModel->getIdByCode('catalog_product', $attCode);    // [A]
    $attribute = $attributeModel->load($attributeId);    // [B]

    $attributeTable = $attributeOptionModel->setAttribute($attribute);
    $options = $attributeOptionModel->getAllOptions(false);

    foreach($options as $option) {
        if ($option['label'] == $attributeValue) {
            return $option['value'];
        }
    }

    return false;
}

The variable obtained from lines [A] and [B], $attributeTable, doesn't seem to be used. Yet, if I comment these two lines out, the code doesn't work. What are these lines actually doing and why do $attributeTable for?

Answer 1

You are mistaken when you say they're "not used". They are, in fact:

This line fetches an $attributeId:

$attributeId = $attributeModel->getIdByCode('catalog_product', $attCode);    // [A]

This line loads the attribute:

$attribute = $attributeModel->load($attributeId);    // [B]

This line uses the $attribute in a setter on the $attributeOptionModel:

$attributeTable = $attributeOptionModel->setAttribute($attribute);

getAllOptions requires that the attribute have been set:

$options = $attributeOptionModel->getAllOptions(false);

I think where you're getting tripped up is that $attributeTable is not used, but that's just the return value from the setter method. Magic setters in Magento always return the parent object so that you can construct a fluent interface.

Answer 2

This function returns attribute value which is this attribute is select or multiple select. We can write this function similar:

public function attributeValueExists($attCode, $attributeValue)
{
    $attributeModel = Mage::getModel('eav/entity_attribute');
    $attributeOptionModel = Mage::getModel('eav/entity_attribute_source_table') ;

    //retrieve attribute_id using attribute_code
    $attributeId = $attributeModel->getIdByCode('catalog_product', $attCode);    // [A] 
    //load attribute model using attribute_id
    $attribute = $attributeModel->load($attributeId);    // [B] 

    $options = $attributeOptionModel->setAttribute($attribute)->getAllOptions(false);

    foreach($options as $option) {
        if ($option['label'] == $attributeValue) {
            return $option['value'];
        }
    }

    return false;
}

But this is long way and we can use this snippet to retrieve attribute value:

 public function attributeValueExists($attCode, $attributeValue)
 {
     /**
     * @var $attribute Mage_Eav_Model_Entity_Attribute_Abstract
     */
    $attribute = Mage::getModel('catalog/resource_eav_attribute')
        ->loadByCode(Mage_Catalog_Model_Product::ENTITY, $attCode);

    $options   = $attribute->getSource()->getAllOptions();
    foreach ($options as $option) {
        if ($option['label'] == $attributeValue) {
            return $option['value'];
        }
    }
    return false;
 }