Fix Logging In on Old Magento 1 Installs

On certain Magento instance installs, a valid customer login will seem to fail and redirect to the login page. We’ve seen this on plenty of Magento 1.6s thus far, however newer versions may also be affected.

The problem lies in the login method of the Mage_Customer_Model_Session class. The fix, in this instance is to remove the renewSession call within that method:

 public function login($username, $password)
{
    /** @var $customer Mage_Customer_Model_Customer */
    $customer = Mage::getModel('customer/customer')
        ->setWebsiteId(Mage::app()->getStore()->getWebsiteId());

    if ($customer->authenticate($username, $password)) {
        $this->setCustomerAsLoggedIn($customer);
        // This breaks certain setups
        //$this->renewSession();
        return true;
    }
    return false;
}

This has been rolled into a module here: https://github.com/llapgoch/fix-old-magento-login

Programatically Modifying Products’ Stock Item Objects

Recently we had a project to make all products within a number of different categories available as backorder products. The client did not want to go through and change all of the products individually, so we embarked on attempting to do this programatically.

Our first idea was to do this using observers, so hypothetically whenever a product or product collection loaded we would be able to modify the accompanying stock item object if the product was in one of the categories in question.

The observers we identified to perform this were:

catalog_product_is_salable_after
We would use the above event to detect whether the product was in a particular category and set isSalable on the product object to true if so. This would make the product appear purchasable from the listing and detail pages instead of displaying the Out of Stock message.

catalog_product_collection_load_after
catalog_product_load_after
sales_quote_item_collection_products_after_load
We used the above three events to modify the following values:

  $stockItem->setIsInStock(true)
    ->setData('backorders', Mage_CatalogInventory_Model_Stock::BACKORDERS_YES_NONOTIFY)
    ->setUseConfigBackorders(false)
    ->setData('is_in_stock', true);

This method worked to a certain extent, however the process fell down when on the One Page Checkout; the Mage_CatalogInventory_Model_Stock object’s registerProductsSale creates a stock item object and populates it manually without firing any observers to hook into. This means that the final check in this method will always fail, and the user will be denied purchasing the product in question.

An attempted workaround was to override the Mage_CatalogInventory_Model_Stock class’ registerProductsSale method and perform our category check there. This, however caused another issue in that after registering the sale, the stock object gets saved in order to decrement the stock available; this also saves the values we’ve set meaning that if the client ever wanted to disable this functionality they would be left with any products which had been ordered in a backorder state.

Attempt 2 – Overriding

Against our better judgement, we opted instead to override the *Mage_CatalogInventory_Model_Stock_Item** class rather than changing its values with observers; this got around the issue of the stock item being saved and the values within it being crystallised. Here’s the class in question:

<?php

class Namespace_Module_Model_CatalogInventory_Stock_Item extends Mage_CatalogInventory_Model_Stock_Item
{
    public function getIsInStock()
    {
        if($this->isPurchaseableViaCategory()){
            return true;
        }

        return parent::getIsInStock(); 
    }

    public function getBackorders()
    {
        if($this->isPurchaseableViaCategory()){
            return Mage_CatalogInventory_Model_Stock::BACKORDERS_YES_NONOTIFY;
        }

        return parent::getBackorders();
    }

    public function isPurchaseableViaCategory()
    {
        $product = $this->getProduct();
        if(!$product && $this->getProductId()){
            $product = Mage::getModel('catalog/product')->load($this->getProductId());
        }

        if(!$product){
            return false;
        }

        return Mage::helper('module')->isPurchaseableViaCategory($product);
    }
}

And in our helper, we do the work of checking whether the product is in one of our selected categories (or a subcategory):

class Namespace_Module_Helper_Data extends Mage_Core_Helper_Abstract{
    protected $_allowBackOrderCategories = array("gold");

    public function isPurchaseableViaCategory(Mage_Catalog_Model_Product $product){
        $keys = array();

        $cats = $product->getCategoryCollection()
            ->addAttributeToSelect('url_key');

        foreach($cats as $cat){
            $this->getParentUrlKeys($cat, $keys);
        }

        foreach($this->_allowBackOrderCategories as $cat){
            if(in_array($cat, $keys)){
                return true;
            }
        }
    }

    public function getParentUrlKeys(Mage_Catalog_Model_Category $cat, &$urlKeys) {
        if(!in_array($cat->getUrlKey(), $urlKeys)) {
            $urlKeys[] = $cat->getUrlKey();
        }

        if($cat->getParentCategory()->getId()){
            return $this->getParentUrlKeys($cat->getParentCategory(), $urlKeys);
        }
    }
}

We were still able to complete our saleable check (for the display on the product listing and detail page) using an observer:

<catalog_product_is_salable_after>
    <observers>
        <modify_saleable>
            <type>singleton</type>
            <class>module/observer</class>
            <method>checkIsSaleable</method>
        </modify_saleable>
    </observers>
</catalog_product_is_salable_after>
public function checkIsSaleable($observer) {
    $product = $observer->getProduct();

    if($product->getIgnoreSaleableCategory()){
        return;
    }

    if(Mage::helper('module')->isPurchaseableViaCategory($product)){
        $observer->getSalable()->setIsSalable(true);
    }
}

For completeness, we added a property to the product object to be able to identify whether this product exists in a category and should have been listed as out of stock. We can then identify these products and display a different message (Such as delivery times) on the listing and detail pages. Here’s where it’s used in our Helper:

public function isOutOfStockButPurchasable(Mage_Catalog_Model_Product $product){
    if(!$product){
        return false;
    }

    $salableCheckOne = $product->isSalable();
    $product->setIgnoreSaleableCategory(true);

    $salableCheckTwo = $product->isSalable();
    $product->setIgnoreSaleableCategory(false);

    return $salableCheckOne !== $salableCheckTwo;
}

Our modified products will then be identifiable because the value from the two checks will not match.

Caveats

The only problem from this method is that if the client saves one of the out of stock products within one of these categories, then the values for backorder and is_in_stock will be saved to the database, meaning that if the code is disabled those saved products will still be available via backorder.