Auto category-hide if no products present

Question

Is it possible to automatically hide/unhide a category depending on whether there are products in it to display or not?

i.e. if all products sell out, then the category disappears, and vice versa, if a product comes back into stock, then the category automatically re-appears on the site.

Answer 1

There is no built in function to hide categories that do not have products/stock. You can disable each category manually.

However, large websites this is never ideal. You would need to modify the Magento core slightly.

You will need to rewrite the Mage_Catalog_Block_Navigation block. There is 2 functions that control your categories.

1st function _renderCategoryMenuItemHtml() you will want to replace the loop

foreach ($children as $child) {
    if ($child->getIsActive()) {
        $activeChildren[] = $child;
    }
}

with this:

foreach ($children as $child) {
    if ($child->getIsActive() && $this->_hasProducts($child->entity_id)) {
        $activeChildren[] = $child;
    }
}

and then for the 2nd function renderCategoriesMenuHtml() replace the code

 foreach ($this->getStoreCategories() as $child) {
        if ($child->getIsActive()) {
            $activeCategories[] = $child;
        }
    }

with this:

foreach ($this->getStoreCategories() as $child) {
    if ($child->getIsActive() && $this->_hasProducts($child->entity_id)) {
        $activeCategories[] = $child;
    }
}

In the end create the function to check if a category has products. Products out of stock, are considered inactive.

protected function _hasProducts($category_id) {
    $products = Mage::getModel('catalog/category')->load($category_id)
        ->getProductCollection()
        ->addAttributeToSelect('entity_id')
        ->addAttributeToFilter('status', 1)
        ->addAttributeToFilter('visibility', 4);
    return ( $products->count() > 0 )  ? true : false;
}

This method checks each category individually by using the catalog/category model. If you have many categories, you might want to rewrite the code a bit so you do not run into performance issues since this will run each time a category is generated.