Programmatically add Magento products to categories

Question

I am using Magento 1.4.0.1. I have over 21000 simple products, each entered into a single category. There are hundreds of categories in my site. Some products belong in mult

Answer 1

After looking into the Magento API: Magento adds products to categories in the following way:

public function assignProduct($categoryId, $productId, $position = null, $identifierType = null)
{
    $category = $this->_initCategory($categoryId);
    $positions = $category->getProductsPosition();
    $productId = $this->_getProductId($productId);
    $positions[$productId] = $position;
    $category->setPostedProducts($positions);

    try {
        $category->save();
    } catch (Mage_Core_Exception $e) {
        $this->_fault('data_invalid', $e->getMessage());
    }

    return true;
}

And getting all the asigned products:

public function assignedProducts($categoryId, $store = null)
{
    $category = $this->_initCategory($categoryId);

    $storeId = $this->_getStoreId($store);
    $collection = $category->setStoreId($storeId)->getProductCollection();
    ($storeId == 0)? $collection->addOrder('position', 'asc') : $collection->setOrder('position', 'asc');;

    $result = array();

    foreach ($collection as $product) {
        $result[] = array(
            'product_id' => $product->getId(),
            'type'       => $product->getTypeId(),
            'set'        => $product->getAttributeSetId(),
            'sku'        => $product->getSku(),
            'position'   => $product->getPosition()
        );
    }

    return $result;
}