In a products collection have addAttributeToFilter 'check' child products of a configurable product?

Question

For our API we have an option to use filters, these work great so far and are pretty simply made with the addAttributeToFilter function.
However, the problem is that when a configurable product has a child product with an attribute which indicates that it's blue, and I filter the products on the color attribute with the corresponding blue filter value, it also filters out that configurable product.
We'd like to have these configurable products in our response, but how? I've seen suggestions to use addFieldToFilter, but that gives the same results.

Answer 1

If the child products you are mentioning are simple products then you can do the following:

Include this function:

public function getConfigurableProductsFromSimple($filteredProducts){
    $configurableProducts = new array();
    foreach($filteredProducts as $simpleProduct){
        $parentIds = Mage::getResourceSingleton('catalog/product_type_configurable')
                     ->getParentIdsByChild($simpleProduct->getId());
        $parentId = $parentId[0];
        $configurableProducts[] = Mage::getModel('catalog/product')->load($parentId);
    }
    return $configurableProducts;
}

and then change your filtered products something like this:

$filteredProducts = $this->getConfigurableProductsFromSimple($filteredProducts);