Magento 2 REST API to fetch all the filter attributes based on Category

Question

How can we fetch all the available filter attributes in the category page with REST API?

I'm working with the mobile app for my Magento store. In the category listing page, I need to show all the available filters for the category and with this filter, I need to show the products accordingly.

• Available filter list for the category page.
• Filtering the product in the category page based on the selected filter.

Also, I just want to know how this can be implemented within the search page.

Any help would be appreciable.

Answer 1

Please try the following code

public function getCategoryFilter($id)
{
    $resultJson = $this->_resultJsonFactory->create();

    $objectManager = \Magento\Framework\App\ObjectManager::getInstance();

    $filterableAttributes = $objectManager->getInstance()->get(\Magento\Catalog\Model\Layer\Category\FilterableAttributeList::class);

    $appState = $objectManager->getInstance()->get(\Magento\Framework\App\State::class);
    $layerResolver = $objectManager->getInstance()->get(\Magento\Catalog\Model\Layer\Resolver::class);
    $filterList = $objectManager->getInstance()->create(
        \Magento\Catalog\Model\Layer\FilterList::class,
        [
            'filterableAttributes' => $filterableAttributes
        ]
    );

    $layer = $layerResolver->get();
    if($id != 0)
    {
        $layer->setCurrentCategory($id);
    }        
    $filters = $filterList->getFilters($layer);
    $maxPrice = $layer->getProductCollection()->getMaxPrice();
    $minPrice = $layer->getProductCollection()->getMinPrice();


    $i = 0;
    $finalFilters = [];
    $uid = 0;
    foreach ($filters as $filter) {
        $uid++;
        $finalFilters[$i]['field'] = $filter->getRequestVar();
        $label = ($filter->getRequestVar() == 'cat') ? 'Category' : $filter->getRequestVar();
        $finalFilters[$i]['id'] = $uid;
        $finalFilters[$i]['label'] = ucfirst($label);
        if($filter->getRequestVar() == "price") {
            $finalFilters[$i]['min-price'] = $minPrice;
            $finalFilters[$i]['max-price'] = $maxPrice;
        }
        $k = 0;
        foreach ($filter->getItems() as $item) {

            $k++;
            $optionLabel = strip_tags($item->getLabel());
            $optionValue = $item->getValue();
            $count = $item->getCount();
            $finalFilters[$i]['value'][] = array('label' => $optionLabel, 'value' => $optionValue,'count' => $count);
        }    
       $i++; 
    } 
    $fil = [];
    foreach ($finalFilters as $fill) {
        if (isset($fill['value']))
            $fil[] = $fill;
    }  
    return $fil;     
}