Magento – How to get current product in Magento 2.3.1 without deprecations

Case1:

Rewrite the class Mage_Catalog_Block_Widget_Link and on the rewite class add new funtoin getProductId() on

public function getProductId()
{

if($this->hasStoreId()) {
            $store = Mage::app()->getStore($this->getStoreId());
        } else {
            $store = Mage::app()->getStore();
        }

    if ($this->getData('id_path')) {
            /* @var $urlRewriteResource Mage_Core_Model_Mysql4_Url_Rewrite */
            $urlRewriteResource = Mage::getResourceSingleton('core/url_rewrite');
            $pID = $urlRewriteResource->getProductPathByIdPath($this->getData('id_path'), $store);
    return $pID; 
        }


    return null;
}

Case2:

Rewrite the class Mage_Core_Model_Resource_Url_Rewrite and on the rewrite class add new funtoin getProductPathByIdPath(),which will get product

public function getProductPathByIdPath($idPath, $store)
{
    if ($store instanceof Mage_Core_Model_Store) {
        $storeId = (int)$store->getId();
    } else {
        $storeId = (int)$store;
    }

    $select = $this->_getReadAdapter()->select();
    /** @var $select Varien_Db_Select */
    $select->from(array('main_table' => $this->getMainTable()), 'product_id')
        ->where('main_table.store_id = :store_id')
        ->where('main_table.id_path = :id_path')
     ->where('main_table.product_id IS  NOT NULL)
        ->limit(1);

    $bind = array(
        'store_id' => $storeId,
        'id_path'  => $idPath
    );

    return $this->_getReadAdapter()->fetchOne($select, $bind);
}

this function get Product Id

Case3:

Rewrite the class Mage_Checkout_Helper_Car and on the rewrite class add new funtoin getmyAddUrl().By using this you can get cart url

 public function getmyAddUrl($productId, $additional = array())
    {
        $continueUrl    = Mage::helper('core')->urlEncode($this->getCurrentUrl());
        $urlParamName   = Mage_Core_Controller_Front_Action::PARAM_NAME_URL_ENCODED;

        $routeParams = array(
            $urlParamName   => $continueUrl,
            'product'       => $productId
        );

        if (!empty($additional)) {
            $routeParams = array_merge($routeParams, $additional);
        }


        return $this->_getUrl('checkout/cart/add', $routeParams);
    }

You should not use the ObjectManager directly!

Exception from the rule are:

• in static magic methods like __wakeup, serialize, etc
• in case you should make backward compatibility of constructor
• in global scope, like in fixtures of integration test.
• in class that needs only for creation of object like factory, proxy , etc