What is equivalence class for 'Mage_Core_Helper_Http' and 'Mage_Core_Helper_Data' in Magento 2

Question

In Magento 1, I can have return Mage::helper('core') which is object of Mage_Core_Helper_Data. I wonder what the equivalent class for Magento 2.

Answer 1

I think I figured it out. In Magento 2, the Helper class can be defined as

    class Data extends \Magento\Framework\App\Helper\AbstractHelper
    {
        public function __construct(
          \Magento\Framework\App\Helper\Context $context
     ){
           parent::__construct($context);
      }
    }

If you want to get Mage::helper('core'), then you just define a public function in this class,

    class Data extends \Magento\Framework\App\Helper\AbstractHelper
    {
       public function __construct(
         \Magento\Framework\App\Helper\Context $context
       ){
          parent::__construct($context);
       }

       public function getCoreHelper()
       {
          return $this;
       } 
    }

If you want to get "Mage::helper('core/helper')" like in Magento 1, you just need to use the automatic constructor dependency injection:

    class Data extends \Magento\Framework\App\Helper\AbstractHelper
    {
       protected $httpHelper;

       public function __construct(
          \Magento\Framework\App\Helper\Context $context,
          \Magento\Framework\App\Http $httpHelper
       ){
          parent::__construct($context);
          $this->httpHelper = $httpHelper;
       }

       public function getCoreHelper()
       {
          return $this;
       } 
       public function getHttpHelper()
       {
          return $this->httpHelper;
       }
    }

Answer 2

If you wanting to know which helper class to extend from in order to create your own helper class, it is: \Magento\Framework\App\Helper\AbstractHelper.