What is the equilent of Mage::app()->getResponse()->setHeader('HTTP/1.1','503 Service Unavailable') ->sendResponse(); in Magento 2

Question

What is the equivalent of Magento 1 to Magento 2?

Mage::app()->getResponse()
        ->setHeader('HTTP/1.1','503 Service Unavailable')
        ->sendResponse();

Answer 1

In controller you can use following;

public function execute()
{      
    $this->getResponse()
        ->setStatusCode(\Magento\Framework\App\Response\Http::STATUS_CODE_503)
        ->setContent('503 Service Unavailable');
    return ;
}

EDIT:

You can try injecting \Magento\Framework\Controller\ResultFactory in your class and calling $this->response->setHeader('HTTP/1.1', '503 Service Unavailable', true); (if your object is $response) and return it at end.