<?php
  namespace MageplazaHelloWorldControllerIndex;

  class Display extends MagentoFrameworkAppActionAction
  {
      protected $accountManagement;
      protected $session;

      public function __construct(
         MagentoFrameworkAppActionContext $context,
         MagentoCustomerModelAccountManagement $acm,
         MagentoCustomerModelSession $ses
      )
     {
           $this->accountManagement = $acm;
           $this->session = $ses;
           return parent::__construct($context);
     }

     public function execute()
     {
           //se la richiesta avviene in post
           if($_SERVER['REQUEST_METHOD'] == "POST") {
                //recupero i campi della richiesta
                $username = $_POST['username'];
                $password = $_POST['password'];
                //autentico l'utente
                try {
                    $customer = $this->accountManagement->authenticate($username, $password);
                }
                catch(Exception $e) {
                    echo "Credenziali errate";
                    return;
                }
                //log in del cliente
                echo $customer->getId();
                $this->session->loginById($customer->getId());
                die;
          }

     }
 }