BoxHandler.php

<?php

namespace Home\PageBundle\Handler;

use Symfony\Component\Form\Form;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\RequestStack;

class BoxHandler
{
      protected $form;
      protected $request;

      public function __construct(Form $form, RequestStack $requestStack)
      {
          $this->form = $form;
          $this->request = $requestStack->getCurrentRequest();
      }
 
      public function process()
      {
          $this->form->handleRequest($this->request);
              if ($this->form->isSubmitted() && $this->form->isValid())
          {
               return true;
          }
          
          return false;
      }
      
            public function onsucess()
      {
   
      }
      
      public function getForm()
      {
          return $this->form;
      }
}

controller.php

<?php

class SomeController
{
    /**
     * Creates a new box entity.
     *
     * @Route("/new", name="box_new")
     * @Method({"GET", "POST"})
     */
    public function newAction()
    {
        $box = new Box();
        $form = $this->get('box_form');
       
        $boxhandler = $this->get('box_handler');
                            
        if ($boxhandler->process()) {
            $em = $this->getDoctrine()->getManager();
            $em->persist($box);
            $em->flush();
            
            
           return $this->redirectToRoute('box_show', array('id' => $box->getId()));
        }

        return $this->render('box/new.html.twig', array(
            'box' => $box,
            'form' => $boxhandler->getForm()->createView(),
        ));
    }
}

services.yml

parameters:
    class: Home\PageBundle\Entity\Box

services:
  box_form:
    class: Symfony\Component\Form\Form
    factory: ['@form.factory', create ]

  box_handler:
    class: Home\PageBundle\Handler\BoxHandler
    arguments: 
      - "@box_form"
      - "@request_stack"