Get form errors. Symfony 2.3

gistfile1.php

<?php
namespace Acme\DemoBundle\Controller;

//... 

class ApiController extends Controller
{

    //... 
    
    public function processForm(Request $request)
    {
        // ...
        $form = $this->createForm($documentType, $document, array('method' => $request->getMethod()));
        $form->handleRequest($this->getRequest());
        
        if($form->isValid()) {
            // Save Data
        }
        else {
            $errors = $this->getErrorMessages($form);
            return $errors;
        }
        
        return $response;
    }

    private function getErrorMessages(\Symfony\Component\Form\Form $form) {
        
        $errors = array();
        
        foreach ($form->getErrors() as $key => $error) {
            $errors[$key] = $error->getMessage();
        }
        
        if ($form->count()) {
            foreach ($form->all() as $child) {
                if (!$child->isValid()) {
                    $errors[$child->getName()] = $this->getErrorMessages($child);
                }
            }
        }
        
        return $errors;
    }  
}