$uploaddir = 'file/upload/'.date('Ym/d/');
  is_dir(DT_ROOT.'/'.$uploaddir) or dir_create(DT_ROOT.'/'.$uploaddir);
  $filename = time().'_'.uniqid().'.png';
  file_put_contents('../'.$uploaddir.$filename, base64_decode(preg_replace('#^data:image/\w+;base64,#i', '', file_get_contents("php://input"))));
  
  die(json_encode(['picUrl' => DT_PATH.$uploaddir.$filename]));

  public function uploadAction(Request $request)
  {
      /**
       * 
       * @var \Symfony\Component\Filesystem\Filesystem $filesystem
       */
      $filesystem = $this->get('filesystem');
      $uploadsDir = 'uploads/' . date('Ym/d');
      $filesystem->mkdir($uploadsDir);
      $filename = time().'_'.uniqid().'.png';
      file_put_contents($uploadsDir.$filename, base64_decode(preg_replace('#^data:image/\w+;base64,#i', '', file_get_contents("php://input"))));
      return $this->json([
          'picUrl' => 'http://' . $request->getHost(). '/' .$uploadsDir.$filename
      ]);
  }