Silex: Upload

SUBIR VARIOS FICHEROS:

prueba.twig:
<input type="file" multiple name="imagenAux[]" value="Imagen del banner">

Cxxx.php:
$imagen = "";
$file = $request->files->get('imagenAux');
foreach ($file as $clave=>$valor) {
    if ($valor != NULL) {
        $azar = rand(1,9999);
        $valor->move($ruta."/../public/images/banners/", $azar."_".$valor->getClientOriginalName());
        $imagen = $azar."_".$valor->getClientOriginalName();
    }
}

SUBIR UNO SOLO

prueba.twig:
<input type="file" name="imagenAux" value="Imagen del banner">

Cxxx.php:
$imagen = "";
$file = $request->files->get('imagenAux');
if ($file != NULL) {
    $azar = rand(1,9999);
    $file->move($ruta."/../public/images/banners/", $azar."_".$file->getClientOriginalName());
    $imagen = $azar."_".$file->getClientOriginalName();
}