public function uploadFileByFile(UploadedFile $file_request, $fieldName, $classFileString) {
        $file_content = file_get_contents($file_request->getPathname());
        $file_extension = $file_request->getClientOriginalExtension();

        $file_app_object = $this->writeFileBytes($file_content, $file_extension, $fieldName, $classFileString);
        $this->em->persist($file_app_object);
        $this->em->flush();

        return $file_app_object;
    }