CCloudStorageService::FileExists

public function FileExists($arBucket, $filePath);
/**
 * @param array[string]string $arBucket
 * @param mixed $arFile
 * @param string $filePath
 * @return bool
*/
abstract public function FileCopy($arBucket, $arFile, $filePath);
/**
 * @param array[string]string $arBucket
 * @param mixed $arFile
 * @param string $filePath
 * @return bool
*/
function DownloadToFile($arBucket, $arFile, $filePath)
{
	$url = $this->GetFileSRC($arBucket, $arFile);
	$request = new BitrixMainWebHttpClient(array(
		"streamTimeout" => $this->streamTimeout,
	));
	$result = $request->download($url, $filePath);
	if ($request->getStatus() == 404 || $request->getStatus() == 403)
	{
		return false;
	}
	return $result;
}