PHP-创建并下载ZipArchive在打开时返回CPGZ

函数似乎没有正确创建ZIP文件。下载的文件提示工作正常。然而，当打开它时，它只会创建.cpgz格式的副本。

供参考：foreach ($attachments as $file)输出为"/upload/image.jpg"

function downloadAttachment() {
    $zipname = 'attachments.zip';
    $zip = new ZipArchive;
    $zip->open($zipname, ZipArchive::CREATE);
    foreach ($attachments as $file) {
      $fileSrc = $_SERVER['DOCUMENT_ROOT'] . $file["file_attachment"];
      $zip->addFile($fileSrc);
    }
    $zip->close();
    header('Content-Type: application/zip');
    header('Content-disposition: attachment; filename='.$zipname);
    header('Content-Length: ' . filesize($zipname));
    ob_clean();
    flush();
    readfile($zipname);
}