php文件下载功能实现

/**
 * 文件下载功能
 * @param string $fileName 文件名称
 * @param string $fileExt 文件后缀名称
 */
function downloadFile($fileName, $fileExt = '.txt' )
{
    if( empty($fileName)) return FALSE;
    $fileName .= $fileExt;
    $filePath = TEMI_UPLOAD_PATH . $fileName;
    $file = fopen($filePath, "r");
    Header("Content-type: application/octet-stream");
    Header("Accept-Ranges: bytes");
    Header("Accept-Length: " . filesize($filePath));
    Header("Content-Disposition: attachment; filename=" . $fileName);
    echo fread($file, filesize($filePath));
    fclose($file);
}
?>