当filemtime、stat['mtime']和get\ headers失败时,使用PHP从文件获取上次修改的信息

if (isset($_GET['start']) && "true" === $_GET['start'])
{
    $images = array();

    if ($dir = dir('images'))
    {
        $count = 0;

        while(false !== ($file = $dir->read()))
        {
            if (!is_dir($file) && $file !== '.' && $file !== '..' && (substr($file, -3) === 'jpg' || substr($file, -3) === 'png' || substr($file, -3) === 'gif'))
            {
                $lastModified = filemtime($file);
                $images[$lastModified] = $file;
                ++$count;
            }
        }

        echo json_encode($images);
    }
    else { echo "Could not open directory"; }
}