上传时如何从文件名中删除或接受特殊字符

Question

我将此代码保存在一个名为uploader.php的文件中。我从另一个文件中调用此文件来上传图像，效果很好。在相册中，我看不到缩略图（如果我上传的图像中包含（）和[]字符，则它们为空白。我想在上传时删除类似的字符，或者让它们显示出来。

$maindir = "../alla_bilder/images/";
$maindir_th = "../alla_bilder/images/thumbs/";
$uploaddir = "images/";
$uploaddir_th = "images/thumbs/";
$allowed = array('jpg','jpeg','gif','png');
$max_size = 5048 * 1024;
while (list ($key, $val) = each ($_FILES))
{
if ($_FILES[$key]['size'] <= $max_size) 
{
  $file_ext  = pathinfo($_FILES[$key]['name'],PATHINFO_EXTENSION);
  $file_name = basename($_FILES[$key]['name'],'.'.$file_ext);
  if (in_array(strtolower($file_ext),$allowed)) 
  {
     $name = $_FILES[$key]['name'];
     $x = 1;
     while (file_exists($uploaddir.'/'.$name)) 
     {
        $name = $file_name.'['.$x.'].'.$file_ext;
        $x++;
     }
     if (move_uploaded_file($_FILES[$key]['tmp_name'],$uploaddir.'/'.$name))
     {
        chmod($uploaddir.'/'.$name, 0644);
     }
     else
     {
        die(error_get_last());
     }
  }
  else
  {
     die("Invalid file type");
  }
}
else
{
  die("File size too big");
}
copy($uploaddir.'/'.$name, $maindir.'/'.$name);

  $images = glob("images/thumbs/*.*");  
  foreach($images as $image)  
  {  
       $output .= '<div class="col-md-2" align="center" ><img src="' . $image .'" width="200px" height="140px" style="border:1px solid #ccc;" /></div>';  
  }  


    $modwidth = 200;
    $modheight = 140;

    list($width, $height) = getimagesize($uploaddir.'/'.$name);               
    $ratio_orig = $width/$height;                 
    if ($width/$height > $ratio_orig)
    {         
    $width = $height*$ratio_orig;         
    } else {         
    $height = $width/$ratio_orig;         
    }          
    $tn = imagecreatetruecolor($modwidth, $modheight);
    //$image = imagecreatefromjpeg($uploaddir.'/'.$name);
    $image = imagecreatefromstring(file_get_contents($uploaddir.'/'.$name));
    imagecopyresampled($tn, $image, 0, 0, 0, 0, $modwidth, $modheight, $width, $height);
    imagejpeg($tn, $uploaddir_th.'/'.$name); 
    imagejpeg($tn, $maindir_th.'/'.$name); 

}

//查看缩略图的代码：

$directory = 'images/';
$thumbsdir = 'images/thumbs';
$allowed_types = array('jpg', 'JPG', 'JPEG', 'jpeg', 'gif', 'PNG', 'png');
$fileNames = $files = $file_parts = array();
$ext = '';
/* $title = ''; */
$i = 0;

$toMatch = "{$directory}*.{".implode(',', $allowed_types).'}';
$fileNames = glob($toMatch, GLOB_NOSORT | GLOB_BRACE);  

foreach($fileNames as $file) {
    $f = explode('/', $file);
    $fileName = end($f);
    $files[$fileName] = filemtime($file);
}

arsort($files);

foreach(array_keys($files) as $file)
{
    $file_parts = explode('.',$file);
    $ext = strtolower(array_pop($file_parts));

    /* $title = implode('.',$file_parts);
    $title = htmlspecialchars($title); */

    echo '
    <div class="pic " style="background:url('.$thumbsdir.'/'.$file.') no-repeat 50% 50%;">
    <a href="'.$directory.'/'.$file.'" title="'.$title.'">'.$title.'</a>
    </div>';

    $i++;
}