这个PHP opendir（）在服务器上非常费力吗？

Question

if (is_dir($dir)) {
  if($handle = opendir($dir)) { 
        while($file = readdir($handle)) {
        // Break the filename by period; if there's more than one piece, grab the last piece.
        $parts = explode(".", $file); 
        if (is_array($parts) && count($parts) > 1) {
            $ext = end($parts);
            // If it's an image that we want, echo the code.
          if ($ext == "png" OR $ext == "PNG" OR $ext == "jpg" OR $ext == "JPG" OR $ext == "jpeg" OR $ext == "JPEG" OR $ext == "gif" OR $ext == "GIF")
            echo "<img src=\"$path/$file\" />";
      } 
    }
    closedir($handle);
  }
...

I'm using it in Wordpress, and the page loads pretty slowly, but it could also be from having a lot of images on it. I just wanted to make sure I wasn't doing something that was frowned upon for performance reasons.

Answer 1

Well you could make it more efficient:

$extension = strtoupper(pathinfo($file, PATHINFO_EXTENSION));  
if (in_array($extension(array('PNG', 'JPG', 'JPEG', 'GIF'))) {
    echo '<img src="$path/$file" />'; 
}  

or even using glob() rather than opendir/readdir/closedir... because you can give it a pattern of file extensions.

But there's nothing inherently slow about it