您如何使用PHP在父目录级别列出目录？

Question

I am trying to make a dynamic menu of the directories at the parent directory level using PHP. I can get the child directories with the following code:

<?php
    if ($handle = opendir('.')) 
    {
        while (false !== ($file = readdir($handle))) 
        {
            if ($file != "." && $file != "..") 
            {
                if(is_dir($file))
                {
                    echo '<a href="./' . $file . '">' . $file . '</a><br/>';
                }
            }
        }
        closedir($handle);
    }
?>

When I change opendir to ('..') or ('...') nothing seems to come back. I would like to do something like this:

 /
 |-A
 | |-1
 |-B
 | |-1
 | |-2
 | |-3
 |   |-a
 |   |-b
 |-C

Where if I were down in the /B/2 page, the php output would show that the parent directory level list would have links to A, B, and C and not something symbolic like '..'. The same code would show the same parent level directories if I were in /A/1. If I were in /B/3/a the code would list 1, 2, and 3. Is this possible? If so how would I modify the code to accomplish this?

Answer 1

The filename argument to functions like is_dir() are interpreted relative to the process's current directory, which is not the same directory that you supplied to opendir() . You need to prepend the directory:

if (is_dir("../$file")) {

Answer 2

You would need to link it like this:

<a href="../A/1">A</a>
<a href="../B/1">A</a>
<a href="../C/1">A</a>

Answer 3

It turns out that is was a matter of testing to see if I had a line on a directory. Notice that the sequence begins with

if (is_dir('../'))
{

}

The answer looks like this.

<?php
if (is_dir('../'))
{
  if ($dirhandle = opendir($dir))
  {
    while (($directory = readdir($dirhandle)) !== false)
    {
        if ($directory != "." && 
            $directory != ".." && 
            $directory != ".DS_Store" && 
            $directory != ".metadata"
            )
        {
            echo  '<a href="../' . $directory . '">'. $directory . '</a><br>' . "\n";    
        }
    }
    closedir($dh);
  }
}
?>

You can then modify the list of things your do not want to have listed eg index.php.