Page 362 - Beginning PHP 5.3

Part III: Using PHP in Practice
How It Works
The traverseDir() recursive function traverses the whole directory hierarchy under a specified
directory. First, the function displays the path of the directory it is currently exploring. Then, it opens
the directory with opendir():

if ( !( $handle = opendir( $dir ) ) ) die( “Cannot open $dir.” );

Next the function sets up a $files array to hold the list of filenames within the directory, then uses
readdir() with a while loop to move through each entry in the directory, adding each filename to
the array as it goes (”.” and “..” are skipped). If a particular filename is a directory, a slash (/) is
added to the end of the filename to indicate to the user (and the rest of the function) that the file is in
fact a directory:

$files = array();

while ( $file = readdir( $handle ) ) {
if ( $file != “.” && $file != “..” ) {
if ( is_dir( $dir . “/” . $file ) ) $file .= “/“;
$files[] = $file;
}
}
Now the array of filenames is sorted alphabetically to aid readability, and the filenames are displayed
in an unordered list:

sort( $files );
echo “<ul>“;
foreach ( $files as $file ) echo “<li>$file</li>“;
echo “</ul>“;

The last part of the function loops through the array again, looking for any directories (where the
filename ends in a slash). If it finds a directory, the function calls itself with the directory path (minus
the trailing slash) to explore the contents of the directory:
foreach ( $files as $file ) {
if ( substr( $file, -1 ) == “/” ) traverseDir( “$dir/” . substr( $file,
0, -1 ) );
}
Finally, the directory handle is closed:
closedir( $handle );

The last line of code in the script kicks off the directory traversal, starting with the path to the initial,
topmost directory:
traverseDir( $dirPath );

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