Multiple Random Includes from Directory with Sub-Directories - php

Question

I have a directory containing sub directories which each contain a series of files. I'm looking for a script that will look inside the sub directories and randomly return a specified number of files.
There are a few scripts that can search a single directories (not sub folders), and other scripts that can search sub folders but only return one file.
To put a little context on the situation, the returned files will be included as li's in an rotating banner.
Thanks in advance for any help, hopefully this is possible.
I think I've got there, not exactly what I set out to achieve but works good enough, arguably better for the purpose, I'm using the following function:
<?php function RandomFile($folder='', $extensions='.*'){
// fix path:
$folder = trim($folder);
$folder = ($folder == '') ? './' : $folder;
// check folder:
if (!is_dir($folder)){ die('invalid folder given!'); }
// create files array
$files = array();
// open directory
if ($dir = #opendir($folder)){
// go trough all files:
while($file = readdir($dir)){
if (!preg_match('/^\.+$/', $file) and
preg_match('/\.('.$extensions.')$/', $file)){
// feed the array:
$files[] = $file;
}
}
// close directory
closedir($dir);
}
else {
die('Could not open the folder "'.$folder.'"');
}
if (count($files) == 0){
die('No files where found :-(');
}
// seed random function:
mt_srand((double)microtime()*1000000);
// get an random index:
$rand = mt_rand(0, count($files)-1);
// check again:
if (!isset($files[$rand])){
die('Array index was not found! very strange!');
}
// return the random file:
return $folder . "/" . $files[$rand];
}
$random1 = RandomFile('project-banners/website-design');
while (!$random2 || $random2 == $random1) {
$random2 = RandomFile('project-banners/logo-design');
}
while (!$random3 || $random3 == $random1 || $random3 == $random2) {
$random3 = RandomFile('project-banners/design-for-print');
}
?>
And echoing the results into the container (in this case the ul):
<?php include($random1) ;?>
<?php include($random2) ;?>
<?php include($random3) ;?>
Thanks to quickshiftin for his help, however it was a little above my skill level.
For info the original script which I changed an be found at:
http://randaclay.com/tips-tools/multiple-random-image-php-script/

Answer 1

Scrubbing the filesystem every single time to randomly select a file to display will be really slow. You should index the directory structure ahead of time. You can do this many ways, try a simple find command or if you really want to use PHP my favorite choice would be RecursiveDirectoryIterator plus RecursiveIteratorIterator.
Put all the results into one file and just read from there when you select a file to display. You can use the line numbers as an index, and the rand function to pick a line and thus a file to display. You might want to consider something more evenly distributed than rand though, you know to keep the advertisers happy :)
EDIT:
Adding a simple real-world example:
// define the location of the portfolio directory
define('PORTFOLIO_ROOT', '/Users/quickshiftin/junk-php');
// and a place where we'll store the index
define('FILE_INDEX', '/tmp/porfolio-map.txt');
// if the index doesn't exist, build it
// (this doesn't take into account changes to the portfolio files)
if(!file_exists(FILE_INDEX))
shell_exec('find ' . PORTFOLIO_ROOT . ' > ' . FILE_INDEX);
// read the index into memory (very slow but easy way to do this)
$aIndex = file(FILE_INDEX);
// randomly select an index
$iIndex = rand(0, count($aIndex) - 1);
// spit out the filename
var_dump(trim($aIndex[$iIndex]));