PHP - Checking Folders Exists

Hi folks,

Working on something and I'm not sure how best to do it. It's a system whereby customers can login and see pdf files. Each customer has a unique reference number which is mirrored with a folder on the server, the folder name being the customer reference number. That's the first bit of checking. Then, within that customer folder there will be between 1 and X sub folders which are labelled by unique product reference numbers. Beyond that, each of the product reference folders will have a year folder with a folder for each month of the year going forward. Here's an example of the folder structu

- Customer Number (e.g. 12345678)
  - Product Number (e.g. 456789) (could be more than one)
    - Year (e.g. 2011) (could be more than one)
      -Month (e.g. 01/02/03/04/05/06 etc)

Essentially, I'm just unsure how to check if folders exist and display their contents if they do.

Here's my code so far, which does the first part of checking to see if the product numbers exist, but not the folder checking (I've not activated the hyperlinks in this code yet). This doesn't go as far as years and months yet, just the product number:

Code: [Select]
$query = mysql_query("SELECT * FROM customers where id = '$id'");
while($rst = mysql_fetch_array($query))

{ echo "$rst[company_name]"; }

$query = mysql_query("SELECT * FROM sites where company_name = '$company'");
while($rst = mysql_fetch_array($query))

{ echo "$rst[site]<br>";

if ($rst[product1] !== ""){
echo "- <a href='#'>$rst[product1]</a><br>";
}

if ($rst[product1] == ""){
echo "";
}

if ($rst[product2] !== ""){
echo "- <a href='#'>$rst[product2]</a><br>";
}

if ($rst[product2] == ""){
echo "";
}

if ($rst[product3] !== ""){
echo "- <a href='#'>$rst[product3]</a><br>";
}

if ($rst[product3] == ""){
echo "";
}

if ($rst[product4] !== ""){
echo "- <a href='#'>$rst[product4]</a><br>";
}

if ($rst[product4] == ""){
echo "";
}

if ($rst[product5] !== ""){
echo "- <a href='#'>$rst[product5]</a><br>";
}

if ($rst[product5] == ""){
echo "";
}