how to base32 encode url

Question

first off, sorry about the title.

please can someone help me with this. I have the following statement below and I want to make my pid to be random numbers and letters so I used the function id_encode($id)

http://www.testing/details.php?Sef=canda&ppid=1

I don't want the ppid to show so that the user can not guess how many product I have in my database. That why I used that function.

          $stmt = $conn->prepare(" 
          SELECT * FROM Product
          ");
          $stmt->execute();
            $i = 0;
            $rows = $stmt->fetchAll(PDO::FETCH_ASSOC); 
        foreach ($rows as $row) {
           $id = $row["ppid"]; //id

    function id_encode($id) {
        return base_convert((9999999999 - (float) $id) , 10 , 32 );
        }
    $qstr = http_build_query(array("Sef"=>$row["Sef"], "ProdID"=>$id));

---

I have a view button with links to another page

<a href="<?php fetchdir($apages) ?>product.php?<?= $qstr ?>">View item</a>

In that other page I have

<?php   
 if (isset($_GET['Sef']) && isset($_GET['ppid'])) {
    $id = $_GET["ppid"];
    $id2 = $_GET['Sef'];

error I am getting Fatal error: Cannot redeclare id_encode() (previously declared in.

also the way I am doing this will the other page be able to get this information? because if i remember that function the other page does receive that information for that product.

Please help.

Answer 1

You'd want a function id_decode( $encoded_id ) that reverses whatever it is you do to the number in your encode function.

So if in encode you do ( N - id ) then base10 to base32, in decode you'd do base32 to base10 then ( N - id ) again, because (N - (N - id)) = id.