<?php

require 'conf.php';
$co = new Paydunya_Checkout_Invoice();
?>
<html>
<head>
  <title>La boutique de Sandra</title>
  <style type="text/css">
    body{
      background-color: #272727;
      font-family: Arial;
      font-size: 14px;
    }
    h1{
      font-weight: 500;
    }
    .container{
      margin:60px auto 0 auto;
      width:600px;
      min-height: 400px;
      background-color: #fafafa;
      border: 1px solid #e4e4e4;
      padding: 15px 30px;
    }
    input[type="text"]{
      padding:4px;
      display: block;
      width:300px;
      margin-bottom: 8px;
    }
 function __construct()
 {
     parent::__construct();
 }
<?php

session_start();
require 'conf.php';
$co = new Paydunya_Checkout_Invoice();
$total_amount = 0;
foreach ($_SESSION["cart"] as $product) {
    $co->addItem($product['name'], $product['quantity'], $product['unit_price'], $product['total_price']);
    $total_amount += $product['total_price'];
}
$co->setTotalAmount($total_amount);
if ($co->create()) {
    header("Location: " . $co->getInvoiceUrl());
} else {
    echo $co->response_text;
}