PHP: SESSION data not being stored - php

Question

This data comes from a POST form, the idea is to simply add more lines whenever a new product is added.
The current output is:
l. Banana 3 units: 150
Please take a look into the script (specially the foreach loop):
<?php
session_start();
//Getting the list
$list= $_SESSION['list'];
//stock
$products = array(
'Pineaple' => 500, 'Banana' => 50, 'Mango' => 150,
'Milk' => 500, 'Coffe' => 1200, 'Butter' => 300,
'Bread' => 450, 'Juice' => 780, 'Peanuts' => 800,
'Yogurt' => 450, 'Beer' => 550, 'Wine' => 2500,
);
//Saving the stuff
$_SESSION['list'] = array(
'item' => ($_POST['product']),
'quantity' => ($_POST['quantity']),
'code' => ($_POST['code']),
);
//price
$price = $products[($_SESSION['list']['item'])] * $_SESSION['list']['quantity'];
$_SESSION['list']['price'] = $price;
//listing
echo "<b>SHOPPIGN LIST</b></br>";
foreach($_SESSION as $key => $item)
{
echo $key[''], '. ', $item['item'], ' ', $item['quantity'], ' units: ', $item['price'];
}
//Recycling list
$_SESSION['list'] = $list;
echo "</br> <a href='index.html'>Return to index</a> </br>";
//Printing session
var_dump($_SESSION);
?>

Answer 1

change this code:
//Saving the stuff
$_SESSION['list'] = array(
'item' => ($_POST['product']),
'quantity' => ($_POST['quantity']),
'code' => ($_POST['code']),
);
to
//Saving the stuff
$_SESSION['list'][] = array(
'item' => ($_POST['product']),
'quantity' => ($_POST['quantity']),
'code' => ($_POST['code']),
);
and remove this code:
//Recycling list
$_SESSION['list'] = $list;
Now, you'll get a new entry in $_SESSION every time you POST to the page.
Also, if you want your output to look like:
l. Banana 3 units: 150
2. Orange 5 units: 250
etc
then you'll need to change the echo in the foreach() loop from
echo $key[''] . // everything else
to just
echo ($key+1) . // everything else
Since key will be your array index starting at 0, you'll need to do a +1 every iteration, otherwise your list would look like
0. Banana 3 units: 150
1. Orange 5 units: 250

Answer 2

As iandouglas wrote, you are overwriting the session variable every time. The following code also fixes some undefined index issues and already existing products.
// Test POST data.
$_POST['product'] = 'Pineaple';
$_POST['quantity'] = 1;
$_POST['code'] = 1;
//Getting the list
$_SESSION['list'] = isset($_SESSION['list']) ? $_SESSION['list'] : array();
//stock
$products = array(
'Pineaple' => 500, 'Banana' => 50, 'Mango' => 150,
'Milk' => 500, 'Coffe' => 1200, 'Butter' => 300,
'Bread' => 450, 'Juice' => 780, 'Peanuts' => 800,
'Yogurt' => 450, 'Beer' => 550, 'Wine' => 2500,
);
//Saving the stuff
$new_item = array(
'item' => $_POST['product'],
'quantity' => $_POST['quantity'],
'code' => $_POST['code'],
'price' => $products[$_POST['product']] * $_POST['quantity'],
);
$new_product = true;
foreach($_SESSION['list'] as $key => $item) {
if ($item['item'] == $new_item['item']) {
$_SESSION['list'][$key]['quantity'] += $new_item['quantity'];
$_SESSION['list'][$key]['price'] = $products[$new_item['item']] * $new_item['quantity'];
$new_product = false;
}
}
if ($new_product) {
$_SESSION['list'][] = $new_item;
}
//listing
echo "<b>SHOPPIGN LIST</b></br>";
foreach($_SESSION['list'] as $key => $item) {
echo 'key '. $key. ' '. $item['item'], ' ', $item['quantity'], ' units: ', $item['price']. '<br />';
}