Issue with Unset (PHP) - php

Question

I am trying to unset an item from session array, it unset once then brings back again.
for exg :-
if i click to remove itemId = 5, it removes from session array,
then i click to remove itemId = 6, then i see the old itemId = 5 is back in array again.
/*** delete item from cart ***/
public function deleteCartItem($id, $customerId, $cartId, $wishlistFlag=false) // Param: ProductID, CustomerID, CartID, WishlistFlag
{
$conn = $_SESSION['conn'];
$itemId = false;
$chk = array();
$sql = "DELETE FROM cart_items WHERE product_id=? AND cart_id=?";
$stmt = mysqli_prepare($conn, $sql);//$result = $conn->query($sql);
$stmt->bind_param('ii', $item['id'],$cartId);
$stmt->execute();
$itemId = $i;
echo $itemId;
$chk[] = $_SESSION['cart'];
echo'</br>';
print_r($chk);
}
}
if (isset($_SESSION['cart'][$itemId])){
unset($_SESSION['cart'][$itemId]);
}
}
<?php
$_SESSION['cart'] = array (
0 =>
array (
'id' => 6154353459,
'name' => 'pro one Night Out Mesh Tee',
'display_brand' => 'Widow',
'qty' => 1,
'price' => '28.0000',
'special_price' => 0,
'rule_price' => '',
'attributes' =>
array (
0 => 'BLACK',
1 => 'XX-Large',
),
'option80' => 18,
'option125' => 3457,
'child_product_id' => 61535897,
'giftcard' => '',
'whole_preorder' => 0,
'preorder_shipping_date' => NULL,
'available_qty' => 5,
'isRefundable' => true,
'max_sale_qty' => false,
'isFree' => 0,
'segment' =>
array (
'magento_product_id' => '65315459',
'product_id' => 'P19335935',
'quantity' => 1,
'name' => 'pro one Night Out Mesh Tee',
'brand' => 'Widow',
'price' => 28.0,
'special_price' => NULL,
'regular_price' => 28.0,
'size_type' => 'Regular',
'manufacturer' => 'Widow',
'trend' => 'WID goodie Hour 2020',
'microcategory' => 'Mesh Shirt',
'doll_category' => NULL,
'stock_quantity' => 10,
'sku' => 'S493660',
'child_stock_quantity' => 1,
'size' => 'XX-Large',
'swatch' => 'BLACK',
),
),
5 =>
array (
'id' => 615345465,
'name' => 'pro one Night Out Mesh Leggings',
'display_brand' => 'Widow',
'qty' => 1,
'price' => '30.0000',
'special_price' => 0,
'rule_price' => '',
'attributes' =>
array (
0 => 'BLACK',
1 => 'Medium',
),
'option80' => 18,
'option125' => 3454,
'child_product_id' => 6315890,
'giftcard' => '',
'whole_preorder' => '',
'preorder_shipping_date' => NULL,
'available_qty' => 37,
'isRefundable' => true,
'max_sale_qty' => false,
'isFree' => 0,
'segment' =>
array (
'magento_product_id' => '64334515465',
'product_id' => 'P193936',
'quantity' => 1,
'name' => 'pro one Night Out Mesh Leggings',
'brand' => 'Widow',
'price' => 30.0,
'special_price' => NULL,
'regular_price' => 30.0,
'size_type' => 'Regular',
'manufacturer' => 'Widow',
'trend' => 'WID goodie Hour 2020',
'microcategory' => 'Printed Leggings',
'doll_category' => NULL,
'stock_quantity' => 10,
'sku' => 'S493664',
'child_stock_quantity' => 10,
'size' => 'Medium',
'swatch' => 'BLACK',
),
),
2 =>
array (
'id' => 615445348,
'name' => 'pro two My Lashes Sunglasses',
'display_brand' => '',
'qty' => 1,
'price' => '15.0000',
'special_price' => 0,
'rule_price' => '',
'attributes' =>
array (
0 => 'BLACK',
1 => 'ONE SIZE',
),
'option80' => 18,
'option125' => 6212,
'child_product_id' => 6154345358,
'giftcard' => '',
'whole_preorder' => '',
'preorder_shipping_date' => NULL,
'available_qty' => 295,
'isRefundable' => true,
'max_sale_qty' => false,
'isFree' => 0,
'segment' =>
array (
'magento_product_id' => '6153453448',
'product_id' => 'P19645642180',
'quantity' => 1,
'name' => 'pro two My Lashes Sunglasses',
'brand' => '',
'price' => 15.0,
'special_price' => NULL,
'regular_price' => 15.0,
'size_type' => 'Regular',
'manufacturer' => 'CIEL',
'trend' => 'WID goodie Hour 2020',
'microcategory' => 'Cat Eye Sunglasses',
'category' => 'Accessories,Sunglasses,Cat Eye Sunglasses',
'special_category' => 'What\'s New,Char Test Category,Widow',
'doll_category' => NULL,
'stock_quantity' => 10,
'sku' => 'S486477',
'child_stock_quantity' => 10,
'size' => 'ONE SIZE',
'swatch' => 'BLACK',
),
),
3 =>
array (
'id' => 61465645461,
'name' => 'pro one Night Out goodie Dress',
'display_brand' => 'Widow',
'qty' => 1,
'price' => '45.0000',
'special_price' => 0,
'rule_price' => '',
'attributes' =>
array (
0 => 'BLACK',
1 => 'X-Large',
),
'option80' => 18,
'option125' => 3456,
'giftcard' => '',
'whole_preorder' => '',
'preorder_shipping_date' => NULL,
'available_qty' => 12,
'isRefundable' => true,
'max_sale_qty' => false,
'isFree' => 0,
'segment' =>
array (
'magento_product_id' => '616465461',
'product_id' => 'P1935446934',
'quantity' => 1,
'name' => 'pro one Night Out goodie Dress',
'brand' => 'Widow',
'price' => 45.0,
'special_price' => NULL,
'regular_price' => 45.0,
'size_type' => 'Regular',
'manufacturer' => 'Widow',
'trend' => 'WID goodie Hour 2020',
'microcategory' => 'goodie Dresses',
'category' => 'Clothing,Dresses,Mini,goodie Dresses',
'special_category' => 'Brandsgoodie,Char Test Category,Widow,Widow',
'doll_category' => NULL,
'stock_quantity' => 10,
'sku' => 'S493652',
'child_stock_quantity' => 10,
'size' => 'X-Large',
'swatch' => 'BLACK',
),
),
4 =>
array (
'id' => 6154566225,
'name' => 'Feelings Maxi Dress',
'display_brand' => 'Widow',
'qty' => 1,
'price' => '58.0000',
'special_price' => 0,
'rule_price' => '',
'attributes' =>
array (
0 => 'BLACK',
1 => 'Large',
),
'option80' => 18,
'option125' => 3455,
'child_product_id' => 61456455677,
'giftcard' => '',
'whole_preorder' => '',
'preorder_shipping_date' => NULL,
'available_qty' => 30,
'isRefundable' => true,
'max_sale_qty' => false,
'isFree' => 0,
'segment' =>
array (
'magento_product_id' => '614565225',
'product_id' => 'P1945652050',
'quantity' => 1,
'name' => 'Phantom Feelings Maxi Dress',
'brand' => 'Widow',
'price' => 58.0,
'special_price' => NULL,
'regular_price' => 58.0,
'size_type' => 'Regular',
'manufacturer' => 'Widow',
'trend' => 'WID goodie Hour 2020',
'microcategory' => 'Maxi Dresses',
'category' => 'Dresses,Midi & Maxi,Maxi Dresses',
'special_category' => 'Brandsgoodie,Char Test Category,Widow,Widow',
'doll_category' => NULL,
'stock_quantity' => 10,
'sku' => 'S485794',
'child_stock_quantity' => 10,
'size' => 'Large',
'swatch' => 'BLACK',
),
)
);
$itemId = 5; // comes dybamically;
if ( isset($_SESSION['cart'][$itemId])) {
unset($_SESSION['cart'][$itemId]);
}
?>
I am not getting it,
Any thoughts ?
You can also take a look at the sandbox- http://sandbox.onlinephpfunctions.com/code/6bab394d1da39a301ce82b974022da7b7efaface
Please refer to the whole code here - PHP SESSION UPDATE ISSUE
Thankyou

Answer 1

You're proably re-reading session-data so that deletion you're making is overridden.
<?php
$cart = $_SESSION['cart'];
unset($cart[5]);
echo 'deletion confirmed';
//later in execution..
//accidental re-read of cart from session-variable.
//BAD CODE STARTS HERE
$cart = $_SESSION['cart']; //error since you're re-reading cart from session.
//BAD CODE END
//calc totals in basket or something..
$totals = 0;
foreach($cart as $item) {
$totals = $totals + $item['qty'] * $item['price'];
}
//somewhere in the script, the session variable is updated.
$_SESSION['cart'] = $cart;
GOOD TO KNOW
PHP passes most variables by value as default, meaning that
$cart = $_SESSION['cart'];
copies the content of $_SESSION['cart'] into $cart.
Any change made to $cart will not automatically be updated in $_SESSION['cart'].
If you don't want a copy but a reference, you may use:
$cart = &$_SESSION['cart'];
and you will not need to save $cart into $_SESSION.
(Just make sure $_SESSION['cart'] is initialized when making the reference)
** AND **
Session variables tend to grow to a mess.. Use getters and setters in your application.

Answer 2

The best approach is to after unset get the updated array from session and declare it again
$cart_array = array (
0 =>
array (
'id' => 6154353459,
'name' => 'pro one Night Out Mesh Tee',
'display_brand' => 'Widow',
'qty' => 1,
'price' => '28.0000',
'special_price' => 0,
'rule_price' => '',
'attributes' =>
array (
0 => 'BLACK',
1 => 'XX-Large',
),
'option80' => 18,
'option125' => 3457,
'child_product_id' => 61535897,
'giftcard' => '',
'whole_preorder' => 0,
'preorder_shipping_date' => NULL,
'available_qty' => 5,
'isRefundable' => true,
'max_sale_qty' => false,
'isFree' => 0,
'segment' =>
array (
'magento_product_id' => '65315459',
'product_id' => 'P19335935',
'quantity' => 1,
'name' => 'pro one Night Out Mesh Tee',
'brand' => 'Widow',
'price' => 28.0,
'special_price' => NULL,
'regular_price' => 28.0,
'size_type' => 'Regular',
'manufacturer' => 'Widow',
'trend' => 'WID goodie Hour 2020',
'microcategory' => 'Mesh Shirt',
'doll_category' => NULL,
'stock_quantity' => 10,
'sku' => 'S493660',
'child_stock_quantity' => 1,
'size' => 'XX-Large',
'swatch' => 'BLACK',
),
),
5 =>
array (
'id' => 615345465,
'name' => 'pro one Night Out Mesh Leggings',
'display_brand' => 'Widow',
'qty' => 1,
'price' => '30.0000',
'special_price' => 0,
'rule_price' => '',
'attributes' =>
array (
0 => 'BLACK',
1 => 'Medium',
),
'option80' => 18,
'option125' => 3454,
'child_product_id' => 6315890,
'giftcard' => '',
'whole_preorder' => '',
'preorder_shipping_date' => NULL,
'available_qty' => 37,
'isRefundable' => true,
'max_sale_qty' => false,
'isFree' => 0,
'segment' =>
array (
'magento_product_id' => '64334515465',
'product_id' => 'P193936',
'quantity' => 1,
'name' => 'pro one Night Out Mesh Leggings',
'brand' => 'Widow',
'price' => 30.0,
'special_price' => NULL,
'regular_price' => 30.0,
'size_type' => 'Regular',
'manufacturer' => 'Widow',
'trend' => 'WID goodie Hour 2020',
'microcategory' => 'Printed Leggings',
'doll_category' => NULL,
'stock_quantity' => 10,
'sku' => 'S493664',
'child_stock_quantity' => 10,
'size' => 'Medium',
'swatch' => 'BLACK',
),
),
2 =>
array (
'id' => 615445348,
'name' => 'pro two My Lashes Sunglasses',
'display_brand' => '',
'qty' => 1,
'price' => '15.0000',
'special_price' => 0,
'rule_price' => '',
'attributes' =>
array (
0 => 'BLACK',
1 => 'ONE SIZE',
),
'option80' => 18,
'option125' => 6212,
'child_product_id' => 6154345358,
'giftcard' => '',
'whole_preorder' => '',
'preorder_shipping_date' => NULL,
'available_qty' => 295,
'isRefundable' => true,
'max_sale_qty' => false,
'isFree' => 0,
'segment' =>
array (
'magento_product_id' => '6153453448',
'product_id' => 'P19645642180',
'quantity' => 1,
'name' => 'pro two My Lashes Sunglasses',
'brand' => '',
'price' => 15.0,
'special_price' => NULL,
'regular_price' => 15.0,
'size_type' => 'Regular',
'manufacturer' => 'CIEL',
'trend' => 'WID goodie Hour 2020',
'microcategory' => 'Cat Eye Sunglasses',
'category' => 'Accessories,Sunglasses,Cat Eye Sunglasses',
'special_category' => 'What\'s New,Char Test Category,Widow',
'doll_category' => NULL,
'stock_quantity' => 10,
'sku' => 'S486477',
'child_stock_quantity' => 10,
'size' => 'ONE SIZE',
'swatch' => 'BLACK',
),
),
3 =>
array (
'id' => 61465645461,
'name' => 'pro one Night Out goodie Dress',
'display_brand' => 'Widow',
'qty' => 1,
'price' => '45.0000',
'special_price' => 0,
'rule_price' => '',
'attributes' =>
array (
0 => 'BLACK',
1 => 'X-Large',
),
'option80' => 18,
'option125' => 3456,
'giftcard' => '',
'whole_preorder' => '',
'preorder_shipping_date' => NULL,
'available_qty' => 12,
'isRefundable' => true,
'max_sale_qty' => false,
'isFree' => 0,
'segment' =>
array (
'magento_product_id' => '616465461',
'product_id' => 'P1935446934',
'quantity' => 1,
'name' => 'pro one Night Out goodie Dress',
'brand' => 'Widow',
'price' => 45.0,
'special_price' => NULL,
'regular_price' => 45.0,
'size_type' => 'Regular',
'manufacturer' => 'Widow',
'trend' => 'WID goodie Hour 2020',
'microcategory' => 'goodie Dresses',
'category' => 'Clothing,Dresses,Mini,goodie Dresses',
'special_category' => 'Brandsgoodie,Char Test Category,Widow,Widow',
'doll_category' => NULL,
'stock_quantity' => 10,
'sku' => 'S493652',
'child_stock_quantity' => 10,
'size' => 'X-Large',
'swatch' => 'BLACK',
),
),
4 =>
array (
'id' => 6154566225,
'name' => 'Feelings Maxi Dress',
'display_brand' => 'Widow',
'qty' => 1,
'price' => '58.0000',
'special_price' => 0,
'rule_price' => '',
'attributes' =>
array (
0 => 'BLACK',
1 => 'Large',
),
'option80' => 18,
'option125' => 3455,
'child_product_id' => 61456455677,
'giftcard' => '',
'whole_preorder' => '',
'preorder_shipping_date' => NULL,
'available_qty' => 30,
'isRefundable' => true,
'max_sale_qty' => false,
'isFree' => 0,
'segment' =>
array (
'magento_product_id' => '614565225',
'product_id' => 'P1945652050',
'quantity' => 1,
'name' => 'Phantom Feelings Maxi Dress',
'brand' => 'Widow',
'price' => 58.0,
'special_price' => NULL,
'regular_price' => 58.0,
'size_type' => 'Regular',
'manufacturer' => 'Widow',
'trend' => 'WID goodie Hour 2020',
'microcategory' => 'Maxi Dresses',
'category' => 'Dresses,Midi & Maxi,Maxi Dresses',
'special_category' => 'Brandsgoodie,Char Test Category,Widow,Widow',
'doll_category' => NULL,
'stock_quantity' => 10,
'sku' => 'S485794',
'child_stock_quantity' => 10,
'size' => 'Large',
'swatch' => 'BLACK',
),
)
);
if(!isset($_SESSION['cart'])) {
$_SESSION['cart'] = $cart_array;
} else {
$_SESSION['cart'] = (array) $_SESSION['cart'];
}
$itemId = 3;
if (isset($_SESSION['cart'][$itemId])) {
unset($_SESSION['cart'][$itemId]);
}
print_r($_SESSION['cart']);
Now it will be not back the remove item again, unless if you destroy the session

Answer 3

Why is there $item['id'] used in $stmt->bind_param( (instead of $id?). $item is not a parameter of the function.
Similarly, where does the variable $i come from in $itemId = $i;?
I have written a simplified version of your problem and it works as expected. It uses a form and buttons to give the array indices to the PHP script. If you have a different setup (like using Ajax) you need to clarify that.
session_start();
if (!isset($_SESSION['cart']) || sizeof($_SESSION['cart']) === 0)
{
echo('Resetting cart.' . PHP_EOL);
$_SESSION['cart'] = [0 =>'zero', 1 =>'one', 2 =>'two', 3 =>'three', 4 =>'four'];
}
echo('<pre>before ' . print_r($_SESSION['cart'], TRUE) . '</pre>');
$itemId = isset($_GET['itemid']) ? $_GET['itemid'] : FALSE;
if ($itemId !== FALSE)
{
if (isset($_SESSION['cart'][$itemId]))
{
echo('Unsetting »' . $itemId . '«.' . PHP_EOL);
unset($_SESSION['cart'][$itemId]);
}
else
echo('»' . $itemId . '« not in cart.' . PHP_EOL);
}
else
echo('No item ID given.' . PHP_EOL);
echo('<pre>after ' . print_r($_SESSION['cart'], TRUE) . '</pre>');
echo('<form method="get" action="' . $_SERVER['PHP_SELF'] . '">' . PHP_EOL);
foreach ($_SESSION['cart'] as $key=>$value)
echo('<button name="itemid" value="' . $key . '">' . $value . '</button>' . PHP_EOL);
echo('</form>' . PHP_EOL);

Answer 4

The manual has made it clear
If a globalized variable is unset() inside of a function, only the local variable is destroyed. The variable in the calling environment will retain the same value as before unset() was called.
To unset() a global variable inside of a function, then use the $GLOBALS array to do so:
<?php
function foo()
{
unset($GLOBALS['bar']);
}
$bar = "something";
foo();
?>

Answer 5

$stmt->bind_param('ii', $item['id'],$cartId);
$stmt->execute();
where is $item['id'] from?
Try using different variable names on your bind_param and declare their value before query execute() method.