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Question

Soo I want to be able to update my cart table in mysql database, when you click plus minus button in the cart of my ecommerce website. I want to be able to do this with session_id(), so no login and no cookies. Is this possible?

I tried this:

I also have a page called add_to_cart.php in which i set session_id() and update quantity everytime someone clicks on “add to cart”

<body>
    <h1>Your Cart</h1>
    <div class="cart-container" id="cart-container">
    <div class="cart">
        <?php while ($row = $result->fetch_assoc()): ?>
            <div class="cart-item" id="cart-item" data-product-id=<?php echo $row['product_id'];?>>
                <h2><?php echo $row['productname']; ?></h2>
                <img id="img" style="border-radius:20px;width:150px" src="data:image/jpg;charset=utf;base64, <?php echo base64_encode($row["productimage"]); ?>"/>
                <p>Price: $<?php echo $row['price']; ?></p>
                <div class="quantity-selector"><p>Quantity:</p>
        <button class="minus-btn" onclick="decrement(this)">-</button>
        <input type="number" id="quantity" class="quantity" value="1" min="1">
        <button class="plus-btn" onclick="increment(this)">+</button>
    </div>
                <p>Quantity: <?php echo $row['quantity']; ?></p>
                <span class="quantity">1</span>
                <p>Subtotal: $<?php echo $row['price'] * $row['quantity']; ?></p>
                
            </div>
 
        <?php endwhile; ?>
    </div>
        </div>

    <script>
var item= document.getElementsByClassName("cart-item");

function increment(element) {
    //var quantityInput = document.getElementById('quantity');
    let quantityInput = element.closest("div.cart-item").querySelector(".quantity");
    var productId = element.closest("div.cart-item").getAttribute('data-product-id');
    var currentValue = parseInt(quantityInput.value);
    //var quantitySpan = element.closest("div.cart-item").querySelector('.quantity');
    quantityInput.value = currentValue + 1;
    //var newQuantity = parseInt(quantitySpan.innerText) + 1;
    //updateQuantity(element.closest("div.cart-item").dataset.itemId, quantityInput.value);
    var xhr = new XMLHttpRequest();
    xhr.open('POST', 'update_cart.php', true);
    xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    xhr.onreadystatechange = function() {
        if (xhr.readyState === 4 && xhr.status === 200) {
            // Update the quantity in the UI
            //quantityInput.innerText = quantityInput.value;
            quantityInput.innerText = quantityInput.value;
        }
    };
    xhr.send('product_id=' + productId + '&quantity=' + quantityInput.value);
}

function decrement(element) {
    //var quantityInput = document.getElementById('quantity');
    let quantityInput = element.closest("div.cart-item").querySelector(".quantity");
    var productId = element.closest("div.cart-item").getAttribute('data-product-id');
    var currentValue = parseInt(quantityInput.value);
    if (currentValue > 1) {
        quantityInput.value = currentValue - 1;
    }
    
    //updateQuantity(element.closest("div.cart-item").dataset.itemId, quantityInput.value);
    var xhr = new XMLHttpRequest();
    xhr.open('POST', 'update_cart.php', true);
    xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    xhr.onreadystatechange = function() {
        if (xhr.readyState === 4 && xhr.status === 200) {
            // Update the quantity in the UI
            quantityInput.innerText = quantityInput.value;
        }
    };
    xhr.send('product_id=' + productId + '&quantity=' + quantityInput.value);
}

and this is my 'update_cart.php' file:

<?php
session_start();
if (!isset($_SESSION['user_session'])) {
    // Generate a new session id if not already set
    $_SESSION['user_session'] = session_id();
}

$session_id = $_SESSION['user_session'];
$product_id = $_POST['product_id'];
$new_quantity = $_POST['quantity'];

// Database connection
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "luciavioleta";

$conn = new mysqli($servername, $username, $password, $dbname);

if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

// Update quantity in the database
$sql = "UPDATE cart SET quantity = ? WHERE user_session = ? AND product_id = ?";
$stmt = $conn->prepare($sql);
$stmt->bind_param("isi", $new_quantity, $session_id, $product_id);

if ($stmt->execute()) {
    echo "Quantity updated successfully";
} else {
    echo "Error updating quantity: " . $conn->error;
}

$stmt->close();
$conn->close();

?>

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Danh mục

How to update my cart database on click of plus minus button in cart on ecommerce website with session_id()