使添加到购物车按钮适用于简单的网上商店

Question

I'm trying to make it so that when the "add" button is pressed on a specific product page the product is added to a $_SESSION.

if(isset($_POST['add'])) {
$_SESSION['cart'] [] = array('product_name' => $result['name'], 'product_price'=> $result['price'], 'product_id' => $result['id']); }

<form method="post">
<input type="submit" class="button blueboxbutton userAccountButton" name="add" value="add"></input></br>
</form>

The above piece of code is working without any problems and it saves the required information without any problems, but items are also added when the page is refreshed. How can I make it so that items are only added to the cart when the "add" button is pressed? I've read many "solutions", but somehow I couldn't get them to work correctly. If any additional information is needed I can post it. Thanks in advance!

Answer 1

One method is to redirect after the $_SESSION has been set.

if( isset( $_POST['add'] ) ) {
    $_SESSION['cart'][] = [ 'product_name'  => $result['name'],
                            'product_price' => $result['price'],
                            'product_id'    => $result['id']
                          ]; 
    // redirect to this same page, but without the $_POST variables
    header('location: ' . $_SERVER[ 'PHP_SELF' ] );
    // If you don't die() after redirect, sometimes doesn't actually redirect
    die();
}

You could even, if desired, set a "flag" to indicate the item was added to cart, and display a message:

if( isset( $_POST['add'] ) ) {
    $_SESSION['cart'][] = [ 'product_name'  => $result['name'],
                            'product_price' => $result['price'],
                            'product_id'    => $result['id']
                          ]; 
     $message = urlencode( $result['name'] . ' added to cart.' );
     // redirect to this same page, but without the $_POST variables
     header( 'location: ' . $_SERVER[ 'PHP_SELF' ] . '?message=' . $message );
     // If you don't die() after redirect, sometimes doesn't actually redirect
     die();
}

// Elsewhere in your code display a message if set...
if ( ! empty( $_GET[ 'message' ] ) ) {
    // urldecode is used because we urlencoded above
    // htmlspecialchars is used to help "sanitize" the display
    echo '<div class="message">' . htmlspecialchars( urldecode( $_GET['message'] ) ) . '</div>';
}