Check user is trying to checkout with current cart

app/Http/Controllers/Store/CheckoutController.php

@@ -87,12 +87,20 @@ public function show()
     public function store()
     {
         $order = $this->userCart();
+        $orderId = get_int(request('orderId'));
+        $provider = request('provider');
 
         if ($order->isEmpty()) {
             return ujs_redirect(route('store.cart.show'));
         }
 
-        $provider = Request::input('provider');
+        // check that we aren't checking out using some ancient cart;
+        // otherwise the Xsolla client will use the stale cart.
+        if ($order->order_id !== $orderId) {
+            return $this->setAndRedirectCheckoutError(
+                trans('store.checkout.old_cart')
+            );
+        }
 
         $checkout = new OrderCheckout($order, $provider);
         $checkout->beginCheckout();

resources/assets/lib/store-checkout.coffee

@@ -37,13 +37,14 @@ export class StoreCheckout
 
     $(@CHECKOUT_SELECTOR).on 'click.checkout', (event) =>
       provider = event.target.dataset.provider
+      orderId = event.target.dataset.orderId
       # sanity
       return unless provider?
       LoadingOverlay.show()
       LoadingOverlay.show.flush()
 
       init[provider]?.then =>
-        $.post laroute.route('store.checkout.store'), provider: provider
+        $.post laroute.route('store.checkout.store'), { provider, orderId }
         .done =>
           @startPayment(event.target.dataset)
 

resources/lang/en/store.php

@@ -28,6 +28,7 @@
         'cart_problems_edit' => 'Click here to go edit it.',
         'declined' => 'The payment was cancelled.',
         'error' => 'There was a problem completing your checkout :(',
+        'old_cart' => 'Your cart appears to be out of date and has been reloaded, please try again.',
         'pay' => 'Checkout with Paypal',
         'pending_checkout' => [
             'line_1' => 'A previous checkout was started but did not finish.',

resources/views/store/_checkout_centili.blade.php

@@ -21,6 +21,7 @@
         <button type="button"
                 class="js-store-checkout-button store-payment-button store-payment-button--centili"
                 data-provider="centili"
+                data-order-id="{{ $order->order_id }}"
                 data-url="{{ $checkout->getCentiliPaymentLink() }}"
         >
     </div>

resources/views/store/_checkout_free.blade.php

@@ -19,6 +19,7 @@
     <button type="button"
             class="js-store-checkout-button btn-osu btn-osu-danger"
             data-provider="free"
+            data-order-id="{{ $order->order_id }}"
             data-order-number="{{ $order->getOrderNumber() }}"
     >
         Complete Order

resources/views/store/_checkout_xsolla.blade.php

@@ -21,6 +21,7 @@
         <button type="button"
                 class="js-store-checkout-button store-payment-button store-payment-button--xsolla"
                 data-provider="xsolla"
+                data-order-id="{{ $order->order_id }}"
                 data-order-number="{{ $order->getOrderNumber() }}"
         >
         </button>