Best approach for Laravel Cashier "top up" purchase flow

[sts-ryan-holton]

Hi, I'm building a web application where users can purchase "SMS credits". Each credit can be used to send an SMS. So users will need to purchase credits which are then stored as a CreditTransaction entry with a delta column in my database, this way, each transaction can have a negative or positive delta value and the sum of all of these is the user's credit balance.

My initial approach here, is to have a Laravel job called ProcessCreditTransaction which is triggered on the checkout, I believe this is fine for customers that enter my try block, but for customers that enter the catch, and where additional payment action is required, how can I only trigger my Job if successful?

Right now, for example, if the $e->payment->requiresPaymentMethod() block is triggered, then so is my job to add credits to their account, but if they didn't complete the purchase, then they've now got a positive amount of credits in their account?

How's best to handle this, here's my current checkout purchase flow:

The TODO comments are the parts I need some advice on.

// attempt to charge
try {
    $productPrice = Cashier::stripe()->prices->retrieve($productOption->stripe_id);

    // get user
    $user = Auth::user();

    // get customer
    if (Cashier::findBillable($user->stripe_id)) {
        $user->invoicePrice($productOption->stripe_id);
    } else {
        $user->createOrGetStripeCustomer();
        $user->updateDefaultPaymentMethod($request->input('token'));
        $user->invoicePrice($productOption->stripe_id);
    }

    // update region of API key
    if (!$apiKey->region_code) {
        $apiKey->region_code = $request->input('region');
        $apiKey->save();
    }

    // apply balance
    ProcessCreditTransaction::dispatch(
        Carbon::now(), $user->id, $apiKey->uuid, $productOption->quantity
    )->onQueue('on-demand-runs-now');

    return response()->json([
        'complete' => true,
        'message' => "You've successfully topped-up credits for this API key. You'll soon be able to download the invoice for this item. You can now start sending messages using this API key to the SMS region you specified.",
        'redirectTo' => "$frontendUrl/account/billing/checkout/result/?success=true&id=".$productOption->id,
    ], 200);

} catch (IncompletePayment $e) {

    // if we require some action, perform it here
    if ($e->payment->requiresAction()) {

        // update region of API key
        if (!$apiKey->region_code) {
            $apiKey->region_code = $request->input('region');
            $apiKey->save();
        }

        // apply balance
        // TODO: we may need to move this part to an event
        ProcessCreditTransaction::dispatch(
            Carbon::now(), $user->id, $apiKey->uuid, $productOption->quantity
        )->onQueue('on-demand-runs-now');

        return response()->json([
            'message' => 'We require some payment action from you to complete this purchase, this usually means you need to open your banking app to approve this subscription.',
            'requiresAction' => true,
            'redirectTo' => route('cashier.payment', [
                $e->payment->id,
                'redirect' => "$frontendUrl/account/billing/checkout/result/?id=".$productOption->id,
            ]),
        ], 400);
    } elseif ($e->payment->requiresPaymentMethod()) {

        // update region of API key
        if (!$apiKey->region_code) {
            $apiKey->region_code = $request->input('region');
            $apiKey->save();
        }

        // apply balance
        // TODO: we may need to move this part to an event
        ProcessCreditTransaction::dispatch(
            Carbon::now(), $user->id, $apiKey->uuid, $productOption->quantity
        )->onQueue('on-demand-runs-now');

        return response()->json([
            'message' => "The payment method currently set up is invalid or has sufficient funds, we're going to redirect you to complete this transaction, please wait.",
            'requiresAction' => true,
            'redirectTo' => route('cashier.payment', [
                $e->payment->id,
                'redirect' => "$frontendUrl/account/billing/checkout/result/?id=".$productOption->id,
            ]),
        ], 400);
    } elseif ($e->payment->requiresConfirmation()) {

        // update region of API key
        if (!$apiKey->region_code) {
            $apiKey->region_code = $request->input('region');
            $apiKey->save();
        }

        // apply balance
        // TODO: we may need to move this part to an event
        ProcessCreditTransaction::dispatch(
            Carbon::now(), $user->id, $apiKey->uuid, $productOption->quantity
        )->onQueue('on-demand-runs-now');

        return response()->json([
            'message' => 'We jsut need you to confirm this payment.',
            'requiresAction' => true,
            'redirectTo' => route('cashier.payment', [
                $e->payment->id,
                'redirect' => "$frontendUrl/account/billing/checkout/result/?id=".$productOption->id,
            ]),
        ], 400);
    }

    // generic error
    return response()->json([
        'message' => "We wasn't able to complete this purchase. You haven't been charged. Please try again soon.",
        'requiresAction' => true,
        'redirectTo' => "$frontendUrl/account/billing/checkout/result/?success=false",
    ], 400);
}