I've built an integrated payment service for Payflow Pro, and I've got the link between uCommerce and that working well. The problem is that now I'm having a problem getting the pipeline to add the order to the new orders section, clear the user's basket, and send them a confirmation email.

My payment service is a synchronous, single transaction process. From what I've read about the checkout pipeline, that's relevant.

Here's the relevant code from my payment service:

         public UCommerce.EntitiesV2.Payment ProcessPaymentRequest(PaymentRequest request)
        {
            try
            {
                System.Configuration.AppSettingsReader reader = new AppSettingsReader();
                string sAmt = request.Amount.ToString();
                var amt = Regex.Split(sAmt, @"[^0-9\.]+").Where(c => c != "." && c.Trim() != "");

                string PayPalRequest = "TRXTYPE=S" //S - sale transaction
                     + "&TENDER=C" //C - Credit card
                     + "&FIRSTNAME=" + request.AdditionalProperties["FIRST"]
                     + "&LASTNAME=" + request.AdditionalProperties["LAST"]
                     + "&ACCT=" + request.AdditionalProperties["CCNUM"] //card number
                     + "&EXPDATE=" + request.AdditionalProperties["EXP"]
                     //+ "&CVV2=" + request.AdditionalProperties["CCV"]   //card validation value (card security code)
                     + "&AMT=" + amt.FirstOrDefault().ToString()
                     + "&COMMENT1=Composter Sale"
                     + "&USER=" + reader.GetValue("USER", typeof(string)) //ConfigurationSettings.AppSettings["USER"]
                     + "&VENDOR=" + reader.GetValue("VENDOR", typeof(string)) //ConfigurationSettings.AppSettings["VENDOR"]
                     + "&PARTNER=" + reader.GetValue("PARTNER", typeof(string)) //ConfigurationSettings.AppSettings["PARTNER"]
                     + "&PWD=" + reader.GetValue("PWD", typeof(string)); //ConfigurationSettings.AppSettings["PWD"];

                // Create an instance of PayflowNETAPI.
                PayflowNETAPI PayflowNETAPI = new PayflowNETAPI();

                // RequestId is a unique string that is required for each & every transaction. 
                // The merchant can use her/his own algorithm to generate 
                // this unique request id or use the SDK provided API to generate this
                // as shown below (PayflowUtility.RequestId).
                string PayPalResponse = PayflowNETAPI.SubmitTransaction(PayPalRequest, PayflowUtility.RequestId);

                // Place the data from PayPal into a namevalue collection.
                NameValueCollection RequestCollection = GetPayPalCollection(PayflowNETAPI.TransactionRequest);
                NameValueCollection ResponseCollection = GetPayPalCollection(PayPalResponse);

                // Check for transaction errors, if any.
                string TransErrors = PayflowNETAPI.TransactionContext.ToString();
                if (TransErrors != null && TransErrors.Length > 0)
                {
                    throw new Exception("Error contacting Payflow Pro service. Error: " + TransErrors);
                }

                Payment p = new Payment
                {
                    PaymentMethod = request.PaymentMethod,
                    PaymentStatus = PaymentStatus.Get((int)GetPayflowStatus(ResponseCollection["RESULT"])), // This throws an error in development, but should work in production.
                    Amount = request.Amount.Value,
                    TransactionId = ResponseCollection["PNREF"],
                    ReferenceId = ResponseCollection["PPREF"],
                    PurchaseOrder = request.PurchaseOrder,
                    Fee = 0,
                    FeePercentage = 0,
                    Created = DateTime.Now
                };
                if (p.PaymentStatus.Name != "Authorized")
                {
                    PaymentProperty pp = new PaymentProperty();
                    pp.Key = "RESULT";
                    pp.Value = ResponseCollection["RESULT"];
                    p.PaymentProperties.Add(pp);

                    pp = new PaymentProperty();
                    pp.Key = "RESPMSG";
                    pp.Value = ResponseCollection["RESPMSG"];
                    p.PaymentProperties.Add(pp);
                }

                return p;
            }
            catch (Exception ex)
            {
                Payment p = new Payment();
                p.TransactionId = "-1";
                p.PaymentStatus = new PaymentStatus();
                p.PaymentStatus.Name = "[" + ex.Message + "]" + ex.StackTrace;

                return p;
            }
        }

        public UCommerce.EntitiesV2.Payment RequestPayment(PaymentRequest request)
        {
            // The user has requested to process their payment, so return the result of the processpaymentrequest function.
            return ProcessPaymentRequest(request);
        }

Here's the Razor code that I modified from the demo Razor store. There will be some unneccessary calls in here, from my efforts to make this go:

@using UCommerce
@using UCommerce.EntitiesV2
@using UCommerce.Transactions.Payments
@using UCommerce.Extensions
@using UCommerce.Runtime
@using umbraco.MacroEngines
@using UCommerce.Api
@using UCommerce.Pipelines
@using UCommerce.Transactions

@{
    var basket = SiteContext.Current.OrderContext.GetBasket();
    var po = basket.PurchaseOrder;
    var payment = po.Payments.FirstOrDefault();

    if (HttpContext.Current.Request.HttpMethod == "POST" && HttpContext.Current.Request.Form.AllKeys.Any(x => x == "update-payment"))
    {
        // Get the amount to request
        var amountToRequest = new Money(po.OrderTotal.Value, po.BillingCurrency); 

        // Get the payment method and set up a new payment request
        var paymentMethodName = HttpContext.Current.Request.Form["payment-method"];

        if (paymentMethodName != "")
        {
            var paymentMethod = PaymentMethod.SingleOrDefault(x => x.Name == paymentMethodName);
            var paymentRequest = new PaymentRequest(po, paymentMethod, amountToRequest);

            // Build additional properties to pass in the user's credit card information, if appropriate.
            if(paymentMethod.Name.ToLower() == "pay online")
            {
                paymentRequest.AdditionalProperties.Add("FIRST", HttpContext.Current.Request.Form["first"]);
                paymentRequest.AdditionalProperties.Add("LAST", HttpContext.Current.Request.Form["last"]);
                paymentRequest.AdditionalProperties.Add("CCNUM", HttpContext.Current.Request.Form["ccnum"]);
                paymentRequest.AdditionalProperties.Add("EXP", HttpContext.Current.Request.Form["month"] + HttpContext.Current.Request.Form["year"]);
            }

            // Get the service
            IPaymentMethodService paymentService = paymentMethod.GetPaymentMethodService();

            // Advance to the next stage of the basket pipeline.
            TransactionLibrary.ExecuteBasketPipeline();

            // Request payment with selected service
            Payment payResult = paymentService.RequestPayment(paymentRequest);

            // Check that it's OK
            var okPaymentStatus = PaymentStatus.Get((int)PaymentStatusCode.Authorized); 
            bool ok = payResult.PaymentStatus == okPaymentStatus;

            if(ok)
            {
                try
                {
                <h1>Ok</h1>

                // Add the payment to the purchase order.
                payResult.PaymentStatus = PaymentStatus.Get((int) PaymentStatusCode.Acquired);
                po.AddPayment(payResult);

                // Advance to the next stage of the basket pipeline.
                TransactionLibrary.ExecuteBasketPipeline();

                // Execute the checkout stage of the order pipeline. This clears the basket and sends a confirmation email.
                TransactionLibrary.Checkout();

                // Advance to the next stage of the basket pipeline.
                TransactionLibrary.ExecuteBasketPipeline();

                //HttpContext.Current.Response.Redirect("Confirmation.aspx");
                }
                catch(Exception ex)
                {
                    <p>@ex.Message</p>
                    <p>@ex.InnerException.ToString()</p>
                }
            }
            else
            {
                <h1>There was a problem processing your order.</h1>

                /* For troubleshooting purposes
                <p>@paymentCheck.TransactionId</p>
                <p>@paymentCheck.PaymentStatus.Name</p>

                foreach(PaymentProperty pp in paymentCheck.PaymentProperties)
                {
                    <p>@pp.Key</p>
                    <p>@pp.Value</p>
                }
                */
            }

        }

    }
}

@helper RenderPaymentMethodLabel(PaymentMethod paymentMethod, PurchaseOrder po)
{
    decimal feePercent = paymentMethod.FeePercent;

    var fee = paymentMethod.GetFeeForCurrency(po.BillingCurrency);
    var formattedFee = new Money((fee == null ? 0 : fee.Fee), po.BillingCurrency);

    @paymentMethod.Name <text>(</text>@formattedFee <text>+</text> @feePercent.ToString("0.00")<text>%)</text> 

}


<form  method="post">
    <div class="row-fluid well" >
        <div class="span6">
            <h3>Payment method</h3>
            <br/>
            @foreach (var paymentMethod in TransactionLibrary.GetPaymentMethods())
            {
                <label class="radio">
                <input type="radio" name="payment-method"  @(payment != null && payment.PaymentMethod.Equals(paymentMethod) ? "checked" : string.Empty) 
                value="@paymentMethod.Name" />@RenderPaymentMethodLabel(paymentMethod, po)</label>
            }
        </div>
            <div>
            <p style="font-weight:bold">
            Credit Card Information (if paying online)
            </p>
            <table cellpadding="4" cellspacing="0" border="1">
            <tr>
                <td>
                    Name:
                </td>
                <td>
                    First: <input type="text" name="first" style="width:100px;" /> Last: <input type="text" name="last" style="width:100px;" />
                </td>
            </tr>
            <tr>
                <td>
                    Credit Card Number:
                </td>
                <td>
                    <input type="text" name="ccnum" style="width:200px;" />
                </td>
            </tr>
            <tr>
                <td>
                    Expiry Date:
                </td>
                <td>
                    M:  <input type="text" name="month" style="width:100px;" /> Y:  <input type="text" name="year" style="width:100px;" />
                </td>
            </tr>
        </table>
        </div>

    </div>
    <a href="/cart/shipping.aspx" class="btn btn-small">Back to Shipping Method</a>
    <button name="update-payment" class="pull-right btn btn-large btn-success" type="submit">Continue to Payment Page <i class="icon-arrow-right icon-white"></i></button>
</form>

Here's the modified Checkout.config. I just removed a couple of unneccessary steps:

<configuration>
    <components>
        <!-- Pipeline Instance -->
        <component id="Checkout"
                   service="UCommerce.Pipelines.IPipeline`1[[UCommerce.EntitiesV2.PurchaseOrder, UCommerce]], UCommerce"
                   type="UCommerce.Pipelines.Checkout.CheckoutPipeline, UCommerce.Pipelines">
            <parameters>
                <tasks>
                    <array>
                        <value>${Checkout.AssignOrderNumber}</value>
                        <value>${Checkout.CreateCustomer}</value>
                        <value>${Checkout.ConvertBasketToPurchaseOrder}</value>
                        <value>${Checkout.AddAuditTrailForCurrentOrderStatus}</value>
                        <value>${Checkout.ClearBasketInformation}</value>
                        <value>${Checkout.SavePurchaseOrder}</value>
                        <value>${Checkout.SendConfirmationEmail}</value>
                    </array>
                </tasks>
            </parameters>
        </component>

        <!-- Pipeline Tasks-->
        <component id="Checkout.CreateCustomer"
                   service="UCommerce.Pipelines.IPipelineTask`1[[UCommerce.EntitiesV2.PurchaseOrder, UCommerce]], UCommerce"
                   type="UCommerce.Pipelines.Checkout.CreateCustomerTask, UCommerce.Pipelines" />

        <component id="Checkout.AssignOrderNumber"
                   service="UCommerce.Pipelines.IPipelineTask`1[[UCommerce.EntitiesV2.PurchaseOrder, UCommerce]], UCommerce"
                   type="UCommerce.Pipelines.Checkout.AssignOrderNumberTask, UCommerce.Pipelines" />

        <component id="Checkout.ConvertBasketToPurchaseOrder"
                   service="UCommerce.Pipelines.IPipelineTask`1[[UCommerce.EntitiesV2.PurchaseOrder, UCommerce]], UCommerce"
                   type="UCommerce.Pipelines.Checkout.ConvertBasketToPurchaseOrderTask, UCommerce.Pipelines" />

        <component id="Checkout.SavePurchaseOrder"
                   service="UCommerce.Pipelines.IPipelineTask`1[[UCommerce.EntitiesV2.PurchaseOrder, UCommerce]], UCommerce"
                   type="UCommerce.Pipelines.Common.SavePurchaseOrderTask, UCommerce.Pipelines" />

        <component id="Checkout.AddAuditTrailForCurrentOrderStatus"
                   service="UCommerce.Pipelines.IPipelineTask`1[[UCommerce.EntitiesV2.PurchaseOrder, UCommerce]], UCommerce"
                   type="UCommerce.Pipelines.Common.AddAuditTrailForCurrentOrderStatusTask, UCommerce.Pipelines" />

        <component id="Checkout.ClearBasketInformation"
                   service="UCommerce.Pipelines.IPipelineTask`1[[UCommerce.EntitiesV2.PurchaseOrder, UCommerce]], UCommerce"
                   type="UCommerce.Pipelines.Checkout.ClearBasketInformationTask, UCommerce.Pipelines" />

        <component id="Checkout.SendConfirmationEmail"
                   service="UCommerce.Pipelines.IPipelineTask`1[[UCommerce.EntitiesV2.PurchaseOrder, UCommerce]], UCommerce"
                   type="UCommerce.Pipelines.Common.SendEmailTask, UCommerce.Pipelines">
            <parameters>
                <emailTypeName>OrderConfirmation</emailTypeName>
            </parameters>
        </component>
    </components>
</configuration>

When I call the Checkout method, I'm getting the following error message:

Exception occoured while processing pipeline 'UCommerce.Pipelines.Basket.BasketPipeline'. See inner exception for details.

System.InvalidOperationException: Nullable object must have a value. at System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource) at System.Nullable`1.get_Value() at UCommerce.Pipelines.Basket.CalculatePaymentTotalTask.Execute(PurchaseOrder purchaseOrder) at UCommerce.Pipelines.Pipeline`1.Execute(T subject)

I'd love some help on this. I'm sure I'm just missing a simple step somewhere.

Thanks,

-Sheppe