C# and Google Checkout - getting the reply back from the server?

Question

Are there any tutorials out there on how to get the responses back from a Google Checkout transaction when using C# and the GCheckout API. All of the examples I could find were for previous versions of the API and not the current one (2.5). More specifically, I'd like to see an example reply of what Google will post back to me without and HTTPS connection. I know it's minimal data, but I'd still like to see an example of it and see how others are parsing it.

Answer 1

Google sends notification internally
Create a notification page like this:

<%@ Import Namespace="System.IO" %>
<%@ Import Namespace="GCheckout" %>
<%@ Import Namespace="GCheckout.AutoGen" %>
<%@ Import Namespace="GCheckout.Util" %>
<%@ Import Namespace="System.Data.SqlClient" %>
<%@ Import Namespace="System.Text" %>

<script runat="server" language="c#">

string serialnum = string.Empty;
void Page_Load(Object sender, EventArgs e)
{
    // Extract the XML from the request.
    Stream RequestStream = Request.InputStream;
    StreamReader RequestStreamReader = new StreamReader(RequestStream);
    string RequestXml = RequestStreamReader.ReadToEnd();
    RequestStream.Close();
    // Act on the XML.
    switch (EncodeHelper.GetTopElement(RequestXml))
    {
        case "new-order-notification":
            NewOrderNotification N1 = (NewOrderNotification)EncodeHelper.Deserialize(RequestXml, typeof(NewOrderNotification));

                string OrderNumber1 = N1.googleordernumber;
                string ShipToName = N1.buyershippingaddress.contactname;
                string ShipToAddress1 = N1.buyershippingaddress.address1;
                string ShipToAddress2 = N1.buyershippingaddress.address2;
                string ShipToCity = N1.buyershippingaddress.city;
                string ShipToState = N1.buyershippingaddress.region;
                string ShipToZip = N1.buyershippingaddress.postalcode;
                System.Xml.XmlNode[] arr = N1.shoppingcart.merchantprivatedata.Any;
                String PData = String.Empty;
                try
                {
                    PData = arr[0].InnerText;
                }
                catch { PData = "Error"; }
                decimal TotalPrice = 0.0M;
                foreach (Item ThisItem in N1.shoppingcart.items)
                {
                    string Name = ThisItem.itemname;
                    int Quantity = ThisItem.quantity;
                    decimal Price = ThisItem.unitprice.Value;
                    TotalPrice += Price * Quantity;
                }
                serialnum = N1.serialnumber;
                string Message = "Order No : " + OrderNumber1 + " Total Price = $" + TotalPrice + "\r\nP. Data:" + PData;

             LogTransaction(OrderNumber1, serialnum, Message, PData);
            SendGoogleAcknowledgement();
            break;
        case "risk-information-notification":
            RiskInformationNotification N2 = (RiskInformationNotification)EncodeHelper.Deserialize(RequestXml, typeof(RiskInformationNotification));
            // This notification tells us that Google has authorized the order and it has passed the fraud check.
            // Use the data below to determine if you want to accept the order, then start processing it.
            string OrderNumber2 = N2.googleordernumber;
            string AVS = N2.riskinformation.avsresponse;
            string CVN = N2.riskinformation.cvnresponse;
            bool SellerProtection = N2.riskinformation.eligibleforprotection;
            serialnum = N2.serialnumber;
            break;
        case "order-state-change-notification":
            OrderStateChangeNotification N3 = (OrderStateChangeNotification)EncodeHelper.Deserialize(RequestXml, typeof(OrderStateChangeNotification));
            // The order has changed either financial or fulfillment state in Google's system.
            string OrderNumber3 = N3.googleordernumber;
            string NewFinanceState = N3.newfinancialorderstate.ToString();
            string NewFulfillmentState = N3.newfulfillmentorderstate.ToString();
            string PrevFinanceState = N3.previousfinancialorderstate.ToString();
            string PrevFulfillmentState = N3.previousfulfillmentorderstate.ToString();
            serialnum = N3.serialnumber;
            break;
        case "charge-amount-notification":
            ChargeAmountNotification N4 = (ChargeAmountNotification)EncodeHelper.Deserialize(RequestXml, typeof(ChargeAmountNotification));
            // Google has successfully charged the customer's credit card.
            string OrderNumber4 = N4.googleordernumber;
            decimal ChargedAmount = N4.latestchargeamount.Value;
            serialnum = N4.serialnumber;
            break;
        case "refund-amount-notification":
            RefundAmountNotification N5 = (RefundAmountNotification)EncodeHelper.Deserialize(RequestXml, typeof(RefundAmountNotification));
            // Google has successfully refunded the customer's credit card.
            string OrderNumber5 = N5.googleordernumber;
            decimal RefundedAmount = N5.latestrefundamount.Value;
            serialnum = N5.serialnumber;
            break;
        case "chargeback-amount-notification":
            ChargebackAmountNotification N6 = (ChargebackAmountNotification)EncodeHelper.Deserialize(RequestXml, typeof(ChargebackAmountNotification));
            // A customer initiated a chargeback with his credit card company to get her money back.
            string OrderNumber6 = N6.googleordernumber;
            decimal ChargebackAmount = N6.latestchargebackamount.Value;
            serialnum = N6.serialnumber;
            break;
        default:
            break;
    }
}

private void SendGoogleAcknowledgement()
{
    StringBuilder responseXml = new StringBuilder();
    responseXml.Append("<?xml version='1.0' encoding='UTF-8'?>");
    responseXml.Append("<notifiation-acknowledgment xmlns='http://checkout.google.com/schema/2' />");
    HttpResponse response =
    System.Web.HttpContext.Current.Response;
    response.StatusCode = 200;
    response.ContentType = "text/xml";
    response.Write(responseXml.ToString());
    response.End();

}

protected virtual void LogTransaction(string OrderNo, string SerialNo, string Message, String PData)
{
    try
    {
        //Insert record in database
        string sql = "Update GoogleOrder Set GoogleOrderNumber = @GoogleOrderNumber WHERE PrivateData = @PData";
        using (SqlConnection Conn = new SqlConnection(ConfigurationManager.ConnectionStrings["inCommandConnectionString"].ConnectionString))
        {
            Conn.Open();
            SqlCommand Cmd = new SqlCommand(sql, Conn);
            Cmd.Parameters.AddWithValue("@GoogleOrderNumber", OrderNo);
            Cmd.Parameters.AddWithValue("@PData", PData);
            Cmd.ExecuteNonQuery();
            Conn.Close();

        }
    }
    catch (Exception ex)
    {
        LogError("Error to Save The order No" + OrderNo);
    }
    //Insert record in text file 
    LogError(Message);
}
private void LogError(String Message)
{
    String LogFile = ConfigurationManager.AppSettings.Get("LinkPointLogFile");
    if (LogFile != "")
    {
        byte[] binLogString = Encoding.Default.GetBytes(Message);

        try
        {
            FileStream loFile = new FileStream(LogFile, FileMode.OpenOrCreate, FileAccess.Write, FileShare.Write);
            loFile.Seek(0, SeekOrigin.End);
            loFile.Write(binLogString, 0, binLogString.Length);
            loFile.Close();
        }
        catch { ; }
    }
}

`

on google checkout setting page set the notification page name and path and you will get the response on that page. To test whether notification page is working or not, try to log the transaction into a txt file and once every thing is working smooth you can remove that code.

In this example PData is a number I send to the google checkout to and get back the same number in notification, I used this to match the transaction with a particular order.

Hope this code will help you;