Google Checkout - Callback Notifications Example

I stated in my last post that when I got better knowledge of using Google Checkout, I will show a full example on how to implement Google’s payment provider.

What I wanted to achieve within my own Google Checkout implementation was the ability to ensure I was retrieving sufficient information from the payment provider. So the transaction data stored within my own database would match exactly what is happening within Google. For example, if a payment was accepted/declined some internal processes need to be carried out. The best way of achieving this was by using a call-back page to process notifications from Google synchronously.

Before we get into the call-back code, we need to login to our Google Checkout account as a merchant and carry out some basic configuration setup. My example’s will be based on a sandbox environment.

Google Account Setup

Integration (Settings > Integration)

The Integration configuration is the most important page since it contains the basis to how we would like Google Checkout to work.

Google Checkout - Integration

As you can see, we have specified a call-back URL that will point to a page in our site. The call-back page is what Google uses to let our site know what’s happening with our transactions and if required, we can create our own internal actions to deal with events that are thrown to us. I have set the notifications to be sent in XML format.

Next, we want to ensure the correct API version is used. Issues are bound to occur is the incorrect version is selected. In this case, I am using the most recent API version: 2.5.

I have unselected Notification Filtering because we want to receive all types of notifications. Google Checkout document states:

Google Checkout responds with a <charge-amount-notification> synchronously after a charge-order request. If you have not selected the option to only receive new order notifications, authorization amount notifications and order state change notifications, Google Checkout will also send you a charge-amount-notification anytime an order has been charged.”

We want to receive a “charge amount notification” to allow us to know if the transaction was charged successfully. This is an actual confirmation to state we have received the money. We shouldn’t assume anything until this is received.

Preferences (Settings > Preferences)

Google Checkout - Preferences

I have setup our order processing to automatically authorise the buyers card for an order. You might be thinking: “This is a bit of manual process…” and you’d be right. If we selected the second option to automatically authorise and charge the buyers card, this would leave a big hole in setting up our internal website processes. By authorising a buyers card gives us more flexibility on how to handle the transaction.

It’s not compulsory for the email option to be selected.

Other Setup

You should be good to go on starting to mess around with implementing your site with Google Checkout. What I haven’t covered is the financial settings such as adding Banking information. This should be a straight-forward process. My main aim is to make sure the basics of Google Merchant account setup is complete.

One really useful page that will help you with investigating problematic transactions is the “Integration Console” (Tools > Integration Console). Generally, this should be empty but any issues will be logged here. This has helped me over the course of integrating Google Checkout in my site.

Call-back Page

Ok. We have Google Merchant Account setup. Now we need to concentrate on our call-back page. My call-back page is based on a customer purchasing a News subscription. We are going to capture all the data Google sends us (excluding refunds) and store them in our own database.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
using GCheckout;
using GCheckout.AutoGen;
using GCheckout.Util;
using GCheckout.OrderProcessing;
using System.Xml;

public partial class Pay_GCheckout : System.Web.UI.Page
{
    public string SerialNumber = "";

    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));
                SerialNumber = N1.serialnumber;
                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;

                CustomerSubscription cs = new CustomerSubscription();
                cs.TransactionNumber = OrderNumber1;
                cs.Address1 = ShipToAddress1;
                cs.Address2 = ShipToAddress2;
                cs.Address3 = ShipToCity;
                cs.Region = ShipToState;
                cs.PostCode = ShipToZip;
                cs.TransactionType = CustomerSubscription.TransTypeOnline;
                cs.FinancialOrderState = N1.ordersummary.financialorderstate.ToString();

                foreach (Item ThisItem in N1.shoppingcart.items)
                {
                    string Name = ThisItem.itemname;
                    int Quantity = ThisItem.quantity;
                    decimal Price = ThisItem.unitprice.Value;
                }
                
                if (N1.shoppingcart.merchantprivatedata != null && N1.shoppingcart.merchantprivatedata.Any != null && N1.shoppingcart.merchantprivatedata.Any.Length > 0)
                {
                    foreach (XmlNode node in N1.shoppingcart.merchantprivatedata.Any) 
                    { 
                        if (node.LocalName.Trim() == "customer-id")
                        { 
                            cs.CustomerID = int.Parse(node.InnerText);
                        }

                        if (node.LocalName.Trim() == "subscription-id")
                        {
                            cs.SubscriptionID = int.Parse(node.InnerText);
                        }
                    }
                }

                CustomerSubscription.AddOnlineSubscription(cs);

                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.
                SerialNumber = N2.serialnumber;
                string OrderNumber2 = N2.googleordernumber;
                string AVS = N2.riskinformation.avsresponse;
                string CVN = N2.riskinformation.cvnresponse;
                bool SellerProtection = N2.riskinformation.eligibleforprotection;
                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.
                SerialNumber = N3.serialnumber;
                string OrderNumber3 = N3.googleordernumber;
                string NewFinanceState = N3.newfinancialorderstate.ToString();
                string NewFulfillmentState = N3.newfulfillmentorderstate.ToString();
                string PrevFinanceState = N3.previousfinancialorderstate.ToString();
                string PrevFulfillmentState = N3.previousfulfillmentorderstate.ToString();
                break;
            case "charge-amount-notification":
                ChargeAmountNotification N4 = (ChargeAmountNotification)EncodeHelper.Deserialize(RequestXml, typeof(ChargeAmountNotification));
                // Google has successfully charged the customer's credit card.
                SerialNumber = N4.serialnumber;
                string OrderNumber4 = N4.googleordernumber;
                decimal ChargedAmount = N4.latestchargeamount.Value;

                int customerID = 0;

                if (N4.ordersummary.shoppingcart.merchantprivatedata != null && N4.ordersummary.shoppingcart.merchantprivatedata.Any != null && N4.ordersummary.shoppingcart.merchantprivatedata.Any.Length > 0)
                {
                    foreach (XmlNode node in N4.ordersummary.shoppingcart.merchantprivatedata.Any) 
                    { 
                        if (node.LocalName.Trim() == "customer-id")
                        { 
                            customerID = int.Parse(node.InnerText);
                        }
                    }
                }

                if (N4.ordersummary.financialorderstate == FinancialOrderState.CHARGED)
                {
                    CustomerSubscription.UpdateFinancialOrderState(OrderNumber4, N4.ordersummary.financialorderstate.ToString());

                    //Make user paid member
                    CustomerHelper.UpgradeCustomerToPaid(customerID);
                }

                break;
            case "refund-amount-notification":
                RefundAmountNotification N5 = (RefundAmountNotification)EncodeHelper.Deserialize(RequestXml, typeof(RefundAmountNotification));
                // Google has successfully refunded the customer's credit card.
                SerialNumber = N5.serialnumber;
                string OrderNumber5 = N5.googleordernumber;
                decimal RefundedAmount = N5.latestrefundamount.Value;
                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.
                SerialNumber = N6.serialnumber;
                string OrderNumber6 = N6.googleordernumber;
                decimal ChargebackAmount = N6.latestchargebackamount.Value;

                break;
            case "authorization-amount-notification":
                AuthorizationAmountNotification N7 = (AuthorizationAmountNotification)EncodeHelper.Deserialize(RequestXml, typeof(AuthorizationAmountNotification));
                SerialNumber = N7.serialnumber;
                string OrderNumber7 = N7.googleordernumber;
                
                // Charge Order If Chargeable
                if (N7.ordersummary.financialorderstate == FinancialOrderState.CHARGEABLE)
                {
                    GCheckout.OrderProcessing.ChargeOrderRequest chargeReq = new GCheckout.OrderProcessing.ChargeOrderRequest(OrderNumber7);

                    GCheckoutResponse oneGCheckoutResponse = chargeReq.Send();

                }

                CustomerSubscription.UpdateFinancialOrderState(OrderNumber7, N7.ordersummary.financialorderstate.ToString());

                break;
            default:                
                break;
        }
    }
}

N.B: The code snippet (above) is shown purely as a simple example for you to build on. It is based on the “notification_handshake.aspx” sample code that is downloadable here.

So what’s going on here? Well the events are processed in the following order:

  1. “new-order-notification” - A new order has been received. Details of the News Subscription along with the customer who ordered it will be stored in our database.
  2. “authorization-amount-notification” - Google tells us that the amount has successfully be authorised. If the order state is “chargeable”, we can go ahead charge the order and update the order state. The customer order state will consist of the following statuses: Cancelled, Chargeable, Charged, Charging, Payment Declined and Reviewing. I think it’s a good to store this information because it will allow a site administrator to view statuses of all orders and act on them, if needed.
  3. “charge-amount-notification” – Google verifies the order was successful. If the order state is marked as charged, the customer will be upgraded to a paid News Subscriber.

Outcome

You have successfully setup Google Checkout payment with basic notifications. If you already have Google Checkout code in place where a user can add one or more items to the shopping cart this code can stay. All you need to do is carry out the changes described in this post.

Google Checkout Error - "Expected Serial Number was not contained in notification acknowledgment”

I’ve been busy lately integrating a payment provider into a site I am working in. After looking at the best payment providers, it came down to either using PayPal or Google Checkout. In the end I decided to use Google’s payment provider (as you can probably tell from my post title).

Before I start this post, I assume you have already created a sandbox Google Checkout account and know your way around setup and integration.

For my own Google Checkout integration, I needed to be able to add new transaction item in my database only if a customer has ordered an item and if their payment is approved. This is where Google’s call-back notification service comes into play.

I decided to use an synchronous notification process based on one the sample code that can be downloaded here: http://code.google.com/p/google-checkout-dotnet-sample-code/downloads/list.

Just using the sample code provided by Google out-the-box caused issues. It seems that the code samples do not correctly reflect version changes to the payment provider. One of the repeating errors I got was: “Expected serial number was not contained in notification acknowledgement”.

Google Checkout ErrorList

You will only receive this error only if you are using API version 2.5 and have “Notification Filtering” enabled in account settings. Unfortunately, notification filtering is something I needed to ensure both Google Checkout and my database transactions were in sync.

The Integration Issue error log showed me that the transaction serial number was not getting populated from my call-back notification page.

Google Checkout Error XML Detail

After a lot of debugging it became apparent that the notification page provided by Google Code sample was wrong! It was missing a key case statement: “authorization-amount-notification”. Once this was added no more errors occurred.

If you are using the “notification_extended.aspx”, “notification.aspx” or “notification_handshake.aspx” code samples. Be sure to make the following change:

<%@ Import Namespace="System.IO" %>
<%@ Import Namespace="GCheckout" %>
<%@ Import Namespace="GCheckout.AutoGen" %>
<%@ Import Namespace="GCheckout.Util" %>
<script runat="server" language="c#">

  public string SerialNumber = "";

  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));
        SerialNumber = N1.serialnumber;
        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;
        foreach (Item ThisItem in N1.shoppingcart.items) {
          string Name = ThisItem.itemname;
          int Quantity = ThisItem.quantity;
          decimal Price = ThisItem.unitprice.Value;
        }
        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.
        SerialNumber = N2.serialnumber;
        string OrderNumber2 = N2.googleordernumber;
        string AVS = N2.riskinformation.avsresponse;
        string CVN = N2.riskinformation.cvnresponse;
        bool SellerProtection = N2.riskinformation.eligibleforprotection;
        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.
        SerialNumber = N3.serialnumber;
        string OrderNumber3 = N3.googleordernumber;
        string NewFinanceState = N3.newfinancialorderstate.ToString();
        string NewFulfillmentState = N3.newfulfillmentorderstate.ToString();
        string PrevFinanceState = N3.previousfinancialorderstate.ToString();
        string PrevFulfillmentState = N3.previousfulfillmentorderstate.ToString();
        break;
      case "charge-amount-notification":
        ChargeAmountNotification N4 = (ChargeAmountNotification) EncodeHelper.Deserialize(RequestXml, typeof(ChargeAmountNotification));
        // Google has successfully charged the customer's credit card.
        SerialNumber = N4.serialnumber;
        string OrderNumber4 = N4.googleordernumber;
        decimal ChargedAmount = N4.latestchargeamount.Value;
        break;
      case "refund-amount-notification":
        RefundAmountNotification N5 = (RefundAmountNotification) EncodeHelper.Deserialize(RequestXml, typeof(RefundAmountNotification));
        // Google has successfully refunded the customer's credit card.
        SerialNumber = N5.serialnumber;
        string OrderNumber5 = N5.googleordernumber;
        decimal RefundedAmount = N5.latestrefundamount.Value;
        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.
        SerialNumber = N6.serialnumber;
        string OrderNumber6 = N6.googleordernumber;
        decimal ChargebackAmount = N6.latestchargebackamount.Value;
        break;
    // Edit: Additional case statement for "authorization-amount-notification"
      case "authorization-amount-notification":
        AuthorizationAmountNotification N7 = (AuthorizationAmountNotification)EncodeHelper.Deserialize(RequestXml, typeof(AuthorizationAmountNotification));
        // Information about a successful reauthorization for an order
        SerialNumber = N7.serialnumber;
        string OrderNumber7 = N7.googleordernumber;
        break;
      default:
        break;
    }
  }
</script>
<notification-acknowledgment xmlns="http://checkout.google.com/schema/2" serial-number="<%=SerialNumber %>" />

Once I have got to grips on using Google Checkout I will add another blog post containing my full call-back solution.

Calculate Time Duration in Seconds, Minutes, Hours & Weeks

For a news site I am currently working on, I needed to display the last time a news article was last published. I wanted to be able to show the duration based on respective major time format. For example, if an article was displayed a couple hours ago, I would want it to to display “2 hours” not “120 minutes”.

More importantly, if an article hadn’t been published to the site more than a week, I don’t want the exact time duration to be displayed. I would prefer the following message: “more than a week ago”. This way, if the site administrator gets really lazy the website viewer will not know the exact time period the site was last updated.

Code:

public class TimePassed
{
    public static string GetPassedTime(DateTime since)
    {
        TimeSpan ts = DateTime.Now.Subtract(since);

        if (ts.Days <= 7)
        {
            switch (ts.Days)
            {
                case 0:
                    switch (ts.Hours)
                    {
                        case 0:
                            switch (ts.Minutes)
                            {
                                case 0:
                                    return String.Format("{0} seconds ago", ts.Seconds);
                                case 1:
                                    return "1 minute ago";
                                default:
                                    return String.Format("{0} minutes ago", ts.Minutes);
                            }
                        case 1:
                            return "1 hour ago";
                        default:
                            return String.Format("{0} hours ago", ts.Hours);
                    }
                case 1:
                    return "yesterday";
                default:
                    return String.Format("{0} days ago", ts.Days);
            }
        }
        else
        {
            return "more than a week ago";
        }
    }
}

Get CheckBoxList Values Using jQuery

To be able to retrieve values from a ASP.NET CheckBoxList control or a group of HTML checkboxes, use the following jQuery:

$(document).ready(function () {
    var checkboxValues = [];

    $('#<%=MyCheckBoxList.ClientID %> input[type=checkbox]').click(function () {
        $('input[type=checkbox]:checked').each(function () {
            checkboxValues.push(this.value);
        });        
    });
    
    var values = checkboxValues.toString(); //Output Format: 1,2,3
});

If you do use this code snippet on a CheckBoxList, take a look that this article on how to create a custom CheckBoxList control with a value attribute.

ASP.NET CheckBoxList Control With Value Attribute

ASP.NET server controls is a great way to quickly build a page with dynamic functionality. Even though we do not have much of direct control over the way these controls are rendered, they do a pretty good job and its not very often I get annoyed with them.

Until now.

Generally, I find myself using the .Attributes.Add() method when needing to add additional attributes to certain server controls. No problem! In this case, I wanted to add a “value” attribute that will contain the record ID for that checkbox. I can then use this value within my JavaScript. I would have thought a value attribute would already be there. Its perfectly valid HTML mark-up:

<form>
    <input type="checkbox" name="vehicle" value="Volvo" />
    <input type="checkbox" name="vehicle" value="Volkswagen" />
</form> 

For some reason, when I tried to add my custom attributes after my CheckBoxList was databound (as shown below), the attribute was simply ignored.

NewsCheckList.Items[0].Attributes["value"] = "1";
NewsCheckList.Items[1].Attributes["value"] = "2";
NewsCheckList.Items[2].Attributes["value"] = "3";

So I decided the best way forward would be to create a custom CheckBoxList control that would contain a value attribute. I based my code from an old (but very useful) article that can be found here.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web.UI.WebControls;
using System.IO;
using System.Web.UI;
using System.Collections;
using System.ComponentModel;

namespace Site.WebControls
{
    [DefaultProperty("Text"),
    ToolboxData("<{0}:CheckBoxValueList runat=server></{0}:CheckBoxValueList>")]
    public class CheckBoxValueList : CheckBoxList
    {
        protected override void Render(HtmlTextWriter writer)
        {
            StringBuilder sb = new StringBuilder();
            TextWriter tw = new StringWriter(sb);
            
            HtmlTextWriter originalStream = new HtmlTextWriter(tw);
            base.Render(originalStream);
            string renderedText = sb.ToString();

            int start = 0;
            int labelStart = 0;
            int end = renderedText.Length;

            for (int i = 0; i < this.Items.Count; i++)
            {
                StringBuilder itemAttributeBuilder = new StringBuilder();

                end = renderedText.Length;
                start = renderedText.IndexOf("<input", start, end - start);
                labelStart = renderedText.IndexOf("<label", start, end - start);

                this.Items[i].Attributes.Render(new HtmlTextWriter(new StringWriter(itemAttributeBuilder)));

                renderedText = renderedText.Insert(labelStart + 7, itemAttributeBuilder.ToString() + " ");
                renderedText = renderedText.Insert(start + 7, String.Format("{0} value=\"{1}\" ", itemAttributeBuilder.ToString(), this.Items[i].Value));
                start = renderedText.IndexOf("/>", start, renderedText.Length - start);
            }
            
            writer.Write(renderedText);
        }
    }
}

XmlDocument.Load Error Handling

From one of the projects I have been working on, I came across a snippet of code that used the XmlDocument.Load method. What alarmed me about this piece of code was the fact that there was no error handling. If for some reason the XML file could not be found or a node was missing, the whole page would have crashed. Not good.

I must admit, I am not exactly the best person to speak about implementing wide-scale error handling in every facet of code. But I do ensure the core foundations of an application or website do incorporate sufficient error handling.

So back to the matter in hand. This is the original code using the XmlDocument.Load functionality:

XmlDocument doc = new XmlDocument();

doc.Load(Server.MapPath("/xml/storeGB.xml"));

XmlNode countryNode = doc.SelectSingleNode("//countries");
foreach (XmlNode node in countryNode.ChildNodes)
{
    //Do something with the elements
    Response.Write(node.Name + node.InnerText);
}

I changed the code to the following:

XmlDocument doc = new XmlDocument();

//Check if language XML file exists
if (File.Exists(Server.MapPath("/xml/storeGB.xml")))
{
    try
    {
        doc.Load(Server.MapPath("/xml/storeGB.xml"));

        XmlNode countryNode = doc.SelectSingleNode("//countries");

        if (countryNode != null)
        {
            foreach (XmlNode node in countryNode.ChildNodes)
            {
                //Do something with the elements
                Response.Write(node.Name + node.InnerText);
            }
        }
        else
        {
            //Output error message if there is no node
        }
    }
    catch (XmlException ex)
    {
        Debug.WriteLine(String.Format("XmlException for countries: {0}", ex.Message));
    }
}

I am sure you will agree that this is the better approach to using XmlDocument.Load.

At Last! Created My Own eBay Style Search Using Solrnet

Over the last few months I have been carrying out endless amounts of research and development to find a way to create my own eCommerce styled search similar to the likes of what eBay and Amazon use. Otherwise known as “Faceted Search”, whereby the search results are filtered through a series of facets belonging to your search criteria. Each facet typically corresponds to the possible values of a property common to a set of objects.

Sounds very difficult and complex doesn’t it! Smile Even to this very day, I am sure eBay and Amazon must use some kind of “magic” to get their search to work in a seamlessly and efficient format.

There are numerous search solutions out there that could help you achieve in making this type of search. From my experience I couldn’t find any low cost out-of-the-box solutions that would help me in making my own search. Majority of the search vendors were not only very expensive but they also required a quote to tailor make a solution for you.

In the early stages I tried expanding my Lucene.NET knowledge, but I couldn’t find a flexible way to introduce facets into my search. I must admit I am not exactly an expert in Lucene and this could have also had a part to play in failing miserably.

When I thought all was lost and there was no chance in hell in being able to figure this thing out, I luckily came across a few blog and StackOverflow posts by a guy called Mauricio Scheffer. Mauricio seems to be the brains behind the .NET client version of a search platform called: SolrNet. SolrNet is a  Solr client library built for the .NET Framework. This is one of the strengths of Solr. It can be consumed within other development platforms such as Python and Ruby.

SolrNet just happened to be an ideal solution to what I was looking for and with just over a weeks development I was able to build my own basic search, which looks something like this:

SolrNet1 SolrNet2

As you can see from my screenshots, you can carry out a search by report type and/or global text search. In addition, the showing and hiding of the facet objects are purely dependent on the searches returned.

SolrNet is a very flexible package and I know just enough to implement the basics. But I was really surprised on how well the searches performed even with the most basic implementation. So I am looking forward to adding additional features as over the next few months and perfecting both my Solr search index and code.

I won’t be posting the code that I used to create my search since its quite a big project and tailor made specific to my database architecture. But here are a few links that I found useful to get me started in the world of SolrNet:

Multi Query Search Using Lucene.NET

Over the last few days I have been doing some research on the best way to implement search functionality for a site I am currently building. The site will consists mainly of news articles. The client wanted a search that would allow a user to search across all fields that related to a news article.

Originally, I envisaged writing my own SQL to query a few tables within my database to return some search results. But as I delved further into designing the database architecture in the early planning stages, I found that my original (somewhat closed minded) approach wouldn't be flexible nor scalable enough to search and extract all the information I required.

From what I have researched, the general consensus is to either use SQL Full Text Search or Lucene.NET. Many have favoured the use of Lucene due to its richer querying language and generally more flexible since you have the ability to write a search index tailored to your project. From what I gather, Lucene can work with any type of text data. For example, you not only can index rows in your database but there are also solutions to support indexing physical files in your application. Neat!

I have written some basic code (below) with a couple methods to get started in creating a search index and carrying out a multi-query search across your whole index. You would further enhance this code to only carry out a full index once all required records have been added. Most implementations of Lucene would use incremental indexing, where documents already in the index are just updated individually, rather than deleting the whole index and building a new one every time. I plan to hook up and optimise my Lucene code into a service that would be scheduled to carry out an incremental index every midnight.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Lucene;
using Lucene.Net;
using Lucene.Net.Store;
using Lucene.Net.Analysis;
using Lucene.Net.Analysis.Standard;
using Lucene.Net.Index;
using Lucene.Net.Documents;
using Lucene.Net.QueryParsers;
using Lucene.Net.Search;
using System.Configuration; 

namespace MES.DataManager.Search
{
    public class Lucene
    {
        public static void IndexSite()
        {           
                //The file location of the index
                string indexLocation = @ConfigurationManager.AppSettings["SearchIndexPath"];

                Directory searchDirectory = null;

                if (System.IO.Directory.Exists(indexLocation))
                    searchDirectory = FSDirectory.GetDirectory(indexLocation, false);
                else
                    searchDirectory = FSDirectory.GetDirectory(indexLocation, true); 

                //Create an analyzer to process the text
                Analyzer searchAnalyser = new StandardAnalyzer(); 

                //Create the index writer with the directory and analyzer.
                IndexWriter indexWriter = new IndexWriter(searchDirectory, searchAnalyser, true);

                //Iterate through Article table and populate the index
                foreach (Article a in ArticleBLL.GetArticleDetails())
                {
                    Document doc = new Document();

                    doc.Add(new Field("id", a.ID.ToString(), Field.Store.YES, Field.Index.UN_TOKENIZED, Field.TermVector.YES));
                    doc.Add(new Field("title", a.Title, Field.Store.YES, Field.Index.TOKENIZED, Field.TermVector.YES));
                    doc.Add(new Field("articletype", a.Type.TypeName, Field.Store.YES, Field.Index.TOKENIZED, Field.TermVector.YES)); 

                    if (!String.IsNullOrEmpty(a.Summary))
                        doc.Add(new Field("summary", a.Summary, Field.Store.YES, Field.Index.TOKENIZED, Field.TermVector.YES));                

                    if (!String.IsNullOrEmpty(a.ByLineShort))
                        doc.Add(new Field("bylineshort", a.ByLineShort, Field.Store.YES, Field.Index.TOKENIZED, Field.TermVector.YES));                    

                    if (!String.IsNullOrEmpty(a.ByLineLong))
                        doc.Add(new Field("bylinelong", a.ByLineLong, Field.Store.YES, Field.Index.TOKENIZED, Field.TermVector.YES));                   

                    if (!String.IsNullOrEmpty(a.BasicWords))
                        doc.Add(new Field("basicwords", a.BasicWords, Field.Store.YES, Field.Index.TOKENIZED, Field.TermVector.YES));                   

                    if (!String.IsNullOrEmpty(a.MediumWords))
                        doc.Add(new Field("mediumwords", a.MediumWords, Field.Store.YES, Field.Index.TOKENIZED, Field.TermVector.YES));                   

                    if (!String.IsNullOrEmpty(a.LongWords))
                        doc.Add(new Field("longwords", a.LongWords, Field.Store.YES, Field.Index.TOKENIZED, Field.TermVector.YES));  

                    //Write the document to the index
                    indexWriter.AddDocument(doc);
                }
                          

                //Optimize and close the writer
                indexWriter.Optimize();
                indexWriter.Close();         
        }

        public static List<CoreArticleDetail> SearchArticles(string searchTerm)
        {
            Analyzer analyzer = new StandardAnalyzer(); 

            //Search by multiple fields
            MultiFieldQueryParser parser = new MultiFieldQueryParser(
                                                                new string[]
                                                                {
                                                                    "title",
                                                                    "summary",
                                                                    "bylineshort",
                                                                    "bylinelong",
                                                                    "basicwords",
                                                                    "mediumwords",
                                                                    "longwords"
                                                                },
                                                                analyzer); 

            Query query = parser.Parse(searchTerm); 

            //Create an index searcher that will perform the search
            IndexSearcher searcher = new IndexSearcher(@ConfigurationManager.AppSettings["SearchIndexPath"]); 

            //Execute the query
            Hits hits = searcher.Search(query);

            List<int> articleIDs = new List<int>(); 

            //Iterate through index and return all article id’s
            for (int i = 0; i < hits.Length(); i++)
            {
                Document doc = hits.Doc(i);

                articleIDs.Add(int.Parse(doc.Get("id")));
            } 

            return ArticleBLL.GetArticleSearchInformation(articleIDs);
        }

    }
}

As you can see, my example allows you to carry out a search across as many of your fields as you require which I am sure you will find useful. It took a lot of research to find out how to carry out a multi query search. Majority of the examples I found over the internet showed you how to search only one field.

The main advantage I can see straight away from using Lucene is that since the search data is held on disk, there is hardly any need to query the database. The only downside I can see is problems being caused by the possibility a corrupt index.

For more information on using Lucene, here are a couple of links that you may find useful to get started (I know I did):

http://www.codeproject.com/KB/library/IntroducingLucene.aspx http://ifdefined.com/blog/post/Full-Text-Search-in-ASPNET-using-LuceneNET.aspx

Watermarking Images On The Fly Using ASP.NET

Watermarking and general image manipulation within the .NET Framework has become quite an easy thing to carry out thanks to the features provided by the System.Drawing namespace. The System.Drawing namespace contains types to help you with…well…drawing and rendering images. I will not be covering the basic use of the System.Drawing class. But feel free to carry out a Google.

My example consists of using a .NET (aspx) page and a Generic Handler (ashx). The .NET page will allow me to select an image, add a logo to the top left and some text. The Generic Handler will contain all the magic needed to manipulate the image based on selections made within the .NET page. The screenshot (below) shows my basic program in action.

Image Watermarking

Firstly, let me start off by showing you the code for the Generic Handler.

ImageRenderJpeg.ashx

using System;
using System.Web;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;

public class ImageRenderJpeg : IHttpHandler
{
    public void ProcessRequest(HttpContext context)
    {
        context.Response.ContentType = "image/jpeg";

        //Retrieve image details
        string imageUrl = context.Request.QueryString["ImageUrl"].ToString();
        string imageComment = context.Request.QueryString["ImageComment"].ToString();
        string imageIconUrl = context.Request.QueryString["Icon"].ToString();

        if (!String.IsNullOrEmpty(imageUrl))
        {
            //Get the location of the image
            Image imagePhoto = Image.FromFile(imageUrl);

            // Get dimensions of image
            int imageHeight = imagePhoto.Height;
            int imageWidth = imagePhoto.Width;

            //Create a new Bitmap
            Bitmap oBitmap = new Bitmap(imageWidth, imageHeight, PixelFormat.Format24bppRgb);

            //Load Background Graphic from Image
            Graphics oGraphics = Graphics.FromImage(oBitmap);
            oGraphics.SmoothingMode = SmoothingMode.HighQuality;
            oGraphics.DrawImage(imagePhoto, new Rectangle(0, 0, imageWidth, imageHeight), 0, 0, imageWidth, imageHeight, GraphicsUnit.Pixel);

            //Layer 1: Add an Image Logo to the top left
            if (!String.IsNullOrEmpty(imageIconUrl))
            {
                Image imageIcon = Image.FromFile(imageIconUrl);
                oGraphics.DrawImage(imageIcon, new Rectangle(5, 5, 124, 48), 0, 0, imageIcon.Width, imageIcon.Height, GraphicsUnit.Pixel);

                imageIcon.Dispose();
            }
            
            //Layer 2: Add Comment
            if (!String.IsNullOrEmpty(imageComment))
            {
                Font commentFont = new Font("Arial", 14, FontStyle.Regular); //Font Style
                StringFormat commentFormat = new StringFormat();
                commentFormat.Alignment = StringAlignment.Near; //Align text in left of layer

                SolidBrush commentBrush = new SolidBrush(Color.Black); //Font Colour

                oGraphics.FillRectangle(Brushes.Beige, 5, imageHeight - 55, imageWidth - 15, 50); //Create a rectangle with white background
                oGraphics.DrawString(imageComment, commentFont, commentBrush, new Rectangle(5, imageHeight - 55, imageWidth - 15, 50), commentFormat); //Add comment text inside rectangle
            }
            
            //Layer 3: Add Copyright watermark
            Font watermarkFont = new Font("Arial", 40, FontStyle.Bold); //Font Style
            SolidBrush semiTransBrush = new SolidBrush(Color.LightGray); //Font Colour
            StringFormat watermarkFormat = new StringFormat();
            watermarkFormat.Alignment = StringAlignment.Center; //Align text in center of image

            oGraphics.DrawString("Copyright",
                watermarkFont,
                semiTransBrush,
                new PointF(imageWidth / 2, imageHeight / 2), watermarkFormat);

            //Dispose of graphic objects
            imagePhoto.Dispose();
            oGraphics.Dispose();

            //Output image
            oBitmap.Save(context.Response.OutputStream, ImageFormat.Jpeg);
        }
        else
        {
        }

    }

    public bool IsReusable
    {
        get
        {
            return false;
        }
    }
}

You can see that I am manipulating my image based on the query string parameters I pass from my .NET page into my Generic Handler. Hopefully, my code is commented well enough to explain the general overview on what is going on.

The following code displays how my aspx page parses all the parameters needed to generate an image on the page:

Default.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>Image Generator</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        Select an Image:
        <asp:DropDownList ID="ddlImage" runat="server">
            <asp:ListItem Text="*" Value="*">Select Image</asp:ListItem>
            <asp:ListItem Text="The Tumbler" Value="C:\Users\Surinder\Documents\Visual Studio 2010\WebSites\ImageCreator\Images\batmobile_Tumbler.jpg"></asp:ListItem>
            <asp:ListItem Text="Audi TT" Value="C:\Users\Surinder\Documents\Visual Studio 2010\WebSites\ImageCreator\Images\new-audi-tt-coupe.jpg"></asp:ListItem>
            <asp:ListItem Text="Volvo Concept" Value="C:\Users\Surinder\Documents\Visual Studio 2010\WebSites\ImageCreator\Images\volvo-s60-concept-interior1.jpg"></asp:ListItem>
        </asp:DropDownList>
        <br />
        <br />
        Add Logo: <asp:TextBox ID="txtImage" runat="server"></asp:TextBox>
        <br />
        <br />
        Add a comment:
        <asp:TextBox ID="txtComment" runat="server" TextMode="MultiLine" Width="500" Height="50"></asp:TextBox>
        <br />
        <br />
        <asp:Button ID="btnCreateImage" Text="Create Image" runat="server" onclick="btnCreateImage_Click" />
        <br />
        <br />
        <img id="imgRender" alt="Image Render" title="Image Render" runat="server" />        
    </div>
    </form>
</body>
</html>

Default.aspx.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class _Default : System.Web.UI.Page 
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (ddlImage.SelectedValue == "*")
        {
            imgRender.Visible = false;
        }
        else
        {
            imgRender.Visible = true;
        }
    }

    protected void btnCreateImage_Click(object sender, EventArgs e)
    {
        if (ddlImage.SelectedValue != "*")
        {
            //The Image source will be pointed to our Generic Handler to display the image.
            imgRender.Src = String.Format("ImageRenderJpeg.ashx?ImageUrl={0}&ImageComment={1}&Icon={2}", ddlImage.SelectedValue, txtComment.Text, txtImage.Text);
        }
    }
}

Making Calculations In LINQ

I am currently working on an ASP.NET 4.0  e-commerce site using Entity Framework alongside LINQ. I came across a small issue when I needed to carry out some calculations based on product pricing and the discounts that would need to be applied based on a specific customers allowance.

You maybe thinking, what’s the issue? Well I wanted to be able to make the calculations within my LINQ query since both product pricing and customer discount amounts are stored in the database. So initially wrote the following code:

using (MyEntities myContext = new MyEntities())
{
    int productPrice = (from p in myContext.Products
                        where p.ProductID == 1
                        select p.Price).SingleOrDefault(); 
 
    int customerDiscount = (from cd in myContext.CustomerDiscounts
                            where cd.CustomerID == 15
                            select cd.Discount).SingleOrDefault(); 
 
    int productDiscountedPrice = productPrice - ((productPrice * customerDiscount) / 100);
}

As you can see from my code above, I had to write two separate LINQ queries in order to get the values I wanted and then base my calculations on those values. But I was determined to carry out my calculations in one query. Luckily, LINQ has has a really cool keyword that I totally missed. It’s the “let” keyword which allows you to declare a variable and assign it a calculated value.

using (MyEntities myContext = new MyEntities())
{
    int productDiscount = (from cd in myContext.CustomerDiscounts
                           join p in myContext.Products on cd.ProductID equals cd.ProductID
                           where p.ProductID == 1 && cd.CustomerID == 15
                           let discountAmount = p.Price - ((p.Price * cd.Discount) / 100)
                           select discountAmount).SingleOrDefault();
}

Since my database schema allowed me to join my “CustomerDiscount” and “Products” table, I was able to join the two tables and retrieve values I required through one query.