Nikhil's Blog

Commerce Server 2007 Staging Error: CatalogImport failed; _FullTextCatalog' cannot be reused until after the next BACKUP LOG operation

nikhiln — Mon, 19 Jan 2009 06:46:47 GMT

In one of the production commerce server instances of my client, I suddenly found this error getting logged since a couple of days. Now, the text of the error has nothing to do with Commerce Server 2007 but everything to do with the Sql Server 2005 that...(read more)

Commerce Server 2007 Staging Error : "Error occurred with the database StagingLog.mdb"

nikhiln — Thu, 13 Nov 2008 13:27:43 GMT

Yesterday I came across a very strange Commerce Server Staging error at one of the production boxes of the customer am working for. Strangely, for some reason, the Staging server stopped and started to throw out the below error: Event Type: ...(read more)

Using HttpModules to perform a SSL switch on web pages

nikhiln — Fri, 05 Sep 2008 11:56:36 GMT

A common requirement of any secure website is to make sure that when a user traverses to a "sensitive" part of the website such the login page, the password reset page or even the personal profile page which might contain contact detail you...(read more)

Commerce Server 2007: Accessing multi-valued custom properties in UserObject of Profile System

nikhiln — Thu, 04 Sep 2008 15:34:46 GMT

The MSDN's Managing Profiles section of the commerce server gives an in-depth view of the working of the profile system and the steps needed to create custom properties for the UserObject. The Extending the Profile System section gives out detailed steps...(read more)

EntLib 3.1 DAAB: Be careful with the ExecuteReader

nikhiln — Tue, 08 Jul 2008 09:40:59 GMT

The EntLib 3.1 is simply superb, right?! Well, I would give a typical consultant answer... "It depends!". It depends on the developers who are using it and it depends on motivation of the developers to know the component before "copy-pasting" code and...(read more)

Commerce Server 2007: Catalog Import Error for Large Files

nikhiln — Mon, 16 Jun 2008 14:51:56 GMT

When you are trying to import a large catalog into the commerce server catalog system you might come across this error: The import failed because the import file is larger than the maximum size allowed on your server. Contact your system administrator....(read more)

HttpHandler to Authorize File Downloads - C# Code Sample

nikhiln — Thu, 22 May 2008 07:31:11 GMT

Its quite a common scenario to have a feature in a web site to check for the credentials of the user before allowing a particular download. For example, there might be some documents which should be visible only to a set of users and not to any others....(read more)

.NET 2.0 Symmetric Encryption Code Sample

nikhiln — Sun, 18 May 2008 18:53:00 GMT

One of the most common problems when developing any web site if the need to use Symmetric Encryption to save some data in the Cookie so that it can be looped back to the user's session / identity. .NET provides a very robust mechanism in which this can...(read more)

Commerce Server 2007 Code Samples - Catalog System and Basic Catalog Search

nikhiln — Mon, 14 Apr 2008 08:55:00 GMT

I did some qualitative analysis of the referrals of my blog, and found that a majority of the search terms are for Commerce Server Code Samples or for Commerce Server API usage samples.Though some very good code samples are available at the Microsoft...(read more)

Multi-Threaded Web Service Calls - A C# Code Sample

nikhiln — Sat, 12 Apr 2008 18:51:33 GMT

Sometimes it becomes necessary to call an external web service in a multi threaded manner to speed up processing of records that we have in a buffer so that the overall time spent in waiting for the calls to return is reduced. The high-level steps to...(read more)

Commerce Server 2007 SetJoin API

nikhiln — Wed, 02 Apr 2008 06:45:00 GMT

The official documentation for the commendable SetJoin API in commerce Server 2007 seems more like a class reference without any code samples or introductory material into the way SetJoin should be used. So here's the "low-down" as to how a SetJoin API...(read more)

Commerce Server 2007 Web Services Application Pool Invalid Identity Error

nikhiln — Mon, 03 Dec 2007 10:03:00 GMT

When you are configuring a clean install of Commerce Server 2007, you'll definitely need to go through the hellish and longish configuration steps that this document specifies. But once in a blue moon you might get this Application Pool Invalid Identity...(read more)

Passing property values in Remove action using UAB for MSIs

nikhiln — Wed, 27 Jun 2007 16:03:00 GMT

Problem: An application which you are developing is using UAB (Updater Application Block) to pull in updates from a server. There is a requirement to uninstall the application using UAB with the help of an MSI, but the uninstall needs to happen conditionally so that, based on the value of a property, parts of the uninstall steps are skipped. The issue now is that the infrastructure that the UAB provides does not allow us to pass property-value pairs using the MsiProcessor to invoke the msi uninstall action AND pass some property=value pairs.

Solution: The usual way in which a manifest is authored for a msi processor to use the Remove action will be something like:

<?xml version="1.0" encoding="utf-8" ?>
<manifest manifestId="{311085F7-9320-4318-9A67-9BE32F04E933}" mandatory="True"
xmlns="urn:schemas-microsoft-com:PAG:updater-application-block:v2:manifest">
    <description>TestUAB Manifest</description>
    <application applicationId="{215E1AD7-9ABA-432f-A952-24BABA556850}">
        <entryPoint file="" parameters="" />
        <location>.\..\..</location>
    </application>
    <activation>
        <tasks>
            <task name="MSIProcessorInstall" type="Microsoft.ApplicationBlocks.Updater.ActivationProcessors.MsiProcessor, Microsoft.ApplicationBlocks.Updater.ActivationProcessors" taskId="{425E1AD7-9ABA-432f-A952-24BABA556850}">
                <config>
                    <installType>Remove</installType>
                    <productCode>{F7924949-7D0A-47E5-B133-AD2CC5C081F4}</productCode>
                    <uiLevel>msiUILevelDefault</uiLevel>
                </config>
            </task>
         </tasks>
    </activation>
</manifest>

The one glaring mess-up (uhum... miss-up) is that unlike the Install action, there is no provision to pass propertyValues to the Remove action! There are two things that need to be done for the UAB MSI uninstall or rather the remove action to recognize the various property values being passed.

Modify the MsiProcessor.cs found in Microsoft.ApplicationBlocks.Updater.ActivationProcessors (aka ActivationProcessors project)
Modify the RemoveProduct(...) to include the follow bits of code

...
session = installer.OpenProduct( productCode );
propertyValuePairs = this.GetPropertValuePairs(propertyValues);
for (int i = 0; i < propertyValuePairs.Length; i++)
{
    string[] parts = propertyValuePairs[i].Split('=');
    session.set_Property(parts[0], parts[1]);
}
session.DoAction( "INSTALL" );
...

And, in the same class put in the definition for parsing the property values
private string[] GetPropertValuePairs(string propertyValues)
{
    string[] propertyValuePairs = propertyValues.Split(' ');
    return propertyValuePairs;
}

If this doesn't make much sense the full code is attached along this post!
Modify the Manifest to include the propertyValues tag
Once the MsiProcessor is modified, we need to tag a tag to the manifest so that we will be able to pass on the property to the msiexec.exe process which actually hadles all requests for MSI actions. (Again, refer the RemoveManifest.xml attached in this mail)

That's all folks... you are up and running.

Detecting Session Timeout in ASP.NET 2.0 Web Applications

nikhiln — Thu, 21 Jun 2007 16:40:00 GMT

Problem: An ASP.NET 2.0 web application needs to detect a session timeout condition so that the user can be redirected to a different page and / or an error message is displayed.

Solution: There are three ways of approaching this problem, starting off with the simplest one to the most complicated one. So, here it goes:

Using Session["xxx"] value to determine the session timeout: This is a "quick and dirty" hack that can be introduced into an application to figure out whether a timeout has occured. We need to do two things here.
First, in Global.asax, create your own GUID and put it in the session object,

    void Session_Start(object sender, EventArgs e)
    {
       // Code that runs when a new session is started
       Session["CustomSessionId"] = Guid.NewGuid();
    }

Second, BasePage.cs which would have inherited Page, in PageLoad() event, check whether the Session["CustomSessionId"] == null, if it IS null, it means that the session was timed-out and AspNet runtime cleared it out.

    if( Session["CustomSessionId"] == null)
    {
        Response.Redirect("TimeoutPage.htm");
    }
Using a combination of Session.IsNewSession and Request.Cookies collection: Leveraging the behavior of ASP.NET runtime, we can check whether the Session.IsNewSession flag is true, if its true and we find that Request.Cookies["ASP.NET_SessionId"] has a valid value, it means that a timeout occured and a new request was generated by the runtime. This code fragment can be inserted into the OnInit(...) method in the BasePage class so that it applies across the application.

protected override void OnInit(EventArgs e)
{
    base.OnInit(e);
    if (Context.Session != null)
    {
        //check whether a new session was generated
        if (Session.IsNewSession)
        {
                //check whether a cookies had already been associated with this request
                        HttpCookie sessionCookie = Request.Cookies["ASP.NET_SessionId"];
                        if (sessionCookie != null)
                        {
                                string sessionValue = sessionCookie.Value;
                                if (!string.IsNullOrEmpty(sessionValue))
                                {
                                     // we have session timeout condition!
                                    // Response.Redirect("SessionTimeout.htm");
                                     Session["IsSessionTimeOut"] = true;
                                }
                        }
         }
    }
}

WARNING:- We will have to wireup the "void Session_Start(object sender, EventArgs e)" method in the Global.asax to use the Session.IsNewSession meaningfully. ASP.NET 2.0 runtime is a bit weird in the sense that it will always return the value of Session.IsNewSession as true in case the Event is not wireup!
Using HTTP Module: Arguably the most complex but robust way to tackle this situation. I would rather not go into this as this carries the risk of opening security holes in the HTTP stream

Creating the Other People (aka AddressBook) Certificate Store through Registry

nikhiln — Fri, 04 May 2007 15:41:00 GMT

Problem: A common scenario while installing application which consume certificates from the Other People store (or AddressBook in registry terms) is the failure of CertMgr.exe on a clean machine which doesn't have any other certificates. Now the problem will be, for a clean machine which doesn't already have the Other People store, when we are trying to install the certificate using CertMgr.exe it would fails with an error stating that the store specified is not found! The typical solution listed will be "Open Internet Explorer | Internet Options, flip to the Content tab and press the Certificates button. Click the Other People tab and press the Import button to continue". But in case of an automated installation, this obviously is not the answer!

Solution: Using .NET registry API or if you are authoring the setup in WiX, through the Regitry action, create the following key in registry which should then allow you to execute CertMgr.exe to import the certificate at the AddressBook store.

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SystemCertificates\AddressBook

This will create the Other People store which will be visible in MMC Certificates Snap-in.