Question

In my global.asax.vb file, I have code to re-write the URL if there is a prefix on the URL. We are introducing a new context in our application. So every page will either be of context hair or saliva.

Before the ASP.NET code (stack) even reaches this Global code, it calls an application block called UIProcess. It’s code that Microsoft wrote years ago, and is no longer supported. The UIP block sort of mimics MVC, and you store all views, navigation and controller details inside the web.config. The UIP block is doing a redirect as shown below. Note, they had a known bug that was never fixed (commented out), so I had to recompile it before upgrading from .NET 2.0 to .NET 3.5. That’s what I have commented out. That’s the only bug I’m aware of.

    private void RedirectToNextView(string previousView, ViewSettings viewSettings)
    {
        try
        {
            //if (previousView == null)
            //    HttpContext.Current.Response.Redirect(HttpContext.Current.Request.ApplicationPath + "/" + viewSettings.Type, true);
            //else
            //    HttpContext.Current.Response.Redirect(HttpContext.Current.Request.ApplicationPath + "/" + viewSettings.Type, false);
            if (previousView == null)
                HttpContext.Current.Response.Redirect(HttpContext.Current.Request.ApplicationPath.TrimEnd('/') + viewSettings.Type, true);
            else
                HttpContext.Current.Response.Redirect(HttpContext.Current.Request.ApplicationPath.TrimEnd('/') + viewSettings.Type, false);
        }
        catch (System.Threading.ThreadAbortException) { }
    }

Here is the Global.asax.vb code:
(again this code doesn’t matter right now because it’s not getting here YET with the exception being thrown)

Sub Application_BeginRequest(ByVal sender As Object, _
                             ByVal e As EventArgs)
    ' Fires at the beginning of each request
    Dim originalUri As Uri = Request.Url
    Dim rewrittenUrl As String = String.Empty

    'Rewrite Saliva and Hair Testing urls 
    Select Case True
        Case originalUri.AbsolutePath.StartsWith("/HairTest/")
            rewrittenUrl = originalUri.AbsolutePath.Remove(0, 9)

            If Not originalUri.Query.Contains("SampleTypeContext=247") Then
                rewrittenUrl += "?sampleTypeContext=247"
            End If
        Case originalUri.AbsolutePath.StartsWith("/SalivaTest/")
            rewrittenUrl = originalUri.AbsolutePath.Remove(0, 11)

            If Not originalUri.Query.Contains("SampleTypeContext=3301") Then
                rewrittenUrl += "?sampleTypeContext=3301"
            End If
    End Select

    If rewrittenUrl <> String.Empty Then
        'append the original query if there was one specified
        If originalUri.Query <> String.Empty Then
            If rewrittenUrl.Contains("?") Then
                rewrittenUrl += "&"
            Else
                rewrittenUrl += "?"
            End If
            rewrittenUrl += originalUri.Query.Remove(0, 1)
        End If
        Context.RewritePath(rewrittenUrl)
    End If
End Sub

The application is actually causing an exception above, when I try to pre-pend my URL (viewSettings.Type variable above) with “/HairTest” or “/SalivaTest”. It causes that System.Threading.ThreadAbortException. I’m thinking because that path doesn’t actually exist in our web application, but I’m just guessing. Notice, we’re doing a re-write in our global, not a redirect. Our re-write prepends the URL with “/HairTest” or “/SalivaTest”.

All of the pages in our web application expect that “SampleTypeContext” parameter if it needs it. If you can think of a way that will work better for this situation, let me know. I’ll try to get more details on the exception.

Looking for ideas!! Our architecture approach is still up for discussion if we run into issues with this UIProcess block. We can’t just get rid of the UIP block since it’s used throughout our application, but I can modify the code above (in my first code snippet) if we need to.

Answer 1

There’s no standard way to do this with the UIP block. And Microsoft doesn’t maintain it anymore. I overloaded a bunch of the methods in the library to make it work. So that we can append a query string parameter (applicationScope) on each of our UIP redirect calls.

If you need the code, add a comment here, and I’ll send you the source.