I have written a custom handler that I want to be called after a successful login. It checks the status of the logged in user's email address against a database table and redirects the user to a Classic ASP site they are authorized to view (with a few fallbacks to handle scenarios like no websites allowed or multiple sites allowed).

I want this code to be called in two situations - after successful login and when the user clicks a button to say 'return me to my site'. All other DNN requests should ignore the handler.

I have tried creating a registered users only blank page called RedirectToClassicASP which is accessed using RedirectToClassicASP.aspx. I then added my handler registration alongside the other handlers in web.config:

<add name="ClassicAspAuthenticationHandler" verb="*" path="RedirectToClassicASP.aspx" type="ClassicAspAuthenticationHandler, ClassicAspClientRedirection.Logic" preCondition="integratedMode" />

I was expecting to see this handler invoked when accessing the ~/RedirectToClassicASP.aspx page but it isn't. I get ~/Default.aspx?tabid=377&language=en-US instead and see the blank page. If I change the registration to use Default.aspx instead of RedirectToClassicASP.aspx the handler is called.

Note that this handler also works most of the time if I register it to handle Default.aspx and then include code to jump around the redirection when not needed. Here is the code that has been working for 6 months on our production site:

public void ProcessRequest(HttpContext context)
{
//todo make this use the portalid?
if (context.Request.RawUrl.Contains(@"RedirectToClassicASP"))
{
var redirection = new Redirection();
redirection.Redirect();
} // no redirection so carry on as normal
var handler = PageParser.GetCompiledPageInstance(context.Request.CurrentExecutionFilePath, null, context);
handler.ProcessRequest(context);
}

Unfortunately, some of my applications fail in the handler.ProcessRequest(context) statement. I am not sure why, but until I find out, I am hoping to make handler called only when it is needed.

Where am I going wrong? Is there a better way to achieve this redirection?