What does ServerVariables[“APPL_MD_PATH”] retrieves the metabase path for the Application for the ISAPI DLL mean?

Question

I've trying to get an ASP.net (v2) app to work in the debugger and keep running into a problem because the value returned by the following code is an empty string:

HttpContext.Current.Request.ServerVariables["APPL_MD_PATH"].ToLower()

I have found out that this "Retrieves the metabase path for the Application for the ISAPI DLL". Can anybody shed some light on what this means and why it might be empty?

This code works in our live environment, but I want it to work on my PC and be able to step through source code so I can look at another problem...

Answer 1

Are you running your application locally inside of IIS or inside of the development web server? If it's the latter, then that's probably why: Cassini (the development web server) doesn't do ISAPI, so this value will be empty.