How to determine installed IIS version

Question

What would the preferred way of programmatically determining which the currently installed version of Microsoft Internet Information Services (IIS) is?

I know that it can be found by looking at the MajorVersion key in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W3SVC\Parameters.

Would this be the recommended way of doing it, or is there any safer or more beautiful method available to a .NET developer?

Answer 1

You could build a WebRequest and send it to port 80 on a loopback IP address and get the Server HTTP header.

HttpWebRequest myHttpWebRequest = (HttpWebRequest)WebRequest.Create("http://127.0.0.1/");
HttpWebResponse myHttpWebResponse = null;
try
{
    myHttpWebResponse = (HttpWebResponse)myHttpWebRequest.GetResponse();
}
catch (WebException ex)
{
    myHttpWebResponse = (HttpWebResponse)ex.Response;
}
string WebServer = myHttpWebResponse.Headers["Server"];
myHttpWebResponse.Close();

Not sure if that's a better way of doing it but it's certainly another option.

Answer 2

To identify the version from outside the IIS process, one possibility is like below...

string w3wpPath = Path.Combine(
    Environment.GetFolderPath(Environment.SpecialFolder.System), 
    @"inetsrv\w3wp.exe");
FileVersionInfo versionInfo = FileVersionInfo.GetVersionInfo(w3wpPath);
Console.WriteLine(versionInfo.FileMajorPart);

To identify it from within the worker process at runtime...

using (Process process = Process.GetCurrentProcess())
{
    using (ProcessModule mainModule = process.MainModule)
    {
     // main module would be w3wp
     int version = mainModule.FileVersionInfo.FileMajorPart
    }
}