Determining IIS user for IIS 5

I'm writing a Wix-based s开发者_运维问答etup for a web application and would like to set permissions on the folders it installs so that IIS can access them.

IIS 6 and 7 use IIS_WPG and IIS_USRS respectively, and IIS 5 uses IUSR_COMPUTER NAME. If the user has changed their machine name however, setting permissions using the current computer name fails.

Is there a way of programmatically determining the user account being used by IIS 5 rather than just assuming it will be IUSR_COMPUTERNAME?

I'm doing it like this (don't pretend to offer the best practice solution) - that's an immediate CA which sets the properties you can use later:

  [CustomAction]
  public static ActionResult SetIUSRAccountNameAction(Session session)
  {
     ActionResult actionResult = ActionResult.Failure;
     DirectoryEntry iisAdmin = new DirectoryEntry("IIS://localhost/W3SVC");
     if (iisAdmin != null)
     {
        string iusrName = (string)iisAdmin.Properties["AnonymousUserName"][0];
        if (!string.IsNullOrEmpty(iusrName))
        {
           session["IUSR_USERNAME"] = iusrName;

           string iusrDomain = GetAccountDomain(iusrName, session);
           if (!string.IsNullOrEmpty(iusrDomain))
           {
              session["IUSR_DOMAIN"] = iusrDomain;
           }

           actionResult = ActionResult.Success;
        }
     }

     return actionResult;
  }

where the GetAccountDomain method is defined like this:

  static string GetAccountDomain(string accountName, Session session)
  {
     SelectQuery query = new SelectQuery("Win32_UserAccount", string.Format("Name='{0}'", accountName), new string[] { "Domain" });
     ManagementObjectSearcher searcher = new ManagementObjectSearcher(query);
     try
     {
        foreach (ManagementObject account in searcher.Get())
        {
           return (string)account["Domain"];
        }
     }
     catch (Exception ex)
     {
        session.Log("Failed to get a domain for the user {0}:  {1}", accountName, ex.Message);
     }

     return null;
  }

Hope this helps.