Building URL with www.


// Collect url information being requested
string urlHttps = Request.ServerVariables["HTTPS"];

string urlHost = Request.ServerVariables["HTTP_HOST"];
string urlUrl = Request.ServerVariables["URL"];
string urlQueryString = Request.ServerVariables["QUERY_STRING"];


// Check if www appears in the domain and begin building url to redirect to if it doesn’t
if (!urlHost.Contains("www."))
{
string urlNewUrl = "http://www.";
//Add the domain, folder(s) and page requested as well as remove directory indexes
urlNewUrl = urlNewUrl + urlHost + urlUrl;
//If there is a querystring, add it to the redirect link
if (urlQueryString.Length > 0)
urlNewUrl = urlNewUrl + "?" + urlQueryString;
//Do the actual 301 redirect to the newly constructed url
Response.Status = "301 Moved Permanently";
Response.AddHeader("Location", urlNewUrl);
Response.End();
}