// CheckNonSecuredEndpointForRedirect
// This function does an unauthenticated GET request to a non-https
// URL to see if the server will respond with a 302 redirect. If so, it will
// attempt to use the value of the Location header to perform Autodiscover.
//
// Parameters:
// useSoapEndpoints: Indicates whether SOAP endpoints should be tried.
//
// Returns:
// A Dictionary object that contains the settings returned by the
// Autodiscover process. If null, either the redirect failed or the URL failed.
//
private Dictionary <string, string> CheckNonSecuredEndpointForRedirect(bool useSoapEndpoints)
{
// Get the non-https URL, or "last ditch" URL.
string nonHttpsEndpoint = UrlList.GetLastDitchUrl(EmailAddress);
Tracing.WriteLine("Sending non-authenticated GET to " + nonHttpsEndpoint);
HttpWebRequest getRequest = (HttpWebRequest)WebRequest.Create(nonHttpsEndpoint);
getRequest.Method = "GET";
getRequest.AllowAutoRedirect = false;
getRequest.PreAuthenticate = false;
try
{
HttpWebResponse getResponse = (HttpWebResponse)getRequest.GetResponse();
if (getResponse != null)
{
if (getResponse.StatusCode == HttpStatusCode.Redirect ||
getResponse.StatusCode == HttpStatusCode.Moved ||
getResponse.StatusCode == HttpStatusCode.RedirectKeepVerb ||
getResponse.StatusCode == HttpStatusCode.RedirectMethod)
{
Tracing.WriteLine("Received a redirect status: " + getResponse.StatusCode.ToString());
string redirectUrl = getResponse.Headers["Location"].ToString();
Tracing.WriteLine("Location header: " +
(string.IsNullOrEmpty(redirectUrl) ? "MISSING" : redirectUrl));
if (IsValidRedirectUrl(redirectUrl))
{
// You got a valid redirect; try it.
UrlRedirects++;
return(TryAutodiscoverUrl(AutodiscoverUrlList.NormalizeAutodiscoverUrl(redirectUrl),
useSoapEndpoints));
}
else
{
Tracing.WriteLine("Redirect returned missing or invalid URL, unable to proceed.");
}
}
else
{
Tracing.WriteLine("Received a non-redirect status: " + getResponse.StatusCode.ToString());
}
}
}
catch (WebException e)
{
Tracing.WriteLine("Unable to connect.");
Tracing.WriteLine(e.ToString());
}
return(null);
}
