1 files changed, 46 insertions, 0 deletions
diff --git a/samples/OpenIdRelyingPartyWebForms/DetectGoogleSession.aspx.cs b/samples/OpenIdRelyingPartyWebForms/DetectGoogleSession.aspx.cs
new file mode 100644
index 0000000..98fe745
--- /dev/null
+++ b/samples/OpenIdRelyingPartyWebForms/DetectGoogleSession.aspx.cs
@@ -0,0 +1,46 @@
+namespace OpenIdRelyingPartyWebForms {
+	using System;
+	using DotNetOpenAuth.ApplicationBlock.CustomExtensions;
+	using DotNetOpenAuth.OpenId.Extensions.UI;
+	using DotNetOpenAuth.OpenId.RelyingParty;
+
+	public partial class DetectGoogleSession : System.Web.UI.Page {
+		private const string GoogleOPIdentifier = "https://www.google.com/accounts/o8/id";
+
+		private const string UIModeDetectSession = "x-has-session";
+
+		protected void Page_Load(object sender, EventArgs e) {
+			using (var openid = new OpenIdRelyingParty()) {
+				// In order to receive the UIRequest as a response, we must register a custom extension factory.
+				openid.ExtensionFactories.Add(new UIRequestAtRelyingPartyFactory());
+
+				var response = openid.GetResponse();
+				if (response == null) {
+					// Submit an OpenID request which Google must reply to immediately.
+					// If the user hasn't established a trust relationship with this site yet,
+					// Google will not give us the user identity, but they will tell us whether the user
+					// at least has an active login session with them so we know whether to promote the
+					// "Log in with Google" button.
+					IAuthenticationRequest request = openid.CreateRequest("https://www.google.com/accounts/o8/id");
+					request.AddExtension(new UIRequest { Mode = UIModeDetectSession });
+					request.Mode = AuthenticationRequestMode.Immediate;
+					request.RedirectToProvider();
+				} else {
+					if (response.Status == AuthenticationStatus.Authenticated) {
+						this.YouTrustUsLabel.Visible = true;
+					} else if (response.Status == AuthenticationStatus.SetupRequired) {
+						// Google refused to authenticate the user without user interaction.
+						// This is either because Google doesn't know who the user is yet,
+						// or because the user hasn't indicated to Google to trust this site.
+						// Google uniquely offers the RP a tip as to which of the above situations is true.
+						// Figure out which it is.  In a real app, you might use this value to promote a 
+						// Google login button on your site if you detect that a Google session exists.
+						var ext = response.GetUntrustedExtension<UIRequest>();
+						this.YouAreLoggedInLabel.Visible = ext != null && ext.Mode == UIModeDetectSession;
+						this.YouAreNotLoggedInLabel.Visible = !this.YouAreLoggedInLabel.Visible;
+					}
+				}
+			}
+		}
+	}
+}
+\ No newline at end of file