Remove non-functioning code and instead throw a more helpful platform-not-supported error

src/Essentials/src/WebAuthenticator/WebAuthenticator.shared.cs

@@ -19,11 +19,9 @@ public interface IWebAuthenticator
 		/// <param name="webAuthenticatorOptions">A <see cref="WebAuthenticatorOptions"/> instance containing additional configuration for this authentication call.</param>
 		/// <returns>A <see cref="WebAuthenticatorResult"/> object with the results of this operation.</returns>
 		/// <exception cref="TaskCanceledException">Thrown when the user canceled the authentication flow.</exception>
-		/// <exception cref="HttpRequestException">Windows: Thrown when a HTTP Request error occured.</exception>
-		/// <exception cref="Exception">Windows: Thrown when a unexpected HTTP response was received.</exception>
+		/// <exception cref="PlatformNotSupportedException">Windows: Thrown when called on Windows.</exception>
 		/// <exception cref="FeatureNotSupportedException">iOS/macOS: Thrown when iOS version is less than 13 is used or macOS less than 13.1 is used.</exception>
 		/// <exception cref="InvalidOperationException">
-		/// <para>Windows: Thrown when the callback custom URL scheme is not registered in the AppxManifest.xml file.</para>
 		/// <para>Android: Thrown when the no IntentFilter has been created for the callback URL.</para>
 		/// </exception>
 		Task<WebAuthenticatorResult> AuthenticateAsync(WebAuthenticatorOptions webAuthenticatorOptions);
@@ -76,13 +74,19 @@ public static class WebAuthenticator
 		/// <summary>Begin an authentication flow by navigating to the specified url and waiting for a callback/redirect to the callbackUrl scheme.</summary>
 		/// <param name="url"> Url to navigate to, beginning the authentication flow.</param>
 		/// <param name="callbackUrl"> Expected callback url that the navigation flow will eventually redirect to.</param>
-		/// <returns>Returns a result parsed out from the callback url.</returns>		
+		/// <returns>Returns a result parsed out from the callback url.</returns>
+#if !NETSTANDARD
+		[System.Runtime.Versioning.UnsupportedOSPlatform("windows")]
+#endif
 		public static Task<WebAuthenticatorResult> AuthenticateAsync(Uri url, Uri callbackUrl)
 			=> Current.AuthenticateAsync(url, callbackUrl);
 
 		/// <summary>Begin an authentication flow by navigating to the specified url and waiting for a callback/redirect to the callbackUrl scheme.The start url and callbackUrl are specified in the webAuthenticatorOptions.</summary>
 		/// <param name="webAuthenticatorOptions">Options to configure the authentication request.</param>
 		/// <returns>Returns a result parsed out from the callback url.</returns>
+#if !NETSTANDARD
+		[System.Runtime.Versioning.UnsupportedOSPlatform("windows")]
+#endif
 		public static Task<WebAuthenticatorResult> AuthenticateAsync(WebAuthenticatorOptions webAuthenticatorOptions)
 			=> Current.AuthenticateAsync(webAuthenticatorOptions);
 

src/Essentials/src/WebAuthenticator/WebAuthenticator.uwp.cs

@@ -1,64 +1,13 @@
 using System;
-using System.IO;
-using System.Linq;
-using System.Net.Http;
 using System.Threading.Tasks;
-using System.Xml;
-using System.Xml.Linq;
-using System.Xml.XPath;
-using Microsoft.Maui.ApplicationModel;
-using Microsoft.Maui.Storage;
-using Windows.Security.Authentication.Web;
 
 namespace Microsoft.Maui.Authentication
 {
 	partial class WebAuthenticatorImplementation : IWebAuthenticator
 	{
-		public async Task<WebAuthenticatorResult> AuthenticateAsync(WebAuthenticatorOptions webAuthenticatorOptions)
+		public Task<WebAuthenticatorResult> AuthenticateAsync(WebAuthenticatorOptions webAuthenticatorOptions)
 		{
-			var url = webAuthenticatorOptions?.Url;
-			var callbackUrl = webAuthenticatorOptions?.CallbackUrl;
-
-			if (!IsUriProtocolDeclared(callbackUrl.Scheme))
-				throw new InvalidOperationException($"You need to declare the windows.protocol usage of the protocol/scheme `{callbackUrl.Scheme}` in your AppxManifest.xml file");
-
-			try
-			{
-				var r = await WebAuthenticationBroker.AuthenticateAsync(WebAuthenticationOptions.None, url, callbackUrl);
-
-				switch (r.ResponseStatus)
-				{
-					case WebAuthenticationStatus.Success:
-						// For GET requests this is a URI:
-						var resultUri = new Uri(r.ResponseData.ToString());
-						return new WebAuthenticatorResult(resultUri, webAuthenticatorOptions?.ResponseDecoder);
-					case WebAuthenticationStatus.UserCancel:
-						throw new TaskCanceledException();
-					case WebAuthenticationStatus.ErrorHttp:
-						throw new HttpRequestException("Error: " + r.ResponseErrorDetail);
-					default:
-						throw new Exception("Response: " + r.ResponseData.ToString() + "\nStatus: " + r.ResponseStatus);
-				}
-			}
-			catch (FileNotFoundException)
-			{
-				throw new TaskCanceledException();
-			}
-		}
-
-		static bool IsUriProtocolDeclared(string scheme)
-		{
-			var docPath = FileSystemUtils.PlatformGetFullAppPackageFilePath(PlatformUtils.AppManifestFilename);
-			var doc = XDocument.Load(docPath, LoadOptions.None);
-			var reader = doc.CreateReader();
-			var namespaceManager = new XmlNamespaceManager(reader.NameTable);
-			namespaceManager.AddNamespace("x", PlatformUtils.AppManifestXmlns);
-			namespaceManager.AddNamespace("uap", "http://schemas.microsoft.com/appx/manifest/uap/windows10");
-
-			// Check if the protocol was declared
-			var decl = doc.Root.XPathSelectElements($"//uap:Extension[@Category='windows.protocol']/uap:Protocol[@Name='{scheme}']", namespaceManager);
-
-			return decl != null && decl.Any();
+			throw new PlatformNotSupportedException("This implementation of WebAuthenticator does not support Windows. See https://github.com/microsoft/WindowsAppSDK/issues/441 for more details.");
 		}
 	}
 }

src/Essentials/test/DeviceTests/Tests/WebAuthenticator_Tests.cs

@@ -21,14 +21,21 @@ public class WebAuthenticator_Tests
 		[Trait(Traits.InteractionType, Traits.InteractionTypes.Human)]
 		public async Task Redirect(string urlBase, string callbackScheme, string accessToken, string refreshToken, int expires)
 		{
-			var r = await WebAuthenticator.AuthenticateAsync(
+#pragma warning disable CA1416 // Validate platform compatibility: Not supported on Windows
+			var authenticationTask = WebAuthenticator.AuthenticateAsync(
 				new Uri($"{urlBase}?access_token={accessToken}&refresh_token={refreshToken}&expires={expires}"),
 				new Uri($"{callbackScheme}://"));
+#pragma warning restore CA1416 // Validate platform compatibility
 
+#if WINDOWS
+			var exception = await Assert.ThrowsAsync<PlatformNotSupportedException>(async () => await authenticationTask);
+#else
+			var r = await authenticationTask;
 			Assert.Equal(accessToken, r?.AccessToken);
 			Assert.Equal(refreshToken, r?.RefreshToken);
 			Assert.NotNull(r?.ExpiresIn);
 			Assert.True(r?.ExpiresIn > DateTime.UtcNow);
+#endif
 		}
 
 		[Theory]
@@ -42,18 +49,24 @@ public async Task Redirect(string urlBase, string callbackScheme, string accessT
 		public async Task RedirectWithResponseDecoder(string urlBase, string callbackScheme, string accessToken, string refreshToken, int expires)
 		{
 			var responseDecoder = new TestResponseDecoder();
-			var r = await WebAuthenticator.AuthenticateAsync(new WebAuthenticatorOptions
+#pragma warning disable CA1416 // Validate platform compatibility: Not supported on Windows
+			var authenticationTask = WebAuthenticator.AuthenticateAsync(new WebAuthenticatorOptions
 			{
 				Url = new Uri($"{urlBase}?access_token={accessToken}&refresh_token={refreshToken}&expires={expires}"),
 				CallbackUrl = new Uri($"{callbackScheme}://"),
 				ResponseDecoder = responseDecoder
 			});
-
+#pragma warning restore CA1416 // Validate platform compatibility
+#if WINDOWS
+			var exception = await Assert.ThrowsAsync<PlatformNotSupportedException>(async () => await authenticationTask);
+#else
+			var r = await authenticationTask;
 			Assert.Equal(accessToken, r?.AccessToken);
 			Assert.Equal(refreshToken, r?.RefreshToken);
 			Assert.NotNull(r?.ExpiresIn);
 			Assert.True(r?.ExpiresIn > DateTime.UtcNow);
 			Assert.Equal(1, responseDecoder.CallCount);
+#endif
 		}
 
 		[Theory]