Configuración de la autenticación de PlayFab con aplicaciones para UWP

using System;
using Windows.ApplicationModel;
using Windows.ApplicationModel.Activation;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;

namespace GettingStartedPlayfabUWP
{
    // This class is generated upon project creation.
    // While template on it's own contains a lot of xml comments, we are only interested in lines 17 and 27
    sealed partial class App : Application
    {

        // Replace PLAYFAB_TITLE_ID with your own
        public const string PlayfabTitleId = "PLAYFAB_TITLE_ID";

        /// <summary>
        /// Initializes the singleton application object. This is the first line of authored code
        /// executed, and as such is the logical equivalent of main() or WinMain().
        /// </summary>
        public App()
        {

            // This is the only line of functional code we need to add to this class.
            PlayFab.PlayFabSettings.TitleId = PlayfabTitleId;

            this.InitializeComponent();
            this.Suspending += OnSuspending;
        }

        /// <summary>
        /// Invoked when the application is launched normally by the end user. Other entry points
        /// will be used such as when the application is launched to open a specific file.
        /// </summary>
        /// <param name="e">Details about the launch request and process.</param>
        protected override void OnLaunched(LaunchActivatedEventArgs e)
        {
            Frame rootFrame = Window.Current.Content as Frame;

            // Do not repeat app initialization when the Window already has content,
            // just ensure that the window is active
            if (rootFrame == null)
            {
                // Create a Frame to act as the navigation context and navigate to the first page
                rootFrame = new Frame();

                rootFrame.NavigationFailed += OnNavigationFailed;

                if (e.PreviousExecutionState == ApplicationExecutionState.Terminated)
                {
                    //TODO: Load state from previously suspended application
                }

                // Place the frame in the current Window
                Window.Current.Content = rootFrame;
            }

            if (e.PrelaunchActivated == false)
            {
                if (rootFrame.Content == null)
                {
                    // When the navigation stack isn't restored navigate to the first page,
                    // configuring the new page by passing required information as a navigation
                    // parameter
                    rootFrame.Navigate(typeof(MainPage), e.Arguments);
                }
                // Ensure the current window is active
                Window.Current.Activate();
            }
        }

        /// <summary>
        /// Invoked when Navigation to a certain page fails
        /// </summary>
        /// <param name="sender">The Frame which failed navigation</param>
        /// <param name="e">Details about the navigation failure</param>
        void OnNavigationFailed(object sender, NavigationFailedEventArgs e)
        {
            throw new Exception("Failed to load Page " + e.SourcePageType.FullName);
        }

        /// <summary>
        /// Invoked when application execution is being suspended. Application state is saved
        /// without knowing whether the application will be terminated or resumed with the contents
        /// of memory still intact.
        /// </summary>
        /// <param name="sender">The source of the suspend request.</param>
        /// <param name="e">Details about the suspend request.</param>
        private void OnSuspending(object sender, SuspendingEventArgs e)
        {
            var deferral = e.SuspendingOperation.GetDeferral();
            //TODO: Save application state and stop any background activity
            deferral.Complete();
        }
    }
}

<Page
    x:Class="GettingStartedPlayfabUWP.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:GettingStartedPlayfabUWP"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d">

    <Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
        <StackPanel Margin="0,10,10,0">
            <TextBox x:Name="UsernameInput" TextWrapping="Wrap" Text="" PlaceholderText="Username..."/>
            <Button x:Name="RegisterButton" Content="Register With Hello" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Click="RegisterRequest"/>
            <Button x:Name="LoginButton" Content="Sign In With Hello" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Click="LogInRequest"/>
        </StackPanel>
    </Grid>
</Page>

using System;
using System.Linq;
using System.Threading.Tasks;
using Windows.Foundation;
using Windows.Networking.Connectivity;
using Windows.Security.Credentials;
using Windows.Security.Cryptography;
using Windows.Security.Cryptography.Core;
using Windows.Storage.Streams;
using Windows.UI.Popups;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using PlayFab;
using PlayFab.ClientModels;

namespace GettingStartedPlayfabUWP
{
    public sealed partial class MainPage : Page
    {
        // Shortcut to get current value of UsernameInput
        public string Username => UsernameInput.Text;

        public MainPage()
        {
            this.InitializeComponent();
        }

        /// <summary>
        /// This method is invoked when you select the Register button
        /// This method illustrates the flow for Registration process.
        /// We operate on 2 entities:
        /// - User Credentials of type KeyCredential
        /// - Public Key of type String
        /// We first check if user with this id already has Credentials. If so, we redirect to login procedure.
        /// Then we create new User Credentials. Check CreateKeyCredential for implementation details
        /// Then we get Base64 encoded Public Key using the new User Credentials. Check GetPublicKeyBase64 for implementation details
        /// Then we execute RegisterWithHello api call call. Check CallPlayFabRegisterWithHello for implementation details
        /// </summary>
        private async void RegisterRequest(object sender, RoutedEventArgs e)
        {
            // Check if the user already exists and if so log them in.
            KeyCredentialRetrievalResult retrieveResult = await KeyCredentialManager.OpenAsync(Username);
            if (retrieveResult.Status == KeyCredentialStatus.Success)
            {
                // Redirect to login procedure
                LogInRequest(sender, e);
                return;
            }

            // Create a new KeyCredential for the user on the device.
            var credential = await CreateKeyCredential(Username);
            if (credential == null) return;

            var publicKey = await GetPublicKeyBase64(credential);
            if (string.IsNullOrEmpty(publicKey)) return;
            // Include the name of the current device for the benefit of the user.
            // The server could support a Web interface that shows the user all the devices they
            // have signed in from and revoke access from devices they have lost.

            var registerResponse = await CallPlayFabRegisterWithHello(publicKey, Username);

            await ShowMessage("Registered and signed in with Session Ticket " + registerResponse.Result.SessionTicket);
        }

        //
        /// <summary>
        /// This method is invoked when you select the Log In button
        /// This method shows entities flow during the sign in process.
        /// We have 4 different entities:
        /// - User Credentials of type KeyCredential
        /// - Public Key Hint of type String
        /// - Challenge of type String
        /// - SignedChallenge of type String
        ///
        /// We first acquire the User Credentials. We do it based on Username. Check GetUserCredentials method for implementation details
        /// Next, we get Public Key Hint based on those credentials. Check GetPublicKeyHint for implementation details.
        /// Next we request a Challenge from PlayFab. Check GetPlayFabHelloChallenge for implementation details
        /// Next we sign the Challenge using User Credentials, so we obtain Signed Challenge. Check GetPlayFabHelloChallenge for implementation details
        /// Finally we use Signed Challenge and Public Key Hint to log into PlayFab. Check CallPlayFabLoginWithHello for implementation details
        /// </summary>
        private async void LogInRequest(object sender, RoutedEventArgs e)
        {
            // Get credentials based on current Username.
            var credentials = await GetUserCredentials(Username);
            if (credentials == null) return;

            // Credentials will give us Public Key. We use it to construct Public Key Hint, which is first important entity for PlayFab+UWP authentication.
            var publicKeyHint = GetPublicKeyHintBase64(credentials);
            if (string.IsNullOrEmpty(publicKeyHint)) return;

            // Get PlayFab Challenge to sign for Windows Hello.
            var challenge = await GetPlayFabHelloChallenge(publicKeyHint);
            if (string.IsNullOrEmpty(challenge)) return;

            // Request user to sign the challenge.
            var signedChallenge = await RequestUserSignChallenge(credentials, challenge);
            if (string.IsNullOrEmpty(signedChallenge)) return;

            // Send the signature back to the server to confirm our identity.
            // The publicKeyHint tells the server which public key to use to verify the signature.
            var result = await CallPlayFabLoginWithHello(publicKeyHint, signedChallenge);
            if (result == null) return;

            // Report the result.
            await ShowMessage("Signed in with Session Ticket " + result.Result.SessionTicket);
        }

        public async Task<string> GetPublicKeyBase64(KeyCredential userCredential)
        {

            IBuffer publicKey = userCredential.RetrievePublicKey();

            if (publicKey == null)
            {
                await ShowMessage("Failed to get public key for credential");
                return null;
            }

            return CryptographicBuffer.EncodeToBase64String(publicKey);
        }

        public string GetPublicKeyHintBase64(KeyCredential userCredential)
        {
            HashAlgorithmProvider hashProvider = HashAlgorithmProvider.OpenAlgorithm(HashAlgorithmNames.Sha256);
            var publicKey = userCredential.RetrievePublicKey();
            IBuffer publicKeyHash = hashProvider.HashData(publicKey);
            return CryptographicBuffer.EncodeToBase64String(publicKeyHash);
        }

        public async Task<KeyCredential> GetUserCredentials(string userId)
        {
            // Open credential based on our Username and make sure it is successful
            KeyCredentialRetrievalResult retrieveResult = await KeyCredentialManager.OpenAsync(userId);

            if (retrieveResult.Status != KeyCredentialStatus.Success)
            {
                await ShowMessage("Error: Unable to open credentials! " + retrieveResult.Status);
                return null;
            }

            return retrieveResult.Credential;
        }

        public async Task<string> GetPlayFabHelloChallenge(string publicKeyHint)
        {
            // Request challenge from PlayFab and make sure response has no errors
            var challengeResponse = await PlayFab.PlayFabClientAPI.GetWindowsHelloChallengeAsync(new GetWindowsHelloChallengeRequest
            {
                PublicKeyHint = publicKeyHint,
                TitleId = PlayFab.PlayFabSettings.TitleId
            });

            if (challengeResponse.Error != null)
            {
                await ShowMessage($"Error during getting challenge: {challengeResponse.Error.Error}");
                return null;
            }

            return challengeResponse.Result.Challenge;

        }

        public async Task<string> RequestUserSignChallenge(KeyCredential credentials, string challenge)
        {
            IBuffer challengeBuffer = CryptographicBuffer.DecodeFromBase64String(challenge);
            KeyCredentialOperationResult opResult = await credentials.RequestSignAsync(challengeBuffer);

            if (opResult.Status != KeyCredentialStatus.Success)
            {
                await ShowMessage("Failed sign the challenge string: " + opResult.Status);
                return null;
            }

            return CryptographicBuffer.EncodeToBase64String(opResult.Result);
        }

        public async Task<PlayFabResult<LoginResult>> CallPlayFabLoginWithHello(string publicKeyHint, string signedChallenge)
        {
            var loginResponse = await PlayFab.PlayFabClientAPI.LoginWithWindowsHelloAsync(new LoginWithWindowsHelloRequest
            {
                ChallengeSignature = signedChallenge,
                PublicKeyHint = publicKeyHint
            });

            if (loginResponse.Error != null)
            {
                await ShowMessage($"Failed to log in: {loginResponse.Error.Error}");
                return null;
            }

            return loginResponse;
        }

        public IAsyncOperation<IUICommand> ShowMessage(string messageString)
        {
            MessageDialog message = new MessageDialog($"{messageString}");
            return message.ShowAsync();
        }

        public async Task<PlayFabResult<LoginResult>> CallPlayFabRegisterWithHello(string publicKey, string username)
        {
            var hostNames = NetworkInformation.GetHostNames();
            var localName = hostNames.FirstOrDefault(name => name.DisplayName.Contains(".local"));
            string computerName = localName.DisplayName.Replace(".local", "");

            var registerResult = await PlayFab.PlayFabClientAPI.RegisterWithWindowsHelloAsync(new RegisterWithWindowsHelloRequest
            {
                DeviceName = computerName,
                PublicKey = publicKey,
                UserName = username
            });

            if (registerResult.Error != null)
            {
                await ShowMessage(registerResult.Error.GenerateErrorReport());
                return null;
            }

            return registerResult;
        }

        public async Task<KeyCredential> CreateKeyCredential(string username)
        {
            KeyCredentialRetrievalResult keyCreationResult = await KeyCredentialManager.RequestCreateAsync(username, KeyCredentialCreationOption.ReplaceExisting);
            if (keyCreationResult.Status != KeyCredentialStatus.Success)
            {
                // User has authenticated with Windows Hello and the key credential is created.
                await ShowMessage("Failed to create key credential: " + keyCreationResult.Status);
                return null;
            }

            return keyCreationResult.Credential;
        }

    }

}