Merge pull request #47 from tparnell8/master

twitch oauth works

Owin.Security.Providers/Owin.Security.Providers.csproj

@@ -206,6 +206,15 @@
     <Compile Include="TripIt\TripItAuthenticationHandler.cs" />
     <Compile Include="TripIt\TripItAuthenticationMiddleware.cs" />
     <Compile Include="TripIt\TripItAuthenticationOptions.cs" />
+    <Compile Include="Twitch\Constants.cs" />
+    <Compile Include="Twitch\TwitchAuthenticationExtensions.cs" />
+    <Compile Include="Twitch\TwitchAuthenticationHandler.cs" />
+    <Compile Include="Twitch\TwitchAuthenticationMiddleware.cs" />
+    <Compile Include="Twitch\TwitchAuthenticationOptions.cs" />
+    <Compile Include="Twitch\Provider\TwitchAuthenticatedContext.cs" />
+    <Compile Include="Twitch\Provider\TwitchAuthenticationProvider.cs" />
+    <Compile Include="Twitch\Provider\TwitchReturnEndpointContext.cs" />
+    <Compile Include="Twitch\Provider\ITwitchAuthenticationProvider.cs" />
     <Compile Include="WordPress\WordPressAuthenticationExtensions.cs" />
     <Compile Include="WordPress\WordPressAuthenticationHandler.cs" />
     <Compile Include="WordPress\WordPressAuthenticationMiddleware.cs" />

Owin.Security.Providers/Twitch/Constants.cs

@@ -0,0 +1,7 @@
+namespace Owin.Security.Providers.Twitch
+{
+    internal static class Constants
+    {
+        public const string DefaultAuthenticationType = "Twitch";
+    }
+}

Owin.Security.Providers/Twitch/Provider/ITwitchAuthenticationProvider.cs

@@ -0,0 +1,24 @@
+using System.Threading.Tasks;
+
+namespace Owin.Security.Providers.Twitch
+{
+    /// <summary>
+    /// Specifies callback methods which the <see cref="TwitchAuthenticationMiddleware"></see> invokes to enable developer control over the authentication process. />
+    /// </summary>
+    public interface ITwitchAuthenticationProvider
+    {
+        /// <summary>
+        /// Invoked whenever Twitch succesfully authenticates a user
+        /// </summary>
+        /// <param name="context">Contains information about the login session as well as the user <see cref="System.Security.Claims.ClaimsIdentity"/>.</param>
+        /// <returns>A <see cref="Task"/> representing the completed operation.</returns>
+        Task Authenticated(TwitchAuthenticatedContext context);
+
+        /// <summary>
+        /// Invoked prior to the <see cref="System.Security.Claims.ClaimsIdentity"/> being saved in a local cookie and the browser being redirected to the originally requested URL.
+        /// </summary>
+        /// <param name="context"></param>
+        /// <returns>A <see cref="Task"/> representing the completed operation.</returns>
+        Task ReturnEndpoint(TwitchReturnEndpointContext context);
+    }
+}

Owin.Security.Providers/Twitch/Provider/TwitchAuthenticatedContext.cs

@@ -0,0 +1,89 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
+
+using System;
+using System.Globalization;
+using System.Security.Claims;
+using Microsoft.Owin;
+using Microsoft.Owin.Security;
+using Microsoft.Owin.Security.Provider;
+using Newtonsoft.Json.Linq;
+
+namespace Owin.Security.Providers.Twitch
+{
+    /// <summary>
+    /// Contains information about the login session as well as the user <see cref="System.Security.Claims.ClaimsIdentity"/>.
+    /// </summary>
+    public class TwitchAuthenticatedContext : BaseContext
+    {
+        /// <summary>
+        /// Initializes a <see cref="TwitchAuthenticatedContext"/>
+        /// </summary>
+        /// <param name="context">The OWIN environment</param>
+        /// <param name="user">The JSON-serialized user</param>
+        /// <param name="accessToken">Twitch Access token</param>
+        public TwitchAuthenticatedContext(IOwinContext context, JObject user, string accessToken)
+            : base(context)
+        {
+            User = user;
+            AccessToken = accessToken;
+
+            Id = TryGetValue(user, "_id");
+            Name = TryGetValue(user, "name");
+            Link = TryGetValue(user, "url");
+            UserName = TryGetValue(user, "name");
+            Email = TryGetValue(user, "email");
+        }
+
+        /// <summary>
+        /// Gets the JSON-serialized user
+        /// </summary>
+        /// <remarks>
+        /// Contains the Twitch user obtained from the User Info endpoint. By default this is https://api.Twitch.com/user but it can be
+        /// overridden in the options
+        /// </remarks>
+        public JObject User { get; private set; }
+
+        /// <summary>
+        /// Gets the Twitch access token
+        /// </summary>
+        public string AccessToken { get; private set; }
+
+        /// <summary>
+        /// Gets the Twitch user ID
+        /// </summary>
+        public string Id { get; private set; }
+
+        /// <summary>
+        /// Gets the user's name
+        /// </summary>
+        public string Name { get; private set; }
+
+        public string Link { get; private set; }
+
+        /// <summary>
+        /// Gets the Twitch username
+        /// </summary>
+        public string UserName { get; private set; }
+
+        /// <summary>
+        /// Gets the Twitch email
+        /// </summary>
+        public string Email { get; private set; }
+
+        /// <summary>
+        /// Gets the <see cref="ClaimsIdentity"/> representing the user
+        /// </summary>
+        public ClaimsIdentity Identity { get; set; }
+
+        /// <summary>
+        /// Gets or sets a property bag for common authentication properties
+        /// </summary>
+        public AuthenticationProperties Properties { get; set; }
+
+        private static string TryGetValue(JObject user, string propertyName)
+        {
+            JToken value;
+            return user.TryGetValue(propertyName, out value) ? value.ToString() : null;
+        }
+    }
+}

Owin.Security.Providers/Twitch/Provider/TwitchAuthenticationProvider.cs

@@ -0,0 +1,50 @@
+using System;
+using System.Threading.Tasks;
+
+namespace Owin.Security.Providers.Twitch
+{
+    /// <summary>
+    /// Default <see cref="ITwitchAuthenticationProvider"/> implementation.
+    /// </summary>
+    public class TwitchAuthenticationProvider : ITwitchAuthenticationProvider
+    {
+        /// <summary>
+        /// Initializes a <see cref="TwitchAuthenticationProvider"/>
+        /// </summary>
+        public TwitchAuthenticationProvider()
+        {
+            OnAuthenticated = context => Task.FromResult<object>(null);
+            OnReturnEndpoint = context => Task.FromResult<object>(null);
+        }
+
+        /// <summary>
+        /// Gets or sets the function that is invoked when the Authenticated method is invoked.
+        /// </summary>
+        public Func<TwitchAuthenticatedContext, Task> OnAuthenticated { get; set; }
+
+        /// <summary>
+        /// Gets or sets the function that is invoked when the ReturnEndpoint method is invoked.
+        /// </summary>
+        public Func<TwitchReturnEndpointContext, Task> OnReturnEndpoint { get; set; }
+
+        /// <summary>
+        /// Invoked whenever Twitch succesfully authenticates a user
+        /// </summary>
+        /// <param name="context">Contains information about the login session as well as the user <see cref="System.Security.Claims.ClaimsIdentity"/>.</param>
+        /// <returns>A <see cref="Task"/> representing the completed operation.</returns>
+        public virtual Task Authenticated(TwitchAuthenticatedContext context)
+        {
+            return OnAuthenticated(context);
+        }
+
+        /// <summary>
+        /// Invoked prior to the <see cref="System.Security.Claims.ClaimsIdentity"/> being saved in a local cookie and the browser being redirected to the originally requested URL.
+        /// </summary>
+        /// <param name="context"></param>
+        /// <returns>A <see cref="Task"/> representing the completed operation.</returns>
+        public virtual Task ReturnEndpoint(TwitchReturnEndpointContext context)
+        {
+            return OnReturnEndpoint(context);
+        }
+    }
+}

Owin.Security.Providers/Twitch/Provider/TwitchReturnEndpointContext.cs

@@ -0,0 +1,26 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
+
+using Microsoft.Owin;
+using Microsoft.Owin.Security;
+using Microsoft.Owin.Security.Provider;
+
+namespace Owin.Security.Providers.Twitch
+{
+    /// <summary>
+    /// Provides context information to middleware providers.
+    /// </summary>
+    public class TwitchReturnEndpointContext : ReturnEndpointContext
+    {
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="context">OWIN environment</param>
+        /// <param name="ticket">The authentication ticket</param>
+        public TwitchReturnEndpointContext(
+            IOwinContext context,
+            AuthenticationTicket ticket)
+            : base(context, ticket)
+        {
+        }
+    }
+}

Owin.Security.Providers/Twitch/TwitchAuthenticationExtensions.cs

@@ -0,0 +1,41 @@
+using System;
+
+namespace Owin.Security.Providers.Twitch
+{
+    public static class TwitchAuthenticationExtensions
+    {
+        /// <summary>
+        ///  Login with Twitch. http://yourUrl/signin-Twitch will be used as the redirect URI
+        /// </summary>
+        /// <param name="app"></param>
+        /// <param name="options"></param>
+        /// <returns></returns>
+        public static IAppBuilder UseTwitchAuthentication(this IAppBuilder app,
+            TwitchAuthenticationOptions options)
+        {
+            if (app == null)
+                throw new ArgumentNullException("app");
+            if (options == null)
+                throw new ArgumentNullException("options");
+
+            app.Use(typeof(TwitchAuthenticationMiddleware), app, options);
+
+            return app;
+        }
+        /// <summary>
+        /// Login with Twitch. http://yourUrl/signin-Twitch will be used as the redirect URI
+        /// </summary>
+        /// <param name="app"></param>
+        /// <param name="clientId"></param>
+        /// <param name="clientSecret"></param>
+        /// <returns></returns>
+        public static IAppBuilder UseTwitchAuthentication(this IAppBuilder app, string clientId, string clientSecret)
+        {
+            return app.UseTwitchAuthentication(new TwitchAuthenticationOptions
+            {
+                ClientId = clientId,
+                ClientSecret = clientSecret
+            });
+        }
+    }
+}

Owin.Security.Providers/Twitch/TwitchAuthenticationHandler.cs

@@ -0,0 +1,241 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Http;
+using System.Net.Http.Headers;
+using System.Security.Claims;
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.Owin;
+using Microsoft.Owin.Infrastructure;
+using Microsoft.Owin.Logging;
+using Microsoft.Owin.Security;
+using Microsoft.Owin.Security.Infrastructure;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
+
+namespace Owin.Security.Providers.Twitch
+{
+    public class TwitchAuthenticationHandler : AuthenticationHandler<TwitchAuthenticationOptions>
+    {
+        private const string XmlSchemaString = "http://www.w3.org/2001/XMLSchema#string";
+
+        private readonly ILogger logger;
+        private readonly HttpClient httpClient;
+
+        public TwitchAuthenticationHandler(HttpClient httpClient, ILogger logger)
+        {
+            this.httpClient = httpClient;
+            this.logger = logger;
+        }
+
+        protected override async Task<AuthenticationTicket> AuthenticateCoreAsync()
+        {
+            AuthenticationProperties properties = null;
+
+            try
+            {
+                string code = null;
+                string state = null;
+
+                IReadableStringCollection query = Request.Query;
+                IList<string> values = query.GetValues("code");
+                if (values != null && values.Count == 1)
+                {
+                    code = string.Copy(values.First());
+                }
+                values = query.GetValues("state");
+                if (values != null && values.Count == 1)
+                {
+                    state = values[0];
+                }
+
+                properties = Options.StateDataFormat.Unprotect(state);
+                if (properties == null)
+                {
+                    return null;
+                }
+
+                // OAuth2 10.12 CSRF
+                if (!ValidateCorrelationId(properties, logger))
+                {
+                    return new AuthenticationTicket(null, properties);
+                }
+
+                string requestPrefix = Request.Scheme + "://" + Request.Host;
+                string redirectUri = requestPrefix + Request.PathBase + Options.CallbackPath;
+
+                // Build up the body for the token request
+                var body = new List<KeyValuePair<string, string>>();
+                body.Add(new KeyValuePair<string, string>("client_id", Options.ClientId));
+                body.Add(new KeyValuePair<string, string>("client_secret", Options.ClientSecret));
+                body.Add(new KeyValuePair<string, string>("grant_type", "authorization_code"));
+                body.Add(new KeyValuePair<string, string>("redirect_uri", redirectUri));
+                body.Add(new KeyValuePair<string, string>("code", code));
+
+                // Request the token
+                var requestMessage = new HttpRequestMessage(HttpMethod.Post, Options.Endpoints.TokenEndpoint);
+                requestMessage.Content = new FormUrlEncodedContent(body);
+                requestMessage.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
+                HttpResponseMessage tokenResponse = await httpClient.SendAsync(requestMessage);
+                tokenResponse.EnsureSuccessStatusCode();
+                string text = await tokenResponse.Content.ReadAsStringAsync();
+
+                // Deserializes the token response
+                dynamic response = JsonConvert.DeserializeObject<dynamic>(text);
+                string accessToken = (string)response.access_token;
+
+                // Get the Twitch user
+                HttpRequestMessage userRequest = new HttpRequestMessage(HttpMethod.Get, Options.Endpoints.UserInfoEndpoint + "?oauth_token=" + Uri.EscapeDataString(accessToken));
+                userRequest.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
+                HttpResponseMessage userResponse = await httpClient.SendAsync(userRequest, Request.CallCancelled);
+                userResponse.EnsureSuccessStatusCode();
+                text = await userResponse.Content.ReadAsStringAsync();
+                JObject user = JObject.Parse(text);
+
+                var context = new TwitchAuthenticatedContext(Context, user, accessToken);
+                context.Identity = new ClaimsIdentity(
+                    Options.AuthenticationType,
+                    ClaimsIdentity.DefaultNameClaimType,
+                    ClaimsIdentity.DefaultRoleClaimType);
+                if (!string.IsNullOrEmpty(context.Id))
+                {
+                    context.Identity.AddClaim(new Claim(ClaimTypes.NameIdentifier, context.Id, XmlSchemaString, Options.AuthenticationType));
+                }
+                if (!string.IsNullOrEmpty(context.UserName))
+                {
+                    context.Identity.AddClaim(new Claim(ClaimsIdentity.DefaultNameClaimType, context.UserName, XmlSchemaString, Options.AuthenticationType));
+                }
+                if (!string.IsNullOrEmpty(context.Email))
+                {
+                    context.Identity.AddClaim(new Claim(ClaimTypes.Email, context.Email, XmlSchemaString, Options.AuthenticationType));
+                }
+                if (!string.IsNullOrEmpty(context.Name))
+                {
+                    context.Identity.AddClaim(new Claim("urn:Twitch:name", context.Name, XmlSchemaString, Options.AuthenticationType));
+                }
+                if (!string.IsNullOrEmpty(context.Link))
+                {
+                    context.Identity.AddClaim(new Claim("urn:Twitch:url", context.Link, XmlSchemaString, Options.AuthenticationType));
+                }
+                context.Properties = properties;
+
+                await Options.Provider.Authenticated(context);
+
+                return new AuthenticationTicket(context.Identity, context.Properties);
+            }
+            catch (Exception ex)
+            {
+                logger.WriteError(ex.Message);
+            }
+            return new AuthenticationTicket(null, properties);
+        }
+
+        protected override Task ApplyResponseChallengeAsync()
+        {
+            if (Response.StatusCode != 401)
+            {
+                return Task.FromResult<object>(null);
+            }
+
+            AuthenticationResponseChallenge challenge = Helper.LookupChallenge(Options.AuthenticationType, Options.AuthenticationMode);
+
+            if (challenge != null)
+            {
+                string baseUri =
+                    Request.Scheme +
+                    Uri.SchemeDelimiter +
+                    Request.Host +
+                    Request.PathBase;
+
+                string currentUri =
+                    baseUri +
+                    Request.Path +
+                    Request.QueryString;
+
+                string redirectUri =
+                    baseUri +
+                    Options.CallbackPath;
+
+                AuthenticationProperties properties = challenge.Properties;
+                if (string.IsNullOrEmpty(properties.RedirectUri))
+                {
+                    properties.RedirectUri = currentUri;
+                }
+
+                // OAuth2 10.12 CSRF
+                GenerateCorrelationId(properties);
+
+                // comma separated
+                string scope = string.Join(",", Options.Scope);
+
+                string state = Options.StateDataFormat.Protect(properties);
+
+                string authorizationEndpoint =
+                    Options.Endpoints.AuthorizationEndpoint +
+                        "?client_id=" + Uri.EscapeDataString(Options.ClientId) +
+                        "&redirect_uri=" + Uri.EscapeDataString(redirectUri) +
+                        "&scope=" + Uri.EscapeDataString(scope) +
+                        "&response_type=" + "code" +
+                        "&state=" + Uri.EscapeDataString(state);
+
+                Response.Redirect(authorizationEndpoint);
+            }
+
+            return Task.FromResult<object>(null);
+        }
+
+        public override async Task<bool> InvokeAsync()
+        {
+            return await InvokeReplyPathAsync();
+        }
+
+        private async Task<bool> InvokeReplyPathAsync()
+        {
+            if (Options.CallbackPath.HasValue && Options.CallbackPath == Request.Path)
+            {
+                // TODO: error responses
+
+                AuthenticationTicket ticket = await AuthenticateAsync();
+                if (ticket == null)
+                {
+                    logger.WriteWarning("Invalid return state, unable to redirect.");
+                    Response.StatusCode = 500;
+                    return true;
+                }
+
+                var context = new TwitchReturnEndpointContext(Context, ticket);
+                context.SignInAsAuthenticationType = Options.SignInAsAuthenticationType;
+                context.RedirectUri = ticket.Properties.RedirectUri;
+
+                await Options.Provider.ReturnEndpoint(context);
+
+                if (context.SignInAsAuthenticationType != null &&
+                    context.Identity != null)
+                {
+                    ClaimsIdentity grantIdentity = context.Identity;
+                    if (!string.Equals(grantIdentity.AuthenticationType, context.SignInAsAuthenticationType, StringComparison.Ordinal))
+                    {
+                        grantIdentity = new ClaimsIdentity(grantIdentity.Claims, context.SignInAsAuthenticationType, grantIdentity.NameClaimType, grantIdentity.RoleClaimType);
+                    }
+                    Context.Authentication.SignIn(context.Properties, grantIdentity);
+                }
+
+                if (!context.IsRequestCompleted && context.RedirectUri != null)
+                {
+                    string redirectUri = context.RedirectUri;
+                    if (context.Identity == null)
+                    {
+                        // add a redirect hint that sign-in failed in some way
+                        redirectUri = WebUtilities.AddQueryString(redirectUri, "error", "access_denied");
+                    }
+                    Response.Redirect(redirectUri);
+                    context.RequestCompleted();
+                }
+
+                return context.IsRequestCompleted;
+            }
+            return false;
+        }
+    }
+}

Owin.Security.Providers/Twitch/TwitchAuthenticationMiddleware.cs

@@ -0,0 +1,87 @@
+using System;
+using System.Globalization;
+using System.Net.Http;
+using Microsoft.Owin;
+using Microsoft.Owin.Logging;
+using Microsoft.Owin.Security;
+using Microsoft.Owin.Security.DataHandler;
+using Microsoft.Owin.Security.DataProtection;
+using Microsoft.Owin.Security.Infrastructure;
+using Owin.Security.Providers.Properties;
+
+namespace Owin.Security.Providers.Twitch
+{
+    public class TwitchAuthenticationMiddleware : AuthenticationMiddleware<TwitchAuthenticationOptions>
+    {
+        private readonly HttpClient httpClient;
+        private readonly ILogger logger;
+
+        public TwitchAuthenticationMiddleware(OwinMiddleware next, IAppBuilder app,
+            TwitchAuthenticationOptions options)
+            : base(next, options)
+        {
+            if (String.IsNullOrWhiteSpace(Options.ClientId))
+                throw new ArgumentException(String.Format(CultureInfo.CurrentCulture,
+                    Resources.Exception_OptionMustBeProvided, "ClientId"));
+            if (String.IsNullOrWhiteSpace(Options.ClientSecret))
+                throw new ArgumentException(String.Format(CultureInfo.CurrentCulture,
+                    Resources.Exception_OptionMustBeProvided, "ClientSecret"));
+
+            logger = app.CreateLogger<TwitchAuthenticationMiddleware>();
+
+            if (Options.Provider == null)
+                Options.Provider = new TwitchAuthenticationProvider();
+
+            if (Options.StateDataFormat == null)
+            {
+                IDataProtector dataProtector = app.CreateDataProtector(
+                    typeof (TwitchAuthenticationMiddleware).FullName,
+                    Options.AuthenticationType, "v1");
+                Options.StateDataFormat = new PropertiesDataFormat(dataProtector);
+            }
+
+            if (String.IsNullOrEmpty(Options.SignInAsAuthenticationType))
+                Options.SignInAsAuthenticationType = app.GetDefaultSignInAsAuthenticationType();
+
+            httpClient = new HttpClient(ResolveHttpMessageHandler(Options))
+            {
+                Timeout = Options.BackchannelTimeout,
+                MaxResponseContentBufferSize = 1024*1024*10,
+            };
+            httpClient.DefaultRequestHeaders.UserAgent.ParseAdd("Microsoft Owin Twitch middleware");
+            httpClient.DefaultRequestHeaders.ExpectContinue = false;
+        }
+
+        /// <summary>
+        ///     Provides the <see cref="T:Microsoft.Owin.Security.Infrastructure.AuthenticationHandler" /> object for processing
+        ///     authentication-related requests.
+        /// </summary>
+        /// <returns>
+        ///     An <see cref="T:Microsoft.Owin.Security.Infrastructure.AuthenticationHandler" /> configured with the
+        ///     <see cref="T:Owin.Security.Providers.Twitch.TwitchAuthenticationOptions" /> supplied to the constructor.
+        /// </returns>
+        protected override AuthenticationHandler<TwitchAuthenticationOptions> CreateHandler()
+        {
+            return new TwitchAuthenticationHandler(httpClient, logger);
+        }
+
+        private HttpMessageHandler ResolveHttpMessageHandler(TwitchAuthenticationOptions options)
+        {
+            HttpMessageHandler handler = options.BackchannelHttpHandler ?? new WebRequestHandler();
+
+            // If they provided a validator, apply it or fail.
+            if (options.BackchannelCertificateValidator != null)
+            {
+                // Set the cert validate callback
+                var webRequestHandler = handler as WebRequestHandler;
+                if (webRequestHandler == null)
+                {
+                    throw new InvalidOperationException(Resources.Exception_ValidatorHandlerMismatch);
+                }
+                webRequestHandler.ServerCertificateValidationCallback = options.BackchannelCertificateValidator.Validate;
+            }
+
+            return handler;
+        }
+    }
+}

Owin.Security.Providers/Twitch/TwitchAuthenticationOptions.cs

@@ -0,0 +1,145 @@
+using System;
+using System.Collections.Generic;
+using System.Net.Http;
+using Microsoft.Owin;
+using Microsoft.Owin.Security;
+
+namespace Owin.Security.Providers.Twitch
+{
+    public class TwitchAuthenticationOptions : AuthenticationOptions
+    {
+        public class TwitchAuthenticationEndpoints
+        {
+            /// <summary>
+            /// Endpoint which is used to redirect users to request Twitch access
+            /// </summary>
+            /// <remarks>
+            /// Defaults to https://api.twitch.tv/kraken/oauth2/authorize
+            /// </remarks>
+            public string AuthorizationEndpoint { get; set; }
+
+            /// <summary>
+            /// Endpoint which is used to exchange code for access token
+            /// </summary>
+            /// <remarks>
+            /// Defaults to https://api.twitch.tv/kraken/oauth2/token
+            /// </remarks>
+            public string TokenEndpoint { get; set; }
+
+            /// <summary>
+            /// Endpoint which is used to obtain user information after authentication
+            /// </summary>
+            /// <remarks>
+            /// Defaults to https://api.twitch.tv/kraken/user
+            /// </remarks>
+            public string UserInfoEndpoint { get; set; }
+        }
+
+        private const string AuthorizationEndPoint = "https://api.twitch.tv/kraken/oauth2/authorize";
+        private const string TokenEndpoint = "https://api.twitch.tv/kraken/oauth2/token";
+        private const string UserInfoEndpoint = "https://api.twitch.tv/kraken/user";
+
+        /// <summary>
+        ///     Gets or sets the a pinned certificate validator to use to validate the endpoints used
+        ///     in back channel communications belong to Twitch.
+        /// </summary>
+        /// <value>
+        ///     The pinned certificate validator.
+        /// </value>
+        /// <remarks>
+        ///     If this property is null then the default certificate checks are performed,
+        ///     validating the subject name and if the signing chain is a trusted party.
+        /// </remarks>
+        public ICertificateValidator BackchannelCertificateValidator { get; set; }
+
+        /// <summary>
+        ///     The HttpMessageHandler used to communicate with Twitch.
+        ///     This cannot be set at the same time as BackchannelCertificateValidator unless the value
+        ///     can be downcast to a WebRequestHandler.
+        /// </summary>
+        public HttpMessageHandler BackchannelHttpHandler { get; set; }
+
+        /// <summary>
+        ///     Gets or sets timeout value in milliseconds for back channel communications with Twitch.
+        /// </summary>
+        /// <value>
+        ///     The back channel timeout in milliseconds.
+        /// </value>
+        public TimeSpan BackchannelTimeout { get; set; }
+
+        /// <summary>
+        ///     The request path within the application's base path where the user-agent will be returned.
+        ///     The middleware will process this request when it arrives.
+        ///     Default value is "/signin-Twitch".
+        /// </summary>
+        public PathString CallbackPath { get; set; }
+
+        /// <summary>
+        ///     Get or sets the text that the user can display on a sign in user interface.
+        /// </summary>
+        public string Caption
+        {
+            get { return Description.Caption; }
+            set { Description.Caption = value; }
+        }
+
+        /// <summary>
+        ///     Gets or sets the Twitch supplied Client ID
+        /// </summary>
+        public string ClientId { get; set; }
+
+        /// <summary>
+        ///     Gets or sets the Twitch supplied Client Secret
+        /// </summary>
+        public string ClientSecret { get; set; }
+
+        /// <summary>
+        /// Gets the sets of OAuth endpoints used to authenticate against Twitch.  Overriding these endpoints allows you to use Twitch Enterprise for
+        /// authentication.
+        /// </summary>
+        public TwitchAuthenticationEndpoints Endpoints { get; set; }
+
+        /// <summary>
+        ///     Gets or sets the <see cref="ITwitchAuthenticationProvider" /> used in the authentication events
+        /// </summary>
+        public ITwitchAuthenticationProvider Provider { get; set; }
+
+        /// <summary>
+        /// A list of permissions to request.
+        /// </summary>
+        public IList<string> Scope { get; private set; }
+
+        /// <summary>
+        ///     Gets or sets the name of another authentication middleware which will be responsible for actually issuing a user
+        ///     <see cref="System.Security.Claims.ClaimsIdentity" />.
+        /// </summary>
+        public string SignInAsAuthenticationType { get; set; }
+
+        /// <summary>
+        ///     Gets or sets the type used to secure data handled by the middleware.
+        /// </summary>
+        public ISecureDataFormat<AuthenticationProperties> StateDataFormat { get; set; }
+
+        /// <summary>
+        ///     Initializes a new <see cref="TwitchAuthenticationOptions" />
+        /// </summary>
+        public TwitchAuthenticationOptions()
+            : base("Twitch")
+        {
+            Caption = Constants.DefaultAuthenticationType;
+            CallbackPath = new PathString("/signin-Twitch");
+            AuthenticationMode = AuthenticationMode.Passive;
+            Scope = new List<string>
+            {
+                "user_read"
+            };
+            BackchannelTimeout = TimeSpan.FromSeconds(60);
+            Endpoints = new TwitchAuthenticationEndpoints
+            {
+                AuthorizationEndpoint = AuthorizationEndPoint,
+                TokenEndpoint = TokenEndpoint,
+                UserInfoEndpoint = UserInfoEndpoint
+            };
+        }
+    }
+}

OwinOAuthProvidersDemo/App_Start/Startup.Auth.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Security.Claims;
 using Microsoft.AspNet.Identity;
 using Microsoft.Owin;
 using Microsoft.Owin.Security.Cookies;
@@ -17,6 +18,7 @@ using Owin.Security.Providers.Reddit;
 using Owin.Security.Providers.Salesforce;
 using Owin.Security.Providers.StackExchange;
 using Owin.Security.Providers.TripIt;
+using Owin.Security.Providers.Twitch;
 using Owin.Security.Providers.Yahoo;
 using Owin.Security.Providers.OpenID;
 using Owin.Security.Providers.Steam;
@@ -87,6 +89,46 @@ namespace OwinOAuthProvidersDemo
             //options.MomentTypes.Add("http://schemas.google.com/BuyActivity");
             //app.UseGooglePlusAuthentication(options);
 
+            /*
+             * Twitch sign-ins use /signin-Twitch as the URL for authentication
+             *            
+             
+             */
+
+            ////Simple Twitch Sign-in
+            //app.UseTwitchAuthentication("", "");
+
+            ////More complex Twitch Sign-in
+            //var opt = new TwitchAuthenticationOptions()
+            //{
+            //    ClientId = "",
+            //    ClientSecret = "",
+            //    Provider = new TwitchAuthenticationProvider()
+            //    {
+                  
+            //        OnAuthenticated = async z =>
+            //        {
+            ////            Getting the twitch users picture
+            //            z.Identity.AddClaim(new Claim("Picture", z.User.GetValue("logo").ToString()));
+            //        }
+            ////    You should be able to access these claims with  HttpContext.GetOwinContext().Authentication.GetExternalLoginInfoAsync().Claims in your Account Controller
+            //        //    Commonly used in the ExternalLoginCallback() in AccountController.cs
+            //        /*
+                      
+            //           if (user != null)
+            //                {
+            //                    var claim = (await AuthenticationManager.GetExternalLoginInfoAsync()).ExternalIdentity.Claims.First(
+            //                    a => a.Type == "Picture");
+            //                    user.Claims.Add(new IdentityUserClaim() { ClaimType = claim.Type, ClaimValue = claim.Value });
+            //                    await SignInAsync(user, isPersistent: false);
+            //                    return RedirectToLocal(returnUrl);
+            //                }
+            //         */
+            //    }
+            //};
+            //app.UseTwitchAuthentication(opt);
+            
+
 
             //app.UseOpenIDAuthentication("http://me.yahoo.com/", "Yahoo");