Add Dropbox provider

Owin.Security.Providers/Dropbox/Constants.cs

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

Owin.Security.Providers/Dropbox/DropboxAuthenticationExtensions.cs

@@ -0,0 +1,29 @@
+using System;
+
+namespace Owin.Security.Providers.Dropbox
+{
+    public static class DropboxAuthenticationExtensions
+    {
+        public static IAppBuilder UseDropboxAuthentication(this IAppBuilder app,
+            DropboxAuthenticationOptions options)
+        {
+            if (app == null)
+                throw new ArgumentNullException("app");
+            if (options == null)
+                throw new ArgumentNullException("options");
+
+            app.Use(typeof(DropboxAuthenticationMiddleware), app, options);
+
+            return app;
+        }
+
+        public static IAppBuilder UseDropboxAuthentication(this IAppBuilder app, string appKey, string appSecret)
+        {
+            return app.UseDropboxAuthentication(new DropboxAuthenticationOptions
+            {
+                AppKey = appKey,
+                AppSecret = appSecret
+            });
+        }
+    }
+}

Owin.Security.Providers/Dropbox/DropboxAuthenticationHandler.cs

@@ -0,0 +1,229 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Net.Http;
+using System.Security.Claims;
+using System.Threading.Tasks;
+using Microsoft.Owin;
+using Microsoft.Owin.Infrastructure;
+using Microsoft.Owin.Logging;
+using Microsoft.Owin.Security;
+using Microsoft.Owin.Security.DataHandler.Encoder;
+using Microsoft.Owin.Security.Infrastructure;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
+
+namespace Owin.Security.Providers.Dropbox
+{
+    public class DropboxAuthenticationHandler : AuthenticationHandler<DropboxAuthenticationOptions>
+    {
+        private const string StateCookie = "_DropboxState";
+        private const string XmlSchemaString = "http://www.w3.org/2001/XMLSchema#string";
+        private const string TokenEndpoint = "https://api.dropbox.com/1/oauth2/token";
+        private const string UserInfoEndpoint = "https://api.dropbox.com/1/account/info";
+
+        private readonly ILogger logger;
+        private readonly HttpClient httpClient;
+
+        public DropboxAuthenticationHandler(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 = values[0];
+                }
+
+                state = Request.Cookies[StateCookie];
+                properties = Options.StateDataFormat.Unprotect(state);
+                if (properties == null)
+                {
+                    return null;
+                }
+
+                // OAuth2 10.12 CSRF
+                if (!ValidateCorrelationId(properties, logger))
+                {
+                    return new AuthenticationTicket(null, properties);
+                }
+
+                // Check for error
+                if (Request.Query.Get("error") != null)
+                    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>("grant_type", "authorization_code"));
+                body.Add(new KeyValuePair<string, string>("code", code));
+                body.Add(new KeyValuePair<string, string>("redirect_uri", redirectUri));
+                body.Add(new KeyValuePair<string, string>("client_id", Options.AppKey));
+                body.Add(new KeyValuePair<string, string>("client_secret", Options.AppSecret));
+
+                // Request the token
+                HttpResponseMessage tokenResponse =
+                    await httpClient.PostAsync(TokenEndpoint, new FormUrlEncodedContent(body));
+                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 Dropbox user
+                HttpResponseMessage graphResponse = await httpClient.GetAsync(
+                    UserInfoEndpoint + "?access_token=" + Uri.EscapeDataString(accessToken), Request.CallCancelled);
+                graphResponse.EnsureSuccessStatusCode();
+                text = await graphResponse.Content.ReadAsStringAsync();
+                JObject user = JObject.Parse(text);
+
+                var context = new DropboxAuthenticatedContext(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.Name))
+                {
+                    context.Identity.AddClaim(new Claim(ClaimsIdentity.DefaultNameClaimType, context.Name, 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);
+
+                string authorizationEndpoint =
+                    "https://www.dropbox.com/1/oauth2/authorize" +
+                    "?response_type=code" +
+                    "&client_id=" + Uri.EscapeDataString(Options.AppKey) +
+                    "&redirect_uri=" + Uri.EscapeDataString(redirectUri);
+
+                var cookieOptions = new CookieOptions
+                {
+                    HttpOnly = true,
+                    Secure = Request.IsSecure
+                };
+
+                Response.StatusCode = 302;
+                Response.Cookies.Append(StateCookie, Options.StateDataFormat.Protect(properties), cookieOptions);
+                Response.Headers.Set("Location", 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 DropboxReturnEndpointContext(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/Dropbox/DropboxAuthenticationMiddleware.cs

@@ -0,0 +1,85 @@
+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.Dropbox
+{
+    public class DropboxAuthenticationMiddleware : AuthenticationMiddleware<DropboxAuthenticationOptions>
+    {
+        private readonly HttpClient httpClient;
+        private readonly ILogger logger;
+
+        public DropboxAuthenticationMiddleware(OwinMiddleware next, IAppBuilder app,
+            DropboxAuthenticationOptions options)
+            : base(next, options)
+        {
+            if (String.IsNullOrWhiteSpace(Options.AppKey))
+                throw new ArgumentException(String.Format(CultureInfo.CurrentCulture,
+                    Resources.Exception_OptionMustBeProvided, "AppKey"));
+            if (String.IsNullOrWhiteSpace(Options.AppSecret))
+                throw new ArgumentException(String.Format(CultureInfo.CurrentCulture,
+                    Resources.Exception_OptionMustBeProvided, "AppSecret"));
+
+            logger = app.CreateLogger<DropboxAuthenticationMiddleware>();
+
+            if (Options.Provider == null)
+                Options.Provider = new DropboxAuthenticationProvider();
+
+            if (Options.StateDataFormat == null)
+            {
+                IDataProtector dataProtector = app.CreateDataProtector(
+                    typeof (DropboxAuthenticationMiddleware).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
+            };
+        }
+
+        /// <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.Dropbox.DropboxAuthenticationOptions" /> supplied to the constructor.
+        /// </returns>
+        protected override AuthenticationHandler<DropboxAuthenticationOptions> CreateHandler()
+        {
+            return new DropboxAuthenticationHandler(httpClient, logger);
+        }
+
+        private HttpMessageHandler ResolveHttpMessageHandler(DropboxAuthenticationOptions 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/Dropbox/DropboxAuthenticationOptions.cs

@@ -0,0 +1,92 @@
+using System;
+using System.Net.Http;
+using Microsoft.Owin;
+using Microsoft.Owin.Security;
+
+namespace Owin.Security.Providers.Dropbox
+{
+    public class DropboxAuthenticationOptions : AuthenticationOptions
+    {
+        /// <summary>
+        ///     Gets or sets the a pinned certificate validator to use to validate the endpoints used
+        ///     in back channel communications belong to Dropbox
+        /// </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 Dropbox.
+        ///     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 Dropbox.
+        /// </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-dropbox".
+        /// </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 Dropbox supplied Application Key
+        /// </summary>
+        public string AppKey { get; set; }
+
+        /// <summary>
+        ///     Gets or sets the Dropbox supplied Application Secret
+        /// </summary>
+        public string AppSecret { get; set; }
+
+        /// <summary>
+        ///     Gets or sets the <see cref="IDropboxAuthenticationProvider" /> used in the authentication events
+        /// </summary>
+        public IDropboxAuthenticationProvider Provider { get; 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="DropboxAuthenticationOptions" />
+        /// </summary>
+        public DropboxAuthenticationOptions()
+            : base("Dropbox")
+        {
+            Caption = Constants.DefaultAuthenticationType;
+            CallbackPath = new PathString("/signin-dropbox");
+            AuthenticationMode = AuthenticationMode.Passive;
+            BackchannelTimeout = TimeSpan.FromSeconds(60);
+        }
+    }
+}

Owin.Security.Providers/Dropbox/Provider/DropboxAuthenticatedContext.cs

@@ -0,0 +1,73 @@
+// 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.Dropbox
+{
+    /// <summary>
+    /// Contains information about the login session as well as the user <see cref="System.Security.Claims.ClaimsIdentity"/>.
+    /// </summary>
+    public class DropboxAuthenticatedContext : BaseContext
+    {
+        /// <summary>
+        /// Initializes a <see cref="DropboxAuthenticatedContext"/>
+        /// </summary>
+        /// <param name="context">The OWIN environment</param>
+        /// <param name="user">The JSON-serialized user</param>
+        /// <param name="accessToken">Dropbox Access token</param>
+        public DropboxAuthenticatedContext(IOwinContext context, JObject user, string accessToken)
+            : base(context)
+        {
+            AccessToken = accessToken;
+            User = user;
+
+            Id = TryGetValue(user, "uid");
+            Name = TryGetValue(user, "display_name");
+        }
+
+        /// <summary>
+        /// Gets the JSON-serialized user
+        /// </summary>
+        /// <remarks>
+        /// Contains the Dropbox user obtained from the endpoint https://api.dropbox.com/1/account/info
+        /// </remarks>
+        public JObject User { get; private set; }
+
+        /// <summary>
+        /// Gets the Dropbox OAuth access token
+        /// </summary>
+        public string AccessToken { get; private set; }
+
+        /// <summary>
+        /// Gets the Dropbox user ID
+        /// </summary>
+        public string Id { get; private set; }
+
+        /// <summary>
+        /// The name of the user
+        /// </summary>
+        public string Name { 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/Dropbox/Provider/DropboxAuthenticationProvider.cs

@@ -0,0 +1,50 @@
+using System;
+using System.Threading.Tasks;
+
+namespace Owin.Security.Providers.Dropbox
+{
+    /// <summary>
+    /// Default <see cref="IDropboxAuthenticationProvider"/> implementation.
+    /// </summary>
+    public class DropboxAuthenticationProvider : IDropboxAuthenticationProvider
+    {
+        /// <summary>
+        /// Initializes a <see cref="DropboxAuthenticationProvider"/>
+        /// </summary>
+        public DropboxAuthenticationProvider()
+        {
+            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<DropboxAuthenticatedContext, Task> OnAuthenticated { get; set; }
+
+        /// <summary>
+        /// Gets or sets the function that is invoked when the ReturnEndpoint method is invoked.
+        /// </summary>
+        public Func<DropboxReturnEndpointContext, Task> OnReturnEndpoint { get; set; }
+
+        /// <summary>
+        /// Invoked whenever Dropbox successfully 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(DropboxAuthenticatedContext 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(DropboxReturnEndpointContext context)
+        {
+            return OnReturnEndpoint(context);
+        }
+    }
+}

Owin.Security.Providers/Dropbox/Provider/DropboxReturnEndpointContext.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.Dropbox
+{
+    /// <summary>
+    /// Provides context information to middleware providers.
+    /// </summary>
+    public class DropboxReturnEndpointContext : ReturnEndpointContext
+    {
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="context">OWIN environment</param>
+        /// <param name="ticket">The authentication ticket</param>
+        public DropboxReturnEndpointContext(
+            IOwinContext context,
+            AuthenticationTicket ticket)
+            : base(context, ticket)
+        {
+        }
+    }
+}

Owin.Security.Providers/Dropbox/Provider/IDropboxAuthenticationProvider.cs

@@ -0,0 +1,24 @@
+using System.Threading.Tasks;
+
+namespace Owin.Security.Providers.Dropbox
+{
+    /// <summary>
+    /// Specifies callback methods which the <see cref="DropboxAuthenticationMiddleware"></see> invokes to enable developer control over the authentication process. />
+    /// </summary>
+    public interface IDropboxAuthenticationProvider
+    {
+        /// <summary>
+        /// Invoked whenever Dropbox successfully 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(DropboxAuthenticatedContext 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(DropboxReturnEndpointContext context);
+    }
+}

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

@@ -76,6 +76,15 @@
     <Compile Include="Buffer\Provider\BufferAuthenticationProvider.cs" />
     <Compile Include="Buffer\Provider\BufferReturnEndpointContext.cs" />
     <Compile Include="Buffer\Provider\IBufferAuthenticationProvider.cs" />
+    <Compile Include="Dropbox\DropboxAuthenticationExtensions.cs" />
+    <Compile Include="Dropbox\DropboxAuthenticationHandler.cs" />
+    <Compile Include="Dropbox\DropboxAuthenticationMiddleware.cs" />
+    <Compile Include="Dropbox\DropboxAuthenticationOptions.cs" />
+    <Compile Include="Dropbox\Constants.cs" />
+    <Compile Include="Dropbox\Provider\DropboxAuthenticatedContext.cs" />
+    <Compile Include="Dropbox\Provider\DropboxAuthenticationProvider.cs" />
+    <Compile Include="Dropbox\Provider\DropboxReturnEndpointContext.cs" />
+    <Compile Include="Dropbox\Provider\IDropboxAuthenticationProvider.cs" />
     <Compile Include="GitHub\Constants.cs" />
     <Compile Include="GitHub\GitHubAuthenticationExtensions.cs" />
     <Compile Include="GitHub\GitHubAuthenticationHandler.cs" />

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

@@ -1,4 +1,6 @@
 <wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
 	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=Buffer_005CProvider/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=DropBox_005CProvider/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=Dropbox_005CProvider/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=GitHub_005CProvider/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=WordPress_005CProvider/@EntryIndexedValue">True</s:Boolean></wpf:ResourceDictionary>

OwinOAuthProvidersDemo/App_Start/Startup.Auth.cs

@@ -5,6 +5,7 @@ using Microsoft.Owin.Security.Cookies;
 using Owin;
 using Owin.Security.Providers.ArcGISOnline;
 using Owin.Security.Providers.Buffer;
+using Owin.Security.Providers.Dropbox;
 using Owin.Security.Providers.GitHub;
 using Owin.Security.Providers.GooglePlus;
 using Owin.Security.Providers.GooglePlus.Provider;
@@ -129,9 +130,13 @@ namespace OwinOAuthProvidersDemo
             //    clientId: "",
             //    clientSecret: "");
 
-            app.UseWordPressAuthentication(
-                clientId: "",
-                clientSecret: "");
+            //app.UseWordPressAuthentication(
+            //    clientId: "",
+            //    clientSecret: "");
+
+            //app.UseDropboxAuthentication(
+            //    appKey: "",
+            //    appSecret: "");
         }
     }
 }