Simple Auth

Every API needs authentication, yet no developer wants to deal with authentication. Simple Auth embeds authentication into the API so you dont need to deal with it. Most importantly it works great with traditional Xamarin and Xamarin.Forms

Android:

iOS/MacOS:

General information

Available on Nuget

Clancey.SimpleAuth

Providers

Current Built in Providers

• Azure Active Directory
• Amazon
• Dropbox
• Facebook
• Github
• Google
• Instagram
• Linked In
• Microsoft Live Connect
• Twitter

Simple auth ships with some built in providers so you just need to add your keys and scopes.

var scopes = new[]
{
	"https://www.googleapis.com/auth/userinfo.email",
	"https://www.googleapis.com/auth/userinfo.profile"
};
var api = new GoogleApi("google",
	   "clientid",
	   "clientsecret")
{
	Scopes = scopes,
};

var account = await api.Authenticate();

Restful Api Requests

Restful Api Requests couldnt be simpler

var song = await api.Get<Song>("http://myapi/Song/",songId);

Paramaters can be added as part of the path

var todoItem = await api.Get<TodoItem>("http://myapi/user/{UserId}/TodoItem",new Dictionary<string,string>{["UserId"] = "1", ["itemID"] = "22"});

Generates the following Url:

http://myapi/user/1/TodoItem?itemID=22

Attribute your Api Requests (Optional)

[Path("/pet")]
[ContentType("application/json")]
[Accepts("application/json")]
public virtual Task AddPet(Pet body) {
    return Post( body);
}

iOS/Mac Specific

OnePassword Support (iOS)

One password support is for iOS Only.
Simply add the project or the Nuget

Clancey.SimpleAuth.OnePassword

Then call the following line in your iOS project prior to calling api.Authenticate();

SimpleAuth.OnePassword.Activate();

Native Twitter Support via Twitter App

You can use the Twitter app to authenticate with SimpleAuth on iOS.

Add the following to your Info.Plist

// Info.plist
<key>CFBundleURLTypes</key>
<array>
  <dict>
    <key>CFBundleURLSchemes</key>
    <array>
      <string>twitterkit-<consumerKey></string>
    </array>
  </dict>
</array>
<key>LSApplicationQueriesSchemes</key>
<array>
    <string>twitter</string>
    <string>twitterauth</string>
</array>

Then call the following line in your iOS AppDelegate FinishedLaunching method;

SimpleAuth.Providers.Twitter.Init();

Also add the following override in your AppDelegate

public override bool OpenUrl (UIApplication app, NSUrl url, NSDictionary options)
{
	if (SimpleAuth.Native.OpenUrl(app, url, options))
		return true;
	return base.OpenUrl(app,url,options);
}

Native Facebook Support via iOS SDK

Simply add the project or the Nuget

Clancey.SimpleAuth.Facebook.iOS

The Facebook SDK requires you modify your info.plist : https://components.xamarin.com/gettingstarted/facebookios

Then call the following line in your iOS AppDelegate FinishedLaunching method;

SimpleAuth.Providers.Facebook.Init(app, options);

Also add the following override in your AppDelegate

public override bool OpenUrl (UIApplication app, NSUrl url, NSDictionary options)
{
	if (SimpleAuth.Native.OpenUrl(app, url, options))
		return true;
	return base.OpenUrl(app,url,options);
}

Native Google Support via iOS SDK

Clancey.SimpleAuth.Google.iOS

The Google SDK can do Cross-Client Login. This allows you to get tokens for the server, with one login.

To use Cross-client you need to set the ServerClientId on the GoogleApi.

Call the following in your FinishedLaunching Method;

SimpleAuth.Providers.Google.Init()

Also add the following to your AppDelegate

public override bool OpenUrl (UIApplication app, NSUrl url, NSDictionary options)
{
	if (SimpleAuth.Native.OpenUrl(app, url, options))
		return true;
	return base.OpenUrl(app,url,options);
}

If you need Cross-client authentication

var api = new GoogleApi("google","client_id"){
	ServerClientId = "server_client_id""
};
var account = await api.Authenticate ();
var serverToken = account.UserData ["ServerToken"];

Troubleshooting

System.Exception: Error Domain=com.google.GIDSignIn Code=-2 "keychain error" UserInfo={NSLocalizedDescription=keychain error}

Under the iOS Build Signing, Custom Entitlements: make sure an entitlement.plist is set

Native SFSafariViewController iOS/MacOS

SFSafariViewController Allows users to use Safari to login, instead of embedded webviews.

Google now requires this mode and is enabled by default for Google Authentication on iOS/MacOS.

To use the Native Safari Authenticator, you are required to add the following snippet in your AppDelegate (iOS Only)

public override bool OpenUrl (UIApplication app, NSUrl url, NSDictionary options)
{
	if (SimpleAuth.Native.OpenUrl(app, url, options))
		return true;
	return base.OpenUrl(app,url,options);
}

You are also required to add the following to add a CFBundleURLSchemes to your info.plist

For Google: com.googleusercontent.apps.YOUR_CLIENT_ID

	<key>CFBundleURLTypes</key>
	<array>
		<dict>
			<key>CFBundleURLSchemes</key>
			<array>
				<string>com.googleusercontent.apps.YOURCLIENTID</string>
			</array>
			<key>CFBundleURLName</key>
			<string>googleLogin</string>
		</dict>
	</array>
	

Android

Google Sign-In on Android

Simple Auth supports the native Google Sign-in for Android.

1. Add the nuget Clancey.SimpleAuth.Google.Droid

2. Create OAuth Client Id (Web Application): Link

3. Create and OAuth Android app: Link

   • Sign your app using the same Keystore

4. Use both the Web Application ClientID. ClientSecret is not required but reccomended.

5. Add the following code to your Main Activity

   protected override void OnCreate(Bundle bundle)
   {
   	base.OnCreate(bundle);
   	SimpleAuth.Providers.Google.Init(this.Application);
   	//The rest of your initialize code
   }
   
   protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
   {
      base.OnActivityResult(requestCode, resultCode, data);
   	SimpleAuth.Native.OnActivityResult (requestCode,resultCode,data); 
   }
   

If you need Cross-Client authentication pass your ServerClientId into the google api

var api = new GoogleApi("google","client_id"){
	ServerClientId = "server_client_id""
};
var account = await api.Authenticate ();
var serverToken = account.UserData ["ServerToken"];

Troubleshooting

If you get: Unable to find explicit activity class {com.google.android.gms.auth.api.signin.internal.SignInHubActivity}; have you declared this activity in your AndroidManifest.xml?

Add the following to your AndroidManifest.xml

<activity android:name="com.google.android.gms.auth.api.signin.internal.SignInHubActivity"
		android:screenOrientation="portrait"
		android:windowSoftInputMode="stateAlwaysHidden|adjustPan" />
	</application>

Status Code 12501 (unknown) Your app signing or tokens are invalid

1. Check your app is signed with the same KeyStore noted in for your android app Link
2. Regenerate new OAuth 2 Client id, create the WebApplication kind.

Native Facebook for Android

Simple Auth supports the native Facebook SDK for Android.

1. Add the nuget Clancey.SimpleAuth.Facebook.Droid

2. Create an Android App: Link

3. Add the following to your String.xml in Resources/values. If your appId was 1066763793431980

   <string name="facebook_app_id">1066763793431980</string>
   <string name="fb_login_protocol_scheme">fb1066763793431980</string>
   

4. Add a meta-data element to the application element:

   [assembly: MetaData("com.facebook.sdk.ApplicationId", Value = "@string/facebook_app_id")]
   

5. Add FacebookActivity to your AndroidManifest.xml:

   <activity android:name="com.facebook.FacebookActivity"
         android:configChanges=
                "keyboard|keyboardHidden|screenLayout|screenSize|orientation"
         android:label="@string/app_name" />          
   <activity
       android:name="com.facebook.CustomTabActivity"
       android:exported="true">
       <intent-filter>
           <action android:name="android.intent.action.VIEW" />
           <category android:name="android.intent.category.DEFAULT" />
           <category android:name="android.intent.category.BROWSABLE" />
           <data android:scheme="@string/fb_login_protocol_scheme" />
       </intent-filter>
   </activity>
   

6. Add the following code to your Main Activity

   protected override void OnCreate(Bundle bundle)
   {
   	base.OnCreate(bundle);
   	SimpleAuth.Providers.Google.Init(this.Application);
   	//The rest of your initialize code
   }
   
   protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
   {
      base.OnActivityResult(requestCode, resultCode, data);
   	Native.OnActivityResult (requestCode,resultCode,data); 
   }
   

CustomTabs for Android

SimpleAuth supports using Custom Tabs for authorization.

1. Add the nuget Clancey.SimpleAuth.Droid.CustomTabs

2. In your Droid project, create a subclass of SimpleAuthCallbackActivity to handle your url scheme, replacing the value of DataScheme with the scheme you used for the redirectUrl parameter of the Api constructor

   [Activity(NoHistory = true, LaunchMode = Android.Content.PM.LaunchMode.SingleTop)]
   [IntentFilter(new [] { Intent.ActionView},
       Categories = new[] { Intent.CategoryDefault, Intent.CategoryBrowsable},
       DataScheme = "YOUR CUSTOM SCHEME")]
   public class MyCallbackActivity : SimpleAuthCallbackActivity
   {
   }
   

.Net Core

You will need to implement an AuthStorage

using System;
using System.Collections.Generic;
using System.IO;
using System.Security.Cryptography;
using System.Text;
using System.Linq;

namespace SimpleAuth
{
	public class AuthStorage : IAuthStorage
	{
		private const int Keysize = 128;
		private const int DerivationIterations = 1000;

		public static string EncryptString(string plainText, string passPhrase)
		{
			var saltStringBytes = Generate256BitsOfRandomEntropy();
			var ivStringBytes = Generate256BitsOfRandomEntropy();
			var plainTextBytes = Encoding.UTF8.GetBytes(plainText);
			using (var password = new Rfc2898DeriveBytes(passPhrase, saltStringBytes, DerivationIterations))
			{
				var keyBytes = password.GetBytes(Keysize / 8);
				using (var symmetricKey = new RijndaelManaged())
				{
					symmetricKey.BlockSize = Keysize;
					symmetricKey.Mode = CipherMode.CBC;
					symmetricKey.Padding = PaddingMode.PKCS7;
					using (var encryptor = symmetricKey.CreateEncryptor(keyBytes, ivStringBytes))
					{
						using (var memoryStream = new MemoryStream())
						{
							using (var cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
							{
								cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
								cryptoStream.FlushFinalBlock();
								// Create the final bytes as a concatenation of the random salt bytes, the random iv bytes and the cipher bytes.
								var cipherTextBytes = saltStringBytes;
								cipherTextBytes = cipherTextBytes.Concat(ivStringBytes).ToArray();
								cipherTextBytes = cipherTextBytes.Concat(memoryStream.ToArray()).ToArray();
								memoryStream.Close();
								cryptoStream.Close();
								return Convert.ToBase64String(cipherTextBytes);
							}
						}
					}
				}
			}
		}

		public static string DecryptString(string cipherText, string passPhrase)
		{
			var cipherTextBytesWithSaltAndIv = Convert.FromBase64String(cipherText);
			var saltStringBytes = cipherTextBytesWithSaltAndIv.Take(Keysize / 8).ToArray();
			var ivStringBytes = cipherTextBytesWithSaltAndIv.Skip(Keysize / 8).Take(Keysize / 8).ToArray();
			var cipherTextBytes = cipherTextBytesWithSaltAndIv.Skip((Keysize / 8) * 2).Take(cipherTextBytesWithSaltAndIv.Length - ((Keysize / 8) * 2)).ToArray();

			using (var password = new Rfc2898DeriveBytes(passPhrase, saltStringBytes, DerivationIterations))
			{
				var keyBytes = password.GetBytes(Keysize / 8);
				using (var symmetricKey = new RijndaelManaged())
				{
					symmetricKey.BlockSize = Keysize;
					symmetricKey.Mode = CipherMode.CBC;
					symmetricKey.Padding = PaddingMode.PKCS7;
					using (var decryptor = symmetricKey.CreateDecryptor(keyBytes, ivStringBytes))
					{
						using (var memoryStream = new MemoryStream(cipherTextBytes))
						{
							using (var cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read))
							{
								var plainTextBytes = new byte[cipherTextBytes.Length];
								var decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
								memoryStream.Close();
								cryptoStream.Close();
								return Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);
							}
						}
					}
				}
			}
		}

		private static byte[] Generate256BitsOfRandomEntropy()
		{
			var randomBytes = new byte[16];
			using (var rngCsp = new RNGCryptoServiceProvider())
			{
				rngCsp.GetBytes(randomBytes);
			}
			return randomBytes;
		}

		static string CalculateMD5Hash(string input)
		{
			var md5 = MD5.Create();

			var inputBytes = Encoding.ASCII.GetBytes(input);
			var hash = md5.ComputeHash(inputBytes);
			var sb = new StringBuilder();

			for (int i = 0; i < hash.Length; i++)
			{
				sb.Append(hash[i].ToString("X2"));
			}

			return sb.ToString();

		}

		public void SetSecured(string identifier, string value, string clientId, string clientSecret, string sharedGroup)
		{
			var key = $"{clientId}-{identifier}-{clientId}-{sharedGroup}";
			var newKey = CalculateMD5Hash(key);
			var encrypted = EncryptString(value, clientSecret);
			Plugin.Settings.CrossSettings.Current.AddOrUpdateValue(newKey, encrypted);
		}

		public string GetSecured(string identifier, string clientId, string clientSecret, string sharedGroup)
		{
			try
			{
				var key = $"{clientId}-{identifier}-{clientId}-{sharedGroup}";
				var newKey = CalculateMD5Hash(key);
				var cryptText = Plugin.Settings.CrossSettings.Current.GetValueOrDefault(newKey, "");
				return DecryptString(cryptText, clientSecret);
			}
			catch (Exception ex)
			{
				//Console.WriteLine(ex);
			}
			return null;
		}
	}
}

For console apps, you will also need to implement the Authenticators:

Basic Auth

using System;
using System.Security;
using System.Threading.Tasks;
namespace SimpleAuth
{
    public class BasicAuthController
    {
        readonly IBasicAuthenicator authenticator;

        public BasicAuthController(IBasicAuthenicator authenticator)
        {
            this.authenticator = authenticator;
        }


        public async Task<Tuple<string, string>> GetCredentials(string title, string details = "")
        {
            try
            {
                Console.WriteLine("******************");
                Console.WriteLine(title);
                Console.WriteLine(details);
                Console.WriteLine("******************");
                Console.WriteLine("Enter Username:");
                var username = Console.ReadLine();
                Console.WriteLine("Enter Password:");
                var password = GetPassword();

                var result = new Tuple<string, string>(username, password);
                try
                {
                    bool success = false;
                    var basic = authenticator;
                    if (basic != null)
                    {
                        success = await basic.VerifyCredentials(result.Item1, result.Item2);
                    }
                    if (!success)
                        throw new Exception("Invalid Credentials");
                }
                catch (Exception ex)
                {
                    result = await GetCredentials(title, $"Error: {ex.Message}");
                }
                return result;
            }
            catch (TaskCanceledException)
            {
                authenticator.OnCancelled();
                return null;
            }
        }
        public string GetPassword()
        {
            var pwd = "";
            while (true)
            {
                ConsoleKeyInfo i = Console.ReadKey(true);
                if (i.Key == ConsoleKey.Enter)
                {
                    break;
                }
                else if (i.Key == ConsoleKey.Backspace)
                {
                    if (pwd.Length > 0)
                    {
                        pwd.Remove(pwd.Length - 1);
                        Console.Write("\b \b");
                    }
                }
                else
                {
                    pwd += (i.KeyChar);
                    Console.Write("*");
                }
            }
            return pwd;
        }
    }
}

Web Authenticator

using System;
using System.Threading.Tasks;
using System.Diagnostics;
using System.Runtime.InteropServices;
namespace SimpleAuth
{
    public class WebAuthenticatorController
    {
        readonly WebAuthenticator authenticator;

        public WebAuthenticatorController(WebAuthenticator authenticator)
        {
            this.authenticator = authenticator;
        }


        public async Task GetCredentials(string title, string details = "")
        {
            try
            {
                var url = await authenticator.GetInitialUrl();
                Console.WriteLine("******************");
                Console.WriteLine(title);
                Console.WriteLine(details);
                Console.WriteLine($"Launching Url: \"{url}\"");
                Console.WriteLine("******************");
                Console.WriteLine("Paste the Redirected URL Here:");
                OpenBrowser(url);
                var username = Console.ReadLine();

                try
                {
                    bool success = false;
                    var basic = authenticator;
                    if (basic != null)
                    {
                        success = basic.CheckUrl(new Uri(username), null);
                    }
                    if (!success)
                        throw new Exception("Invalid Credentials");
                }
                catch (Exception ex)
                {
                    await GetCredentials(title, $"Error: {ex.Message}");
                }
            }
            catch (TaskCanceledException)
            {
                authenticator.OnCancelled();
            }
        }

        public static void OpenBrowser(Uri uri)
        {
            OpenBrowser(uri.AbsoluteUri);
        }

        public static void OpenBrowser(string url)
        {
            try
            {
                Process.Start(url);
            }
            catch
            {
                // hack because of this: https://github.com/dotnet/corefx/issues/10361
                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
                {
                    url = url.Replace("&", "^&");
                    Process.Start(new ProcessStartInfo("cmd", $"/c start {url}") { CreateNoWindow = true });
                }
                else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
                {
                    Process.Start("xdg-open", url);
                }
                else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
                {
                    Process.Start("open", url);
                }
                else
                {
                    throw;
                }
            }
        }
    }
}