Documentation update (#60)

* Update README.md

* improved intellisense, added default value for QRPixelsPerModule, added QRException

Google.Authenticator.WebSample/Default.aspx.cs

@@ -19,7 +19,7 @@ protected void Page_Load(object sender, EventArgs e)
             this.lblSecretKey.Text = Request.QueryString["key"];
 
             TwoFactorAuthenticator tfa = new TwoFactorAuthenticator();
-            var setupInfo = tfa.GenerateSetupCode("Test Two Factor", "[email protected]", Request.QueryString["key"], false, 3);
+            var setupInfo = tfa.GenerateSetupCode("Test Two Factor", "[email protected]", Request.QueryString["key"], false, 10);
 
             string qrCodeImageUrl = setupInfo.QrCodeSetupImageUrl;
             string manualEntrySetupCode = setupInfo.ManualEntryKey;

Google.Authenticator/Google.Authenticator.csproj

@@ -7,7 +7,7 @@
     <Description>Google Authenticator Two-Factor Authentication Library (Not officially affiliated with Google.)</Description>
     <Authors>Brandon Potter</Authors>
     <Company>Brandon Potter</Company>
-    <Version>2.1.0</Version>
+    <Version>2.1.1</Version>
     <PackageLicenseExpression>Apache-2.0</PackageLicenseExpression>
     <PackageProjectUrl>https://github.com/BrandonPotter/GoogleAuthenticator</PackageProjectUrl>
     <PackageId>GoogleAuthenticator</PackageId>

Google.Authenticator/QRException.cs

@@ -0,0 +1,13 @@
+using System;
+
+namespace Google.Authenticator
+{
+    public class QRException : Exception
+    {
+        public QRException(string message) : base(message)
+        { }
+
+        public QRException(string message, Exception innerException) : base(message, innerException)
+        { }
+    }
+}

Google.Authenticator/TwoFactorAuthenticator.cs

@@ -32,9 +32,9 @@ public TwoFactorAuthenticator()
         /// <param name="accountTitleNoSpaces">Account Title (no spaces)</param>
         /// <param name="accountSecretKey">Account Secret Key</param>
         /// <param name="secretIsBase32">Flag saying if accountSecretKey is in Base32 format or original secret</param>
-        /// <param name="QRPixelsPerModule">Number of pixels per QR Module (2 pixels give ~ 100x100px QRCode)</param>
+        /// <param name="QRPixelsPerModule">Number of pixels per QR Module (2 pixels give ~ 100x100px QRCode, should be 10 or less)</param>
         /// <returns>SetupCode object</returns>
-        public SetupCode GenerateSetupCode(string issuer, string accountTitleNoSpaces, string accountSecretKey, bool secretIsBase32, int QRPixelsPerModule)
+        public SetupCode GenerateSetupCode(string issuer, string accountTitleNoSpaces, string accountSecretKey, bool secretIsBase32, int QRPixelsPerModule = 3)
         {
             byte[] key = secretIsBase32 ? Base32Encoding.ToBytes(accountSecretKey) : Encoding.UTF8.GetBytes(accountSecretKey);
             return GenerateSetupCode(issuer, accountTitleNoSpaces, key, QRPixelsPerModule);
@@ -46,9 +46,9 @@ public SetupCode GenerateSetupCode(string issuer, string accountTitleNoSpaces, s
         /// <param name="issuer">Issuer ID (the name of the system, i.e. 'MyApp'), can be omitted but not recommended https://github.com/google/google-authenticator/wiki/Key-Uri-Format </param>
         /// <param name="accountTitleNoSpaces">Account Title (no spaces)</param>
         /// <param name="accountSecretKey">Account Secret Key as byte[]</param>
-        /// <param name="QRPixelsPerModule">Number of pixels per QR Module (2 = ~120x120px QRCode)</param>
+        /// <param name="QRPixelsPerModule">Number of pixels per QR Module (2 = ~120x120px QRCode, should be 10 or less)</param>
         /// <returns>SetupCode object</returns>
-        public SetupCode GenerateSetupCode(string issuer, string accountTitleNoSpaces, byte[] accountSecretKey, int QRPixelsPerModule, bool generateQrCode = true)
+        public SetupCode GenerateSetupCode(string issuer, string accountTitleNoSpaces, byte[] accountSecretKey, int QRPixelsPerModule = 3, bool generateQrCode = true)
         {
             if (String.IsNullOrWhiteSpace(accountTitleNoSpaces)) { throw new NullReferenceException("Account Title is null"); }
             accountTitleNoSpaces = RemoveWhitespace(Uri.EscapeUriString(accountTitleNoSpaces));
@@ -89,7 +89,13 @@ public SetupCode GenerateSetupCode(string issuer, string accountTitleNoSpaces, b
                     {
                         throw new MissingDependencyException("It looks like libgdiplus has not been installed - see https://github.com/codebude/QRCoder/issues/227", e);
                     }
-
+                }
+                catch (System.Runtime.InteropServices.ExternalException e)
+                {
+                    if (e.Message.Contains("GDI+") && QRPixelsPerModule > 10)
+                    {
+                        throw new QRException($"There was a problem generating a QR code. The value of {nameof(QRPixelsPerModule)} should be set to a value of 10 or less for optimal results.", e);
+                    }
                 }
             }
 

README.md

@@ -5,9 +5,9 @@ Simple, easy to use server-side two-factor authentication library for .NET that
 
 [`Install-Package GoogleAuthenticator`](https://www.nuget.org/packages/GoogleAuthenticator)
 
-See blog post for usage instructions:
+See blog post for usage instructions *(1.x only - does not apply to 2.x, see [Wiki](https://github.com/BrandonPotter/GoogleAuthenticator/wiki) for 2.x)*:
 
 https://csharprookie.wordpress.com/2015/03/17/implementing-free-two-factor-authentication-in-net-using-google-authenticator/
 
 # Notes
-On linux, you need to ensure `libgdiplus` is installed if you want to generate QR Codes. See [https://github.com/codebude/QRCoder/issues/227](https://github.com/codebude/QRCoder/issues/227).
+On linux, you need to ensure `libgdiplus` is installed if you want to generate QR Codes. See [https://github.com/codebude/QRCoder/issues/227](https://github.com/codebude/QRCoder/issues/227).