support otpauth:// URIs in otp field as used by KeeWeb (closes #118)

src/keepass2android/Totp/KeeWebOtpPluginAdapter.cs

@@ -0,0 +1,43 @@
+using System;
+using System.Collections.Generic;
+using System.Web;
+using Android.Content;
+using PluginTOTP;
+
+namespace keepass2android
+{
+    internal class KeeWebOtpPluginAdapter : ITotpPluginAdapter
+    {
+        public TotpData GetTotpData(IDictionary<string, string> entryFields, Context ctx, bool muteWarnings)
+        {
+            TotpData res = new TotpData();
+            string data;
+            if (!entryFields.TryGetValue("otp", out data))
+            {
+                return res;
+            }
+
+            string otpUriStart = "otpauth://totp/";
+
+            if (!data.StartsWith(otpUriStart))
+                return res;
+
+
+            try
+            {
+                Uri myUri = new Uri(data);
+                var parsedQuery = HttpUtility.ParseQueryString(myUri.Query);
+                res.TotpSeed = parsedQuery.Get("secret");
+                res.Length = parsedQuery.Get("digits");
+                res.Duration = parsedQuery.Get("period");
+            }
+            catch (Exception)
+            {
+                return res;
+            }
+            
+            res.IsTotpEnry = true;
+            return res;
+        }
+    }
+}

src/keepass2android/Totp/Kp2aTotp.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using Android.App;
@@ -11,7 +10,7 @@ namespace keepass2android
 	class Kp2aTotp
 	{
 
-		readonly ITotpPluginAdapter[] _pluginAdapters = new ITotpPluginAdapter[] { new TrayTotpPluginAdapter(), new KeeOtpPluginAdapter() };
+		readonly ITotpPluginAdapter[] _pluginAdapters = new ITotpPluginAdapter[] { new TrayTotpPluginAdapter(), new KeeOtpPluginAdapter(), new KeeWebOtpPluginAdapter() };
 
 		public void OnOpenEntry()
 		{

src/keepass2android/keepass2android.csproj

@@ -102,6 +102,7 @@
     <Reference Include="Java.Interop" />
     <Reference Include="System" />
     <Reference Include="System.Net.Http" />
+    <Reference Include="System.Web.Services" />
     <Reference Include="System.Xml" />
     <Reference Include="System.Core" />
     <Reference Include="Mono.Android" />
@@ -255,6 +256,7 @@
     <Compile Include="Totp\Base32.cs" />
     <Compile Include="Totp\ITotpPluginAdapter.cs" />
     <Compile Include="Totp\KeeOtpPluginAdapter.cs" />
+    <Compile Include="Totp\KeeWebOtpPluginAdapter.cs" />
     <Compile Include="Totp\Kp2aTotp.cs" />
     <Compile Include="Totp\TimeCorrectionProvider.cs" />
     <Compile Include="Totp\TotpData.cs" />