refactor(CryptographerExtensions): In die Abstraktionsschicht verschieben

DigitalData.Core.Abstractions/Security/CryptographerExtensions.cs

@@ -0,0 +1,21 @@
+namespace DigitalData.Core.Abstractions.Security
+{
+    public static class CryptographerExtensions
+    {
+        public static IEnumerable<TRSACryptographer> GetByIssuer<TRSACryptographer>(this IEnumerable<TRSACryptographer> cryptographers, string issuer) where TRSACryptographer: IRSACryptographer
+            => cryptographers.Where(c => c.Issuer == issuer);
+
+        public static IEnumerable<TRSACryptographer> GetByAudience<TRSACryptographer>(this IEnumerable<TRSACryptographer> cryptographers, string audience) where TRSACryptographer : IRSACryptographer
+            => cryptographers.Where(c => c.Audience == audience);
+
+        public static TRSACryptographer Get<TRSACryptographer>(this IEnumerable<TRSACryptographer> cryptographers, string issuer, string audience) where TRSACryptographer : IRSACryptographer
+            => cryptographers.Where(c => c.Issuer == issuer && c.Audience == audience).SingleOrDefault()
+            ?? throw new InvalidOperationException($"No {typeof(TRSACryptographer).GetType().Name.TrimStart('I')} found with Issuer: {issuer} and Audience: {audience}.");
+
+        public static bool TryGet<TRSACryptographer>(this IEnumerable<TRSACryptographer> cryptographers, string issuer, string audience, out TRSACryptographer? cryptographer) where TRSACryptographer : IRSACryptographer
+        {
+            cryptographer = cryptographers.SingleOrDefault(c => c.Issuer == issuer && c.Audience == audience);
+            return cryptographer is not null;
+        }
+    }
+}