Added a json converter to deserialize base64 strings to a byte array

src/Docker.DotNet/JsonBase64Converter.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Collections.Generic;
+using Newtonsoft.Json;
+
+namespace Docker.DotNet
+{
+    internal class JsonBase64Converter : JsonConverter
+    {
+        public override bool CanRead => true;
+
+        public override bool CanWrite => false;
+
+        public override void WriteJson(JsonWriter writer, object value, Newtonsoft.Json.JsonSerializer serializer)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, Newtonsoft.Json.JsonSerializer serializer)
+        {
+            var strVal = reader.Value as string;
+
+            return Convert.FromBase64String(strVal);
+        }
+
+        public override bool CanConvert(Type objectType)
+        {
+            return objectType == typeof (IList<byte>);
+        }
+    }
+}

src/Docker.DotNet/JsonSerializer.cs

@@ -1,4 +1,4 @@
-using Newtonsoft.Json;
+using Newtonsoft.Json;
 using Newtonsoft.Json.Converters;
 
 namespace Docker.DotNet
@@ -17,7 +17,8 @@ internal class JsonSerializer
                 new JsonVersionConverter(),
                 new StringEnumConverter(),
                 new TimeSpanSecondsConverter(),
-                new TimeSpanNanosecondsConverter()
+                new TimeSpanNanosecondsConverter(),
+                new JsonBase64Converter()
             }
         };
 
@@ -35,4 +36,4 @@ public string SerializeObject<T>(T value)
             return JsonConvert.SerializeObject(value, this._settings);
         }
     }
-}
+}