Properly Support Binary Characteristics

Author: jdomnitz

HomeKitDotNet/Models/BinaryCharacteristic.cs

@@ -0,0 +1,66 @@
+using HomeKitDotNet.JSON;
+using System.Buffers.Text;
+using System.Text.Json;
+
+namespace HomeKitDotNet.Models
+{
+    public class BinaryCharacteristic : CharacteristicBase
+    {
+        public delegate Task AsyncEventHandler(Service service, BinaryCharacteristic characteristic, byte[] newValue);
+        public event AsyncEventHandler? Updated;
+        protected BinaryCharacteristic(Service service, CharacteristicJSON json) : base(service, json)
+        {
+            LastValue = MapValue(json.Value);
+        }
+
+        protected async Task<bool> Write(byte[] value)
+        {
+            if (!CanWrite)
+                throw new InvalidOperationException("Writing is prohibited");
+            CharacteristicValueJSON write = new CharacteristicValueJSON(service.Accessory.ID, InstanceID);
+            write.Value = JsonSerializer.SerializeToElement(Convert.ToBase64String(value));
+            Dictionary<string, CharacteristicValueJSON[]> dict = new Dictionary<string, CharacteristicValueJSON[]>();
+            dict.Add("characteristics", [write]);
+            return (await service.Accessory.EndPoint.Connection.Put("/characteristics", JsonSerializer.SerializeToUtf8Bytes(dict))).StatusCode == System.Net.HttpStatusCode.NoContent;
+        }
+
+        protected async Task<byte[]> Read()
+        {
+            if (!CanRead)
+                throw new InvalidOperationException("Reading is prohibited");
+            HttpResponseMessage msg = await service.Accessory.EndPoint.Connection.Get($"/characteristics?id={service.Accessory.ID}.{InstanceID}");
+            if (!msg.IsSuccessStatusCode)
+                return Array.Empty<byte>();
+            CharacteristicsJSON? chars = JsonSerializer.Deserialize<CharacteristicsJSON>(msg.Content.ReadAsStream());
+            if (chars == null || chars.Characteristics.Length == 0)
+                return Array.Empty<byte>();
+            LastValue = MapValue(chars.Characteristics[0].Value);
+            return LastValue;
+        }
+
+        protected byte[] MapValue(JsonElement? value)
+        {
+            if (value.HasValue)
+            {
+                if (value.Value.ValueKind == JsonValueKind.String)
+                    return Convert.FromBase64String(value.Value.GetString() ?? string.Empty);
+                else
+                    throw new ArgumentException("Value Mismatch " + value);
+            }
+            else
+                return Array.Empty<byte>();
+        }
+
+        internal override void FireUpdate(JsonElement? value)
+        {
+            byte[] newVal = MapValue(value);
+            if (Updated != null)
+                Updated.Invoke(service, this, newVal);
+            LastValue = newVal;
+        }
+
+        public byte[] LastValue { get; set; }
+        public float? MaxLength => _json.MaxLength;
+        public float? MaxDataLength => _json.MaxDataLength;
+    }
+}

HomeKitDotNet/Models/Characteristic.cs

@@ -29,7 +29,7 @@ protected async Task<bool> Write(T value)
             if (!CanWrite)
                 throw new InvalidOperationException("Writing is prohibited");
             CharacteristicValueJSON write = new CharacteristicValueJSON(service.Accessory.ID, InstanceID);
-            write.Value = JsonSerializer.SerializeToElement(LastValue);
+            write.Value = JsonSerializer.SerializeToElement(value);
             Dictionary<string, CharacteristicValueJSON[]> dict = new Dictionary<string, CharacteristicValueJSON[]>();
             dict.Add("characteristics", [write]);
             return (await service.Accessory.EndPoint.Connection.Put("/characteristics", JsonSerializer.SerializeToUtf8Bytes(dict))).StatusCode == System.Net.HttpStatusCode.NoContent;