Add converter to make sure we have a string value when expect it (#1126)

* Add converter to make sure we have a string value when expect it

* Fixed comment

Author: helto4real

src/Client/NetDaemon.HassClient.Tests/Json/EnsureStringConverterTests.cs

@@ -0,0 +1,69 @@
+
+namespace NetDaemon.HassClient.Tests.Json;
+
+public class EnsureStringConverterTests
+{
+    /// <summary>
+    ///     Default Json serialization options, Hass expects intended
+    /// </summary>
+    private readonly JsonSerializerOptions _defaultSerializerOptions = new()
+    {
+        WriteIndented = false,
+        DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
+    };
+
+    [Fact]
+    public void TestConvertAValidString()
+    {
+        const string jsonDevice = @"
+        {
+            ""config_entries"": [],
+            ""connections"": [],
+            ""manufacturer"": ""Google Inc."",
+            ""model"": 123123,
+            ""name"": 123,
+            ""serial_number"": ""1.0"",
+            ""sw_version"": ""100"",
+            ""hw_version"": null,
+            ""id"": ""42cdda32a2a3428e86c2e27699d79ead"",
+            ""via_device_id"": null,
+            ""area_id"": null,
+            ""name_by_user"": null
+        }
+        ";
+        var hassDevice = JsonSerializer.Deserialize<HassDevice>(jsonDevice, _defaultSerializerOptions);
+        hassDevice!.SerialNumber.Should().Be("1.0");
+        hassDevice!.SoftwareVersion.Should().Be("100");
+        hassDevice!.HardwareVersion.Should().BeNull();
+    }
+
+    [Fact]
+    public void TestConverAInvalidString()
+    {
+        const string jsonDevice = @"
+        {
+            ""config_entries"": [],
+            ""connections"": [],
+            ""model"": ""Chromecast"",
+            ""serial_number"": [""1.0"", ""2.0""],
+            ""name"": ""My TV"",
+            ""sw_version"": { ""attribute"": ""1.0"" },
+            ""manufacturer"": ""Google Inc."",
+            ""hw_version"": 100,
+            ""id"": ""42cdda32a2a3428e86c2e27699d79ead"",
+            ""via_device_id"": null,
+            ""area_id"": null,
+            ""name_by_user"": null
+        }
+        ";
+        var hassDevice = JsonSerializer.Deserialize<HassDevice>(jsonDevice, _defaultSerializerOptions);
+        hassDevice!.SerialNumber.Should().BeNull();
+        hassDevice!.SoftwareVersion.Should().BeNull();
+        hassDevice!.HardwareVersion.Should().BeNull();
+
+        // Make sure it is skipped correctly by checking the next property is read
+        hassDevice!.Manufacturer.Should().Be("Google Inc.");
+        hassDevice!.Id.Should().Be("42cdda32a2a3428e86c2e27699d79ead");
+        hassDevice!.Name.Should().Be("My TV");
+    }
+}

src/Client/NetDaemon.HassClient/Common/HomeAssistant/Model/HassDevice.cs

@@ -22,7 +22,10 @@ public record HassDevice
     #pragma warning disable CA1056 // It's ok for this URL to be a string
     [JsonPropertyName("configuration_url")] public string? ConfigurationUrl { get; init; }
     #pragma warning restore CA1056
+    [JsonConverter(typeof(EnsureStringConverter))]
     [JsonPropertyName("hw_version")] public string? HardwareVersion { get; init; }
+    [JsonConverter(typeof(EnsureStringConverter))]
     [JsonPropertyName("sw_version")] public string? SoftwareVersion { get; init; }
+    [JsonConverter(typeof(EnsureStringConverter))]
     [JsonPropertyName("serial_number")] public string? SerialNumber { get; init; }
 }

src/Client/NetDaemon.HassClient/Internal/Json/EnsureStringConverter.cs

@@ -0,0 +1,23 @@
+using System.Diagnostics;
+
+namespace NetDaemon.Client.Internal.Json;
+
+/// <summary>
+/// Converts a Json element that can be a string or returns null if it is not a string
+/// </summary>
+class EnsureStringConverter : JsonConverter<string?>
+{
+    public override string? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+    {
+        if (reader.TokenType == JsonTokenType.String)
+        {
+            return reader.GetString() ?? throw new UnreachableException("Token is expected to be a string");
+        }
+
+        // Skip the children of current token
+        reader.Skip();
+        return null;
+    }
+
+    public override void Write(Utf8JsonWriter writer, string? value, JsonSerializerOptions options) => throw new NotSupportedException();
+}