Files
monorepo/LCU.API.Internal.Document/LCU.Library.Internal.DocumentModels/Converter/PolymorphicJsonConverter.cs
T
2026-03-13 09:11:35 -05:00

107 lines
3.7 KiB
C#

using System;
using System.Linq;
using System.Reflection;
using System.Text.Json;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using JsonSerializer = System.Text.Json.JsonSerializer;
namespace LCU.Library.Internal.DocumentModels.Converter;
internal static class PolymorphicJsonConverter
{
public const string TypeProperty = "_t";
public static Exception NotSupported<T>() => new NotSupportedException($"{typeof(T).Name} must specify known deserialization types");
public static bool IsSerializationSupportedFor<T>(Type actualType) => typeof(T).GetCustomAttribute<JsonKnownTypesAttribute>() is { } knownTypes
&& knownTypes.Subclasses.Contains(actualType);
public static Type DeserializationTypeFor<T>(string actualType) => typeof(T)
.GetCustomAttribute<JsonKnownTypesAttribute>()
.Subclasses
.Single(t => t.Name == actualType);
}
public class SystemPolymorphicJsonConverter<T> : System.Text.Json.Serialization.JsonConverter<T>
{
public override T Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
{
var document = JsonDocument.ParseValue(ref reader);
var type = document.RootElement.GetProperty(PolymorphicJsonConverter.TypeProperty).GetString();
var deserializationType = PolymorphicJsonConverter.DeserializationTypeFor<T>(type);
return (T)document.Deserialize(deserializationType, options);
}
public override void Write(Utf8JsonWriter writer, T value, JsonSerializerOptions options)
{
var actualType = value.GetType();
if (!PolymorphicJsonConverter.IsSerializationSupportedFor<T>(actualType))
{
throw PolymorphicJsonConverter.NotSupported<T>();
}
writer.WriteStartObject();
writer.WriteString(PolymorphicJsonConverter.TypeProperty, actualType.Name);
var actualValue = JsonSerializer.Serialize(value, actualType, options);
writer.WriteRawValue(actualValue.Substring(1, actualValue.Length - 2), true);
writer.WriteEndObject();
}
}
public class NewtonsoftPolymorphicJsonConverter<T> : Newtonsoft.Json.JsonConverter<T>
{
public override bool CanRead => _canRead;
private bool _canRead = true;
public override T ReadJson(JsonReader reader, Type objectType, T existingValue, bool hasExistingValue, Newtonsoft.Json.JsonSerializer serializer)
{
var document = JObject.Load(reader);
var type = document.GetValue(PolymorphicJsonConverter.TypeProperty)!.Value<string>();
var deserializationType = PolymorphicJsonConverter.DeserializationTypeFor<T>(type);
T result;
lock (this)
{
_canRead = false;
result = (T)JsonConvert.DeserializeObject(document.ToString(), deserializationType);
_canRead = true;
}
return result;
}
public override bool CanWrite => _canWrite;
private bool _canWrite = true;
public override void WriteJson(JsonWriter writer, T value, Newtonsoft.Json.JsonSerializer serializer)
{
var actualType = value.GetType();
if (!PolymorphicJsonConverter.IsSerializationSupportedFor<T>(actualType))
{
throw PolymorphicJsonConverter.NotSupported<T>();
}
writer.WriteStartObject();
writer.WritePropertyName(PolymorphicJsonConverter.TypeProperty);
writer.WriteValue(actualType.Name);
JObject jValue;
lock (this)
{
_canWrite = false;
jValue = JObject.FromObject(value);
_canWrite = true;
}
foreach (var property in jValue.Properties())
{
property.WriteTo(writer);
}
writer.WriteEndObject();
}
}