WIP

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Useful newtonsoft utilities (3 files)

AbstractListPropertyConverter.cs

using Newtonsoft.Json;

namespace Utils.Newtonsoft;

/* 
Usage: 
    [JsonConverter(typeof(AbstractListPropertyConverter<IEdge, ConcreteEdge>))]
    public List<IEdge> Edges { get; set; }
*/
public class AbstractListPropertyConverter<TInterface, TImplementation> : JsonConverter
    where TImplementation : TInterface
{
    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        serializer.Serialize(writer, value);
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        // todo: why not passing only the concrete like this?
        // var res = serializer.Deserialize<List<TImplementation>>(reader);
        var res = serializer.Deserialize<List<TInterface>>(reader);
        return res.Select(item => (TImplementation)item).ToList();
    }

    public override bool CanConvert(Type objectType)
    {
        // todo: why not return this?
        // return objectType == typeof(TImplementation);
        return objectType == typeof(TInterface);
    }
}

AbstractPropertyConverter.cs

using Newtonsoft.Json;

namespace Utils.Newtonsoft;

/* 
Usage: 
    [JsonConverter(typeof(AbstractPropertyConverter<ConcreteEdge>))]
    public IEdge Edge { get; set; }
*/
public class AbstractPropertyConverter<TImplementation> : JsonConverter
{
    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        serializer.Serialize(writer, value);
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        return serializer.Deserialize<TImplementation>(reader);
    }

    public override bool CanConvert(Type objectType)
    {
        return true;
    }
}

JsonConverterInstance.cs

using Newtonsoft.Json;

namespace Utils.Newtonsoft;

/// <summary>
/// Usage: you must declare a settings object and pass it to `DeserializeObject` method, for example:
/// 1. `var conv = new JsonConverterInstance[TAbstract, TConcrete]();`
/// 2. `JsonConvert.DeserializeObject(json, type, settings);`
/// Full Example in NewtonsoftTests.cs
/// </summary>
internal class JsonConverterInstance<TAbstract, TReal>
    : JsonConverter where TReal : TAbstract // where TReal : class, TAbstract, new()
{
    public override bool CanConvert(Type objectType)
        => objectType == typeof(TAbstract);

    public override object ReadJson(JsonReader reader, Type type, object value, JsonSerializer jser)
        => jser.Deserialize<TReal>(reader);

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer jser)
        => jser.Serialize(writer, value);
}