Support (serializing) sub types with generic type parameters when using JsonSubtypesConverterBuilder about jsonsubtypes HOT 7 CLOSED

Hi,

Here is the not working solution https://dotnetfiddle.net/wBWRMw

The is no enough information in .RegisterSubtype(typeof(Some<>), "Some") to know which target type need to be instantiated, how would you resole to the fact that it should deserialize to Some<int> ?

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Yeah, I figured it would probably be impossible to deserialize. But what about only serialization? In this particular instance, that's really the only thing I need.

That said, I'd understand if you would not want to add additional logic for a serialize-only solution.

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Actually, this just made me think. Why not also use extra JSON properties to encode the generic type(s)? The above case could be serialized to {"Type": "Some", "T": "System.Int32", "Value": 42} by default, and you could introduce extra attributes to annotate the type parameters in order to customize the JSON property. Then this information could be used to determine the concrete type during deserialization.

I can imagine that including raw system type names (and any actual type names for that matter) in JSON is not desirable (not portable, potential security risk). In the same fashion as the "known subtypes" approach, maybe the user could configure a custom mapping of supported generic types to type names to use in the serialized JSON. Something like this:

[JsonSubtypes.KnownGenericType(typeof(int), "Integer")]
[JsonSubtypes.KnownGenericType(typeof(string), "Text")]
[JsonSubtypes.KnownGenericType(typeof(IResult), "Result")]
public class Some<[JsonSubtypes.GenericType("ResultType")] T> : IResult
{
    public T Value { get; set; }
}

With the above configuration, the serialized JSON would look like {"Type": "Some", "ResultType": "Integer", "Value": 42}.

I understand this is quite the extension to your library and might be out of scope, but I think it could be a valuable addition for some users.

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Hi @EdeMeijer

The following sample does not work with the lines in comment, but it seems to be close to something that already exists:

using System;
using JsonSubTypes;
using Newtonsoft.Json;

namespace subTypesIssue
{
    public class Program
    {
        public static void Main()
        {
      
            var input = new SomeInteger {Value = 42};
            var json = JsonConvert.SerializeObject(input);

            Console.WriteLine(json);
			
            var result = JsonConvert.DeserializeObject<IResult>(json);

            Console.WriteLine(result);
        }
    }
			
	[JsonConverter(typeof(JsonSubtypes), "Type")]	
	[JsonSubtypes.KnownSubType(typeof(Some<>), "Some")]												
	public interface IResult
    {
		string Type { get;}
    }

	public class SomeInteger: Some<int> {
		public override string ResultType { get { return "SomeInteger"; }} 
		
	}

	public class SomeText: Some<string> {
		public override string ResultType { get { return "SomeText"; }} 
		
	}

	[JsonConverter(typeof(JsonSubtypes), "ResultType")]
	//[JsonSubtypes.KnownSubType(typeof(SomeInteger), "SomeInteger")]
	//[JsonSubtypes.KnownSubType(typeof(SomeText), "SomeText")]
	public abstract class Some<T> : IResult
	{
	
		public string Type { get { return "Some"; }} 
		public abstract string ResultType { get; }
		public T Value { get; set; }
	}
}

See: https://dotnetfiddle.net/EGqf2C

I've not debug yet the reason why...

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That's... interesting. You're stacking two [JsonConverter] attributes in the same type hierarchy. But even is this would work, it would require the user to still declare every type he might be using as a sub type. Not exactly what I had in mind.

That said, for my current use case, I worked around the problem in a different way (using come custom wrapper type) so I'd say, don't put too much effort into this if you don't feel like this is very important to you.

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Some generic handling implemented in : #140

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Published with version 1.9.0

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