Aviationexam.GeneratedJsonConverters.SourceGenerator 0.1.1

Aviationexam.GeneratedJsonConverters.SourceGenerator

Motivation for this library are polymorphic contracts with discriminator property not present as first property.

i.e. this JSON

{
    "baseProperty": 1,
    "$type": 2,
    "anotherLeafProperty": 2
}

is deserialized correctly into AnotherLeafContract using this library.

Install

<ItemGroup>
    <PackageReference Include="Aviationexam.GeneratedJsonConverters.SourceGenerator" Version="0.1.0" PrivateAssets="all" />
</ItemGroup>

How to use library

// file=contracts.cs
using Aviationexam.GeneratedJsonConverters.Attributes;

[JsonPolymorphic] // notice, that attributes are from `Aviationexam.GeneratedJsonConverters.Attributes` namespace, not `System.Text.Json.Serialization`
[JsonDerivedType(typeof(LeafContract), typeDiscriminator: nameof(LeafContract))]
[JsonDerivedType(typeof(AnotherLeafContract), typeDiscriminator: 2)]
public abstract class BaseContract
{
    public int BaseProperty { get; set; }
}
public sealed class LeafContract : BaseContract
{
    public int LeafProperty { get; set; }
}
public sealed class AnotherLeafContract : BaseContract
{
    public int AnotherLeafProperty { get; set; }
}

// file=MyJsonSerializerContext.cs
using System.Text.Json.Serialization;

[JsonSerializable(typeof(BaseContract))] // this line is neccesary, generator searches for JsonSerializableAttribute with argument type decorated by JsonPolymorphicAttribute
[JsonSerializable(typeof(LeafContract))] // notice, it's necessary to specify leaf types
[JsonSerializable(typeof(AnotherLeafContract))]
public partial class MyJsonSerializerContext : JsonSerializerContext
{
    static MyJsonSerializerContext()
    {
        // register generated converters to options
        UsePolymorphicConverters(s_defaultOptions.Converters);
    }
}