lwardzala / Json.Abstraction

Abstraction convertion functionalities for the .NET System.Text.Json library

Json.Abstraction

Abstraction conversion functionalities for the .NET System.Text.Json library.

Includes:

• Support for deleted polymorphism in System.Text.Json;
• Automate searching in the abstract type's assembly for appropriate types convertion;
• Adding types convertion to a global registry;
• Converter for abstractions based on discriminator;
• Converter for interfaces;
• Converter factory;
• Synchronization with JsonSerializerOptions.

Table of content

• Json.Abstraction
  • Includes:
  • Table of content
  • Installation
    • NuGet
  • Configuration
    • JsonSerializerOptions setup
    • MVC AddJsonOptions
  • Working with interface convertion
  • Working with abstraction convertion
  • Changelog
  • Authors

Installation

NuGet

https://www.nuget.org/packages/Json.Abstraction/

Configuration

To initialize the abstraction convertion, you need to add a JsonAbstractionConverter factory to a System.Text.Json JsonSerializerOptions. It's a similar process to configuring the JsonStringEnumConverter.

JsonSerializerOptions setup

When providing serializer options to JsonSerializer:

using Json.Abstraction;

new JsonSerializerOptions
{
    IgnoreNullValues = true,
    PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
    Converters = { new JsonAbstractionConverter(), new JsonStringEnumConverter() }
};

MVC AddJsonOptions

Or when configuring MVC app:

[when configuring services]

services.AddControllers().AddJsonOptions(opts =>
{
    opts.JsonSerializerOptions.PropertyNamingPolicy = JsonNamingPolicy.CamelCase;
    opts.JsonSerializerOptions.IgnoreNullValues = true;
    opts.JsonSerializerOptions.Converters.Add(new JsonStringEnumConverter());
    opts.JsonSerializerOptions.Converters.Add(new JsonAbstractionConverter());
});

Working with interface convertion

The interface converter tries to detect automatically an appropriate class. If the interface and class exists in the same assembly, there is no need to register that types convertion.

Also there is no need to use discriminators if there is only one class that implements the interface. If there are more than one class, the converter factory tries to use AbstractionConverter with discriminators.

However, there is still an option to register a missing types convertion by JsonAbstractSerializer:

using Json.Abstraction.Serializers;

JsonAbstractSerializer.RegisterInterfaceConversion(typeof(IModel), typeof(Model));
// OR
JsonAbstractSerializer.RegisterInterfaceConversion<IModel, Model>();

Working with abstraction convertion

The abstraction converter tries to detect automatically an appropriate class. If the JSON data includes "_t" discriminator prameter with the class name, converter tries to locate the class type by reflection.

However, when the abstraction and it's class is not located in the same assembly, there is still a possibility to register that types convertion in the global registry.

using Json.Abstraction.Serializers;

JsonAbstractSerializer.RegisterAbstractionConversion<ModelBase>(typeof(Model1), typeof(Model2));
// OR separately in different locations
JsonAbstractSerializer.RegisterAbstractionConversion<ModelBase>(typeof(Model1)); // In one file
JsonAbstractSerializer.RegisterAbstractionConversion<ModelBase>(typeof(Model2)); // In another file

Abstraction converter writes JSON structure with "_t" discriminator parameter based on class name. So in case of model:

public abstract class NestedBase
{
    public int Param1 { get; set; }
}

public class Nested : NestedBase
{
    public string Param2 { get; set; }
}

Serialization of object:

new Nested
{
    Param1 = 3,
    Param2 = "Test"
}

// in resource:

public class TestResource
{
    public NestedBase NestedObject { get; set; }
}

is going to produce:

{
    "nestedObject": {
        "_t": "Nested",
        "param2": "Test",
        "param1": 3
    }
}

Abstraction converter works both with abstract classes and interfaces.

Changelog

https://github.com/lwardzala/Json.Abstraction/blob/master/Changelog.md

Authors

• Lukasz Wardzala - github