https://github.com/wivuu/wivuu.jsonpolymorphism

Adds System.Text.Json serializer support for polymorphism with a discriminator attribute
https://github.com/wivuu/wivuu.jsonpolymorphism

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Adds System.Text.Json serializer support for polymorphism with a discriminator attribute

• Host: GitHub
• URL: https://github.com/wivuu/wivuu.jsonpolymorphism
• Owner: wivuu
• License: mit
• Created: 2020-11-20T20:59:44.000Z (about 4 years ago)
• Default Branch: master
• Last Pushed: 2024-04-15T19:15:46.000Z (9 months ago)
• Last Synced: 2025-01-05T18:46:43.910Z (7 days ago)
• Language: C#
• Size: 72.3 KB
• Stars: 25
• Watchers: 4
• Forks: 3
• Open Issues: 5
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# JsonPolymorphism

[![Nuget](https://github.com/wivuu/Wivuu.JsonPolymorphism/workflows/Nuget/badge.svg)](https://github.com/wivuu/Wivuu.JsonPolymorphism/actions?query=workflow%3ANuget)

[![wivuu.jsonpolymorphism](https://img.shields.io/nuget/v/wivuu.jsonpolymorphism.svg?label=wivuu.jsonpolymorphism)](https://www.nuget.org/packages/Wivuu.JsonPolymorphism/)

Easily add System.Text.Json serialization support for polymorphic models in C# / .NET 5. Works by generating a `JsonConverter` tailored to your class/record at compile-time and attaching it via `JsonConverterAttribute`. All you need is a `discriminator` property on your base types marked with the new `JsonDiscriminator` attribute

## Install

Since this project relies on Source Code Generation, this project can only be used with C# (not F#) projects targeting net5.0.

```sh

dotnet add package Wivuu.JsonPolymorphism

```

## Usage

The `JsonDiscriminator` attribute can be attached to either a record parameter or class/record property. Once attached the type of that discriminator will be used to find all classes which derive from your base type. Any enum types without a corresponding inherited type will result in a compile-time error.

```C#

enum AnimalType

{

    Insect,

    Mammal,

    Reptile,

    Bird // <- This causes an easy to understand build error if it's missing a corresponding inherited type!

}

// My base type is 'Animal'

abstract partial record Animal( [JsonDiscriminator] AnimalType type, string Name );

// Animals with type = 'Insect' will automatically deserialize as `Insect`

record Insect(int NumLegs = 6, int NumEyes=4) : Animal(AnimalType.Insect, "Insectoid");

record Mammal(int NumNipples = 2) : Animal(AnimalType.Mammal, "Mammalian");

record Reptile(bool ColdBlooded = true) : Animal(AnimalType.Reptile, "Reptilian");

```

## Serialize and Deserialize with ease!

Make sure to use consistent `JsonSerializerOptions`; Currently the discriminator value when deserializing is case-sensitive.

```C#

JsonSerializerOptions options = new();

Animal[] animals = 

{

    new Insect(NumLegs: 8, NumEyes: 6),

    new Mammal(NumNipples: 6),

    new Reptile(ColdBlooded: false),

};

var serialized          = JsonSerializer.Serialize(animals, options);

var animalsDeserialized = JsonSerializer.Deserialize(serialized, options);

if (animalsDeserialized is null)

    throw new System.Exception("Unable to deserialize");

    

Assert.Equal(animals.Length, animalsDeserialized.Length);

for (var i = 0; i < animals.Length; ++i)

    Assert.Equal(animals[i], animalsDeserialized[i]);

```