.Net 8 json code generator doen't work with Controllers

[olganos]

Hello,

I have an api project and I want to use source generation with controllers and Rest Api Dtos.
It doesn't work.

This is my code:

Program.cs

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.

builder.Services.AddControllers().AddJsonOptions(
static options =>
options.JsonSerializerOptions.TypeInfoResolverChain.Insert(0, MyJsonContext.Default));

// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
app.UseSwagger();
app.UseSwaggerUI();
}

app.UseHttpsRedirection();

app.UseAuthorization();

app.MapControllers();

app.Run();

WeatherForcast.cs

using System.Text.Json.Serialization;
using webApi;

namespace webApi
{
    public class WeatherForecast
    {
        public DateOnly Date { get; set; }

        public int TemperatureC { get; set; }

        public int TemperatureF => 32 + (int)(TemperatureC / 0.5556);

        public string? Summary { get; set; }
    }
}

[JsonSourceGenerationOptions(
PropertyNamingPolicy = JsonKnownNamingPolicy.SnakeCaseLower,
GenerationMode = JsonSourceGenerationMode.Metadata)]
[JsonSerializable(typeof(WeatherForecast))]
[JsonSerializable(typeof(IEnumerable))]
[JsonSerializable(typeof(WeatherForecast[]))]
internal partial class MyJsonContext : JsonSerializerContext { }

controller

using Microsoft.AspNetCore.Mvc;

namespace webApi.Controllers
{
[ApiController]
[Route("[controller]")]
public class WeatherForecastController : ControllerBase
{
   private static readonly string[] Summaries = new[]
   {
      "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
   };

    private readonly ILogger<WeatherForecastController> _logger;

    public WeatherForecastController(ILogger<WeatherForecastController> logger)
    {
        _logger = logger;
    }

    [HttpGet(Name = "GetWeatherForecast")]
    public IEnumerable<WeatherForecast> Get()
    {
        return Enumerable.Range(1, 5).Select(index => new WeatherForecast
        {
            Date = DateOnly.FromDateTime(DateTime.Now.AddDays(index)),
            TemperatureC = Random.Shared.Next(-20, 55),
            Summary = Summaries[Random.Shared.Next(Summaries.Length)]
        })
        .AsEnumerable();
    }
  }
}

progect file

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>net8.0</TargetFramework>
    <Nullable>enable</Nullable>
    <ImplicitUsings>enable</ImplicitUsings>
	  <JsonSerializerIsReflectionEnabledByDefault>false</JsonSerializerIsReflectionEnabledByDefault>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Swashbuckle.AspNetCore" Version="6.6.2" />
  </ItemGroup>

</Project>

output

Still camel case, but I want snake case.

[CyrusNajmabadi]

This does not seem to be a Roslyn issue. Unfortunately, GitHub is not letting me transfer this to the runtime repo

[olganos]

Do you want I close this issue and create a new one in runtime? Actually I tired, but it just reopens a new page with the list of templates....

[CyrusNajmabadi]

@eiriktsarpalis can you transfer this? I cannot.

[eiriktsarpalis]

Your configuration is only copying the TypeInfoResolver which decribes how .NET types map to JSON contracts but not any other configuration. You should additionally explicitly set or copy any other configuration on the ASP.NET options:

builder.Services.AddControllers().AddJsonOptions(
static options =>
{
    options.JsonSerializerOptions.TypeInfoResolverChain.Insert(0, MyJsonContext.Default));
    options.JsonSerializerOptions.PropertyNamingPolicy = MyJsonContext.Default.PropertyNamingPolicy;
    // additionally set or copy any other options you want your web application to observe
}

Hope this helps.