AspNet Core - input/output JSON serialization settings at Controller Level

Question

My application requires the (almost default) JSON serialization settings:

services.AddMvc()
            .SetCompatibilityVersion(CompatibilityVersion.Version_2_2)
            .AddJsonOptions(options =>
            {
                options.SerializerSettings.ReferenceLoopHandling = ReferenceLoopHandling.Ignore;
                options.SerializerSettings.DateFormatHandling = DateFormatHandling.MicrosoftDateFormat;
                options.SerializerSettings.DateTimeZoneHandling = DateTimeZoneHandling.Local;
            });

For one controller only, I need to use a different naming strategy for both input (where I use model binding with [FromBody] myComplexObject and output with

options.SerializerSettings.ContractResolver = new DefaultContractResolver();

My question is virtually identical to Web API: Configure JSON serializer settings on action or controller level with the exception that I'm asking for AspNet Core 2.2+, in which IControllerConfiguration is no longer existent.

The Core 2.1+ equivalent question has a response here: Configure input/output formatters on controllers with ASP.NET Core 2.1

The answers there appear slightly fragmented or incomplete - it's hard to imagine that there is no easier way to achieve this. Would anyone have an idea on how to use a DefaultContractResolver for all input and output within a single controller?

Answer 1

The answer you link works well enough, but you can extend it further by wrapping it in an attribute that you can apply to any action or controller. For example:

public class JsonConfigFilterAttribute : ActionFilterAttribute
{
    public override void OnResultExecuting(ResultExecutingContext context)
    {
        if (context.Result is ObjectResult objectResult)
        {
            var serializerSettings = new JsonSerializerSettings
            {
                ContractResolver = new DefaultContractResolver()
            };

            var jsonFormatter = new JsonOutputFormatter(
                serializerSettings, 
                ArrayPool<char>.Shared);

            objectResult.Formatters.Add(jsonFormatter);
        }

        base.OnResultExecuting(context);
    }
}

And just add it to action methods or controllers:

[JsonConfigFilter]
public ActionResult<Foo> SomeAction()
{
    return new Foo
    {
        Bar = "hello"
    };
}

Answer 2

For Global Setting in Startup.cs, having installed Newtonsoft.json, you will have this

services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2)
            .AddJsonOptions(options => options.SerializerSettings.ContractResolver = new DefaultContractResolver());

For Individual Controller, you can override the global setting below

 public JsonResult GetStates()
    {
        var model = new List<StateObject>();
        if (!string.IsNullOrEmpty(id))
        {
            var schedule = _settingsService.GetStates().ToList();
            return Json(new SelectList(schedule, "StateCode", "Name"), new JsonSerializerSettings() { ContractResolver = new CamelCasePropertyNamesContractResolver() });
        }
        else
            return Json(new SelectList(model, "StateCode", "Name"), new JsonSerializerSettings() { ContractResolver = new CamelCasePropertyNamesContractResolver() });
    }

Let me know if this solves your problem, or you need further Assitance.