Specific JSON settings per controller on ASP.NET MVC 6

Question

I need specific JSON settings per controller in my ASP.NET MVC 6 webApi. I found this sample that works (I hope !) for MVC 5 : Force CamelCase on ASP.NET WebAPI Per Controller

using System;
using System.Linq;
using System.Web.Http.Controllers;
using System.Net.Http.Formatting;
using Newtonsoft.Json.Serialization;

public class CamelCaseControllerConfigAttribute : Attribute, IControllerConfiguration 
{
    public void Initialize(HttpControllerSettings controllerSettings, HttpControllerDescriptor controllerDescriptor)
    {
        var formatter = controllerSettings.Formatters.OfType<JsonMediaTypeFormatter>().Single();
        controllerSettings.Formatters.Remove(formatter);

        formatter = new JsonMediaTypeFormatter
        {
            SerializerSettings = {ContractResolver = new CamelCasePropertyNamesContractResolver()}
        };

        controllerSettings.Formatters.Add(formatter);

    }
}

You don't want to receive your API(s) with the same name as your Model classes? Instead, you want them in pasalCase for each model? — Janshair Khan, May 02 '16 at 14:48
It's just a sample for accessing the `JsonSerializerSettings` object. In my case, I need to change the binder for some controller used by a mobile application — Karine, May 02 '16 at 15:02

score 8 · Accepted Answer · answered May 02 '16 at 15:09

This class works fine :

using System;
using System.Linq;
using Newtonsoft.Json.Serialization;
using Microsoft.AspNet.Mvc.Filters;
using Newtonsoft.Json;
using Microsoft.AspNet.Mvc.Formatters;

namespace Teedl.Web.Infrastructure
{
    [AttributeUsage(AttributeTargets.Class, AllowMultiple = false, Inherited = true)]

    public class MobileControllerConfiguratorAttribute : Attribute, IResourceFilter
    {
        private readonly JsonSerializerSettings serializerSettings;

        public MobileControllerConfiguratorAttribute()
        {
            serializerSettings = new JsonSerializerSettings()
            {
                ContractResolver = new CamelCasePropertyNamesContractResolver(),
                TypeNameHandling = Newtonsoft.Json.TypeNameHandling.Objects,
                TypeNameAssemblyFormat = System.Runtime.Serialization.Formatters.FormatterAssemblyStyle.Simple,
                Binder = new TypeNameSerializationBinder("Teedl.Model.Mobile.{0}, Teedl.Model.ClientMobile")
        };
        }


        public void OnResourceExecuted(ResourceExecutedContext context)
        {
        }

        public void OnResourceExecuting(ResourceExecutingContext context)
        {
            var mobileInputFormatter = new JsonInputFormatter(serializerSettings);
            var inputFormatter = context.InputFormatters.FirstOrDefault(frmtr => frmtr is JsonInputFormatter);
            if (inputFormatter != null)
            {
                context.InputFormatters.Remove(inputFormatter);
            }
            context.InputFormatters.Add(mobileInputFormatter);

            var mobileOutputFormatter = new JsonOutputFormatter(serializerSettings);
            var outputFormatter = context.OutputFormatters.FirstOrDefault(frmtr => frmtr is JsonOutputFormatter);
            if (outputFormatter != null)
            {
                context.OutputFormatters.Remove(outputFormatter);
            }
            context.OutputFormatters.Add(mobileOutputFormatter);
        }
    }
}

Use :

[Route("api/mobile/businessrequest")]
[Authorize]
[MobileControllerConfigurator]
public class MobileBusinessRequestController : BaseController
{

Input/OutputFormatters do not exist anymore on the Resource context. Does anyone know how they can be accessed now? — Jake Shakesworth, Jun 29 '17 at 02:42
Want the solution for "Microsoft.AspNetCore.Mvc.Filters" too. — HappyLiang, Nov 07 '17 at 04:53
maybe for different framework versions you can use https://stackoverflow.com/a/44499722/782022 — aeroson, Mar 01 '18 at 13:46
Also see https://stackoverflow.com/a/52193035/10391 for a way to customize input formatters in the latest Core MVC — dcstraw, Sep 05 '18 at 20:37

score 7 · Answer 2 · edited Aug 08 '18 at 12:16

7

You can use a return type of JsonResult on your controller action methods. In my case, I needed specific actions to return Pascal Case for certain legacy scenarios. The JsonResult object allows you to pass an optional parameter as the JsonSerializerSettings.

public JsonResult Get(string id)
{
    var data = _service.getData(id);

    return Json(data, new JsonSerializerSettings
    {
        ContractResolver = new DefaultContractResolver()
    });

}

To have more consistent controller method signatures I ended up creating an extension method:

public static JsonResult ToPascalCase(this Controller controller, object model)
{
    return controller.Json(model, new JsonSerializerSettings
    {
        ContractResolver = new DefaultContractResolver()
    });
}

Now I can simply call the extension method inside my controller like below:

public IActionResult Get(string id)
{
    var data = _service.getData(id);
    return this.ToPascalCase(data);
}

edited Aug 08 '18 at 12:16

smn.tino

2,272
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answered Dec 14 '16 at 21:53

Mike Lunn

2,310
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Yup that's what I'm doing as well - similar scenario: Legacy library that has JS dependencies that were built with older code depending on default case. Can't control app settings client gets the right case. Wish there was a different way to do this to preserve the simpler contract interface. – Rick Strahl Sep 14 '17 at 10:27
@RickStrahl Edited answer to include an extension method for handling this. A little cleaner. – Mike Lunn Sep 15 '17 at 13:22
Does this work with OpenApi specs? – Liero Aug 01 '23 at 10:54

Specific JSON settings per controller on ASP.NET MVC 6

2 Answers2

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