camelCase JSON Response in ASP.NET Projects

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Introduction

While generating JSON in ASP.NET MVC project, I found out the generated JSON responses are actually not in camel case format. Plus:

• JSON not indented
• Exception while serializing the single null value
• Exception with reference loop properties

Today, I am going to share how to use Newtonsoft.Json and configure JSON serialization settings in different types of projects.

JSON Example

MVC

Using a custom JsonResult class for camel case JSON:

using System;
using System.Text;
using System.Web;
using System.Web.Mvc;
using Newtonsoft.Json;
using Newtonsoft.Json.Serialization;

public class JsonCamelCaseResult : JsonResult
{
    public Encoding ContentEncoding { get; set; }
    public string ContentType { get; set; }
    public object Data { get; set; }

    private const string HttpMethod = "GET";
    private const string DefaultContentType = "application/json";

    public override void ExecuteResult(ControllerContext context)
    {
        if (context == null)
        {
            throw new ArgumentNullException(nameof(context));
        }
        if (JsonRequestBehavior == JsonRequestBehavior.DenyGet && 
             String.Equals(context.HttpContext.Request.HttpMethod, 
                           HttpMethod, StringComparison.OrdinalIgnoreCase))
        {
            throw new InvalidOperationException("HttpMethod 'GET' is not allowed");
        }

        HttpResponseBase response = context.HttpContext.Response;
        response.ContentType = string.IsNullOrEmpty(ContentType) ? DefaultContentType : ContentType;
        if (ContentEncoding != null)
        {
            response.ContentEncoding = ContentEncoding;
        }
        var jsonSerializerSettings = new JsonSerializerSettings
        {
            ContractResolver = new CamelCasePropertyNamesContractResolver(),
            Formatting = Formatting.Indented,
            ReferenceLoopHandling = ReferenceLoopHandling.Ignore,
            PreserveReferencesHandling = PreserveReferencesHandling.None    /*prevent $id/$ref 
                                                                              at client end*/
        };

        response.Write(JsonConvert.SerializeObject(Data, jsonSerializerSettings));
    }
}

JSON helper class:

public class CamelJsonHelper
{
    public JsonCamelCaseResult Json(object data)
    {
        return new JsonCamelCaseResult
        {
            Data = data,
            JsonRequestBehavior = JsonRequestBehavior.AllowGet
        };
    }
}

add a new method to the Controller or BaseController to use this helper class:

/*hide base*/
//public new JsonResult Json(object value)
//{
//    return new CamelJsonHelper().Json(value);
//}

/*new method*/
public JsonResult JsonCamel(object value)
{
    return new CamelJsonHelper().Json(value);
}

For MVC projects, there is no global setting option.

Web Form

Add serialization setting at Global.asax.cs.

/*comment and see the regular serialization*/
JsonConvert.DefaultSettings = () => new JsonSerializerSettings
{
    ContractResolver = new CamelCasePropertyNamesContractResolver(),
    Formatting = Formatting.Indented,
    ReferenceLoopHandling = ReferenceLoopHandling.Ignore,
    PreserveReferencesHandling = PreserveReferencesHandling.None    /*prevent $id/$ref at client end*/
};

now serializing object like:

string json = JsonConvert.SerializeObject(DataProvider.Hierarchy())

This is also applicable for Aspx, Razor & C# !!!

If we don't want to configure it globally, we can do:

var settings = new JsonSerializerSettings
{
    ContractResolver = new CamelCasePropertyNamesContractResolver(),
    Formatting = Formatting.Indented,
    ReferenceLoopHandling = ReferenceLoopHandling.Ignore,
    PreserveReferencesHandling = PreserveReferencesHandling.None    /*prevent $id/$ref at client end*/
};
var data = DataProvider.Hierarchy();

string json = JsonConvert.SerializeObject(data, settings);

Web API

Add new config class to App_Start:

public class ResponseSerializerConfig
{
    public static void Register(HttpConfiguration configuration)
    {
        JsonResponse(configuration);
        XmlResponse(configuration);
    }

    private static void XmlResponse(HttpConfiguration config)
    {
        config.Formatters.Remove(config.Formatters.XmlFormatter);
    }

    private static void JsonResponse(HttpConfiguration config)
    {
        config.Formatters.JsonFormatter.SerializerSettings = new JsonSerializerSettings
        {
            ContractResolver = new CamelCasePropertyNamesContractResolver(),
            Formatting = Formatting.Indented,
            ReferenceLoopHandling = ReferenceLoopHandling.Ignore,
            PreserveReferencesHandling = PreserveReferencesHandling.None    /*prevent $id/$ref 
                                                                              at client end*/
        };
    }
}

Apply this config class at Global.asax.cs.

ResponseSerializerConfig.Register(GlobalConfiguration.Configuration);

Addition Settings

Enum

{"Enum":"Hello"} rather than {"Enum":0}

Converters = new List<JsonConverter> { new StringEnumConverter() }

Reference Loop

ReferenceLoopHandling = ReferenceLoopHandling.Serialize

References $id/$ref

/*PreserveReferencesHandling.Objects is more popular*/
PreserveReferencesHandling = PreserveReferencesHandling.All;

To manage $id/$ref at js client, please do check:

• https://gist.github.com/kolodny/8043084
• https://stackoverflow.com/questions/15312529/resolve-circular-references-from-json-object

TimeZone & DateTime

DateTimeZoneHandling = DateTimeZoneHandling.Utc,
DateFormatHandling = DateFormatHandling.IsoDateFormat

This post will help you to quick start projects will minimal JSON serializer settings. Please do check the attached VS2017 example project.