Add Json Options to AspNetCore2 Application, Configuration.

Startup.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.AspNetCore.Http;
using System;
using Microsoft.AspNetCore.ResponseCompression;
using System.IO.Compression;
using Newtonsoft.Json.Serialization;
using System.Runtime;
using Newtonsoft.Json.Converters;
using Newtonsoft.Json;

namespace memoryDB
{
    public class Startup
    {
        public Startup(IHostingEnvironment env)
        {
            var builder = new ConfigurationBuilder()
                .SetBasePath(env.ContentRootPath)
                .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true);

            Configuration = builder.Build();
        }

        public IConfigurationRoot Configuration { get; }

        public void ConfigureServices(IServiceCollection services)
        {

            services.AddMvcCore().
                     AddDataAnnotations().
                     AddJsonFormatters();

            services.Configure<GzipCompressionProviderOptions>
                  (options => options.Level = CompressionLevel.Fastest);
            services.AddResponseCompression(options =>
               {
                   options.Providers.Add<GzipCompressionProvider>();
               });

            services.AddMvc((options) =>
            {
                options.CacheProfiles.Add("default", new CacheProfile()
                {
                    Duration = 0,
                    Location = ResponseCacheLocation.None
                });

            }).AddJsonOptions(
o =>
{
    CamelCasePropertyNamesContractResolver resorver = new CamelCasePropertyNamesContractResolver();
    resorver.NamingStrategy = null;
    o.SerializerSettings.ContractResolver = resorver;
    o.SerializerSettings.Converters.Add(new StringEnumConverter());
    o.SerializerSettings.Formatting = Formatting.None;
    o.SerializerSettings.NullValueHandling = NullValueHandling.Include;
    o.SerializerSettings.MissingMemberHandling = MissingMemberHandling.Ignore;
    o.SerializerSettings.ReferenceLoopHandling = ReferenceLoopHandling.Error;

});

        }

        public void Configure(IApplicationBuilder app, ILoggerFactory loggerFactory)
        {

            loggerFactory.AddConsole(Configuration.GetSection("Logging"));
            loggerFactory.AddConsole();


            var logger = loggerFactory.CreateLogger("Start");
            logger.LogInformation($"- Application started  ");

            string strGName = "";
            if (GCSettings.IsServerGC == true)
                strGName = "server";
            else
                strGName = "workstation";
            logger.LogInformation($"The {strGName} garbage collector is running.");

            app.UseResponseCompression();
            app.UseStaticFiles();
            app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "{controller=Home}/{action=Index}/{id?}");
            });

        }
    }
}