public void Configuration(IAppBuilder app) { HttpConfiguration config = new HttpConfiguration(); var cors = new EnableCorsAttribute("*", "*", "*"); config.EnableCors(cors); config.MapHttpAttributeRoutes(); var settings = new JsonSerializerSettings(); settings.ContractResolver = new CamelCasePropertyNamesContractResolver(); settings.NullValueHandling = NullValueHandling.Ignore; settings.DefaultValueHandling = DefaultValueHandling.IgnoreAndPopulate; config.Formatters.JsonFormatter.SerializerSettings = settings; var factory = new DefaultOpenPermitAdapterFactory(); var adapter = factory.GetOpenPermitAdapter(); config.Services.Add(typeof(IFilterProvider), new DefaultOpenPermitAdapterFilter(adapter)); config.MessageHandlers.Insert(0, new ServerCompressionHandler(4096, new GZipCompressor(), new DeflateCompressor())); app.UseWebApi(config); }