Wsrtjtyk

I have the Json shown below.

This is actually a far more complex object in reality, but this extract demonstrates my question.

I am looking at shrinking the size of the Json response being generated. This is currently being generated using the standard JsonResult in MVC,

Is there a way of getting JSonResult to not stream properties that have a value of 0? If that is possible, it would shrink my json response a lot! This in turn would make parsing faster.

 {

    "firstValue": 0.2000,

    "secondValue": 30.80,

    "thirdValue": 0.0,

    "fourthValue": 30.80,

    "fifthValue": 0.0

}

So I would only actually end up passing back the response below to the caller:

 {

    "firstValue": 0.2000,

    "secondValue": 30.80,

    "fourthValue": 30.80,

}

I have seen answers pointing me to using App_Start in my web api but I am using Kestrel which doesnt have an app start - this is being hosted by Service Fabric

protected override IEnumerable<ServiceInstanceListener> CreateServiceInstanceListeners()

{

    return new

    {

        new ServiceInstanceListener(

            serviceContext =>

                new KestrelCommunicationListener(

                    serviceContext,

                    (url, listener) =>

                    {

                        ServiceEventSource.Current.ServiceMessage(serviceContext, $"Starting Kestrel on {url}");



                        return new WebHostBuilder()

                            .UseKestrel(options => { options.Listen(IPAddress.Any, 8081); })

                            .ConfigureServices(

                                services => services

                                    .AddSingleton(serviceContext)

                                    .AddSingleton(new ConfigSettings(serviceContext))

                                    .AddSingleton(new HttpClient())

                                    .AddSingleton(new FabricClient()))

                            .UseContentRoot(Directory.GetCurrentDirectory())

                            .UseServiceFabricIntegration(listener, ServiceFabricIntegrationOptions.None)

                            .UseStartup<Startup>()

                            .UseSerilog(_log, true)

                            .UseUrls(url)

                            .Build();

                    }))

    };

}

That's super easy. Just specify a value for DefaultValueHandling with the value Ignore.

As the description in that link says:

Ignore members where the member value is the same as the member's default value when serializing objects so that it is not written to JSON. This option will ignore all default values (e.g. null for objects and nullable types; 0 for integers, decimals and floating point numbers; and false for booleans). The default value ignored can be changed by placing the DefaultValueAttribute on the property.

As Kit suggested, you could use the DefaultValueHandling behavior.

Besides, you can always custom your own ContractResolver to solve such questions. Here's a version of using custom ContractResolver to ignore default value:

public class IgnoreZeroContractResolver : DefaultContractResolver

{

    public IgnoreZeroContractResolver( ){ }



    protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)

    {

        JsonProperty property = base.CreateProperty(member, memberSerialization);



        property.ShouldSerialize = instance => {

            var shouldSerialize = true;  // indicate should we serialize this property



            var type = instance.GetType();

            var pi = type.GetProperty(property.PropertyName);  

            var pv = pi.GetValue(instance);

            var pvType = pv.GetType();



            // if current value equals the default values , ignore this property 

            if (pv.GetType().IsValueType){

                var defaultValue = Activator.CreateInstance(pvType);  

                if (pv.Equals(defaultValue)) { shouldSerialize = false; } 

            }

            return shouldSerialize;

        };



        return property;

    }



}

And now you can set your resover as the ContractResolver:

public void ConfigureServices(IServiceCollection services)

{



    // ...

    services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1)

        .AddJsonOptions(o =>{

           o.SerializerSettings.ContractResolver =new IgnoreZeroContractResolver();

        });



    // ...



}

Test Case :

var x = new {

    FirstValue =0.2000,

    SecondValue= 30.80,

    ThirdValue= 0.0,

    FourthValue= 30.80,

    FifthValue= 0.0,        // double 0

    SixValue= 0             // int 0

};

return new JsonResult(x);

and the response will be :

{"FirstValue":0.2,"SecondValue":30.8,"FourthValue":30.8}