What replaces WCF in .Net Core?

Question

I am used to creating a .Net Framework console application and exposing a Add(int x, int y) function via a WCF service from scratch with Class Library (.Net Fra

Answer 1

You can use gRPC for hosting web services inside .NET core application.

Introduction

1. gRPC is a high performance, open source RPC framework initially developed by Google.
2. The framework is based on a client-server model of remote procedure calls. A client application can directly call methods on a server application as if it was a local object.

Example

Server Code

class Program
{
    static void Main(string[] args)
    {
        RunAsync().Wait();
    }

    private static async Task RunAsync()
    {
        var server = new Grpc.Core.Server
        {
            Ports = { { "127.0.0.1", 5000, ServerCredentials.Insecure } },
            Services =
            {
                ServerServiceDefinition.CreateBuilder()
                    .AddMethod(Descriptors.Method, async (requestStream, responseStream, context) =>
                    {
                        await requestStream.ForEachAsync(async additionRequest =>
                        {
                            Console.WriteLine($"Recieved addition request, number1 = {additionRequest.X} --- number2 = {additionRequest.Y}");
                            await responseStream.WriteAsync(new AdditionResponse {Output = additionRequest.X + additionRequest.Y});
                        });
                    })
                    .Build()
            }
        };

        server.Start();

        Console.WriteLine($"Server started under [127.0.0.1:5000]. Press Enter to stop it...");
        Console.ReadLine();

        await server.ShutdownAsync();
    }
}

Client Code

class Program
{
    static void Main(string[] args)
    {
        RunAsync().Wait();
    }

    private static async Task RunAsync()
    {
        var channel = new Channel("127.0.0.1", 5000, ChannelCredentials.Insecure);
        var invoker = new DefaultCallInvoker(channel);
        using (var call = invoker.AsyncDuplexStreamingCall(Descriptors.Method, null, new CallOptions{}))
        {
            var responseCompleted = call.ResponseStream
                .ForEachAsync(async response => 
                {
                    Console.WriteLine($"Output: {response.Output}");
                });

            await call.RequestStream.WriteAsync(new AdditionRequest { X = 1, Y = 2});
            Console.ReadLine();

            await call.RequestStream.CompleteAsync();
            await responseCompleted;
        }

        Console.WriteLine("Press enter to stop...");
        Console.ReadLine();

        await channel.ShutdownAsync();
    }
}

Shared Classes between Client and Server

[Schema]
public class AdditionRequest
{
    [Id(0)]
    public int X { get; set; }
    [Id(1)]
    public int Y { get; set; }
}

[Schema]
public class AdditionResponse
{
    [Id(0)]
    public int Output { get; set; }
}

Service descriptors

using Grpc.Core;
public class Descriptors
{
    public static Method<AdditionRequest, AdditionResponse> Method =
            new Method<AdditionRequest, AdditionResponse>(
                type: MethodType.DuplexStreaming,
                serviceName: "AdditonService",
                name: "AdditionMethod",
                requestMarshaller: Marshallers.Create(
                    serializer: Serializer<AdditionRequest>.ToBytes,
                    deserializer: Serializer<AdditionRequest>.FromBytes),
                responseMarshaller: Marshallers.Create(
                    serializer: Serializer<AdditionResponse>.ToBytes,
                    deserializer: Serializer<AdditionResponse>.FromBytes));
}

Serializer/Deserializer

public static class Serializer<T>
{
    public static byte[] ToBytes(T obj)
    {
        var buffer = new OutputBuffer();
        var writer = new FastBinaryWriter<OutputBuffer>(buffer);
        Serialize.To(writer, obj);
        var output = new byte[buffer.Data.Count];
        Array.Copy(buffer.Data.Array, 0, output, 0, (int)buffer.Position);
        return output;
    }

    public static T FromBytes(byte[] bytes)
    {
        var buffer = new InputBuffer(bytes);
        var data = Deserialize<T>.From(new FastBinaryReader<InputBuffer>(buffer));
        return data;
    }
}

Output

Sample client output

Sample Server output

References

1. https://blogs.msdn.microsoft.com/dotnet/2018/12/04/announcing-net-core-3-preview-1-and-open-sourcing-windows-desktop-frameworks/
2. https://grpc.io/docs/
3. https://grpc.io/docs/quickstart/csharp.html
4. https://github.com/grpc/grpc/tree/master/src/csharp

Benchmarks

1. http://csharptest.net/787/benchmarking-wcf-compared-to-rpclibrary/index.html

Answer 2

You can also self-host ASP.NET Core Web API.

<!-- SelfHosted.csproj -->
<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp3.1</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <!-- see: https://docs.microsoft.com/en-us/aspnet/core/migration/22-to-30?view=aspnetcore-3.1&tabs=visual-studio#framework-reference -->
    <FrameworkReference Include="Microsoft.AspNetCore.App" />
    <PackageReference Include="Microsoft.Extensions.Hosting" Version="3.1.0" />
  </ItemGroup>

</Project>

// Program.cs
using System.IO;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;

namespace SelfHosted
{
    class Program
    {
        static void Main(string[] args)
        {
            CreateHostBuilder(args).Build().Run();
        }

        public static IHostBuilder CreateHostBuilder(string[] args)
        {
            // see: https://docs.microsoft.com/en-us/aspnet/core/fundamentals/host/generic-host?view=aspnetcore-3.1
            return Host.CreateDefaultBuilder(args)
                .ConfigureHostConfiguration(configHost =>
                {
                    configHost.SetBasePath(Directory.GetCurrentDirectory());
                    configHost.AddJsonFile("appsettings.json", optional: true);
                    configHost.AddEnvironmentVariables(prefix: "SelfHosted_");
                    configHost.AddCommandLine(args);
                })
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.CaptureStartupErrors(true);
                    webBuilder.UseStartup<Startup>();
                });
        }
    }
}

// Startup.cs
using System;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

namespace SelfHosted
{
    public class Startup
    {
        public Startup(IConfiguration configuration, IWebHostEnvironment env)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        public void ConfigureServices(IServiceCollection services)
        {
            // see: https://github.com/aspnet/AspNetCore.Docs/tree/master/aspnetcore/web-api/index/samples/3.x
            services.AddControllers();
        }

        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Error");
                app.UseHsts();
            }

            app.UseHttpsRedirection();
            app.UseStaticFiles();

            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
        }
    }
}

// Controllers\TestController.cs
using System.Net.Mime;
using Microsoft.AspNetCore.Mvc;

namespace SelfHosted.Controllers
{
    [ApiController]
    [Produces(MediaTypeNames.Application.Json)]
    [Route("[controller]")]
    public class HelloController : SelfHostedControllerBase
    {
        [HttpGet]
        public ActionResult<string> HelloWorld() => "Hello World!";

        [HttpGet("{name}")]
        public ActionResult<string> HelloName(string name) => $"Hello {name}!";
    }
}

Answer 3

There is a .NET Core port available: https://github.com/dotnet/wcf It's still in preview, but they are actively developing it.

Answer 4

WCF is not supported in .NET Core since it's a Windows specific technology and .NET Core is supposed to be cross-platform.

If you are implementing inter-process communication consider trying the IpcServiceFramework project.

It allows creating services in WCF style like this:

1. Create service contract

   public interface IComputingService
   {
       float AddFloat(float x, float y);
   }
   

2. Implement the service

   class ComputingService : IComputingService
   {
       public float AddFloat(float x, float y)
       {
           return x + y;
       }
   }
   

3. Host the service in Console application

   class Program
   {
       static void Main(string[] args)
       {
           // configure DI
           IServiceCollection services = ConfigureServices(new ServiceCollection());
   
           // build and run service host
           new IpcServiceHostBuilder(services.BuildServiceProvider())
               .AddNamedPipeEndpoint<IComputingService>(name: "endpoint1", pipeName: "pipeName")
               .AddTcpEndpoint<IComputingService>(name: "endpoint2", ipEndpoint: IPAddress.Loopback, port: 45684)
               .Build()
               .Run();
       }
   
       private static IServiceCollection ConfigureServices(IServiceCollection services)
       {
           return services
               .AddIpc()
               .AddNamedPipe(options =>
               {
                   options.ThreadCount = 2;
               })
               .AddService<IComputingService, ComputingService>();
       }
   }
   

4. Invoke the service from client process

   IpcServiceClient<IComputingService> client = new IpcServiceClientBuilder<IComputingService>()
       .UseNamedPipe("pipeName") // or .UseTcp(IPAddress.Loopback, 45684) to invoke using TCP
       .Build();
   
   float result = await client.InvokeAsync(x => x.AddFloat(1.23f, 4.56f));
   

Answer 5

There is a community repo https://github.com/CoreWCF/CoreWCF that implements some parts of WCF. You can use it to support some simple WCF services. However not all features are supported.

Answer 6

So from my research the best solution does not have the auto-generated proxy classes. This best solution is to create a RESTful service and to serialise the response body into model objects. Where the models are the usual model objects found in the MVC design pattern.

Thank you for your responses