How to have a Self Hosting signalR server running as as NetCore Console App

Question

I would like to create a SignalR Self hosting Server within a console app using .NetCore.

I am completely new to web development and .Net Core but would like to use SignalR as a real-time web based protocol. No web page is required, and so I would like to have a console app.

I have successfully tested the .Net Framework example below and would like to replicate this using .Net Core 3.1, so that it can run on Linux. However I cannot find any suitable examples.

using System;
using Microsoft.AspNet.SignalR;
using Microsoft.Owin.Hosting;
using Owin;
using Microsoft.Owin.Cors;

namespace SignalRSelfHost
{
    class Program
    {
        static void Main(string[] args)
        {
            // This will *ONLY* bind to localhost, if you want to bind to all addresses
            // use http://*:8080 to bind to all addresses. 
            // See http://msdn.microsoft.com/library/system.net.httplistener.aspx 
            // for more information.
            string url = "http://localhost:8088";
            using (WebApp.Start<Startup>(url))
            {
                Console.WriteLine("Server running on {0}", url);
                Console.ReadLine();
            }
        }
    }
    class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            app.UseCors(CorsOptions.AllowAll);
            app.MapSignalR();
        }
    }
    public class MyHub : Hub
    {
        public void Send(string name, string message)
        {
            Clients.All.addMessage(name, message);
            Clients.All.addMessage(name, "World");
        }
    }
}

In an attempt to use Owin to create a server console app I have the following code and this compiles, however complains about no server service being registered when I run the program. Could someone please advise what to add to have a web server without web page? The example I copied specified UseKestrel() but I think this is for a web page, so I think I need something else.

using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Text;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.Extensions.DependencyInjection;

namespace OwinConsole
{
    public class Startup
    {
        // For more information on how to configure your application, visit http://go.microsoft.com/fwlink/?LinkID=398940
        public void ConfigureServices(IServiceCollection services)
        {
        }

        public void Configure(IApplicationBuilder app)
        {
            app.UseOwin(pipeline =>
            {
                pipeline(next => OwinHello);
            });
        }

        public Task OwinHello(IDictionary<string, object> environment)
        {
            string responseText = "Hello World via OWIN";
            byte[] responseBytes = Encoding.UTF8.GetBytes(responseText);

            // OWIN Environment Keys: http://owin.org/spec/spec/owin-1.0.0.html
            var responseStream = (Stream)environment["owin.ResponseBody"];
            var responseHeaders = (IDictionary<string, string[]>)environment["owin.ResponseHeaders"];

            responseHeaders["Content-Length"] = new string[] { responseBytes.Length.ToString(CultureInfo.InvariantCulture) };
            responseHeaders["Content-Type"] = new string[] { "text/plain" };

            return responseStream.WriteAsync(responseBytes, 0, responseBytes.Length);
        }
    }
}
using System.IO;
using Microsoft.AspNetCore.Hosting;

namespace OwinConsole
{
    public class Program
    {
        public static void Main(string[] args)
        {
            var host = new WebHostBuilder()
                .UseContentRoot(Directory.GetCurrentDirectory())
                .UseStartup<Startup>()
                .Build();

            host.Run();
        }
    }
}

Thanks.

Answer 1

As mentioned by Noah, my solution was based on

[https://learn.microsoft.com/en-us/aspnet/core/tutorials/signalr?view=aspnetcore-5.0&tabs=visual-studio]

But instead was built as a console app referencing Microsoft.AspNetCore.App (2.2.8).

ChatHub

using Microsoft.AspNetCore.SignalR;
using System.Threading.Tasks;

namespace SignalRServer
{
    public class ChatHub : Hub
    {
        public async Task SendMessage(string user, string message)
        {
            await Clients.All.SendAsync("ReceiveMessage", user, message);
        }
    }
}

Startup

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

namespace SignalRServer
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            //services.AddRazorPages();
            services.AddSignalR();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Error");
                // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
                app.UseHsts();
            }

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

            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                //endpoints.MapRazorPages();
                endpoints.MapHub<ChatHub>("/chatHub");
            });
        }
    }
}

Program

using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Hosting;

namespace SignalRServer
{

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

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>();
                    webBuilder.UseUrls("http://localhost:2803");
                });
    }
}