asp.net-core - 如何让自托管 signalR 服务器作为 NetCore 控制台应用程序运行

Question

我想使用 .NetCore 在控制台应用程序中创建一个 SignalR 自托管服务器。

我对 Web 开发和 .Net Core 完全陌生，但想将 SignalR 用作基于 Web 的实时协议(protocol)。不需要网页，所以我想要一个控制台应用程序。

我已经成功测试了下面的 .Net Framework 示例，并想使用 .Net Core 3.1 复制它，以便它可以在 Linux 上运行。但是我找不到任何合适的例子。

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");
        }
    }
}

在尝试使用 Owin 创建服务器控制台应用程序时，我有以下代码并且可以编译，但是在我运行该程序时提示没有注册服务器服务。有人可以建议添加什么来拥有没有网页的网络服务器吗？我复制的示例指定了 UseKestrel()，但我认为这是针对网页的，所以我想我需要其他东西。

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();
        }
    }
}

谢谢。

Answer 1

对于那些想要在 .NET 6 中实现这一目标的人:

要创建一个简单的服务器作为控制台应用程序，您必须创建一个新的空 ASP.NET Core 项目。在 .NET 6 中，您不再需要“startup.cs”。您只需更改“Program.cs”中的一些内容即可配置 SignalR。

Program.cs

var builder = WebApplication.CreateBuilder(args);

//builder.Services.AddRazorPages();
builder.Services.AddSignalR();

var app = builder.Build();

if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Error");
    app.UseHsts();
}

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

app.UseRouting();

app.UseAuthorization();

//app.MapRazorPages();
app.MapHub<ChatHub>("/chatHub");

app.Run();

添加中心

public class ChatHub : Hub
{
    public async Task SendMessage(string user, string message)
    {
        Console.WriteLine("Received message, sending back echo");
        await Clients.All.SendAsync("ReceiveMessage", user, message);
    }
}

客户端(控制台应用程序)

例如:

using Microsoft.AspNetCore.SignalR.Client;

namespace Client
{
    public class Program
    {
        private static HubConnection _connection;
        public static async Task Main(string[] args)
        {            
            _connection = new HubConnectionBuilder()
                .WithUrl("https://localhost:7116/chatHub")                
                .Build();

            _connection.Closed += async (error) =>
            {
                await Task.Delay(new Random().Next(0, 5) * 1000);
                await _connection.StartAsync();
            };

            await ConnectAsync();
            
            bool stop = false;
            while (!stop)
            {
                Console.WriteLine("Press any key to send message to server and receive echo");
                Console.ReadKey();
                Send("testuser", "msg");
                Console.WriteLine("Press q to quit or anything else to resume");
                var key = Console.ReadLine();
                if (key == "q") stop = true;
            }                        
        }

        private static async Task ConnectAsync()
        {
            _connection.On<string, string>("ReceiveMessage", (user, message) =>
            {
                Console.WriteLine("Received message");
                Console.WriteLine($"user: {user}");
                Console.WriteLine($"message: {message}");
            });
            try
            {
                await _connection.StartAsync();
            }
            catch(Exception e)
            {
                Console.WriteLine("Exception: {0}", e);
            }
        }

        private static async void Send(string user, string msg)
        {
            try
            {
                await _connection.InvokeAsync("SendMessage", user, msg);
            }
            catch (Exception e)
            {
                Console.WriteLine($"Exception: {e}");
            }
        }
    }
}

客户端将连接到服务器，然后在一个循环中，您可以通过按任意键向服务器发送消息，服务器将向您发送相同的消息。

在“launchSettings.json”(服务器)中，您可以找到 applicaitonUrl