C# 与信号集线器的连接失败，协商404（未找到）

我已经研究这个问题3天了，但找不到解决方案。我用以下代码创建了一个信号集线器：

using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.SignalR;

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

很简单，启动代码是：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Messenger.Hubs;

namespace Messenger
{
    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.Configure<CookiePolicyOptions>(options =>
            {
                // This lambda determines whether user consent for non-essential cookies is needed for a given request.
                options.CheckConsentNeeded = context => true;
                options.MinimumSameSitePolicy = SameSiteMode.None;
            });


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

            services.AddSignalR();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Error");
                app.UseHsts();
            }

            app.UseHttpsRedirection();
            app.UseStaticFiles();
            app.UseCookiePolicy();
            app.UseSignalR(routes =>
            {
                routes.MapHub<ChatHub>("c:/myapp/Messenger");
            });
            app.UseMvc();
        }
    }
}

尝试连接到集线器会产生以下错误：

{System.Net.Http.HttpRequestException: 404 (Not Found)

  at System.Net.Http.HttpResponseMessage.EnsureSuccessStatusCode () [0x0002a] in <25ebe1083eaf4329b5adfdd5bbb7aa57>:0

  at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection+<NegotiateAsync>d__44.MoveNext () [0x00226] in <843c441fa9954906b53e3710152bebb9>:0

--- End of stack trace from previous location where exception was thrown
  --- at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection+<GetNegotiationResponseAsync>d__51.MoveNext () [0x00077] in <843c441fa9954906b53e3710152bebb9>:0

--- End of stack trace from previous location where exception was thrown
  ---
 at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection+<SelectAndStartTransport>d__43.MoveNext () [0x00169] in <843c441fa9954906b53e3710152bebb9>:0

--- End of stack trace from previous location where exception was thrown
  ---
  at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection+<StartAsyncCore>d__40.MoveNext () [0x00118] in <843c441fa9954906b53e3710152bebb9>:0

--- End of stack trace from previous location where exception was thrown
  --- at System.Threading.Tasks.ForceAsyncAwaiter.GetResult () [0x0000c] in <843c441fa9954906b53e3710152bebb9>:0

  at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection+<StartAsync>d__39.MoveNext () [0x0008b] in <843c441fa9954906b53e3710152bebb9>:0

--- End of stack trace from previous location where exception was thrown
  --- at Microsoft.AspNetCore.SignalR.Client.HttpConnectionFactory+<ConnectAsync>d__3.MoveNext () [0x0009d] in <d50de232736c4c8f910083ea0cb358a8>:0

--- End of stack trace from previous location where exception was thrown
  ---
 at Microsoft.AspNetCore.SignalR.Client.HttpConnectionFactory+<ConnectAsync>d__3.MoveNext () [0x00142] in <d50de232736c4c8f910083ea0cb358a8>:0

--- End of stack trace from previous location where exception was thrown
  ---
 at Microsoft.AspNetCore.SignalR.Client.HubConnection+<StartAsyncCore>d__47.MoveNext () [0x00130] in <f381011e9b214489bcb373743f31ed9d>:0

--- End of stack trace from previous location where exception was thrown
  ---
 at System.Threading.Tasks.ForceAsyncAwaiter.GetResult () [0x0000c] in <f381011e9b214489bcb373743f31ed9d>:0

  at Microsoft.AspNetCore.SignalR.Client.HubConnection+<StartAsync>d__39.MoveNext () [0x00091] in <f381011e9b214489bcb373743f31ed9d>:0

--- End of stack trace from previous location where exception was thrown
  ---
  at SignalR.Client.Hubs.SampleHub+<ConnectAsync>d__6.MoveNext () [0x00037] in C:\Users\<username>\Documents\Visual Studio 2017\Projects\signalr_client\signalr_client\Resources\layout\Client.cs:28 }

---

我不知道下一步该怎么做。

我今天遇到了这个错误，在浪费了一些时间之后，我忘了添加：

app.UseEndpoints(endpoints =>
{
    endpoints.MapHub<FooHub>("/FooHub");
});

app.UseEndpoints（端点=>
{
endpoints.MapHub（“/FooHub”）；
});

在.NET 5 ASP.NET应用程序中配置（…）到Startup.cs>>public void

---

自最初发布以来，情况发生了一些变化（我确实看到了一些Xamarin），但希望这能给将来的人提供一些指导。

我对SignalR NetCore 5也有同样的问题，Blazor webassembly项目在部署到IIS时，在开发机器上的localhost中运行良好

解决方案是在集线器连接中使用完整url： 首先在Startup.cs中包括集线器端点

 endpoints.MapHub<BroadcastHub>("/broadcastHub");

使用完整url:

     hubConnection = new HubConnectionBuilder()
            .WithUrl("http://myserver.com/bcwa/broadcastHub")
            .Build();

---

bcwa是我的IIS部署文件夹

您在服务器中有

chatHub

，但正在尝试在客户端中使用

MessengerHub

。只需一个类名，就更改了它。。。没有区别，完全相同的问题。如果您有这样声明的hub:public-class-ChatHub:hub，那么您必须确保使用camel-case引用：routes.MapHub（“/ChatHub”）；（这会奏效）。但是，这将不起作用：routes.MapHub（“/chathub”）；routes.MapHub（“/ChatHub”）；不确定您在上面更改了什么，因为您没有显示更改。显然问题在于服务器没有找到Signal，我在routes.MapHub中放置了什么并不重要，服务器正在routes.MapHub中定义的路径上查找名为

协商

的文件夹，该路径在配置中不存在。不知道这是从哪里来的，也不知道如何解决。仅供参考。。。我从中复制了集线器代码，在IIS Express中运行，显然不是IIS 8.5。

"POST /MessengerHub/negotiate HTTP/1.1" 303 446
"GET /MessengerHub/negotiate HTTP/1.1" 404 1509

app.UseEndpoints(endpoints =>
{
    endpoints.MapHub<FooHub>("/FooHub");
});

 endpoints.MapHub<BroadcastHub>("/broadcastHub");

   hubConnection = new HubConnectionBuilder()
              .WithUrl(navigationManager.ToAbsoluteUri("/broadcastHub")
                 .Build();

     hubConnection = new HubConnectionBuilder()
            .WithUrl("http://myserver.com/bcwa/broadcastHub")
            .Build();