Question

我在面向.Net 4.6.2的WPF应用程序中使用Microsoft.AspNetCore.SignalR.Client（1.1.0v）。我正在设置客户端，例如：

public class SignalRClient
{
   private readonly HubConnection hubConnection;

   public SignalRClient()
   {
      this.hubConnection = new HubConnectionBuilder()
                .WithUrl("http://localhost:8089/MyDataHub")
                .Build();
   }

   // I'm calling the following method through a callback function in Autofac container after the DI container is built (but I tried doing this directly in the ctor and I got the same issue).

   public void Initialize()
   {
      Task.Factory.StartNew(
           () => 
           {
               // This is where I get the error.
               this.hubConnection.StartAsync().Wait();
           })
   }
}

服务器端日志显示：

16:56:45.380  Info | Request starting HTTP/1.1 GET http://localhost:8089/MyDataHub?id=7qLNfG-iV1Xr3oN_r8U_nA
info: Microsoft.AspNetCore.Hosting.Internal.WebHost[1]
      Request starting HTTP/1.1 POST http://localhost:8089/MyDataHub/negotiate  0
16:56:45.540  Info | Request starting HTTP/1.1 POST http://localhost:8089/MyDataHub/negotiate  0
info: Microsoft.AspNetCore.Hosting.Internal.WebHost[2]
      Request finished in 11.2669ms 200 application/json
16:56:45.552  Info | Request finished in 11.2669ms 200 application/json
info: Microsoft.AspNetCore.Hosting.Internal.WebHost[1]
      Request starting HTTP/1.1 POST http://localhost:8089/MyDataHub/negotiate  0
16:56:45.703  Info | Request starting HTTP/1.1 POST http://localhost:8089/MyDataHub/negotiate  0
info: Microsoft.AspNetCore.Hosting.Internal.WebHost[2]
      Request finished in 7.7109ms 200 application/json
16:56:45.703  Info | Request finished in 7.7109ms 200 application/json
info: Microsoft.AspNetCore.Hosting.Internal.WebHost[1]
      Request starting HTTP/1.1 GET http://localhost:8089/MyDataHub?id=4TN4k9wZWXsZ5iPyGNKSOA
16:56:45.719  Info | Request starting HTTP/1.1 GET http://localhost:8089/MyDataHub?id=4TN4k9wZWXsZ5iPyGNKSOA
info: Microsoft.AspNetCore.Hosting.Internal.WebHost[2]
      Request finished in 6.7847ms 200 application/octet-stream
16:56:45.719  Info | Request finished in 6.7847ms 200 application/octet-stream
fail: Microsoft.AspNetCore.SignalR.HubConnectionContext[5]
      Failed connection handshake.
16:56:51.013 Error | Failed connection handshake.
info: Microsoft.AspNetCore.Hosting.Internal.WebHost[2]
      Request finished in 20012.9772ms 101
16:57:05.393  Info | Request finished in 20012.9772ms 101

错误消息客户端：

Unable to connect to the server with any of the available transports

我不太了解此错误的含义以及解决方法。看来服务器和客户端无法达成传输协议？

请注意，服务器正在使用Microsoft.AspNet.SignalR（2.4.0v）。服务器项目是一个Asp.Net Core 2.1应用程序（我在这里不能更改任何内容）。我正在尝试将AspNet Core版本用于客户端（这似乎是可能的，因为当我针对完全相同的框架版本与其他.Net Framework WPF和Console项目进行测试时，我没有收到此错误）。

此特定错误的可能原因是什么？
可能的修复程序。

编辑：

服务器中的路由映射：

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
   app.UseSignalR(routes => { routes.MapHub<MyDataHub>("/MyDataHub"); });
}

编辑2：

MyDataHub.cs类：

public class MyDataHub : Hub<IMyDataHub>
{
   public async Task SendMessage(MyData data)
   {
      await this.Clients.All.SendMessage(data);
   }

   // Some other business methods here defined in `IMyDataHub` interface that are meant to be invoked by clients.
}

Answer 1

事实证明，这个问题与ode本身无关。事实证明，解决方案中的不同项目（有很多！）正在使用不同版本的System.Threading.Tasks.Extensions软件包（有些使用4.3.0，而另一种使用4.5.1）。而且在app.config中有一个绑定重定向，例如

<dependentAssembly>
    <assemblyIdentity name="System.Threading.Tasks.Extensions" publicKeyToken="sdhke3jdj" culture="neutral" />
    <bindingRedirect oldVersion="0.0.0.0-4.1.0.0" newVersion="4.1.0.0" />
</dependentAssembly>

这没有什么意义，因为我在任何地方都没有4.1.0。因此，我首先通过将其升级到4.5.1来整合整个解决方案的System.Threading.Tasks.Extensions。然后从app.config文件中删除上述绑定重定向，它开始工作。

SignalR：无法使用任何可用的传输连接到服务器

1 个答案: