SignalR WebSocket终端报错排查：网站可通信但终端持续报错

报错信息 #

"WebSocket failed to connect. The connection could not be found on the server, either the endpoint may not be a SignalR endpoint, the connection ID is not present on the server, or there is a proxy blocking WebSockets. If you have multiple servers check that sticky sessions are enabled"

尽管网站控制台无警告、能正常连接服务器，且可通过connectionId接收其他客户端消息、在ASP.NET中正常完成授权，但运行程序时终端始终弹出上述报错。

相关代码 #

Angular 客户端代码 #

public connect(): void {
    this.hubConnection = new signalR.HubConnectionBuilder()
      .withUrl(this.webSockeUrl, {
        transport: signalR.HttpTransportType.WebSockets,
        skipNegotiation:true,
        accessTokenFactory: () => { return this.token!},
      })
      .withAutomaticReconnect()
      .build();

    this.hubConnection
      .start()
      .then(() => console.log("Connection started"))
      .catch(err => console.error("Error establishing connection: ", err));
  }

  public addReceiveMessageListener(): void {
    this.hubConnection.on("ReceiveMessage", (message: string) => {
      console.log("Receive Message from server:", message);
    });

    this.hubConnection.on("ReceivePrivateMessage", (message: string) => {
      console.log("Receive Message from another client:", message);
    });
  }

ASP.NET 服务器端代码 #

[Authorize]
public class ChatHub : Hub
{
    public async Task SendMessage(string connectionId, string message)
    {
        await Clients.Client(connectionId).SendAsync("ReceivePrivateMessage", message);   
    }

    public override async Task OnConnectedAsync()
    {
        var connectionId = Context.ConnectionId;
        await Clients.All.SendAsync("ReceiveMessage", $"{connectionId} has joined");
    }
}

已尝试的解决方案 #

• 移除skipNegotiation，但出现协商未完成问题
• 添加服务器端口44398至防火墙入站规则
• 开启Windows功能中的“WebSocket协议”
• 查阅多篇相关文章并尝试方案，但报错仍未消除

建议的排查方向 #

1. 排查自动重连的触发原因
   启用了withAutomaticReconnect()，终端的报错可能是重连过程中出现的临时失败。可以添加重连状态监听，确认报错是否来自重连阶段：

   this.hubConnection.onreconnecting(error => {
     console.error("Reconnecting failed: ", error);
   });
   this.hubConnection.onreconnected(connectionId => {
     console.log("Reconnected with connectionId: ", connectionId);
   });
   

2. 确认WebSocket传输的配置兼容性
   强制指定WebSockets传输并开启skipNegotiation，需要确保服务器端配置完全支持无协商的WebSocket连接。检查服务器Startup/Program.cs中是否正确配置了SignalR：

   app.MapHub<ChatHub>("/chathub"); // 确保路由与客户端的webSockeUrl一致
   

   同时，若服务器使用HTTPS，需确认客户端的webSockeUrl是wss://开头而非ws://。

3. 检查服务器端的连接日志
   在ASP.NET服务器端添加日志，查看连接断开的细节，确认是否有连接被意外断开后触发重连：

   public override async Task OnDisconnectedAsync(Exception? exception)
   {
       if (exception != null)
       {
           Console.WriteLine($"Connection {Context.ConnectionId} disconnected with error: {exception.Message}");
       }
       else
       {
           Console.WriteLine($"Connection {Context.ConnectionId} disconnected normally");
       }
       await base.OnDisconnectedAsync(exception);
   }
   

4. 排查代理或SSL中间件影响
   即使防火墙规则已添加，若服务器部署在反向代理（如IIS、Nginx）之后，需确保代理已正确配置WebSocket支持：

   • IIS需确保WebSocket协议已启用，且站点的WebSocket设置未被禁用
   • 若使用Nginx，需在配置中添加WebSocket的转发规则

5. 验证连接ID的有效性
   报错中提到“connection ID is not present on the server”，可以在客户端连接成功后，打印当前的connectionId，并在服务器端通过IHubContext<ChatHub>验证该ID是否存在于活跃连接列表中。

内容的提问来源于stack exchange，提问作者Long