Question

我正在使用https://blogs.msdn.microsoft.com/webdev/2017/09/14/announcing-signalr-for-asp-net-core-2-0/中的这个示例创建一个控制台应用程序，可以将消息从简单的控制台应用程序发送到网页。

下面是控制台应用程序的简单示例，它读取用户输入并在屏幕上打印输入，我也想将相同的用户输入发送到网页。

static void Main(string[] args)
        {
            while (true)
            {
                Console.WriteLine("Enter input:");
                string line = Console.ReadLine();
                if (line == "exit")
                {
                    break;
                }
                sendSignalToClient(line);
                Console.Write("Message Sent To Client: " + line);
            }
        }

        private static void sendSignalToClient(string line)
        {
            //Send a message from this app to web client using signalR
        }

我刚开始学习这个。任何与此相关的材料或建议都表示赞赏。 -Thanks

编辑：我正在使用示例signalR聊天应用程序。

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

        public static IWebHost BuildWebHost(string[] args) =>
            WebHost.CreateDefaultBuilder(args)
                .UseStartup<Startup>()
                .Build();
    }

public class ChatHub : Hub
    {
        public void Send(string name, string message)
        {
            // Call the broadcastMessage method to update clients.
            Clients.All.InvokeAsync("broadcastMessage", name, message);
        }
    }

public class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddSignalR();
        }

        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            app.UseFileServer();

            app.UseSignalR(routes =>
            {
                routes.MapHub<ChatHub>("chat");
            });
        }

以下是向网页发送消息的控制台应用程序的代码

class Program : Hub
{
    static void Main(string[] args)
    {
        Task.Run(Run).Wait();
    }

    static async Task Run()
    {
        var connection = new HubConnectionBuilder()
            .WithUrl("http://localhost:59768/chat")
            .WithConsoleLogger()
            .WithMessagePackProtocol()
            .WithTransport(TransportType.WebSockets)
            .Build();

        await connection.StartAsync();

        Console.WriteLine("Starting connection. Press Ctrl-C to close.");
        var cts = new CancellationTokenSource();
        Console.CancelKeyPress += (sender, a) =>
        {
            a.Cancel = true;
            cts.Cancel();
        };

        connection.Closed += e =>
        {
            Console.WriteLine("Connection closed with error: {0}", e);

            cts.Cancel();
            return Task.CompletedTask;
        };

        connection.On("broadcastMessage", async () =>
        {


        });

        while (true)
        {
            Thread.Sleep(2000);

            await connection.SendAsync("send", "alex", "hello");

        }
    }

所有代码都在运行，但在控制台应用程序上我收到了这个例外：

 Microsoft.AspNetCore.Sockets.Client.HttpConnection[19]
      09/17/2017 13:47:17: Connection Id 40da6d4b-9c47-4831-802f-628bbb172e10: An exception was thrown from the 'Received' event handler.
System.FormatException: Target method expects 0 arguments(s) but invocation has 2 argument(s).
   at Microsoft.AspNetCore.SignalR.Internal.Protocol.MessagePackHubProtocol.CreateInvocationMessage(Unpacker unpacker, IInvocationBinder binder)
   at Microsoft.AspNetCore.SignalR.Internal.Protocol.MessagePackHubProtocol.TryParseMessages(ReadOnlyBuffer`1 input, IInvocationBinder binder, IList`1& messages)
   at Microsoft.AspNetCore.SignalR.Internal.HubProtocolReaderWriter.ReadMessages(Byte[] input, IInvocationBinder binder, IList`1& messages)
   at Microsoft.AspNetCore.SignalR.Client.HubConnection.<OnDataReceivedAsync>d__31.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Sockets.Client.HttpConnection.<>c__DisplayClass49_0.<<ReceiveAsync>b__0>d.MoveNext()

Answer 1

您的事件处理程序应采用字符串参数，它应如下所示：

connection.On<string>("broadcastMessage", data =>
{

});

Answer 2

看看这个教程，因为虽然它有点旧，但它会给你很好的建议：

https://docs.microsoft.com/en-us/aspnet/signalr/overview/getting-started/tutorial-getting-started-with-signalr

一方面，您的网页需要连接到SignalR Hub，另一方面您的控制台应该连接到服务，可能在您的Web项目中，将消息发送到集线器，然后从那里发送到所有注册的客户端。关键是集线器在客户端执行JavaScript功能，但由于注册，它必须知道客户端，并且必须调用中心实例才能执行方法。让我感觉到的是将集线器注入API控制器，并使用httpclient将输入发布到控制器。

另一个很好的教程，但这个是最近的：

https://spontifixus.github.io/ASPNET-Core-SignalR-with-Aurelia-and-Webpack/

我希望它有所帮助。

涓

修改

我刚刚在这里找到了同一个问题的答案（2017年5月）：

SignalR Console app example

在服务器端：

[HubName("MyHub")] public class MyHub : Hub { public void Send(string name, string message) { Clients.All.addMessage(name, message); } }

在客户端：

var myHub = connection.CreateHubProxy("MyHub"); ... // To write received messages: myHub.On<string, string>("addMessage", (s1, s2) => { Console.WriteLine(s1 + ": " + s2); }); ... // To send messages: myHub.Invoke<string>("Send", name, message).ContinueWith(task1 => { if (task1.IsFaulted) { Console.WriteLine("There was an error calling send: {0}", task1.Exception.GetBaseException()); } else { Console.WriteLine(task1.Result); } });

这也许对你来说也是亚历山大。

我希望它有所帮助。

涓

使用新的signalR for DotNet核心将消息从控制台App发送到网页

2 个答案: