c# - Xamarin Mono ClientWebSocket 实现不适用于安全套接字

Question

我在 Osx 上实现安全的网络套接字客户端时遇到问题。我正在使用 System.Net.WebSockets 中的 ClientWebSocket。这是一些测试代码:

    static async Task RunLoop()
    {
        ClientWebSocket ws = new ClientWebSocket();
        await ws.ConnectAsync(new Uri("wss://echo.websocket.org"), CancellationToken.None);

        do
        {
            Console.Write("Enter message:");
            var msg = Console.ReadLine();
            if (msg == "quit")
            {
                break;
            }

            var b = new ArraySegment<byte>(UTF8Encoding.UTF8.GetBytes(msg));
            await ws.SendAsync(b, WebSocketMessageType.Text, true, CancellationToken.None);

            byte[] bb = new byte[2048];
            ArraySegment<byte> buffer = new ArraySegment<byte>(bb);

            var result = await ws.ReceiveAsync(buffer, CancellationToken.None);

            switch (result.MessageType)
            {
                case WebSocketMessageType.Text:
                    Console.WriteLine(UTF8Encoding.UTF8.GetString(buffer.Array));
                    break;
                case WebSocketMessageType.Close:
                    await ws.CloseAsync(WebSocketCloseStatus.NormalClosure, "", CancellationToken.None);
                    break;
            }

        } while (true);
    }

    static void Main(string[] args)
    {
        var task = RunLoop();
        task.Wait();
    }

每次我在调用 ReceiveAsync 时收到此异常。

Cannot access a disposed object.

对象名称:“System.Net.Sockets.NetworkStream”。

    at System.Net.WebConnection.Read (System.Net.HttpWebRequest request, System.Byte[] buffer, System.Int32 offset, System.Int32 size) [0x0001f] in /private/tmp/source-mono-4.6.0-c8sr0/bockbuild-mono-4.6.0-branch-c8sr0/profiles/mono-mac-xamarin/build-root/mono-x86/mcs/class/System/System.Net/WebConnection.cs:1038 
  at System.Net.WebSockets.ClientWebSocket+<ReceiveAsync>c__AnonStorey5.<>m__0 () [0x0017c] in /private/tmp/source-mono-4.6.0-c8sr0/bockbuild-mono-4.6.0-branch-c8sr0/profiles/mono-mac-xamarin/build-root/mono-x86/mcs/class/System/System.Net.WebSockets/ClientWebSocket.cs:259 
  at System.Threading.Tasks.Task`1[TResult].InnerInvoke () [0x00012] in /private/tmp/source-mono-4.6.0-c8sr0/bockbuild-mono-4.6.0-branch-c8sr0/profiles/mono-mac-xamarin/build-root/mono-x86/mcs/class/referencesource/mscorlib/system/threading/Tasks/Future.cs:680 
  at System.Threading.Tasks.Task.Execute () [0x00016] in /private/tmp/source-mono-4.6.0-c8sr0/bockbuild-mono-4.6.0-branch-c8sr0/profiles/mono-mac-xamarin/build-root/mono-x86/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:2502 
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in /private/tmp/source-mono-4.6.0-c8sr0/bockbuild-mono-4.6.0-branch-c8sr0/profiles/mono-mac-xamarin/build-root/mono-x86/mcs/class/referencesource/mscorlib/system/runtime/exceptionservices/exceptionservicescommon.cs:143 
  at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x00047] in /private/tmp/source-mono-4.6.0-c8sr0/bockbuild-mono-4.6.0-branch-c8sr0/profiles/mono-mac-xamarin/build-root/mono-x86/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:187 
  at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x0002e] in /private/tmp/source-mono-4.6.0-c8sr0/bockbuild-mono-4.6.0-branch-c8sr0/profiles/mono-mac-xamarin/build-root/mono-x86/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:156 
  at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x0000b] in /private/tmp/source-mono-4.6.0-c8sr0/bockbuild-mono-4.6.0-branch-c8sr0/profiles/mono-mac-xamarin/build-root/mono-x86/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:128 
  at System.Runtime.CompilerServices.TaskAwaiter`1[TResult].GetResult () [0x00000] in /private/tmp/source-mono-4.6.0-c8sr0/bockbuild-mono-4.6.0-branch-c8sr0/profiles/mono-mac-xamarin/build-root/mono-x86/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:357 
      at Test.MainClass+<RunLoop>c__async2.MoveNext () [0x001c0] in Program.cs:81

看起来套接字以某种方式被处理掉了，但我不知道为什么以及在哪里。相同的代码适用于非安全的 websockets(“ws://echo.websocket.org”)。

也尝试了 WebSocket.Portable 实现，但遇到了几乎相同的问题。对于非安全的 websockets 它工作正常但对于安全的 websockets OnMessage 事件从未被调用过。 https://github.com/NVentimiglia/WebSocket.Portable

Answer 1

我找到了解决此问题的方法。我用了SocketRocker这是一个 Objective C 实现。 Square.SocketRocket 是原生 Objective C 库的 Xamarin 包装器。在 GitHub您还会在示例目录中找到一些示例。