Added TCP client sample to HubSample (#1805)

- Ripped of Kestrel's SocketConnection to make a TcpConnection
IConnection implementation.
- Fixed issue with SignalR assuming there will always be a non-null user
on the ConnectionContext.

samples/ClientSample/ClientSample.csproj

@@ -7,6 +7,10 @@
     <OutputType>Exe</OutputType>
   </PropertyGroup>
 
+  <ItemGroup>
+    <Compile Include="..\..\src\Common\DuplexPipe.cs" Link="DuplexPipe.cs" />
+  </ItemGroup>
+
   <ItemGroup>
     <ProjectReference Include="..\..\src\Microsoft.AspNetCore.SignalR.Client\Microsoft.AspNetCore.SignalR.Client.csproj" />
   </ItemGroup>

samples/ClientSample/HubSample.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Linq;
+using System.Net;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.SignalR.Client;
@@ -27,12 +28,11 @@ internal static void Register(CommandLineApplication app)
 
         public static async Task<int> ExecuteAsync(string baseUrl)
         {
-            baseUrl = string.IsNullOrEmpty(baseUrl) ? "http://localhost:5000/default" : baseUrl;
-
-            Console.WriteLine("Connecting to {0}", baseUrl);
+            var endpoint = new IPEndPoint(IPAddress.Loopback, 9001);
+            Console.WriteLine("Connecting to {0}", endpoint);
             var connection = new HubConnectionBuilder()
-                .WithUrl(baseUrl)
-                .WithConsoleLogger(LogLevel.Trace)
+                .WithEndPoint(endpoint)
+                .WithConsoleLogger(LogLevel.Information)
                 .Build();
 
             try
@@ -44,7 +44,7 @@ public static async Task<int> ExecuteAsync(string baseUrl)
 
                 await ConnectAsync(connection);
 
-                Console.WriteLine("Connected to {0}", baseUrl);
+                Console.WriteLine("Connected to {0}", endpoint);
 
                 var sendCts = new CancellationTokenSource();
 

samples/ClientSample/Tcp/BufferExtensions.cs

@@ -0,0 +1,24 @@
+using System;
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+using System.Text;
+
+namespace System
+{
+    public static class BufferExtensions
+    {
+        public static ArraySegment<byte> GetArray(this Memory<byte> memory)
+        {
+            return ((ReadOnlyMemory<byte>)memory).GetArray();
+        }
+
+        public static ArraySegment<byte> GetArray(this ReadOnlyMemory<byte> memory)
+        {
+            if (!MemoryMarshal.TryGetArray(memory, out var result))
+            {
+                throw new InvalidOperationException("Buffer backed by array was expected");
+            }
+            return result;
+        }
+    }
+}

samples/ClientSample/Tcp/SocketAwaitable.cs

@@ -0,0 +1,71 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.IO.Pipelines;
+using System.Net.Sockets;
+using System.Runtime.CompilerServices;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace ClientSample
+{
+    public class SocketAwaitable : ICriticalNotifyCompletion
+    {
+        private static readonly Action _callbackCompleted = () => { };
+
+        private readonly PipeScheduler _ioScheduler;
+
+        private Action _callback;
+        private int _bytesTransferred;
+        private SocketError _error;
+
+        public SocketAwaitable(PipeScheduler ioScheduler)
+        {
+            _ioScheduler = ioScheduler;
+        }
+
+        public SocketAwaitable GetAwaiter() => this;
+        public bool IsCompleted => ReferenceEquals(_callback, _callbackCompleted);
+
+        public int GetResult()
+        {
+            Debug.Assert(ReferenceEquals(_callback, _callbackCompleted));
+
+            _callback = null;
+
+            if (_error != SocketError.Success)
+            {
+                throw new SocketException((int)_error);
+            }
+
+            return _bytesTransferred;
+        }
+
+        public void OnCompleted(Action continuation)
+        {
+            if (ReferenceEquals(_callback, _callbackCompleted) ||
+                ReferenceEquals(Interlocked.CompareExchange(ref _callback, continuation, null), _callbackCompleted))
+            {
+                Task.Run(continuation);
+            }
+        }
+
+        public void UnsafeOnCompleted(Action continuation)
+        {
+            OnCompleted(continuation);
+        }
+
+        public void Complete(int bytesTransferred, SocketError socketError)
+        {
+            _error = socketError;
+            _bytesTransferred = bytesTransferred;
+            var continuation = Interlocked.Exchange(ref _callback, _callbackCompleted);
+
+            if (continuation != null)
+            {
+                _ioScheduler.Schedule(state => ((Action)state)(), continuation);
+            }
+        }
+    }
+}

samples/ClientSample/Tcp/SocketReceiver.cs

@@ -0,0 +1,40 @@
+using System;
+using System.Collections.Generic;
+using System.IO.Pipelines;
+using System.Net.Sockets;
+using System.Text;
+
+namespace ClientSample
+{
+    public class SocketReceiver
+    {
+        private readonly Socket _socket;
+        private readonly SocketAsyncEventArgs _eventArgs = new SocketAsyncEventArgs();
+        private readonly SocketAwaitable _awaitable;
+
+        public SocketReceiver(Socket socket, PipeScheduler scheduler)
+        {
+            _socket = socket;
+            _awaitable = new SocketAwaitable(scheduler);
+            _eventArgs.UserToken = _awaitable;
+            _eventArgs.Completed += (_, e) => ((SocketAwaitable)e.UserToken).Complete(e.BytesTransferred, e.SocketError);
+        }
+
+        public SocketAwaitable ReceiveAsync(Memory<byte> buffer)
+        {
+#if NETCOREAPP2_1
+            _eventArgs.SetBuffer(buffer);
+#else
+            var segment = buffer.GetArray();
+
+            _eventArgs.SetBuffer(segment.Array, segment.Offset, segment.Count);
+#endif
+            if (!_socket.ReceiveAsync(_eventArgs))
+            {
+                _awaitable.Complete(_eventArgs.BytesTransferred, _eventArgs.SocketError);
+            }
+
+            return _awaitable;
+        }
+    }
+}

samples/ClientSample/Tcp/SocketSender.cs

@@ -0,0 +1,100 @@
+using System;
+using System.Buffers;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.IO.Pipelines;
+using System.Net.Sockets;
+using System.Runtime.InteropServices;
+using System.Text;
+
+namespace ClientSample
+{
+    public class SocketSender
+    {
+        private readonly Socket _socket;
+        private readonly SocketAsyncEventArgs _eventArgs = new SocketAsyncEventArgs();
+        private readonly SocketAwaitable _awaitable;
+
+        private List<ArraySegment<byte>> _bufferList;
+
+        public SocketSender(Socket socket, PipeScheduler scheduler)
+        {
+            _socket = socket;
+            _awaitable = new SocketAwaitable(scheduler);
+            _eventArgs.UserToken = _awaitable;
+            _eventArgs.Completed += (_, e) => ((SocketAwaitable)e.UserToken).Complete(e.BytesTransferred, e.SocketError);
+        }
+
+        public SocketAwaitable SendAsync(ReadOnlySequence<byte> buffers)
+        {
+            if (buffers.IsSingleSegment)
+            {
+                return SendAsync(buffers.First);
+            }
+
+#if NETCOREAPP2_1
+            if (!_eventArgs.MemoryBuffer.Equals(Memory<byte>.Empty))
+#else
+            if (_eventArgs.Buffer != null)
+#endif
+            {
+                _eventArgs.SetBuffer(null, 0, 0);
+            }
+
+            _eventArgs.BufferList = GetBufferList(buffers);
+
+            if (!_socket.SendAsync(_eventArgs))
+            {
+                _awaitable.Complete(_eventArgs.BytesTransferred, _eventArgs.SocketError);
+            }
+
+            return _awaitable;
+        }
+
+        private SocketAwaitable SendAsync(ReadOnlyMemory<byte> memory)
+        {
+            // The BufferList getter is much less expensive then the setter.
+            if (_eventArgs.BufferList != null)
+            {
+                _eventArgs.BufferList = null;
+            }
+
+#if NETCOREAPP2_1
+            _eventArgs.SetBuffer(MemoryMarshal.AsMemory(memory));
+#else
+            var segment = memory.GetArray();
+
+            _eventArgs.SetBuffer(segment.Array, segment.Offset, segment.Count);
+#endif
+            if (!_socket.SendAsync(_eventArgs))
+            {
+                _awaitable.Complete(_eventArgs.BytesTransferred, _eventArgs.SocketError);
+            }
+
+            return _awaitable;
+        }
+
+        private List<ArraySegment<byte>> GetBufferList(ReadOnlySequence<byte> buffer)
+        {
+            Debug.Assert(!buffer.IsEmpty);
+            Debug.Assert(!buffer.IsSingleSegment);
+
+            if (_bufferList == null)
+            {
+                _bufferList = new List<ArraySegment<byte>>();
+            }
+            else
+            {
+                // Buffers are pooled, so it's OK to root them until the next multi-buffer write.
+                _bufferList.Clear();
+            }
+
+            foreach (var b in buffer)
+            {
+                _bufferList.Add(b.GetArray());
+            }
+
+            return _bufferList;
+        }
+    }
+}