Made some fixes to the disconnect sequence

- Fixed ChannelConnection to use IChannel<T> for
both sides of the connection. This allows use to close both the
input and the output when we are tearing down.
- Use TryComplete instead of complete to avoid exceptions thrown on
Complete(), particularly ChannelClosedException.

src/Microsoft.AspNetCore.Sockets/HttpConnectionDispatcher.cs

@@ -93,7 +93,6 @@ namespace Microsoft.AspNetCore.Sockets
                 state.Active = true;
 
                 var longPolling = new LongPollingTransport(application.Input, _loggerFactory);
-                RegisterLongPollingDisconnect(context, longPolling);
 
                 // Start the transport
                 var transportTask = longPolling.ProcessRequestAsync(context);
@@ -110,6 +109,9 @@ namespace Microsoft.AspNetCore.Sockets
                     // REVIEW: This is super gross, this all needs to be cleaned up...
                     state.Close = async () =>
                     {
+                        // Close the end point's connection
+                        state.Connection.Dispose();
+
                         try
                         {
                             await endpointTask;
@@ -118,8 +120,6 @@ namespace Microsoft.AspNetCore.Sockets
                         {
                             // possibly invoked on a ThreadPool thread
                         }
-
-                        state.Connection.Dispose();
                     };
 
                     endpointTask = endpoint.OnConnectedAsync(state.Connection);
@@ -139,6 +139,7 @@ namespace Microsoft.AspNetCore.Sockets
                     {
                         state.TerminateTransport(endpointTask.Exception.InnerException);
                     }
+
                     state.Connection.Dispose();
 
                     await transportTask;
@@ -180,9 +181,6 @@ namespace Microsoft.AspNetCore.Sockets
                                                          HttpContext context,
                                                          ConnectionState state)
         {
-            // Register this transport for disconnect
-            RegisterDisconnect(context, state);
-
             // Start the transport
             var transportTask = transport.ProcessRequestAsync(context);
 
@@ -199,18 +197,6 @@ namespace Microsoft.AspNetCore.Sockets
             await Task.WhenAll(endpointTask, transportTask);
         }
 
-        private static void RegisterLongPollingDisconnect(HttpContext context, LongPollingTransport transport)
-        {
-            // For long polling, we need to end the transport but not the overall connection so we write 0 bytes
-            context.RequestAborted.Register(state => ((LongPollingTransport)state).Cancel(), transport);
-        }
-
-        private static void RegisterDisconnect(HttpContext context, ConnectionState connectionState)
-        {
-            // We just kill the output writing as a signal to the transport that it is done
-            context.RequestAborted.Register(state => ((ConnectionState)state).Dispose(), connectionState);
-        }
-
         private Task ProcessGetId(HttpContext context, ConnectionMode mode)
         {
             // Establish the connection

src/Microsoft.AspNetCore.Sockets/Internal/ChannelConnection.cs

@@ -11,10 +11,14 @@ namespace Microsoft.AspNetCore.Sockets.Internal
 {
     public class ChannelConnection<T> : IChannelConnection<T>
     {
-        public IReadableChannel<T> Input { get; }
-        public IWritableChannel<T> Output { get; }
+        public IChannel<T> Input { get; }
+        public IChannel<T> Output { get; }
 
-        public ChannelConnection(IReadableChannel<T> input, IWritableChannel<T> output)
+        IReadableChannel<T> IChannelConnection<T>.Input => Input;
+
+        IWritableChannel<T> IChannelConnection<T>.Output => Output;
+
+        public ChannelConnection(IChannel<T> input, IChannel<T> output)
         {
             Input = input;
             Output = output;
@@ -22,9 +26,8 @@ namespace Microsoft.AspNetCore.Sockets.Internal
 
         public void Dispose()
         {
-            Output.Complete();
-            (Input as IDisposable)?.Dispose();
-            (Output as IDisposable)?.Dispose();
+            Output.TryComplete();
+            Input.TryComplete();
         }
     }
 }

src/Microsoft.AspNetCore.Sockets/Transports/LongPollingTransport.cs

@@ -14,7 +14,6 @@ namespace Microsoft.AspNetCore.Sockets.Transports
     public class LongPollingTransport : IHttpTransport
     {
         private readonly IReadableChannel<Message> _connection;
-        private CancellationTokenSource _cancellationSource = new CancellationTokenSource();
         private readonly ILogger _logger;
 
         public LongPollingTransport(IReadableChannel<Message> connection, ILoggerFactory loggerFactory)
@@ -35,7 +34,10 @@ namespace Microsoft.AspNetCore.Sockets.Transports
 
             try
             {
-                using (var message = await _connection.ReadAsync(_cancellationSource.Token))
+                // TODO: We need the ability to yield the connection without completing the channel.
+                // This is to force ReadAsync to yield without data to end to poll but not the entire connection.
+                // This is for cases when the client reconnects see issue #27
+                using (var message = await _connection.ReadAsync(context.RequestAborted))
                 {
                     _logger.LogDebug("Writing {0} byte message to response", message.Payload.Buffer.Length);
                     context.Response.ContentLength = message.Payload.Buffer.Length;
@@ -58,10 +60,5 @@ namespace Microsoft.AspNetCore.Sockets.Transports
                 throw;
             }
         }
-
-        public void Cancel()
-        {
-            _cancellationSource.Cancel();
-        }
     }
 }

src/Microsoft.AspNetCore.Sockets/Transports/ServerSentEventsTransport.cs

@@ -32,7 +32,7 @@ namespace Microsoft.AspNetCore.Sockets.Transports
             {
                 while (true)
                 {
-                    using (var message = await _application.ReadAsync())
+                    using (var message = await _application.ReadAsync(context.RequestAborted))
                     {
                         await Send(context, message);
                     }
@@ -42,6 +42,10 @@ namespace Microsoft.AspNetCore.Sockets.Transports
             {
                 // Gross that we have to catch this this way. See https://github.com/dotnet/corefxlab/issues/1068
             }
+            catch (OperationCanceledException)
+            {
+                // Closed connection
+            }
         }
 
         private async Task Send(HttpContext context, Message message)

src/Microsoft.AspNetCore.Sockets/Transports/WebSocketsTransport.cs

@@ -152,7 +152,7 @@ namespace Microsoft.AspNetCore.Sockets.Transports
 
         private async Task StartSending(IWebSocketConnection ws)
         {
-            while (!_connection.Input.Completion.IsCompleted)
+            while (true)
             {
                 // Get a frame from the application
                 try
@@ -188,6 +188,7 @@ namespace Microsoft.AspNetCore.Sockets.Transports
                 catch (Exception ex) when (ex.GetType().IsNested && ex.GetType().DeclaringType == typeof(Channel))
                 {
                     // Gross that we have to catch this this way. See https://github.com/dotnet/corefxlab/issues/1068
+                    break;
                 }
             }
         }