aspnetcore/src/Microsoft.AspNetCore.Signal.../HubConnection.cs

428 lines
17 KiB
C#

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Threading;
using System.Threading.Tasks;
using System.Threading.Tasks.Channels;
using Microsoft.AspNetCore.SignalR.Client.Internal;
using Microsoft.AspNetCore.SignalR.Internal;
using Microsoft.AspNetCore.SignalR.Internal.Encoders;
using Microsoft.AspNetCore.SignalR.Internal.Protocol;
using Microsoft.AspNetCore.Sockets;
using Microsoft.AspNetCore.Sockets.Client;
using Microsoft.AspNetCore.Sockets.Features;
using Microsoft.AspNetCore.Sockets.Internal;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Logging.Abstractions;
using Newtonsoft.Json;
namespace Microsoft.AspNetCore.SignalR.Client
{
public class HubConnection
{
private readonly ILoggerFactory _loggerFactory;
private readonly ILogger _logger;
private readonly IConnection _connection;
private readonly IHubProtocol _protocol;
private readonly HubBinder _binder;
private HubProtocolReaderWriter _protocolReaderWriter;
private readonly object _pendingCallsLock = new object();
private readonly CancellationTokenSource _connectionActive = new CancellationTokenSource();
private readonly Dictionary<string, InvocationRequest> _pendingCalls = new Dictionary<string, InvocationRequest>();
private readonly ConcurrentDictionary<string, InvocationHandler> _handlers = new ConcurrentDictionary<string, InvocationHandler>();
private int _nextId = 0;
public event Func<Exception, Task> Closed
{
add { _connection.Closed += value; }
remove { _connection.Closed -= value; }
}
public HubConnection(IConnection connection, IHubProtocol protocol, ILoggerFactory loggerFactory)
{
if (connection == null)
{
throw new ArgumentNullException(nameof(connection));
}
if (protocol == null)
{
throw new ArgumentNullException(nameof(protocol));
}
_connection = connection;
_binder = new HubBinder(this);
_protocol = protocol;
_loggerFactory = loggerFactory ?? NullLoggerFactory.Instance;
_logger = _loggerFactory.CreateLogger<HubConnection>();
_connection.Received += OnDataReceivedAsync;
_connection.Closed += Shutdown;
}
public async Task StartAsync() => await StartAsyncCore().ForceAsync();
private async Task StartAsyncCore()
{
var transferModeFeature = _connection.Features.Get<ITransferModeFeature>();
if (transferModeFeature == null)
{
transferModeFeature = new TransferModeFeature();
_connection.Features.Set(transferModeFeature);
}
var requestedTransferMode =
_protocol.Type == ProtocolType.Binary
? TransferMode.Binary
: TransferMode.Text;
transferModeFeature.TransferMode = requestedTransferMode;
await _connection.StartAsync();
var actualTransferMode = transferModeFeature.TransferMode;
_protocolReaderWriter = new HubProtocolReaderWriter(_protocol, GetDataEncoder(requestedTransferMode, actualTransferMode));
_logger.HubProtocol(_protocol.Name);
using (var memoryStream = new MemoryStream())
{
NegotiationProtocol.WriteMessage(new NegotiationMessage(_protocol.Name), memoryStream);
await _connection.SendAsync(memoryStream.ToArray(), _connectionActive.Token);
}
}
private IDataEncoder GetDataEncoder(TransferMode requestedTransferMode, TransferMode actualTransferMode)
{
if (requestedTransferMode == TransferMode.Binary && actualTransferMode == TransferMode.Text)
{
// This is for instance for SSE which is a Text protocol and the user wants to use a binary
// protocol so we need to encode messages.
return new Base64Encoder();
}
Debug.Assert(requestedTransferMode == actualTransferMode, "All transports besides SSE are expected to support binary mode.");
return new PassThroughEncoder();
}
public async Task DisposeAsync() => await DisposeAsyncCore().ForceAsync();
private async Task DisposeAsyncCore()
{
await _connection.DisposeAsync();
}
// TODO: Client return values/tasks?
public void On(string methodName, Type[] parameterTypes, Func<object[], Task> handler)
{
var invocationHandler = new InvocationHandler(parameterTypes, handler);
_handlers.AddOrUpdate(methodName, invocationHandler, (_, __) => invocationHandler);
}
public async Task<ReadableChannel<object>> StreamAsync(string methodName, Type returnType, object[] args, CancellationToken cancellationToken = default(CancellationToken))
{
return await StreamAsyncCore(methodName, returnType, args, cancellationToken).ForceAsync();
}
private async Task<ReadableChannel<object>> StreamAsyncCore(string methodName, Type returnType, object[] args, CancellationToken cancellationToken)
{
var irq = InvocationRequest.Stream(cancellationToken, returnType, GetNextId(), _loggerFactory, out var channel);
await InvokeCore(methodName, irq, args, nonBlocking: false);
return channel;
}
public async Task<object> InvokeAsync(string methodName, Type returnType, object[] args, CancellationToken cancellationToken = default(CancellationToken)) =>
await InvokeAsyncCore(methodName, returnType, args, cancellationToken).ForceAsync();
private async Task<object> InvokeAsyncCore(string methodName, Type returnType, object[] args, CancellationToken cancellationToken)
{
var irq = InvocationRequest.Invoke(cancellationToken, returnType, GetNextId(), _loggerFactory, out var task);
await InvokeCore(methodName, irq, args, nonBlocking: false);
return await task;
}
public async Task SendAsync(string methodName, object[] args, CancellationToken cancellationToken = default(CancellationToken)) =>
await SendAsyncCore(methodName, args, cancellationToken).ForceAsync();
private Task SendAsyncCore(string methodName, object[] args, CancellationToken cancellationToken)
{
var irq = InvocationRequest.Invoke(cancellationToken, typeof(void), GetNextId(), _loggerFactory, out _);
return InvokeCore(methodName, irq, args, nonBlocking: true);
}
private Task InvokeCore(string methodName, InvocationRequest irq, object[] args, bool nonBlocking)
{
ThrowIfConnectionTerminated(irq.InvocationId);
if (nonBlocking)
{
_logger.PreparingNonBlockingInvocation(irq.InvocationId, methodName, args.Length);
}
else
{
_logger.PreparingBlockingInvocation(irq.InvocationId, methodName, irq.ResultType.FullName, args.Length);
}
// Create an invocation descriptor. Client invocations are always blocking
var invocationMessage = new InvocationMessage(irq.InvocationId, nonBlocking, methodName, args);
// We don't need to track invocations for fire an forget calls
if (!nonBlocking)
{
// I just want an excuse to use 'irq' as a variable name...
_logger.RegisterInvocation(invocationMessage.InvocationId);
AddInvocation(irq);
}
// Trace the full invocation
_logger.IssueInvocation(invocationMessage.InvocationId, irq.ResultType.FullName, methodName, args);
// We don't need to wait for this to complete. It will signal back to the invocation request.
return SendInvocation(invocationMessage, irq);
}
private async Task SendInvocation(InvocationMessage invocationMessage, InvocationRequest irq)
{
try
{
var payload = _protocolReaderWriter.WriteMessage(invocationMessage);
_logger.SendInvocation(invocationMessage.InvocationId);
await _connection.SendAsync(payload, irq.CancellationToken);
_logger.SendInvocationCompleted(invocationMessage.InvocationId);
}
catch (Exception ex)
{
_logger.SendInvocationFailed(invocationMessage.InvocationId, ex);
irq.Fail(ex);
TryRemoveInvocation(invocationMessage.InvocationId, out _);
}
}
private async Task OnDataReceivedAsync(byte[] data)
{
if (_protocolReaderWriter.ReadMessages(data, _binder, out var messages))
{
foreach (var message in messages)
{
InvocationRequest irq;
switch (message)
{
case InvocationMessage invocation:
_logger.ReceivedInvocation(invocation.InvocationId, invocation.Target, invocation.Arguments);
await DispatchInvocationAsync(invocation, _connectionActive.Token);
break;
case CompletionMessage completion:
if (!TryRemoveInvocation(completion.InvocationId, out irq))
{
_logger.DropCompletionMessage(completion.InvocationId);
return;
}
DispatchInvocationCompletion(completion, irq);
irq.Dispose();
break;
case StreamItemMessage streamItem:
// Complete the invocation with an error, we don't support streaming (yet)
if (!TryGetInvocation(streamItem.InvocationId, out irq))
{
_logger.DropStreamMessage(streamItem.InvocationId);
return;
}
DispatchInvocationStreamItemAsync(streamItem, irq);
break;
default:
throw new InvalidOperationException($"Unknown message type: {message.GetType().FullName}");
}
}
}
}
private Task Shutdown(Exception ex = null)
{
_logger.ShutdownConnection();
if (ex != null)
{
_logger.ShutdownWithError(ex);
}
lock (_pendingCallsLock)
{
// We cancel inside the lock to make sure everyone who was part-way through registering an invocation
// completes. This also ensures that nobody will add things to _pendingCalls after we leave this block
// because everything that adds to _pendingCalls checks _connectionActive first (inside the _pendingCallsLock)
_connectionActive.Cancel();
foreach (var outstandingCall in _pendingCalls.Values)
{
_logger.RemoveInvocation(outstandingCall.InvocationId);
if (ex != null)
{
outstandingCall.Fail(ex);
}
outstandingCall.Dispose();
}
_pendingCalls.Clear();
}
return Task.CompletedTask;
}
private Task DispatchInvocationAsync(InvocationMessage invocation, CancellationToken cancellationToken)
{
// Find the handler
if (!_handlers.TryGetValue(invocation.Target, out InvocationHandler handler))
{
_logger.MissingHandler(invocation.Target);
return Task.CompletedTask;
}
// TODO: Return values
// TODO: Dispatch to a sync context to ensure we aren't blocking this loop.
return handler.Handler(invocation.Arguments);
}
// This async void is GROSS but we need to dispatch asynchronously because we're writing to a Channel
// and there's nobody to actually wait for us to finish.
private async void DispatchInvocationStreamItemAsync(StreamItemMessage streamItem, InvocationRequest irq)
{
_logger.ReceivedStreamItem(streamItem.InvocationId);
if (irq.CancellationToken.IsCancellationRequested)
{
_logger.CancelingStreamItem(irq.InvocationId);
}
else if (!await irq.StreamItem(streamItem.Item))
{
_logger.ReceivedStreamItemAfterClose(irq.InvocationId);
}
}
private void DispatchInvocationCompletion(CompletionMessage completion, InvocationRequest irq)
{
_logger.ReceivedInvocationCompletion(completion.InvocationId);
if (irq.CancellationToken.IsCancellationRequested)
{
_logger.CancelingCompletion(irq.InvocationId);
}
else
{
if (!string.IsNullOrEmpty(completion.Error))
{
irq.Fail(new HubException(completion.Error));
}
else
{
irq.Complete(completion.Result);
}
}
}
private void ThrowIfConnectionTerminated(string invocationId)
{
if (_connectionActive.Token.IsCancellationRequested)
{
_logger.InvokeAfterTermination(invocationId);
throw new InvalidOperationException("Connection has been terminated.");
}
}
private string GetNextId() => Interlocked.Increment(ref _nextId).ToString();
private void AddInvocation(InvocationRequest irq)
{
lock (_pendingCallsLock)
{
ThrowIfConnectionTerminated(irq.InvocationId);
if (_pendingCalls.ContainsKey(irq.InvocationId))
{
_logger.InvocationAlreadyInUse(irq.InvocationId);
throw new InvalidOperationException($"Invocation ID '{irq.InvocationId}' is already in use.");
}
else
{
_pendingCalls.Add(irq.InvocationId, irq);
}
}
}
private bool TryGetInvocation(string invocationId, out InvocationRequest irq)
{
lock (_pendingCallsLock)
{
ThrowIfConnectionTerminated(invocationId);
return _pendingCalls.TryGetValue(invocationId, out irq);
}
}
private bool TryRemoveInvocation(string invocationId, out InvocationRequest irq)
{
lock (_pendingCallsLock)
{
ThrowIfConnectionTerminated(invocationId);
if (_pendingCalls.TryGetValue(invocationId, out irq))
{
_pendingCalls.Remove(invocationId);
return true;
}
else
{
return false;
}
}
}
private class HubBinder : IInvocationBinder
{
private HubConnection _connection;
public HubBinder(HubConnection connection)
{
_connection = connection;
}
public Type GetReturnType(string invocationId)
{
if (!_connection._pendingCalls.TryGetValue(invocationId, out InvocationRequest irq))
{
_connection._logger.ReceivedUnexpectedResponse(invocationId);
return null;
}
return irq.ResultType;
}
public Type[] GetParameterTypes(string methodName)
{
if (!_connection._handlers.TryGetValue(methodName, out InvocationHandler handler))
{
_connection._logger.MissingHandler(methodName);
return Type.EmptyTypes;
}
return handler.ParameterTypes;
}
}
private struct InvocationHandler
{
public Func<object[], Task> Handler { get; }
public Type[] ParameterTypes { get; }
public InvocationHandler(Type[] parameterTypes, Func<object[], Task> handler)
{
Handler = handler;
ParameterTypes = parameterTypes;
}
}
private class TransferModeFeature : ITransferModeFeature
{
public TransferMode TransferMode { get; set; }
}
}
}