aspnetcore/src/Microsoft.AspNetCore.SignalR/HubEndPoint.cs

373 lines
15 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.Generic;
using System.Linq;
using System.Reflection;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.AspNetCore.SignalR.Internal;
using Microsoft.AspNetCore.SignalR.Internal.Protocol;
using Microsoft.AspNetCore.Sockets;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Internal;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
namespace Microsoft.AspNetCore.SignalR
{
public class HubEndPoint<THub> : HubEndPoint<THub, IClientProxy> where THub : Hub<IClientProxy>
{
public HubEndPoint(HubLifetimeManager<THub> lifetimeManager,
IHubProtocolResolver protocolResolver,
IHubContext<THub> hubContext,
ILogger<HubEndPoint<THub>> logger,
IServiceScopeFactory serviceScopeFactory)
: base(lifetimeManager, protocolResolver, hubContext, logger, serviceScopeFactory)
{
}
}
public class HubEndPoint<THub, TClient> : EndPoint, IInvocationBinder where THub : Hub<TClient>
{
private readonly Dictionary<string, HubMethodDescriptor> _methods = new Dictionary<string, HubMethodDescriptor>(StringComparer.OrdinalIgnoreCase);
private readonly HubLifetimeManager<THub> _lifetimeManager;
private readonly IHubContext<THub, TClient> _hubContext;
private readonly ILogger<HubEndPoint<THub, TClient>> _logger;
private readonly IServiceScopeFactory _serviceScopeFactory;
private readonly IHubProtocolResolver _protocolResolver;
public HubEndPoint(HubLifetimeManager<THub> lifetimeManager,
IHubProtocolResolver protocolResolver,
IHubContext<THub, TClient> hubContext,
ILogger<HubEndPoint<THub, TClient>> logger,
IServiceScopeFactory serviceScopeFactory)
{
_protocolResolver = protocolResolver;
_lifetimeManager = lifetimeManager;
_hubContext = hubContext;
_logger = logger;
_serviceScopeFactory = serviceScopeFactory;
DiscoverHubMethods();
}
public override async Task OnConnectedAsync(ConnectionContext connection)
{
try
{
// Resolve the Hub Protocol for the connection and store it in metadata
// Other components, outside the Hub, may need to know what protocol is in use
// for a particular connection, so we store it here.
connection.Metadata[HubConnectionMetadataNames.HubProtocol] = _protocolResolver.GetProtocol(connection);
await _lifetimeManager.OnConnectedAsync(connection);
await RunHubAsync(connection);
}
finally
{
await _lifetimeManager.OnDisconnectedAsync(connection);
}
}
private async Task RunHubAsync(ConnectionContext connection)
{
await HubOnConnectedAsync(connection);
try
{
await DispatchMessagesAsync(connection);
}
catch (Exception ex)
{
_logger.LogError(0, ex, "Error when processing requests.");
await HubOnDisconnectedAsync(connection, ex);
throw;
}
await HubOnDisconnectedAsync(connection, null);
}
private async Task HubOnConnectedAsync(ConnectionContext connection)
{
try
{
using (var scope = _serviceScopeFactory.CreateScope())
{
var hubActivator = scope.ServiceProvider.GetRequiredService<IHubActivator<THub, TClient>>();
var hub = hubActivator.Create();
try
{
InitializeHub(hub, connection);
await hub.OnConnectedAsync();
}
finally
{
hubActivator.Release(hub);
}
}
}
catch (Exception ex)
{
_logger.LogError(0, ex, "Error when invoking OnConnectedAsync on hub.");
throw;
}
}
private async Task HubOnDisconnectedAsync(ConnectionContext connection, Exception exception)
{
try
{
using (var scope = _serviceScopeFactory.CreateScope())
{
var hubActivator = scope.ServiceProvider.GetRequiredService<IHubActivator<THub, TClient>>();
var hub = hubActivator.Create();
try
{
InitializeHub(hub, connection);
await hub.OnDisconnectedAsync(exception);
}
finally
{
hubActivator.Release(hub);
}
}
}
catch (Exception ex)
{
_logger.LogError(0, ex, "Error when invoking OnDisconnectedAsync on hub.");
throw;
}
}
private async Task DispatchMessagesAsync(ConnectionContext connection)
{
// We use these for error handling. Since we dispatch multiple hub invocations
// in parallel, we need a way to communicate failure back to the main processing loop. The
// cancellation token is used to stop reading from the channel, the tcs
// is used to get the exception so we can bubble it up the stack
var cts = new CancellationTokenSource();
var completion = new TaskCompletionSource<object>();
var protocol = connection.Metadata.Get<IHubProtocol>(HubConnectionMetadataNames.HubProtocol);
try
{
while (await connection.Transport.Input.WaitToReadAsync(cts.Token))
{
while (connection.Transport.Input.TryRead(out var incomingMessage))
{
var hubMessage = protocol.ParseMessage(incomingMessage.Payload, this);
switch (hubMessage)
{
case InvocationMessage invocationMessage:
if (_logger.IsEnabled(LogLevel.Debug))
{
_logger.LogDebug("Received hub invocation: {invocation}", invocationMessage);
}
// Don't wait on the result of execution, continue processing other
// incoming messages on this connection.
var ignore = ProcessInvocation(connection, protocol, invocationMessage, cts, completion);
break;
// Other kind of message we weren't expecting
default:
_logger.LogError("Received unsupported message of type '{messageType}'", hubMessage.GetType().FullName);
throw new NotSupportedException($"Received unsupported message: {hubMessage}");
}
}
}
}
catch (OperationCanceledException)
{
// Await the task so the exception bubbles up to the caller
await completion.Task;
}
}
private async Task ProcessInvocation(ConnectionContext connection,
IHubProtocol protocol,
InvocationMessage invocationMessage,
CancellationTokenSource dispatcherCancellation,
TaskCompletionSource<object> dispatcherCompletion)
{
try
{
// If an unexpected exception occurs then we want to kill the entire connection
// by ending the processing loop
await Execute(connection, protocol, invocationMessage);
}
catch (Exception ex)
{
// Set the exception on the task completion source
dispatcherCompletion.TrySetException(ex);
// Cancel reading operation
dispatcherCancellation.Cancel();
}
}
private async Task Execute(ConnectionContext connection, IHubProtocol protocol, InvocationMessage invocationMessage)
{
HubMethodDescriptor descriptor;
if (!_methods.TryGetValue(invocationMessage.Target, out descriptor))
{
// Send an error to the client. Then let the normal completion process occur
_logger.LogError("Unknown hub method '{method}'", invocationMessage.Target);
await SendMessageAsync(connection, protocol, CompletionMessage.WithError(invocationMessage.InvocationId, $"Unknown hub method '{invocationMessage.Target}'"));
}
else
{
var result = await Invoke(descriptor, connection, invocationMessage);
await SendMessageAsync(connection, protocol, result);
}
}
private async Task SendMessageAsync(ConnectionContext connection, IHubProtocol protocol, HubMessage hubMessage)
{
var payload = await protocol.WriteToArrayAsync(hubMessage);
var message = new Message(payload, protocol.MessageType, endOfMessage: true);
while (await connection.Transport.Output.WaitToWriteAsync())
{
if (connection.Transport.Output.TryWrite(message))
{
return;
}
}
// Output is closed. Cancel this invocation completely
_logger.LogWarning("Outbound channel was closed while trying to write hub message");
throw new OperationCanceledException("Outbound channel was closed while trying to write hub message");
}
private async Task<CompletionMessage> Invoke(HubMethodDescriptor descriptor, ConnectionContext connection, InvocationMessage invocationMessage)
{
var methodExecutor = descriptor.MethodExecutor;
using (var scope = _serviceScopeFactory.CreateScope())
{
var hubActivator = scope.ServiceProvider.GetRequiredService<IHubActivator<THub, TClient>>();
var hub = hubActivator.Create();
try
{
InitializeHub(hub, connection);
object result = null;
if (methodExecutor.IsMethodAsync)
{
if (methodExecutor.MethodReturnType == typeof(Task))
{
await (Task)methodExecutor.Execute(hub, invocationMessage.Arguments);
}
else
{
result = await methodExecutor.ExecuteAsync(hub, invocationMessage.Arguments);
}
}
else
{
result = methodExecutor.Execute(hub, invocationMessage.Arguments);
}
return CompletionMessage.WithResult(invocationMessage.InvocationId, result);
}
catch (TargetInvocationException ex)
{
_logger.LogError(0, ex, "Failed to invoke hub method");
return CompletionMessage.WithError(invocationMessage.InvocationId, ex.InnerException.Message);
}
catch (Exception ex)
{
_logger.LogError(0, ex, "Failed to invoke hub method");
return CompletionMessage.WithError(invocationMessage.InvocationId, ex.Message);
}
finally
{
hubActivator.Release(hub);
}
}
}
private void InitializeHub(THub hub, ConnectionContext connection)
{
hub.Clients = _hubContext.Clients;
hub.Context = new HubCallerContext(connection);
hub.Groups = new GroupManager<THub>(connection, _lifetimeManager);
}
private void DiscoverHubMethods()
{
var hubType = typeof(THub);
foreach (var methodInfo in hubType.GetMethods().Where(m => IsHubMethod(m)))
{
var methodName = methodInfo.Name;
if (_methods.ContainsKey(methodName))
{
throw new NotSupportedException($"Duplicate definitions of '{methodName}'. Overloading is not supported.");
}
var executor = ObjectMethodExecutor.Create(methodInfo, hubType.GetTypeInfo());
_methods[methodName] = new HubMethodDescriptor(executor);
if (_logger.IsEnabled(LogLevel.Debug))
{
_logger.LogDebug("Hub method '{methodName}' is bound", methodName);
}
}
}
private static bool IsHubMethod(MethodInfo methodInfo)
{
// TODO: Add more checks
if (!methodInfo.IsPublic || methodInfo.IsSpecialName)
{
return false;
}
var baseDefinition = methodInfo.GetBaseDefinition().DeclaringType;
var baseType = baseDefinition.GetTypeInfo().IsGenericType ? baseDefinition.GetGenericTypeDefinition() : baseDefinition;
if (typeof(Hub<>) == baseType)
{
return false;
}
return true;
}
Type IInvocationBinder.GetReturnType(string invocationId)
{
return typeof(object);
}
Type[] IInvocationBinder.GetParameterTypes(string methodName)
{
HubMethodDescriptor descriptor;
if (!_methods.TryGetValue(methodName, out descriptor))
{
return Type.EmptyTypes;
}
return descriptor.ParameterTypes;
}
// REVIEW: We can decide to move this out of here if we want pluggable hub discovery
private class HubMethodDescriptor
{
public HubMethodDescriptor(ObjectMethodExecutor methodExecutor)
{
MethodExecutor = methodExecutor;
ParameterTypes = methodExecutor.MethodParameters.Select(p => p.ParameterType).ToArray();
}
public ObjectMethodExecutor MethodExecutor { get; }
public Type[] ParameterTypes { get; }
}
}
}