private async Task Invoke(HubMethodDescriptor descriptor, HubConnectionContext connection,
HubMethodInvocationMessage hubMethodInvocationMessage, bool isStreamResponse, bool isStreamCall)
{
var methodExecutor = descriptor.MethodExecutor;
var disposeScope = true;
var scope = _serviceScopeFactory.CreateScope();
IHubActivator <THub> hubActivator = null;
THub hub = null;
try
{
if (!await IsHubMethodAuthorized(scope.ServiceProvider, connection, descriptor.Policies, descriptor.MethodExecutor.MethodInfo.Name, hubMethodInvocationMessage.Arguments))
{
Log.HubMethodNotAuthorized(_logger, hubMethodInvocationMessage.Target);
await SendInvocationError(hubMethodInvocationMessage.InvocationId, connection,
$"Failed to invoke '{hubMethodInvocationMessage.Target}' because user is unauthorized");
return;
}
if (!await ValidateInvocationMode(descriptor, isStreamResponse, hubMethodInvocationMessage, connection))
{
return;
}
hubActivator = scope.ServiceProvider.GetRequiredService <IHubActivator <THub> >();
hub = hubActivator.Create();
try
{
var clientStreamLength = hubMethodInvocationMessage.StreamIds?.Length ?? 0;
var serverStreamLength = descriptor.StreamingParameters?.Count ?? 0;
if (clientStreamLength != serverStreamLength)
{
var ex = new HubException($"Client sent {clientStreamLength} stream(s), Hub method expects {serverStreamLength}.");
Log.InvalidHubParameters(_logger, hubMethodInvocationMessage.Target, ex);
await SendInvocationError(hubMethodInvocationMessage.InvocationId, connection,
ErrorMessageHelper.BuildErrorMessage($"An unexpected error occurred invoking '{hubMethodInvocationMessage.Target}' on the server.", ex, _enableDetailedErrors));
return;
}
InitializeHub(hub, connection);
Task invocation = null;
CancellationTokenSource cts = null;
var arguments = hubMethodInvocationMessage.Arguments;
if (descriptor.HasSyntheticArguments)
{
// In order to add the synthetic arguments we need a new array because the invocation array is too small (it doesn't know about synthetic arguments)
arguments = new object[descriptor.OriginalParameterTypes.Count];
var streamPointer = 0;
var hubInvocationArgumentPointer = 0;
for (var parameterPointer = 0; parameterPointer < arguments.Length; parameterPointer++)
{
if (hubMethodInvocationMessage.Arguments.Length > hubInvocationArgumentPointer &&
(hubMethodInvocationMessage.Arguments[hubInvocationArgumentPointer] == null ||
descriptor.OriginalParameterTypes[parameterPointer].IsAssignableFrom(hubMethodInvocationMessage.Arguments[hubInvocationArgumentPointer].GetType())))
{
// The types match so it isn't a synthetic argument, just copy it into the arguments array
arguments[parameterPointer] = hubMethodInvocationMessage.Arguments[hubInvocationArgumentPointer];
hubInvocationArgumentPointer++;
}
else
{
if (descriptor.OriginalParameterTypes[parameterPointer] == typeof(CancellationToken))
{
cts = CancellationTokenSource.CreateLinkedTokenSource(connection.ConnectionAborted, default);
arguments[parameterPointer] = cts.Token;
}
else if (isStreamCall && ReflectionHelper.IsStreamingType(descriptor.OriginalParameterTypes[parameterPointer], mustBeDirectType: true))
{
Log.StartingParameterStream(_logger, hubMethodInvocationMessage.StreamIds[streamPointer]);
var itemType = descriptor.StreamingParameters[streamPointer];
arguments[parameterPointer] = connection.StreamTracker.AddStream(hubMethodInvocationMessage.StreamIds[streamPointer],
itemType, descriptor.OriginalParameterTypes[parameterPointer]);
streamPointer++;
}
else
{
// This should never happen
Debug.Assert(false, $"Failed to bind argument of type '{descriptor.OriginalParameterTypes[parameterPointer].Name}' for hub method '{methodExecutor.MethodInfo.Name}'.");
}
}
}
}
if (isStreamResponse)
{
var result = await ExecuteHubMethod(methodExecutor, hub, arguments);
if (result == null)
{
Log.InvalidReturnValueFromStreamingMethod(_logger, methodExecutor.MethodInfo.Name);
await SendInvocationError(hubMethodInvocationMessage.InvocationId, connection,
$"The value returned by the streaming method '{methodExecutor.MethodInfo.Name}' is not a ChannelReader<> or IAsyncEnumerable<>.");
return;
}
cts = cts ?? CancellationTokenSource.CreateLinkedTokenSource(connection.ConnectionAborted, default);
connection.ActiveRequestCancellationSources.TryAdd(hubMethodInvocationMessage.InvocationId, cts);
var enumerable = descriptor.FromReturnedStream(result, cts.Token);
Log.StreamingResult(_logger, hubMethodInvocationMessage.InvocationId, methodExecutor);
_ = StreamResultsAsync(hubMethodInvocationMessage.InvocationId, connection, enumerable, scope, hubActivator, hub, cts, hubMethodInvocationMessage);
}
else
{
// Invoke or Send
async Task ExecuteInvocation()
{
object result;
try
{
result = await ExecuteHubMethod(methodExecutor, hub, arguments);
Log.SendingResult(_logger, hubMethodInvocationMessage.InvocationId, methodExecutor);
}
catch (Exception ex)
{
Log.FailedInvokingHubMethod(_logger, hubMethodInvocationMessage.Target, ex);
await SendInvocationError(hubMethodInvocationMessage.InvocationId, connection,
ErrorMessageHelper.BuildErrorMessage($"An unexpected error occurred invoking '{hubMethodInvocationMessage.Target}' on the server.", ex, _enableDetailedErrors));
return;
}
finally
{
// Stream response handles cleanup in StreamResultsAsync
// And normal invocations handle cleanup below in the finally
if (isStreamCall)
{
await CleanupInvocation(connection, hubMethodInvocationMessage, hubActivator, hub, scope);
}
}
// No InvocationId - Send Async, no response expected
if (!string.IsNullOrEmpty(hubMethodInvocationMessage.InvocationId))
{
// Invoke Async, one reponse expected
await connection.WriteAsync(CompletionMessage.WithResult(hubMethodInvocationMessage.InvocationId, result));
}
}
invocation = ExecuteInvocation();
}
if (isStreamCall || isStreamResponse)
{
// don't await streaming invocations
// leave them running in the background, allowing dispatcher to process other messages between streaming items
disposeScope = false;
}
else
{
// complete the non-streaming calls now
await invocation;
}
}
catch (TargetInvocationException ex)
{
Log.FailedInvokingHubMethod(_logger, hubMethodInvocationMessage.Target, ex);
await SendInvocationError(hubMethodInvocationMessage.InvocationId, connection,
ErrorMessageHelper.BuildErrorMessage($"An unexpected error occurred invoking '{hubMethodInvocationMessage.Target}' on the server.", ex.InnerException, _enableDetailedErrors));
}
catch (Exception ex)
{
Log.FailedInvokingHubMethod(_logger, hubMethodInvocationMessage.Target, ex);
await SendInvocationError(hubMethodInvocationMessage.InvocationId, connection,
ErrorMessageHelper.BuildErrorMessage($"An unexpected error occurred invoking '{hubMethodInvocationMessage.Target}' on the server.", ex, _enableDetailedErrors));
}
}
finally
{
if (disposeScope)
{
await CleanupInvocation(connection, hubMethodInvocationMessage, hubActivator, hub, scope);
}
}
}
private async Task StreamAsync(string invocationId, HubConnectionContext connection, object[] arguments, IServiceScope scope,
IHubActivator <THub> hubActivator, THub hub, CancellationTokenSource streamCts, HubMethodInvocationMessage hubMethodInvocationMessage, HubMethodDescriptor descriptor)
{
string error = null;
streamCts = streamCts ?? CancellationTokenSource.CreateLinkedTokenSource(connection.ConnectionAborted);
try
{
if (!connection.ActiveRequestCancellationSources.TryAdd(invocationId, streamCts))
{
Log.InvocationIdInUse(_logger, invocationId);
error = $"Invocation ID '{invocationId}' is already in use.";
return;
}
object result;
try
{
result = await ExecuteHubMethod(descriptor.MethodExecutor, hub, arguments, connection, scope.ServiceProvider);
}
catch (Exception ex)
{
Log.FailedInvokingHubMethod(_logger, hubMethodInvocationMessage.Target, ex);
error = ErrorMessageHelper.BuildErrorMessage($"An unexpected error occurred invoking '{hubMethodInvocationMessage.Target}' on the server.", ex, _enableDetailedErrors);
return;
}
if (result == null)
{
Log.InvalidReturnValueFromStreamingMethod(_logger, descriptor.MethodExecutor.MethodInfo.Name);
error = $"The value returned by the streaming method '{descriptor.MethodExecutor.MethodInfo.Name}' is not a ChannelReader<> or IAsyncEnumerable<>.";
return;
}
var enumerable = descriptor.FromReturnedStream(result, streamCts.Token);
Log.StreamingResult(_logger, hubMethodInvocationMessage.InvocationId, descriptor.MethodExecutor);
await foreach (var streamItem in enumerable)
{
// Send the stream item
await connection.WriteAsync(new StreamItemMessage(invocationId, streamItem));
}
}
catch (ChannelClosedException ex)
{
// If the channel closes from an exception in the streaming method, grab the innerException for the error from the streaming method
error = ErrorMessageHelper.BuildErrorMessage("An error occurred on the server while streaming results.", ex.InnerException ?? ex, _enableDetailedErrors);
}
catch (Exception ex)
{
// If the streaming method was canceled we don't want to send a HubException message - this is not an error case
if (!(ex is OperationCanceledException && streamCts.IsCancellationRequested))
{
error = ErrorMessageHelper.BuildErrorMessage("An error occurred on the server while streaming results.", ex, _enableDetailedErrors);
}
}
finally
{
await CleanupInvocation(connection, hubMethodInvocationMessage, hubActivator, hub, scope);
streamCts.Dispose();
connection.ActiveRequestCancellationSources.TryRemove(invocationId, out _);
await connection.WriteAsync(CompletionMessage.WithError(invocationId, error));
}
}
