private async Task InvokeQueryHandler(MessageInvocationContext context, Message message)
{
var resultType = GetQueryResultType(message.Body);
var handlerType = typeof(IQueryHandler <,>).MakeGenericType(message.Body.GetType(), resultType);
var handlers = _scope.Create(handlerType).ToList();
if (handlers.Count == 0)
{
throw new NoHandlerRegisteredException($"Missing handler for query '{message.Body}'.");
}
if (handlers.Count > 1)
{
throw new OnlyOneQueryHandlerAllowedException(
$"Queries may only have one handler, '{message.Body}' got [{string.Join(", ", handlers.Select(x => x.GetType().FullName))}].");
}
var handler = handlers[0];
Task task;
Stopwatch sw = null;
var args1 = new InvokingHandlerEventArgs(_scope, handler, message)
{
Principal = context.Principal
};
try
{
if (HandlerInvoked != null)
{
sw = Stopwatch.StartNew();
}
InvokingHandler?.Invoke(this, args1);
task = (Task)handler
.GetType()
.GetMethod("HandleAsync")
.Invoke(handler, new[] { context, message.Body });
await task;
sw?.Stop();
var e = new HandlerInvokedEventArgs(_scope, handler, message, args1, sw?.Elapsed ?? TimeSpan.Zero)
{
Principal = context.Principal
};
HandlerInvoked?.Invoke(this, e);
}
catch (Exception ex)
{
var e = new HandlerInvokedEventArgs(_scope, handler, message, args1.ApplicationState,
sw?.Elapsed ?? TimeSpan.Zero)
{
Exception = ex
};
HandlerInvoked?.Invoke(this, e);
ExceptionDispatchInfo.Capture(ex).Throw();
return;
}
var resultProperty = typeof(Task <>).MakeGenericType(resultType).GetProperty("Result");
var result = resultProperty.GetValue(task);
await context.ReplyAsync(result);
}
private async Task InvokeMessageHandlers(IMessageContext context, Message message)
{
var messageType = message.Body.GetType();
var handleMethodParameterTypes = new Type[] { typeof(IMessageContext), messageType };
var type = typeof(IMessageHandler <>).MakeGenericType(messageType);
var handlers = _scope.Create(type).ToList();
if (handlers.Count == 0)
{
Logger?.Invoke(LogLevel.Warning, message.MessageId.ToString("N"), "Missing handler for " + message.Body.GetType());
var e = new HandlerMissingEventArgs(context.Principal, message, _scope);
HandlerMissing?.Invoke(this, e);
if (e.Handler != null)
{
handlers.Add(e.Handler);
}
else if (e.ThrowException)
{
throw new NoHandlerRegisteredException("Failed to find handler for '" + message.Body + "'.");
}
else
{
return;
}
}
if (InvokeHandlersInParallel)
{
var tasks = handlers.Select(async handler =>
{
var mi = handler.GetType().GetMethod("HandleAsync", handleMethodParameterTypes);
var task = (Task)mi.Invoke(handler, new[] { context, message.Body });
Stopwatch sw = null;
var args1 = new InvokingHandlerEventArgs(_scope, handler, message)
{
Principal = context.Principal
};
try
{
if (HandlerInvoked != null)
{
sw = Stopwatch.StartNew();
}
Logger?.Invoke(LogLevel.Info, message.MessageId.ToString("N"), "Invoking " + handler.GetType());
InvokingHandler?.Invoke(this, args1);
await task;
sw?.Stop();
var e = new HandlerInvokedEventArgs(_scope, handler, message, args1,
sw?.Elapsed ?? TimeSpan.Zero)
{
Principal = context.Principal
};
HandlerInvoked?.Invoke(this, e);
}
catch (Exception ex)
{
Logger?.Invoke(LogLevel.Error, message.MessageId.ToString("N"),
$"Handler failed: {handler.GetType()}, Exception: {ex}");
var e = new HandlerInvokedEventArgs(_scope, handler, message, args1.ApplicationState,
sw?.Elapsed ?? TimeSpan.Zero)
{
Exception = ex,
Principal = context.Principal
};
HandlerInvoked?.Invoke(this, e);
ExceptionDispatchInfo.Capture(ex).Throw();
}
}).ToArray();
try
{
await Task.WhenAll(tasks);
}
catch (Exception)
{
var failedHandlers = new List <FailedHandler>();
for (var i = 0; i < handlers.Count; i++)
{
var task = tasks[i];
var handler = handlers[i];
if (task.IsFaulted)
{
failedHandlers.Add(new FailedHandler
{
Exception = task.Exception.InnerException,
HandlerType = handler.GetType()
});
}
}
throw new HandlersFailedException(message, failedHandlers);
}
}
else
{
var failedHandlers = new List <FailedHandler>();
foreach (var handler in handlers)
{
var mi = handler.GetType().GetMethod("HandleAsync", handleMethodParameterTypes);
var task = (Task)mi.Invoke(handler, new[] { context, message.Body });
Stopwatch sw = null;
var args1 = new InvokingHandlerEventArgs(_scope, handler, message)
{
Principal = context.Principal
};
try
{
if (HandlerInvoked != null)
{
sw = Stopwatch.StartNew();
}
InvokingHandler?.Invoke(this, args1);
await task;
sw?.Stop();
var e = new HandlerInvokedEventArgs(_scope, handler, message, args1,
sw?.Elapsed ?? TimeSpan.Zero)
{
Principal = context.Principal
};
HandlerInvoked?.Invoke(this, e);
}
catch (Exception ex)
{
var e = new HandlerInvokedEventArgs(_scope, handler, message, args1.ApplicationState,
sw?.Elapsed ?? TimeSpan.Zero)
{
Exception = ex,
Principal = context.Principal
};
HandlerInvoked?.Invoke(this, e);
failedHandlers.Add(new FailedHandler()
{
Exception = ex, HandlerType = handlers.GetType()
});
}
}
if (failedHandlers.Any())
{
throw new HandlersFailedException(message, failedHandlers);
}
}
}
