private async Task TryReportError <TEvent>(Exception exception, IEventHandlerAsync <TEvent> handler, TEvent @event)
{
try
{
await handler.OnErrorAsync(exception, @event).ConfigureAwait(false);
}
catch
{
// yes, we mute exceptions here
}
}
private async Task TryRunHandler <TEvent>(IEventHandlerAsync <TEvent> handler, TEvent @event)
{
try
{
if (!await handler.ShouldHandleAsync(@event).ConfigureAwait(false))
{
return;
}
await handler.HandleAsync(@event).ConfigureAwait(false);
}
catch (Exception exception)
{
await TryReportError(exception, handler, @event).ConfigureAwait(false);
}
}
/// <summary>
/// Removes subscription for events of type <typeparamref name="TEvent"/>.
/// </summary>
/// <typeparam name="TEvent">The type of the event.</typeparam>
/// <param name="handler">An instance of IEventHandler<TEvent> to remove form subscribers.</param>
public void Unsubscribe <TEvent>(IEventHandlerAsync <TEvent> handler)
{
Unsubscribe <TEvent>(x => x.IsWrapping(handler));
}
/// <summary>
/// Adds subscription for events of type <typeparamref name="TEvent"/>.
/// </summary>
/// <typeparam name="TEvent">The type of the event.</typeparam>
/// <param name="handler">An instance of IEventHandler<TEvent> which Handle method will be invoked when event is published.</param>
public void Subscribe <TEvent>(IEventHandlerAsync <TEvent> handler)
{
var handlers = _subscribers.GetOrAdd(typeof(TEvent), _ => new List <object>());
handlers.Add(new EventHandlerAsyncWrapper <TEvent>(handler));
}
public bool IsWrapping(IEventHandlerAsync <TEvent> eventHandler) => _eventHandler == eventHandler;
public EventHandlerAsyncWrapper(Func <TEvent, Task> handler, Func <TEvent, Task <bool> > filter = null, Func <Exception, TEvent, Task> onError = null)
{
_eventHandler = new DelegateEventHandlerAsync <TEvent>(handler, filter, onError);
_handler = handler;
IsSubscribed = true;
}
public EventHandlerAsyncWrapper(IEventHandlerAsync <TEvent> eventHandler)
{
_eventHandler = eventHandler;
_handler = eventHandler.HandleAsync;
IsSubscribed = true;
}
public static ISubscription WithEventHandlerAsync <TEvent>(this IBusClient bus,
IEventHandlerAsync <TEvent> handler, string exchangeName = null, string routingKey = null) where TEvent : IEvent
=> bus.SubscribeAsync <TEvent>(async(msg, context) => await handler.HandleAsync(msg),
cfg => cfg.WithExchange(e => e.WithName(exchangeName)).WithRoutingKey(routingKey));