Subscribe to direct messages with RequestConfirm and correlationKey (.NET)

General Discussions
1

Hi,
I’m using .NET. I would like to subscribe to direct messages.
I have set session property SubscribeBlocking to false . I plan to use TaskCompletionSource as correlationKey and complete it when handling SubscriptionOk or SubscriptionError .
Unfortunately I can’t find suitable overload of ISession.Subscribe .
There are 3 overloads. Only 2 allow me to specify correlationKey . Of those 2 one takes IDispatchTarget but I have topic dispatch turned off. And the last candidate needs IEndpoint and I don’t know where to get IEndpoint for current session ( null doesn’t work).
Thanks

2

At a glance it appears your observations are correct - supplying a subscription correlationKey is only available when using a topic dispatch target or when subscribing directly to an IQueue or IClientName > instance.
One workaround would be to enable topic-dispatch, but if you are not interested in using that feature, you can decorate global message handler and pass that in as the topic handler for all subscriptions:
var sessionProperties = new SessionProperties()

{
// other…
SubscribeBlocking = false,
TopicDispatch = true
};
using var context = ContextFactory.Instance.CreateContext(contextProperties, null);
using var session = context.CreateSession(sessionProperties, MessageEvent, SessionEvent);
session.Connect();
using var topic = ContextFactory.Instance.CreateTopic(topicString);
// This could be wrapped up into a helper or extension method, .SubscribeAsync(topic)
var tsc = new TaskCompletionSource();
var target = session.CreateDispatchTarget(topic, (s,e) => MessageEvent(session, e));
session.Subscribe(target, SubscribeFlag.RequestConfirm, tsc);
// Now it is awaitable
var result = await tsc.Task;
Meanwhile elsewhere:
private void SessionEvent(object sender, MessageEventArgs e)
{
var tsc = e.CorrelationKey as TaskCompletionSource;
switch(e.Event)
{
case SessionEvent.SubscriptionOk:
tsc?.SetResult(ReturnCode.SOLCLIENT_OK);
break;
case SessionEvent.SubscriptionError:
tsc?.SetResult(ReturnCode.SOLCLIENT_FAIL); // Or .SetException(…)
break;
}
}