private void SubscribeStream(string symbol)
{
//if there is already subscribed stream - unsubscribe it and subscribe for new symbol
_currentTicksStream?.Close();
_glue.Interop.Subscribe(_ticksEndpoint,
new ClientEventStreamHandler
{
// this lambda is invoked when the status of the stream has changed
EventStreamStatusChanged = (info, status, cookie) => LogMessage($"{info.EventStreamingMethod.Name} to {info.Server} is {status}"),
// this lambda is invoked when there is data published to the stream
EventHandler = (info, data, cookie) =>
DispatchAction(() =>
{
var isOOB = data.IsCallbackStream;
// if isOOB is true the data has been pushed only to this subscriber
var subscriptionItem = $"{data.ResultContext.AsString()}";
ListViewSubscriptions.Items.Add(subscriptionItem);
ListViewSubscriptions.ScrollIntoView(subscriptionItem);
})
},
// these are the arguments sent in the subscription request
mib => mib.SetContext(cb => cb.AddValue("reject", false).AddValue("symbol", symbol)),
// additional settings - specify target await timeout
new TargetSettings().WithTargetAwaitTimeout(TimeSpan.FromSeconds(5)),
// stream settings, specifying that we accept 'personal' (out-of-band) stream pushes
new ClientEventStreamSettings {
AllowCallbacks = true, ReestablishStream = false
}
)
.ContinueWith(eventStream =>
{
_currentTicksStream = eventStream.Status == TaskStatus.RanToCompletion ? eventStream.Result : null;
});
}
private void SubscriberHandler(IServerEventStream stream, IEventStreamSubscriber subscriber, IEventStreamBranch branch, object cookie)
{
IEventStreamSubscriptionRequest request = subscriber.Subscription;
// log the subscriber
LogMessage($"New subscriber {request.Caller} {request.SubscriptionContext.Arguments.AsString()}");
// push an 'image' to that subscriber which is received *only* by it (last image pattern)
// this will be received as an OOB data - see the demo subscriber code
subscriber.Push(cb =>
cb.AddValue("SubscribersAsImage", _glue.AGMObjectSerializer.Serialize(stream.GetBranches()
.SelectMany(b =>
b.GetSubscribers().Select(sb => sb.Subscription.Caller)))));
// e.g. keep the subscriptions in a list
var subscriptionItem = $"{request.Caller.ApplicationName} {request.SubscriptionContext.Arguments.AsString()}";
DispatchAction(() =>
{
ListViewSubscriptions.Items.Add(subscriptionItem);
ListViewSubscriptions.ScrollIntoView(subscriptionItem);
});
}
