How to know socket of OpcUaClient session is closed?

Are there some Event/Callback/Listener when socket of OpcUaClient session is closed ?

Consider this scenario：While OPC UA session is connected, unplug the network cable.

I have tried using below methods, but didn’t work.

• org.eclipse.milo.opcua.sdk.client.OpcUaClient#addSessionActivityListener
• org.eclipse.milo.opcua.sdk.client.OpcUaClient#addFaultListener

[TTia]

Hello @frankiezdh, from my experience, Eclipse Milo handles internally the reconnection (StackOverflow).

Something like: UaSubscription subscription = client.getSubscriptionManager().createSubscription(opcPublishingInterval).get(); UInteger subscriptionId = subscription.getSubscriptionId(); client.getSubscriptionManager().addSubscriptionListener(...your listener...);

Then, override UaSubscriptionManager.SubscriptionListener::onSubscriptionTransferFailed and handle the failure (which happens only if the subscription has not been moved to the newly created session, that was generated automatically when the host was back online).

In my implementation, I create a brand new subscription. That’s it.

[kevinherron]

@TTia is correct.

The closest thing you have is a SessionActivityListener.

Because of the way TCP works there can sometimes be a delay before the connection loss is detected. The current recommendation is to implement some kind of “keep alive” yourself by reading, for example, the server’s CurrentTime and State nodes.

In 0.3 I’ve actually implemented this keep alive in the FSM that manages the session.

Even in 0.3 you’ll still just receive the callback that your session is active or inactive.