Firebase offline no CompletionListener on setValue

Question

I have this codebase where I set a value. In offline mode it writes successfully but is not calling the CompletionListener.onComplete callback function.

newOrderRef.setValue(order, (firebaseError, firebase) -> {
            if (firebaseError != null) {
                Timber.e(firebaseError.toException(), "Order create failed, id: %s", order.getOrderId());
                subscriber.onError(firebaseError.toException());

            } else {
                Timber.i("Order created, id: %s", order.getOrderId());
                newOrderRef.setPriority(0 - timestamp);
                subscriber.onNext(firebase.getKey());
                subscriber.onCompleted();
            }
        });

The callback never gets called. But writes fine.

In another case even after unsubscribing in onDestroy using CompositeSubscription, the subscriber gets called when the value gets to write to firebase server even when the fragment is not running.

Is this the correct behavior ?

      Subscription orderSubscription = OrderManager.createOrder(order)
                        .subscribe(s -> {
                            fabShowSuccess();
                            showSnackbar("onnext Order created " + order.getOrderId());
                        }, throwable -> {
                            showSnackbar("Order failed. Make sure your are connected to internet.");
                            fabShowFailed();
                        }, () -> {
                            fabShowSuccess();
                            showSnackbar("Order created " + order.getOrderId());
                        });
                mCompositeSubscription.add(orderSubscription);

In onDestroy() I call mCompositeSubscription.unsubscribe(); , but the subscriber gets called later.

Answer 1

The completion listener for write operations will be invoked when the write has been committed to the database on the Firebase servers. When you're offline, that won't happen.

There is no way to unsubscribe a completion listener. If the listener still exists when the write operation completes, it will be invoked.