Suddenly getting: Cannot render error page for request [/login] and exception

Flow
1

Hi,

i get suddenly the issue: Cannot render error page for request [/login] and exception [Unregistered node was not found based on its id. The tree is most likely corrupted.]

All pages are blank but i cant find any issue or have glue where to start.

Does anyone has a hint where to search?

2

After removing the “generated” folder and prepeared and build frontend with maven again, it works again. Strange behaviour

But the issue comes back when i override the onAttachMethod in a view

I dont find a working solution. Maybe some one has an idea?

I want to call an external API when the page has been opened. Wanted to make this call in the onAttach method but obviously it doesnt work

3

Any stacktrace in the server console?

I have no idea for why clearing client-side stuff would have a difference for a Flow view.

4

Yeah there was a lot of stuff in stack trace but nothing that gave a hint to my view.

Maybe this was an issue with a Spring Bean?

Currently i inject my bean like this, this should be the correct way or is there any better way?

I can try to reproduce the class to the staus when the error came up if that help anyway. But like its now, it works

@AnonymousAllowed
@Route(value = "bookings", layout = MainLayout.class)
public class BookingsView extends VerticalLayout {

    private ApiAdapter apiAdapter;
    Grid<Booking> bookingGrid = new Grid<>(Booking.class, false);

    public RentalMyBookingsView(RentalApiAdapter rentalApiAdapter) {
        this.rentalApiAdapter = rentalApiAdapter;
        createContent();
    }

    @PostConstruct
    void init(){
        bookingGrid.setItems(apiAdapter.getBookings(XYZ));

    }

    private void createContent() {

       //setup grid
        add(bookingGrid);
    }

}
5

That part looks fine though the @PostConstruct method is probably redundant when you use constructor injection. You could just as well do the initialization directly in the constructor.

I suspect nobody will be able to make any guesses on how to help you without seeing those errors from the console.

6

When does the View gets constructed? On start up or on Browser Request?

In the previous version of this class the api get called on start up, thats why i put it into PostContruct

7

Put a breakpoint there and you will find out :slight_smile:. Each user should get their own instance of the view class so the instances should be constructed on demand.

I think @PostConstruct will be run almost immediately after the constructor so that shouldn’t make any difference. But that’s again something you can easily verify in your specific case by setting a breakpoint.