HasUrlParameter.setParameter is executed twice with vaadin.eagerServerLoad=true

[alexanoid]

Description of the bug

I have a View which implements HasUrlParameter<String>.

Also I configured:

vaadin.eagerServerLoad=true (for IndexHtmlRequestListener)

with such setup, HasUrlParameter.setParameter() method is executed twice during the first page load

Expected behavior

HasUrlParameter.setParameter() method is executed only one time during the first page load with vaadin.eagerServerLoad=true

Versions

• Vaadin / Flow version: 23.3.6

[alexanoid]

the same relates to BeforeEnterObserver.beforeEnter() https://stackoverflow.com/questions/75166305/vaadin23-vaadin-eagerserverload-true-and-beforeenterobserver

[alexanoid]

My biggest issue with this is that I have some pretty expensive business logic triggered by HasUrlParameter.setParameter() and thus - I access the database twice, which impacts the performance of the application :( Please help!

[knoobie]

If you know it's always two times called (has to be checked), just a add counter or AtomicBoolean as class field that checks if this is the second call as temporary workaround?

[alexanoid]

Thank you for your reply. The problem with the proposed counter is that the setParameter() method is called twice only on the very first page load... then when the UI loaded and I use the router navigation, eg leave this page and come back - this is correctly called only once. But.. it may be the new instance of the View each time (on each page visit).. so potentially it may work! I have to verify it! Thanks!

[alexanoid]

@knoobie thank you very much! Your workaround with AtomicBoolean did the trick, thanks!

[alexanoid]

@knoobie There is one side effect with this approach - the Router links don't work after the page is loaded. For example, I have a Product Catalog View with multiple pages. When I'm on the page #2 or more, it is very convenient to click on the Product catalog router link to quickly return to the page #1. The view.seParameter() method is executed correctly, but because of the AtomicBoolean == true, the logic inside is skipped, and the page is not updated in this case.

I'll really appreciate if you could fix this issue on your end.

[alexanoid]

Just FYI - I don't know is it related somehow, but during initial start up of the application I may very often see resync issue:

2023-03-16T00:23:51.078+02:00 WARN 21484 --- [ XNIO-1 task-6] c.v.f.s.communication.ServerRpcHandler : Resynchronizing UI by client's request. A network message was lost before reaching the client and the client is reloading the full UI state. This typically happens because of a bad network connection with packet loss or because of some part of the network infrastructure (load balancer, proxy) terminating a push (websocket or long-polling) connection. If you are using push with a proxy, make sure the push timeout is set to be smaller than the proxy connection timeout

[alexanoid]

any chance to fix this problem soon?

[knoobie]

I don't think it has any priority at the moment looking at the impact because it occurs only with eagerServerLoad=true which in turn is a rarely used feature.

[alexanoid]

That's sad ( Is there any other way right now to dynamically change meta tags other than with help of vaadin.eagerServerLoad=true and IndexHtmlRequestListener ?

[Artur-]

I tried a fix for this but there seems to be another underlying problem of the eagerly provided UIDL not being used at all..

[alexanoid]

I tried a fix for this but there seems to be another underlying problem of the eagerly provided UIDL not being used at all..

thank you! I'll really appreciate if you could fix it. It causes a lot of issues to me right now (

[knoobie]

@Artur- #13421 this is the cause of the usage of eager=true if you wanna try to fix this instead.. it would probably help more people as well 😅

[Artur-]

Sure, if you tell how. If the routing happens only on the second request, it is a bit too late to write the response code for the first..

[alexanoid]

@Artur- I see the number of associated commits, what a great news, thank you! Does this mean that potentially this issue will be fixed with help of them? If so, will it be included into Vaadin Flow 24.0.3?

[Artur-]

#16498 fixes this indeed. It will not make it to 24.0.3 but hopefully the following release

[alexanoid]

Awesome news! Thank you very much!

[alexanoid]

Hi @Artur- I just updated to Vaadin 24.0.4 Looks like the fix still hasn't been added there?

[knoobie]

It's not backported

[alexanoid]

Sorry to bother you with this, but do you have any information on when this will be released? I'm just waiting for this fix more than my own birthday :)

[vaadin-bot]

This ticket/PR has been released with Vaadin 24.1.0.alpha3 and is also targeting the upcoming stable 24.1.0 version.