"Processing" message at the first access

asked 2021-11-08 16:18:59 +0800

mikrobe gravatar image mikrobe
100 1 5

A couple of weeks ago, all of the sudden, our application started to display the message "Processing" when accessed for the first time from a browser instance. Refreshing the page or closing the browser tab and reopening, the application correctly loaded. We are using Jdk11, an heavily customized Atlantic theme and ZK 9.0.2 (because we have layout issues with later releases). Our application is quite complex and I cannot reproduce the error with a simpler example. Kindly double check the following image of the inspected code and as you can see, the application page code is present. https://ibb.co/YynqVvZ (because of my low karma I cannot upload images)

Is there anything I can do to trace down the cause? thanks!

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now you can upload images

cor3000 ( 2021-11-09 10:39:20 +0800 )edit

3 Answers

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answered 2021-11-09 18:25:28 +0800

cor3000 gravatar image cor3000
6280 2 7

updated 2021-11-09 18:26:38 +0800

ERROR 400 (BAD REQUEST) is clearly your server rejecting the requests due to something it doesn't like in the client request.

I could imagine (I am guessing here) the JSESSIONID in the URL is rejected due to updated security policies. You can try to disable this legacy feature (called URL rewriting only happening with the first request before a session cookie is established) by setting a dedicated tracking-mode in your web.xml.


here some more explanations: https://www.logicbig.com/tutorials/java-ee-tutorial/java-servlet/session-tracking-mode.html

As said earlier no guarantees I'm just guessing - maybe we're lucky and it's just that.

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Thank you so much Robert! As usual you nailed the problem. Adding that configuration to web.xml solved the issue. But now it's my turn to figure out why this happened because at the best of my knowledge we didn't change anything regarding security policies. Kudos

mikrobe ( 2021-11-10 22:11:06 +0800 )edit

yes you'll have to find out which server http/jee/proxy/firewall/sso/cloudflare is triggering the error 400 in order to draw any conclusions, usually it's somewhere in the logs

cor3000 ( 2021-11-11 11:55:25 +0800 )edit

in the end it's a good thing in general to disable URL rewriting since you don't want session IDs in URLs visible (unencrypted) to any network endpoint in the middle

cor3000 ( 2021-11-11 11:57:15 +0800 )edit

answered 2021-11-09 10:32:02 +0800

cor3000 gravatar image cor3000
6280 2 7

updated 2021-11-09 10:56:41 +0800

Often when the "Processing" message gets "stuck" the errors can be seen either in the "console" or in the "network" tab. As indicated in the screenshot below.

image description

If only the first page load is affected this can indicate a caching/latency problem, of the resources. In order to find the difference you can compare the first and second load sequence in the "Network" tab.

Side note: ZK version 9.0.2 doesn't exist, so please be sure you are using an official version.

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You can also contact our support in case you need dedicated help via zoom to look into your system directly.

cor3000 ( 2021-11-09 10:32:49 +0800 )edit

answered 2021-11-09 15:50:49 +0800

mikrobe gravatar image mikrobe
100 1 5

Thank you for your reply cor3000. About the ZK version, I missed a digit: it is About the devTool, unfortunately Network tab is empty the first time because the problem happens only when you open a new browser instance and you type the application URL. But in the console I found a long list of errors that I (as you kindly enabled me ;P) attach as an image. image description

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Furthermore, I double checked also local storage that is empty and the cache contains the jsessionId only.

mikrobe ( 2021-11-09 16:03:57 +0800 )edit

Tipp: you can open the devtools before loading a URL, just open a new browser tab, without typing the URL yet, press F12 to open the dev tools, then type/paste the URL to be loaded in the address bar

cor3000 ( 2021-11-09 18:16:11 +0800 )edit
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Asked: 2021-11-08 16:18:59 +0800

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Last updated: Nov 09 '21

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