[🐛 BUG] De-synchronized front-ends and back-end

[jrobinAV]

What went wrong? 🤔

Front-ends get de-synchronized when re-running an application.

This is more important than it looks like, as it happens frequently and gives users the wrong impression that their application has a bug.

For example, it happens frequently during an application's development phase, especially with the default behavior of Gui().run(), which opens a new tab without closing the previous tabs.

It also happens when re-deploying a live application, causing the wrong error messages at a very bad time.

Reproduce the situation

The problem arises when:

• We run an application.
• We access the application on a browser tab.
• We shut down the application without closing the tab.
• We re-run the application (or another application on the same port).
• We use the same old tab that does not correspond to the new back-end application. This may create errors, warnings, or inconsistencies.

Expected Behavior

De-synchronized front-ends should be aware that the back-end version they are connected to is incorrect. The front-end application should automatically display a message to let the user know he/she should refresh the browser.

Solution Proposed

What about generating a unique identifier each time we run the server? It could represent a run_identifier. Each of the clients (the tabs) could know this unique run_identifier.
The clients could pass the run_identifier to the back end every time it communicates with it. On the server side, the client request is properly rejected if the run_identifier received from the client does not match its own internal run_identifier. The front end should be able to display a message asking the user to refresh the tab.

Version of Taipy

• 3.X,
• 4.Y,
• develop

Linked issues

• https://github.com/Avaiga/taipy-enterprise/issues/574

Acceptance Criteria

• A unit test reproducing the bug is added.
• Any new code is covered by a unit tested.
• Check code coverage is at least 90%.
• The bug reporter validated the fix.
• Related issue(s) in taipy-doc are created for documentation and Release Notes are updated.

Code of Conduct

• I have checked the existing issues.
• I am willing to work on this issue (optional)