The dismissal of syncXHR during unload is highly incompatible and causes big issues with SAP enterprise customers. Google postponed the changes to Chrome 80 (per group policy or flags still enabled until Chrome 88) due to discussion with SAP (among others).
SAP relies in various products on syncXHR in the unload event to do session handling. Once the browser is closed, refreshed or user navigates from one application to another we sent a syncXHR request during unload event to the server to trigger the logoff. The logoff not only unfreezes resources (session close) but also unlock database objects. If this request doesn’t reach the server the locks remains and nobody can access this object until session timeout (normally between 15-30min).
We used syncXHR also because it is important that the logoff request reaches the server bevor a next applications started especially if both locks the same object. With a async approach is nearly impossible to get the right order of the requests (logoff and then the next start) on the server.
As Google insists of removing the syncXHR and also window.open during unload SAP decided to use sendBeacon and tried with various other mechanism to ensure the synchronous behavior.
SAP customers must upgrade all their onprem systems which are normally mission critical to get our workarounds. Otherwise this change will break the business. Normally it takes years to upgrade all systems as the testing effort is immense and the risk of introducing the new issue are very high. The finacial impactof this change is very high for customers.
Therefore we have to main issues or requirements:
• sendBeacon must work reliable in all cases. To define it more precise: sendBeacons created in the unload event of the main window and/or iframes must be sent out during F5, tab close and complete browser close.
Our tests shows that Firefox not sending a sendBeacon out once the browser is closed (tested with Firefox 72.0.1). It seems to work if one tab remains open or in the F5 refresh case.
• Depending on the timeframe to opt-in the features to give enterprise customer more time to plan, upgrade and test the systems.
Until today SAP did not provide for all scenarios a solution.
Do you have any contact driving this topic so that we could dicuss it in more detail?