Core.CrossDomainLib not working anymore in Azure Web Apps

[YasharGK]

Category

[x ] Bug
[ ] Enhancement

Environment

[ x] Office 365 / SharePoint Online
[ ] SharePoint 2016
[ ] SharePoint 2013

Expected or Desired Behavior

Executing Javascript calls from a SharePoint page to a (provider-hosted) MVC websites, which is hosted on Azure App Service, using Core.CrossDomainLib

Observed Behavior

Solutions based on the Core.CrossDomainLib are not working anymore.

The Javascript calls do not work anymore. Debugging the provider-hosted app code it seems that "SharePointContextProvider.Current.GetSharePointContext(HttpContext)" returns null.

This issue seems to be related to the app-service-samesite-cookie update which is rolled out recently by Microsoft: https://azure.microsoft.com/en-us/updates/app-service-samesite-cookie-update/

[SeznecMoran]

Hi,

I have the same behavior on a SharePoint Hosted App with this code :
https://github.com/SharePoint/PnP/blob/master/Samples/Core.EventReceivers/Core.EventReceiversWeb/SharePointContext.cs

The issue started the 24/01/2020, after the last Azure Update :
https://azure.microsoft.com/en-us/updates/app-service-samesite-cookie-update/

If you find a solution, please share it!

Thanks