Power BI Report Server : UserPrincipalName() or UserName() not useful when using Forms Auth

[samsonfr]

I successfully managed to test Power BI Report Server using Forms Autentication based on this security sample :

https://github.com/Microsoft/Reporting-Services/tree/master/CustomSecuritySample

I was able to create a user and set it as administrator.

Now, in my Power BI analysis, I would like to retrieve the name of the current form user using either UserPrincipalName() or UserName() DAX function. Problem is that :

- UserPrincipalName() returns <servername>$@domain.com

- UserName() return NT SERVICE\PowerBIReportServer

Whereas, when using Windows Authentication, it returns respectively email and windows login ...

Is is a bug? Any other way to get the logged in user name?

Frederick

[oliviernicollet]

Hello, did you find any solution to filter user data when using form auth in Power BI Report Server?

[samsonfr]

I got a response from Microsoft support :

"The issue we are seeing is considered a  by Design behavior. As PBI connects to Azure Analysis Services (AAS) internally and AAS takes only Windows Credentials. When Forms Authentication is used, it uses the Credentials of PBI RS (which is Service account) as Windows username is not available."

So Forms Authentication for PBI Report Server should only be used to define autorizations on folders and files. As there is no way of getting the form user name from within Power BI (using DAX for example), it cannot be used to filter data automatically by on the user.

Frederick