I try to Upload Excel (.xlsx) file to my Power BI using API. Ability to upload excel files was announced by Microsoft: https://msdn.microsoft.com/en-us/library/mt243840.
BUT it works just for .PBIX-files, and I can't to realize uploading .xlsx-file
P.S. for importing pbix-file I used multipart./form-data, but it doesn't work for excel.
People tried realize it year ago, but unsuccessfully.
And what we should think about quality microsoft support?