First, thanks for writing this! I’ve been trying to find a way to do exactly this. Second, I seem to be having an error when attempting the above method, and am wondering if you know what the problem might be. Here’s the error I’m receiving:

DataSource.Error: Web.Contents failed to get contents from ‘https://mycompanydomain-my.sharepoint.com/personal/username_companydomain_com/_api/web/getfilebyserverrelativeurl('/personal/username_companydomain_com/Documents/Workbooks/My_Workbook.xlsx')/$value' (500): Internal Server Error
Details: DataSourceKind=Web DataSourcePath=https://mycompanydomain-my.sharepoint.com/personal/username_companydomain_com/_api/web/getfilebyserverrelativeurl('/personal/username_companydomain_com/Documents/Workbooks/My_Workbook.xlsx')/$value Url=https://mycompanydomain-my.sharepoint.com/personal/username_companydomain_com/_api/web/getfilebyserverrelativeurl('/personal/username_companydomain_com/Documents/Workbooks/My_Workbook.xlsx')/$value