You could not directly load a Workbook file to the Spreadsheet by simply specifying a path to it. You will need to first process the file on the server. Depending on the format in which you will send the file to the client you can either use:
- the fromFile()
method (if you send the file as blob); or
- the fromJSON()
(if you send only the Workbook data as JSON, following the Spreadsheet widget format).