How to convert file via Google API?

Question

Google

How to save .xls/.xlsx file using Google API.
convert file to google format.
Then upload to the server.
The matter is as follows.
The client collects Excel files from its customers.
Uploads them to Google drive (set to auto convert xlsx/xls to Google Spreadsheet).
(In this way, the client unifies all files, i.e. leads to a single format.)
Then it downloads these files.
The resulting converted files are uploaded to the "service" for processing.
The task is to bypass the stage of uploading files to Google drive by the client.
Transfer this function to "service".

Answer 1

described incomprehensibly. Save where? Convert from Excel format to Google Spreadsheet format? That is, upload a spreadsheet to Google Docs?

Answer 2

Example.
The user on the service uploads an Excel file,
the service, using the Google API, converts the file into the Google Spreadsheet format.
and returns the file to the user.
(The bottom line is that using Google document conversion, you can get rid of the problems associated with the difference in Excel formats, infinite cells, Ypres)