[Bug] Wrong content type if download shared .xlsx file

[Rotzbua]

Hi,

I found a bug in the returned mime type for .xlsx files.

Steps to reproduce:

1. Generate test excel file e.g. text.xlsx
2. Generate share link
3. Go to download site
4. Click download button on download site
5. Browser opens window where you can decide to:
   a. open with excel
   b. OR save file

Observed for:

a. if open with excel, file will be opened with excel but with filename text.xlsx.xls and not text.xlsx ! Which cause an error.
b. Save as file which will be correct as text.xlsx

Expected for:

a. Should be opened correctly as text.xlsx and not text.xlsx.xls

Suggested bug:

The return content type for the file will be:

Content-Type: application/vnd.ms-excel

But this is the content type of .xls, but excel recognize the ending .xlsx and so it add an .xls.

The correct content type of .xlsx seems to be

application/vnd.openxmlformats-officedocument.spreadsheetml.sheet

See: https://stackoverflow.com/a/4212908

Best