Unable to download XLSX workbook without errors Springboot / React - reactjs

Question

I have an application that is a Springboot backend and a reactJs frontend. I am able to successfully download an excel workbook on my localhost through the application as well as in postman without any errors, but when I test the app on the server I get an error that the file format or extension is not valid.
Also when I test the apps actual url using postman I get a 200 response but nothing is actually returned.
I am using axios and read over this post.
On the backend, the excel workbook is being put together using Apache POI XSSFworkbook.
The backend response entity looks like this
return ResponseEntity
.ok()
.contentType(MediaType.valueOf("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"))
.header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=" + params.getDeqId() + "Data.xlsx").body(workbook::write);
On the react side, I've tried a few different things. Currently I have:
return axios
.post(`/api/excelexport/watersystemexcel`, submittedData, { responseType: "arraybuffer" })
.then((response) => {
const url = window.URL.createObjectURL(new Blob([response.data]));
const link = document.createElement("a");
link.href = url;
link.setAttribute("download", submittedData.deqId + "Data.xlsx");
document.body.appendChild(link);
link.click();
this.setState(() => ({ downloading: false }));
});
I have also tried formating the axios request like:
axios.post(`/api/excelexport/watersystemexcel`, submittedData, {
responseType: "arraybuffer",
headers: { "Content-Type": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" }
})
but this results in a 415 error, saying that that specified content-type isn't acceptable.
Lastly, I have also tried changing the file extension to .xls rather then .xlsx on both the front and backend. When I do this the workbook does download but when the file is opened there is an error that file extensions don't match, and that the file may be corrupt.

Answer 1

return ResponseEntity
.ok()
.contentType(MediaType.valueOf("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"))
.header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=" + params.getDeqId() + "Data.xlsx")
.body(workbook::write);
When you build your own ResponseEntity object, you have not specified the Content Length, so it could be problematic, and maybe that's why you get a corrupted file at the end.
That's how I do when I need to display images or videos :
return ResponseEntity.status(HttpStatus.OK).contentLength(cr.contentLength()).body(cr);
where cr is a FileSystemResource or a ClasspathResource or whatever Resource you need to send as a HTTP Response Entity.
It seems to be identical, but not, look at the end of my code with the contentLength part before the body part.