Spring REST file download unable to set header content-type attachment - spring-boot

Question

I have a Springboot REST application that downloads files from a given directory.
The downloads can be any file file and have any format, and I want to use the original filename as the filename of the downloaded file.
I used the code below to set the filename in the header, and add the header to the response:
#RestController
#RequestMapping("/downloads")
public class DownloadCsontroller {
...
#GetMapping
public void downloadSingleFile(#RequestParam("file") String filename, HttpServletResponse response) throws IOException {
String filepath = m_attachmentPathLocation + File.separator + filename;
File file = new File(filepath);
String contentType = getContentType(file);
response.setStatus(HttpServletResponse.SC_OK);
response.setContentType(contentType);
response.setHeader("Content-Disposition:", "attachment;filename=\"" + file.getName() + "\"");
...
}
...
}
Tested using both "Content-Disposition" and "Content-Disposition:" in setHeader().
Almost everything works (file types), except for PDF, ZIP, RAR, EXE, etc.
Any files (types) not on the list can be downloaded with the desired filenames.
But when any of the file download (PDF, ZIP, RAR, EXE, etc)... it seems it continuously loads like forever... and I cannot even see any request sent in POSTMAN, inspector, firebug, etc.
If I comment out:
//response.setHeader("Content-Disposition:", "attachment;filename=\"" + file.getName() + "\"");
It would work, but the filename would be set to the name of the request mapping. which in this case is "downloads".
I have seen lots of samples that uses "Content-Disposition" header to change the attachment filename... but it seems it fails on these file types.
I have no configurations yet, and it is kinda weird since in most samples I searched... this should be running or working.
TIA

Answer 1

Please add #GetMapping(produces = MediaType.APPLICATION_OCTET_STREAM_VALUE)
and instead of returning direct file try to return stream.
Also make a note that "Content-Disposition:" header will not work if the requesting app IP & Port number is different from server app IP & Port number.

Answer 2

Things would work If you can alter the code a bit, by setting all header values using org.springframework.http.HttpHeaders class.
Now looking at your code, i suspect you trying to expose an API that allows to download a multipart File.
I would suggest you not to use HttpServletResponse Class to set the Content- Dispositionheader but use HttpHeaders class. Below is the reformatted code
#RestController
public class DownloadCsontroller {
#GetMapping(value="/downloads")
public ResponseEntity<Object> downloadSingleFile(#RequestParam("file")
String filename) throws IOException {
String filepath = m_attachmentPathLocation + File.separator + filename;
File file = new File(filepath);
String contentType = getContentType(file);
/* response.setStatus(HttpServletResponse.SC_OK);
response.setContentType(contentType);
response.setHeader("Content-Disposition:", "attachment;filename=\""
+ file.getName() + "\"");
*/
// Here is the below Code you need to reform for Content-
//Disposition and the remaining header values too.
HttpHeaders headers= new HttpHeaders();
headers.add("Content-Disposition", "attachment; filename
=whatever.pdf");
headers.add("Content-Type",contentType);
// you shall add the body too in the ResponseEntity Return object
return new ResponseEntity<Object>(headers, HttpStatus.OK);
}
}