How to return downloaded file name in Cyrillic?

Question

I want to return file with Cyrillic name.

Now my code looke like:

@GetMapping("/download/{fileId}")
    public void download(@PathVariable Long fileId, HttpServletResponse response) throws IOException {
        ...
        response.setContentType("txt/plain" + "; charset=" + "WINDOWS-1251");
        String filename = "русское_слово.txt";
        response.addHeader("Content-disposition", "attachment; filename=" + filename);
        response.addHeader("Access-Control-Expose-Headers", "Content-disposition");
        //...
    }

When I access url from browser - browser provides me dialog to save file on disk but it show _ instead of Cyrillic symbols.

Looks like it is response header encoding issue:

{
  "access-control-expose-headers": "Content-disposition",
  "content-disposition": "attachment; filename=???_??.txt",
  "date": "Fri, 28 Dec 2018 15:53:44 GMT",
  "transfer-encoding": "chunked",
  "content-type": "txt/plain;charset=WINDOWS-1251"
}

I tried following option:

response.addHeader("Content-disposition", "attachment; filename*=UTF-8''" + filename);

and following:

response.addHeader("Content-disposition", "attachment; filename*=UTF-8''" + URLEncoder.encode(filename,"UTF-8"));

but it doesn't help

How can I fix this issue?

Answer 1

If you're on Spring 5+ you can use ContentDisposition:

String filename = "русское слово.txt";

ContentDisposition contentDisposition = ContentDisposition.builder("attachment")
    .filename(filename, StandardCharsets.UTF_8)
    .build();
System.out.println(contentDisposition.toString());

Output:

attachment; filename*=UTF-8''%D1%80%D1%83%D1%81%D1%81%D0%BA%D0%BE%D0%B5%20%D1%81%D0%BB%D0%BE%D0%B2%D0%BE.txt

The ContentDisposition hides all the work you're trying to do (see its toString implementation):

if (this.filename != null) {
    if (this.charset == null || StandardCharsets.US_ASCII.equals(this.charset)) {
        sb.append("; filename=\"");
        sb.append(this.filename).append('\"');
    }
    else {
        sb.append("; filename*=");
        sb.append(encodeHeaderFieldParam(this.filename, this.charset));
    }
}

---

Also if you don't want to deal with HttpServletRequest directly you can return ResponseEntity instead:

@RequestMapping("/")
public ResponseEntity<Resource> download() {
  HttpHeaders httpHeaders = new HttpHeaders();
  String filename = "русское_слово.txt";

  ContentDisposition contentDisposition = ContentDisposition.builder("attachment")
      .filename(filename, StandardCharsets.UTF_8)
      .build();
  httpHeaders.setContentDisposition(contentDisposition);

  return new ResponseEntity<>(new ByteArrayResource(new byte[0]),
      httpHeaders, HttpStatus.OK);
}