I have a requirement where I need to download a PDF from the website. The PDF needs to be generated within the code, which I thought would be a combination of freemarker and a PDF generation framework like iText. Any better way?
However, my main problem is how do I allow the user to download a file through a Spring Controller?
Download link
<a href="magic.php?file=<?php echo urlencode($row['name']); ?>">Download</a>
magic.php page
<?php
$file = 'C:/xampp/htdocs/myfile/uploads/'.urldecode($_GET['file']);
if (file_exists($file)) {
header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename='.basename($file));
header('Expires: 0');
header('Cache-Control: must-revalidate');
header('Pragma: public');
header('Content-Length: ' . filesize($file));
readfile($file);
exit;
}
?>
Option 1 using an InputStreamResource
Resource implementation for a given InputStream.
Should only be used if no other specific Resource implementation is > applicable. In particular, prefer ByteArrayResource or any of the file-based Resource implementations where possible.
@RequestMapping(path = "/download", method = RequestMethod.GET)
public ResponseEntity<Resource> download(String param) throws IOException {
// ...
InputStreamResource resource = new InputStreamResource(new FileInputStream(file));
return ResponseEntity.ok()
.headers(headers)
.contentLength(file.length())
.contentType(MediaType.APPLICATION_OCTET_STREAM)
.body(resource);
}
Option2 as the documentation of the InputStreamResource suggests - using a ByteArrayResource:
@RequestMapping(path = "/download", method = RequestMethod.GET)
public ResponseEntity<Resource> download(String param) throws IOException {
// ...
Path path = Paths.get(file.getAbsolutePath());
ByteArrayResource resource = new ByteArrayResource(Files.readAllBytes(path));
return ResponseEntity.ok()
.headers(headers)
.contentLength(file.length())
.contentType(MediaType.APPLICATION_OCTET_STREAM)
.body(resource);
}
@RequestMapping(value = "/action/{abcd}/{efgh}", method = RequestMethod.GET)
@PreAuthorize("@authorizationService.authorizeMethod(#id)")
public HttpEntity<byte[]> doAction(@PathVariable ObjectType obj, @PathVariable Date date, HttpServletResponse response) throws IOException {
ZipFileType zipFile = service.getFile(obj1.getId(), date);
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
response.setHeader("Content-Disposition", "attachment; filename=" + zipFile.getFileName());
return new HttpEntity<byte[]>(zipFile.getByteArray(), headers);
}
As stated on spring manual
As with @RequestBody, Spring converts the returned object to a response body by using an HttpMessageConverter
I think your problem is spring doesn't come with a HttpMessageConverter than can process FileSystemResource.
A list of builtin HttpMessageConverter is available here. I suggest you try converting your response into byte array somehow, maybe it will pick ByteArrayHttpMessageConverter instead and help solve your issue
Generally speaking, when you have
response.getOutputStream(), you can write anything there. You can pass this output stream as a place to put generated PDF to your generator. Also, if you know what file type you are sending, you can set