Multipart body is missing #3959
Description
Hi, everyone!
I'm using Spring Cloud Gateway MVC 4.1.2
I need to validate incoming file in multipart request by checking his magic bytes.
Straight approach doesn't work because after opening a stream from a file it becomes unavailable for further filters. I tried to use caching but it doesn't work either, request body is missing downstream. Is there a workaround or maybe a right approach to do this kind of validation with Spring Cloud Gateway MVC?
Here's my code snippet:
@Bean
public RouterFunction<ServerResponse> myRoute() {
return route("gateway").POST(path("/upload"), http("http://localhost:8081")).before(request -> {
var clonedInputStream = cacheBody(request);
var clonedRequest = adaptCachedBody().apply(request);
clonedInputStream.reset();
try {
byte[] pdfSignature = {0x25, 0x50, 0x44, 0x46, 0x2D};
byte[] actualSignature = new byte[pdfSignature.length];
HttpServletRequest httpServletRequest = request.servletRequest();
Part file = httpServletRequest.getPart("file");
file.getInputStream().read(actualSignature);
if (!Arrays.equals(pdfSignature, actualSignature)) {
throw new RuntimeException("Not PDF");
}
} catch (IOException | ServletException e) {
throw new RuntimeException(e);
}
return clonedRequest;
}).build();
}