Spring MVC #RestController and redirect - spring

Question

I have a REST endpoint implemented with Spring MVC #RestController. Sometime, depends on input parameters in my controller I need to send http redirect on client.
Is it possible with Spring MVC #RestController and if so, could you please show an example ?

Answer 1

Add an HttpServletResponse parameter to your Handler Method then call response.sendRedirect("some-url");
Something like:
#RestController
public class FooController {
#RequestMapping("/foo")
void handleFoo(HttpServletResponse response) throws IOException {
response.sendRedirect("some-url");
}
}

Answer 2

To avoid any direct dependency on HttpServletRequest or HttpServletResponse I suggest a "pure Spring" implementation returning a ResponseEntity like this:
HttpHeaders headers = new HttpHeaders();
headers.setLocation(URI.create(newUrl));
return new ResponseEntity<>(headers, HttpStatus.MOVED_PERMANENTLY);
If your method always returns a redirect, use ResponseEntity<Void>, otherwise whatever is returned normally as generic type.

Answer 3

Came across this question and was surprised that no-one mentioned RedirectView. I have just tested it, and you can solve this in a clean 100% spring way with:
#RestController
public class FooController {
#RequestMapping("/foo")
public RedirectView handleFoo() {
return new RedirectView("some-url");
}
}

Answer 4

redirect means http code 302, which means Found in springMVC.
Here is an util method, which could be placed in some kind of BaseController:
protected ResponseEntity found(HttpServletResponse response, String url) throws IOException { // 302, found, redirect,
response.sendRedirect(url);
return null;
}
But sometimes might want to return http code 301 instead, which means moved permanently.
In that case, here is the util method:
protected ResponseEntity movedPermanently(HttpServletResponse response, String url) { // 301, moved permanently,
return ResponseEntity.status(HttpStatus.MOVED_PERMANENTLY).header(HttpHeaders.LOCATION, url).build();
}

Answer 5

As the redirections are usually needed in a not-straightforward path, I think throwing an exception and handling it later is my favourite solution.
Using a ControllerAdvice
#ControllerAdvice
public class RestResponseEntityExceptionHandler
extends ResponseEntityExceptionHandler {
#ExceptionHandler(value = {
NotLoggedInException.class
})
protected ResponseEntity<Object> handleNotLoggedIn(
final NotLoggedInException ex, final WebRequest request
) {
final String bodyOfResponse = ex.getMessage();
final HttpHeaders headers = new HttpHeaders();
headers.add("Location", ex.getRedirectUri());
return handleExceptionInternal(
ex, bodyOfResponse,
headers, HttpStatus.FOUND, request
);
}
}
The exception class in my case:
#Getter
public class NotLoggedInException extends RuntimeException {
private static final long serialVersionUID = -4900004519786666447L;
String redirectUri;
public NotLoggedInException(final String message, final String uri) {
super(message);
redirectUri = uri;
}
}
And I trigger it like this:
if (null == remoteUser)
throw new NotLoggedInException("please log in", LOGIN_URL);

Answer 6

if you #RestController returns an String you can use something like this
return "redirect:/other/controller/";
and this kind of redirect is only for GET request, if you want to use other type of request use HttpServletResponse