Redirect to an external URL from controller action

Question

I have noticed the following code is redirecting the User to a URL inside the project,

@RequestMapping(method = RequestMethod.POST)
public String processForm(HttpServletRequest request, LoginForm loginForm, 
                          BindingResult result, ModelMap model) 
{
    String redirectUrl = "yahoo.com";
    return "redirect:" + redirectUrl;
}

whereas, the following is redirecting properly as intended, but requires http:// or https://

@RequestMapping(method = RequestMethod.POST)
    public String processForm(HttpServletRequest request, LoginForm loginForm, 
                              BindingResult result, ModelMap model) 
    {
        String redirectUrl = "http://www.yahoo.com";
        return "redirect:" + redirectUrl;
    }

I want the redirect to always redirect to the URL specified, whether it has a valid protocol in it or not and do not want to redirect to a view. How can I do that?

Thanks,

Answer 1

In short "redirect:yahoo.com" or "redirect://yahoo.com" will lend you to yahoo.com.

where as "redirect:yahoo.com" will lend you your-context/yahoo.com ie for ex- localhost:8080/yahoo.com

Answer 2

You can use the RedirectView. Copied from the JavaDoc:

View that redirects to an absolute, context relative, or current request relative URL

Example:

@RequestMapping("/to-be-redirected")
public RedirectView localRedirect() {
    RedirectView redirectView = new RedirectView();
    redirectView.setUrl("http://www.yahoo.com");
    return redirectView;
}

You can also use a ResponseEntity, e.g.

@RequestMapping("/to-be-redirected")
public ResponseEntity<Object> redirectToExternalUrl() throws URISyntaxException {
    URI yahoo = new URI("http://www.yahoo.com");
    HttpHeaders httpHeaders = new HttpHeaders();
    httpHeaders.setLocation(yahoo);
    return new ResponseEntity<>(httpHeaders, HttpStatus.SEE_OTHER);
}

And of course, return redirect:http://www.yahoo.com as mentioned by others.

Answer 3

Looking into the actual implementation of UrlBasedViewResolver and RedirectView the redirect will always be contextRelative if your redirect target starts with /. So also sending a //yahoo.com/path/to/resource wouldn't help to get a protocol relative redirect.

So to achieve what you are trying you could do something like:

@RequestMapping(method = RequestMethod.POST)
public String processForm(HttpServletRequest request, LoginForm loginForm, 
                          BindingResult result, ModelMap model) 
{
    String redirectUrl = request.getScheme() + "://www.yahoo.com";
    return "redirect:" + redirectUrl;
}

Answer 4

Did you try RedirectView where you can provide the contextRelative parameter?

Answer 5

For me works fine:

@RequestMapping (value = "/{id}", method = RequestMethod.GET)
public ResponseEntity<Object> redirectToExternalUrl() throws URISyntaxException {
    URI uri = new URI("http://www.google.com");
    HttpHeaders httpHeaders = new HttpHeaders();
    httpHeaders.setLocation(uri);
    return new ResponseEntity<>(httpHeaders, HttpStatus.SEE_OTHER);
}

Answer 6

For external url you have to use "http://www.yahoo.com" as the redirect url.

This is explained in the redirect: prefix of Spring reference documentation.

redirect:/myapp/some/resource

will redirect relative to the current Servlet context, while a name such as

redirect:http://myhost.com/some/arbitrary/path

will redirect to an absolute URL