Redirect to an external URL from controller action in Spring MVC

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,

You can do it with two ways.

First:

@RequestMapping(value = "/redirect", method = RequestMethod.GET)
public void method(HttpServletResponse httpServletResponse) {
    httpServletResponse.setHeader("Location", projectUrl);
    httpServletResponse.setStatus(302);
}

Second:

@RequestMapping(value = "/redirect", method = RequestMethod.GET)
public ModelAndView method() {
    return new ModelAndView("redirect:" + projectUrl);
}

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.

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;
}

You can do this in pretty concise way using ResponseEntity like this:

  @GetMapping
  ResponseEntity<Void> redirect() {
    return ResponseEntity.status(HttpStatus.FOUND)
        .location(URI.create("http://www.yahoo.com"))
        .build();
  }

Another way to do it is just to use the sendRedirect method:

@RequestMapping(
    value = "/",
    method = RequestMethod.GET)
public void redirectToTwitter(HttpServletResponse httpServletResponse) throws IOException {
    httpServletResponse.sendRedirect("https://twitter.com");
}

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);
}

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

Did you try [RedirectView][1] where you can provide the contextRelative parameter?

[1]: http://static.springsource.org/spring/docs/3.0.x/javadoc-api/org/springframework/web/servlet/view/RedirectView.html#RedirectView%28java.lang.String,%20boolean%29 "RedirectView"

This works for me, and solved "Response to preflight request doesn't pass access control check ..." issue.

Controller

    RedirectView doRedirect(HttpServletRequest request){

        String orgUrl = request.getRequestURL()
        String redirectUrl = orgUrl.replaceAll(".*/test/","http://xxxx.com/test/")

        RedirectView redirectView = new RedirectView()
        redirectView.setUrl(redirectUrl)
        redirectView.setStatusCode(HttpStatus.TEMPORARY_REDIRECT)
        return redirectView
    }

and enable securty

@EnableWebSecurity
class SecurityConfigurer extends WebSecurityConfigurerAdapter{
    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.cors().and().csrf().disable()
    }
}

In short "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