如何在Spring Boot中重定向单页应用程序？

Question

I have a signup endpoint for a Spring Boot app. The UI is a React Single Page App.

I want to make the SPA app redirect to "/login" (making a GET request).

How should I do this?

I tried the following two approaches:

The first approach doesn't work as the response http code in postman is 200 and the body only includes "redirect:/login"

@RequestMapping(value = "/signup", method = RequestMethod.POST)
public String signup(@RequestBody CustomUserDetails user, HttpServletResponse response) {

    String userName = user.getUsername();
    logger.debug("User signup attempt with username: " + userName);

    try{
        if(customUserDetailsService.exists(userName))
        {
            logger.debug("Duplicate username " + userName);
            return "redirect:/login";
        } else {
            customUserDetailsService.save(user);
            authenticateUserAndSetSession(user, response);
        }
    } catch(Exception ex) {
    }
            return "redirect:/login";
}

I also tried the following approach. But it throws Method Not Allowed exception. Because I have a controller for login when the request is of type POST

@RequestMapping(value = "/signup", method = RequestMethod.POST)
public ModelAndView signup(@RequestBody CustomUserDetails user, ModelMap model, HttpServletResponse response) {

    String userName = user.getUsername();
    logger.debug("User signup attempt with username: " + userName);

    try{
        if(customUserDetailsService.exists(userName))
        {
            logger.debug("Duplicate username " + userName);
            return new ModelAndView("redirect:/login", model);
        } else {
            customUserDetailsService.save(user);
            authenticateUserAndSetSession(user, response);
        }
    } catch(Exception ex) {
    }
    return new ModelAndView("redirect:/redirectedUrl", model);
}

How am I supposed to handle this redirect ? What is the best practice ?

Answer 1

The best practice is you shouldn't redirect in the Spring Boot Controllers at all.

What you need to do is return status codes from /signup endpoint.

@RequestMapping(value = "/signup", method = RequestMethod.POST)
public ResponseEntity<String> signup(@RequestBody CustomUserDetails user, HttpServletResponse response) {

    String userName = user.getUsername();
    logger.debug("User signup attempt with username: " + userName);

    try{
        if(customUserDetailsService.exists(userName))
        {
            logger.debug("Duplicate username " + userName);
            return new ResponseEntity<String>(HttpStatus.OK);
        } else {
            customUserDetailsService.save(user);
            authenticateUserAndSetSession(user, response);
        }
    } catch(Exception ex) {
    }
    return new ResponseEntity<String>(HttpStatus.NOT_FOUND);
}

So the endpoint will return HTTP status 200 when there is a User with the username in the system and HTTP status 404 when there is no User found with the given username. You have to use this information to make the Routing in the Front End Single Page Application (This is how it is done in AngularJS, etc.)