[FIXED] Spring Boot forward request internally based on a parameter

Issue

I'm making calls to my API for different kind of custom events like:

const eventTypes = [
    'cards.addCard'
    'cards.updateCard',
    'lanes.addLane',
    'lanes.updateLane'
];

fetch(`http://localhost:8080/app/${roomId}/${eventType}`, {
    method: 'POST'
    body: JSON.stringify(data)
    ...
});

The eventType path variable should define which one of these controller methods will be called:

@RestController
@RequestMapping(value = "/cards")
public class CardController {

    @PostMapping("/{roomId}/createCard")
    public void createCard(@PathVariable Long roomId, @RequestBody MyEventData eventData) {
        ...
    }

    @PostMapping("/{roomId}/updateCard")
    public void updateCard(@PathVariable Long roomId, @RequestBody MyEventData eventData) {
        ...
    }

}

@RestController
@RequestMapping(value = "/lanes")
public class LaneController {

    @PostMapping("/{roomId}/addLane")
    public void addLane(@PathVariable Long roomId, @RequestBody MyEventData eventData) {
        ...
    }

    @PostMapping("/{roomId}/updateLane")
    public void updateLane(@PathVariable Long roomId, @RequestBody MyEventData eventData) {
        ...
    }

}

I prefer to use eventType from the path variable of the request but I can also put it inside the request body.

So how is it possible to forward a request in the same API to the right Controller's method by using its parameter (eventType)? For example:

http://localhost:8080/app/2/cards.addCard should call CardController.createCard() http://localhost:8080/app/2/lanes.updateLane should call LaneController.updateLane()

Solution

you can just switch the roomId with the eventType in the path attribute, like this :

@PostMapping("/createCard/{roomId}")

@PostMapping("/updateCard/{roomId}")
...

If you want to do a redirect, you can create a Filter that do a redirect based on the eventTyp, here is an example of doFilter implementation :

@Override
public void doFilter (ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException
{
    HttpServletRequest req = (HttpServletRequest) request;
    HttpServletResponse res = (HttpServletResponse) response;

    String path = req.getRequestURI();


    if (path.equals("/a")) {
        req = new HttpServletRequestWrapper((HttpServletRequest) request) {
            @Override
            public String getRequestURI() {
                return "/b";
            }
        };
    }

    chain.doFilter (req, res);
}

Ref : SpringBoot possible filter issue with redirection

Answered By - Zouhair Dre