Spring UrlHandlerFilter should not strip the trailing slash from root URLs

Affects: 6.2.0-M7

Issue https://github.com/spring-projects/spring-framework/issues/31366 added the new UrlHandlerFilter. That filter should handle root URLs differently by default and not strip the trailing slash from a root URL. It seem reasonable to have a blanket UrlHandlerFilter such as the following in your Spring application:

UrlHandlerFilter.trailingSlashHandler("/**").redirect(HttpStatus.PERMANENT_REDIRECT).build();

For example, a URL such as http://example.com/ is invalid without a trailing slash and browsers (or CURL) do in fact send a trailing slash if you do not specify it for root URLs.

See also: https://webmasters.stackexchange.com/questions/35643/is-trailing-slash-automagically-added-on-click-of-home-page-url-in-browser

Comment From: ghillert

May also be relevant for https://github.com/spring-projects/spring-framework/issues/32830

Comment From: bclozel

Thanks Gunnar for this report (and testing our milestones)!

Comment From: bdshadow

i think, the problem here is more complex.

We have:

server.servlet.contextPath=/myApp

And use the following UrlHandlerFilter:

        UrlHandlerFilter filter = UrlHandlerFilter
            .trailingSlashHandler("/**").wrapRequest()
            .build();

And in this case, both http://localhost:8080/myApp/items and http://localhost:8080/myApp/items/ work fine, however, http://localhost:8080/myApp and http://localhost:8080/myApp/ don't and return 404.

Controller for the root looks like this:

@Controller
@RequestMapping("/")
public class MyAppUiController {
    @GetMapping(value = {"/", "greeting"}, produces = MediaType.APPLICATION_JSON_VALUE)
    public ModelAndView greeting() {
        ModelAndView mav = new ModelAndView("greeting");
        return mav;
    }
}

So when you have server.servlet.contextPath specified, it doesn't work

Comment From: bclozel

@bdshadow I don't think this is related to this particular issue. Can you create a new one with a minimal application that reproduces the problem?

Comment From: bdshadow

@bclozel thank you for your reply. Here is the issue: https://github.com/spring-projects/spring-framework/issues/33565 and a minimal app: https://github.com/bdshadow/SpringTrailingSlashTestProject