Possible to handle routes for base URI without path from extensions

[mabartos]

Description

In our custom extension (Keycloak), I've encountered the impossibility of defining RouteBuildItem for the base URI without path when the root-path (quarkus.http.root-path) is different than "/".

The thing is that I want to automatically redirect from the base URI to the root-path endpoint.

The case:
quarkus.http.root-path=/auth => our app is accessible on localhost:8080/auth
When I access localhost:8080, I want to be redirected to the localhost:8080/auth.

I tried to build my own RouteBuildItem with the HttpRootPathBuildItem, but I'm not able to do it for the base URI, when the root-path is specified.

See this code (pseudo):

@Record(ExecutionTime.STATIC_INIT)
@BuildStep
RouteBuildItem configureRedirectForRootPath(KeycloakRecorder recorder, HttpRootPathBuildItem httpRootPathBuildItem){
    return httpRootPathBuildItem.routeBuilder()
                .route("/")
                .handler(routingContext -> routingContext.redirect("/auth"))
                .build();
}

But it is not possible to do it with a specified route("/") as an absolute path - it's evaluated as relative path to the root-path. When I change the route to something else (route("/something") and then access it, everything works as expected.

Or is there any other approach how to achieve it?

Implementation ideas

Consider .route("/") as an absolute path unrelated to quarkus.http.root-path. Or is it problematic in some cases?

[cescoffier]

This is the code deciding where to mount the route:

if (route.startsWith(buildItem.getRootPath())) {
                // relative to http root (leading slash for vert.x route)
                this.path = "/" + UriNormalizationUtil.relativize(buildItem.getRootPath(), route);
                this.routerType = RouteType.APPLICATION_ROUTE;
            } else if (route.startsWith("/")) {
                // absolute path
                this.path = route;
                this.routerType = RouteType.ABSOLUTE_ROUTE;
            }

I don't see why your route would be mounted on the application router and not as an absolute route.

[mabartos]

@cescoffier The problem is in URI normalization in resolvePath():

route = super.absolutePath = buildItem.resolvePath(route);

Leading to the normalizeWithBase() method.

When considering rootPath=/auth:

UriNormalizationUtil.normalizeWithBase("/auth", "/", false).getPath();  // returns '/auth/'

UriNormalizationUtil.normalizeWithBase("/auth", "/", true).getPath(); // returns '/' => required behavior

[mabartos]

@cescoffier Might this be considered as a fix?

#42896