spark-java: Path exclusion in before filter

Question

I'm new to the spark-java framework and I was wondering if anyone has a good solution for checking if a user is authenticated. If the user isn't authenticated, I want to redirect to "/login". The best solution for this is in a before filter in my opinion. But then we have a redirect loop.

public static void main(String[] args) {
    before((req, res) -> {
        User usr = new User("DUMMY");
        if (!Authentication.isUserAuthenticated(usr)) {
            res.redirect("/login");
        }
    });
    get("/login", (req, res) -> {
        return "Sir, your credentials please!";
    });
    get("/", (req, res) -> {
        return "Welcome!";
    });
}

Is there any way to exclude a specific path? Or do you have any adivice for a better solution?

best regards, Philipp

Answer 1

I think a better approach wold be halting with the http not authorized status instead of redirecting. You cold do so by replacing the redirection in your before filter with halt(401). Then you should handle this status code in your client code. Are you using any framework for your client code, like AngularJs ?