HTTPS Redirect filter for play framework (>=2.5)

HTTPSRedirectFilter.java

package utils.filters;

import akka.stream.Materializer;
import play.Configuration;
import play.mvc.Filter;
import play.mvc.Http;
import play.mvc.Result;

import javax.inject.Inject;
import java.util.concurrent.CompletionStage;
import java.util.function.Function;

import static play.mvc.Results.movedPermanently;

//Note that we create a Filter implementation and not an EssentialFilter one because we do not care about the body
//tested with play framework 2.5
public class HTTPSRedirectFilter extends Filter {

    private boolean httpsRedirect;
    private int sslPort;

    @Inject
    public HTTPSRedirectFilter(Materializer mat, Configuration configuration) {
        super(mat);
        httpsRedirect = configuration.getBoolean("httpsRedirect", false);
        sslPort = configuration.getInt("https.port", 443);
    }

    @Override
    public CompletionStage<Result> apply(Function<Http.RequestHeader, CompletionStage<Result>> nextFilter, Http.RequestHeader rh) {
        if (httpsRedirect) {
            return nextFilter.apply(rh).thenApply(result -> {
                if (!rh.secure()) {
                    return movedPermanently("https://" + rh.host() + ":" + sslPort + rh.uri());
                } else {
                    return result.withHeader("Strict-Transport-Security", "max-age=31536000; includeSubDomains");
                }

            });
        } else {
            return nextFilter.apply(rh);
        }
    }
}