Vertx JWKS/JWT verification throws a 500 with no errors logged - jwt

Question

I have a very basic Vertx demo I'm trying to create that fetches a JWK from an endpoint and creates an RSAPublicKey for verifying a JWT signature:
package example;
import com.auth0.jwk.JwkException;
import com.auth0.jwk.JwkProvider;
import com.auth0.jwt.interfaces.DecodedJWT;
import io.vertx.core.AbstractVerticle;
import io.vertx.core.Promise;
import io.vertx.core.http.HttpServer;
import io.vertx.ext.web.Router;
import com.auth0.jwk.UrlJwkProvider;
import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import java.net.MalformedURLException;
import java.net.URL;
import java.security.interfaces.RSAPublicKey;
import com.auth0.jwt.interfaces.RSAKeyProvider;
import java.security.interfaces.RSAPrivateKey;
public class MainVerticle extends AbstractVerticle {
#Override
public void start(Promise<Void> startPromise) throws Exception {
HttpServer server = vertx.createHttpServer();
Router router = Router.router(vertx);
router.route().handler(routingContext -> {
String authHeader = routingContext.request().getHeader("Authorization");
// pull token from header
String token = authHeader.split(" ")[1];
URL jwksEndpoint = null;
try {
jwksEndpoint = new URL("http://localhost:1080/jwks");
} catch (MalformedURLException e) {
e.printStackTrace();
}
JwkProvider jwkProvider = new UrlJwkProvider(jwksEndpoint);
RSAKeyProvider keyProvider = new RSAKeyProvider() {
#Override
public RSAPublicKey getPublicKeyById(String kid) {
//Received 'kid' value might be null if it wasn't defined in the Token's header
RSAPublicKey publicKey = null;
try {
publicKey = (RSAPublicKey) jwkProvider.get(kid).getPublicKey();
} catch (JwkException e) {
e.printStackTrace();
}
return publicKey;
}
#Override
public RSAPrivateKey getPrivateKey() {
return null;
}
#Override
public String getPrivateKeyId() {
return null;
}
};
Algorithm algorithm = Algorithm.RSA256(keyProvider);
JWTVerifier verifier = JWT.require(algorithm)
.withIssuer("auth0")
.build();
DecodedJWT jwt = verifier.verify(token);
System.out.println(jwt);
routingContext.next();
});
router.route("/hello").handler(ctx -> {
ctx.response()
.putHeader("content-type", "text/html")
.end("<h1>Hello from non-clustered messenger example!</h1>");
});
server.requestHandler(router).listen(8888, http -> {
if(http.succeeded()) {
startPromise.complete();
System.out.println("HTTP server started on port 8888");
} else {
startPromise.fail(http.cause());
}
});
}
}
The problem is that when I make request to the /hello endpoint, the application immediately returns a 500. But nothing appears in the logs (even at debug level).
I've tried manually specifying the kid property to rule out the jwkProvider not returning properly
I'm at a loss at how to gain any more insight into what is failing.

Answer 1

Turns out to completely be my oversight. Wrapping that verifier.verify() call in a try/catch showed me that I was expecting an issuer. This is the same problem I was having while trying to achieve this in Quarkus! I was able to remove that from the builder and now this works perfectly.