How can I add an http interceptor to a Quarkus application?

Question

I would like to add an HTTP interceptor to my Quarkus application so I can intercept all HTTP requests. How can such that be achieved?

Answer 1

Quarkus uses RESTEasy as its JAX-RS engine. That means that you can take advantage of all of RESTEasy's features, including Filters and Interceptors.

For example to create a very simple security mechanism, all you would need to do is add code like the following:

@Provider
public class SecurityInterceptor implements ContainerRequestFilter {
    @Override
    public void filter(ContainerRequestContext context) {
        if ("/secret".equals(context.getUriInfo().getPath())) {
          
  context.abortWith(Response.accepted("forbidden!").build());
        }
    }
}

It should be noted that this only works for requests that are handled by JAX-RS in Quarkus. If the requests are handled by pure Vert.x or Undertow, the filtering mechanisms of those stacks will need to be used.

UPDATE

When using Quarkus REST (which used to be called RESTEasy Reactive) with Quarkus, the @ServerRequestFilter annotation can be used instead of implementing ContainerRequestFilter. See this for more information

class Filters {

    @ServerRequestFilter(preMatching = true)
    public void preMatchingFilter(ContainerRequestContext requestContext) {
        // make sure we don't lose cheese lovers
        if("yes".equals(requestContext.getHeaderString("Cheese"))) {
            requestContext.setRequestUri(URI.create("/cheese"));
        }
    }

    @ServerRequestFilter
    public Optional<RestResponse<Void>> getFilter(ContainerRequestContext ctx) {
        // only allow GET methods for now
        if(ctx.getMethod().equals(HttpMethod.GET)) {
            return Optional.of(RestResponse.status(Response.Status.METHOD_NOT_ALLOWED));
        }
        return Optional.empty();
    }
}