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 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();
    }
}