How to get a request path variable within a Filter? [Micronaut 1.3.2]

Question

Usually in Spring we can retrieve the path variable with:

final Map<String, String> pathVariables = (Map<String, String>) request
                 .getAttribute(HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE);

Here is what I do so far.

Controller:

@Get(value = "/{variable}/anotherpath")
public Single<HttpResponse<ResponseESQ>> myController(String variable)  {}

Filter :

@Filter("/**")
public class myFilter implements HttpServerFilter {
  @Override
  public Publisher<MutableHttpResponse<?>> doFilter(HttpRequest<?> request, ServerFilterChain chain) { 
    // I need here to consume the path variable
    request.getAttribute("variable")
  }
}

I try to use : request.getAttributes() but it doesn't work.

How can we do the same in Micronaut?

Answer 1

Given the following controller with an URI that contains two path variables something and name.

@Controller("/say")
public class SuperController {

  @Get("{something}/to/{name}")
  @Produces
  public String hello(String something, String name) {
    return String.format("%s %s", something, name);
  }
}

You can write a filter that can access the path variables by accessing the io.micronaut.web.router.UriRouteMatch that is contained in io.micronaut.http.HttpMessage#getAttributes.

The following example filter accesses the path variables.

@Filter("/**")
public class SuperFilter implements HttpFilter {
  @Override
  public Publisher<? extends HttpResponse<?>> doFilter(HttpRequest<?> request, FilterChain chain) {
    Optional<UriRouteMatch> uriRouteMatch = request
        .getAttributes()
        .get(HttpAttributes.ROUTE_MATCH.toString(), UriRouteMatch.class);

    if (uriRouteMatch.isPresent()) {
      // access the path variables.
      Map<String, Object> variableValues = uriRouteMatch.get().getVariableValues();
      System.out.println(variableValues);
    }
    return chain.proceed(request);
  }
}

Hope this answers your question. Good luck and have fun with Micronaut.