Spring Cloud Zuul: Apply filter only to specific route

Question

I'm using Spring Cloud's Zuul to proxy some API requests to a few external servers. The proxying itself works well, but each service requires a (different) token provided in the request header.

I've successfully written a simple pre filter for each token that applies the appropriate header. However, I now have a problem. Even after pouring through the documentation, I can't figure out how to make each filter apply only to the proper route. I don't want to perform url-matching as the url changes across environments. Ideally, I'd have some way to get the name of the route in the filter.

My application.yml:

zuul:
  routes:
    foo:
      path: /foo/**
      url: https://fooserver.com
    bar:
      path: /bar/**
      url: https://barserver.com

Ideally I'd like to do something like this in FooFilter.java (a prefilter):

public bool shouldFilter() {
    return RequestContext.getCurrentContext().getRouteName().equals("foo");
}

but I can't seem to find any way to do this.

Answer 1

You can use proxy header in RequestContext to distinguish routed server like below. If you are using ribbon, you can also use serviceId header. But if you specify url direclty like above your example, you should use proxy header. One thing you have to know is that proxy header is set in PreDecorationFilter, so your pre-filter must have bigger value of filter order than the value that PreDecorationFilter has (it is 5 at this moment).

@Override
public int filterOrder() {
    return 10;
}

@Override
public boolean shouldFilter() {
    RequestContext ctx = RequestContext.getCurrentContext();

    if ((ctx.get("proxy") != null) && ctx.get("proxy").equals("foo")) {
        return true;
    }
    return false;
}