Injecting a custom response header in RESTEasy JAX-RS

Question

I have RESTEasy (JAX-RS) server with about 60 services (so far). I would like to automatically inject a custom response header to provider callers with the server build time: X-BuildTime: 20100335.1130.

Is there an easy way to do this without modifying each of my services?

I am trying to use a class that implements org.jboss.resteasy.spi.interception.PostProcessInterceptor with annotations @Provider and @ServerInterceptor, but I can't figure out how to modify the ServerResponse that is passed into my postProcess() method.

Solution 1

I think using javax.servlet.Filter will be a much easier solution:

public void doFilter ( ServletRequest request, ServletResponse response, FilterChain chain ) throws IOException, ServletException {
   HttpServletResponse httpResponse = (HttpServletResponse)response;
   httpResponse.setHeadder(header, headerValue);
   chain.doFilter(request, response);
}

configure it in web.xml for the relevant urls, and you are done.

Solution 2

Although MessageBodyWriterInterceptor does the trick, it is better to use PostProcessInterceptor, as it will intercept responses that do not call MessageBodyWriters (such as Response.created(URI.create("/rest/justcreated")).build()).

For more info, see the official documentation.

import java.util.ArrayList;
import java.util.List;

import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.ext.Provider;

import org.jboss.resteasy.annotations.interception.ServerInterceptor;
import org.jboss.resteasy.core.ServerResponse;
import org.jboss.resteasy.spi.interception.PostProcessInterceptor;

@Provider
@ServerInterceptor
public class MyPostProcessInterceptor implements PostProcessInterceptor {

    @Override
    public void postProcess(ServerResponse response) {
        MultivaluedMap<String, Object> headers = response.getMetadata();
        List<Object> domains = headers.get("X-BuildTime");
        if (domains == null) { domains = new ArrayList<Object>(); }
        domains.add("20100335.1130");
        headers.put("X-BuildTime", domains);
    }

}

Solution 3

How about using javax.ws.rs.core.Response ; this way you can set the header in the same place where you create the response-data.

@GET
@Path("/test")
@Produces(MediaType.APPLICATION_JSON)
public Response test(           ){
    HashMap<String,String> ret = new HashMap<String,String>();
    ret.put("foo","bar");
    return Response
       .status(Response.Status.OK)
       .entity(ret)
       .header("X-say", "Hello world!")
       .build();
}

Solution 4

You can also change header by MessageBodyInterceptors

( check the example at the end of section 30.1 )

@Provider
@ServerInterceptor
public class MyHeaderDecorator implements MessageBodyWriterInterceptor {

    public void write(MessageBodyWriterContext context) throws IOException, WebApplicationException
    {
       context.getHeaders().add("My-Header", "custom");
       context.proceed();
    }
}

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Comments

[shonky linux user]

or if you just wanted to add/replace the header regardless of existing you could use: response.getMetadata().putSingle("X-BuildTime", "20100335.1130");