Injecting a custom response header in RESTEasy JAX-RS

I have RESTEasy (JAX-RS) server with about 60 services (so far). I would like to 开发者_开发问答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.

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);
    }

}

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.

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();
}

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();
    }
}