How to configure ETag response header in standalone.xml in wildfly 12 server?

Question

I want to add etag attribute in each response. I've added the vary-header and a cache-control header (with max-age=600, public) to the responses but i did not find any solution to add etag in response. Can anyone help me please?

Answer 1

The ETag header is just an additional header like the cache-control header you already added. Have a look at the following sample code for generating a ETag header in a JAX-RS resource:

@GET
@Path("/yourResource/{id}")
public Response getPerson(@PathParam("id") String name, @Context Request request){
    CacheControl cc = new CacheControl();
    cc.setMaxAge(86400);

    Response.ResponseBuilder rb = null;

    EntityTag etag = new EntityTag(someService.getById(id).hashCode()+"");

    responseBuilder = req.evaluatePreconditions(etag);

    if (responseBuilder != null) {
       return responseBuilder.cacheControl(cc).tag(etag).build();
    }

    responseBuilder = Response.ok(UserDatabase.getUserById(id)).cacheControl(cc).tag(etag);
    return responseBuilder .build();
}