Does chunking incorporate asynchronous execution? How to stream chunks asynchronously?

Question

In the Play Documentation Chunks are introduced as a solution to "streaming content". I am unsure whether streaming content can be produced slowly without blocking the HTTP thread or if I must separately make the convert the Chunks to an AsyncResult by changing (sc is declared as Chunks):

return ok(sc);

to:

return async(play.libs.Akka.future(new Callable<Result>() {
    @Override
    public Result call() throws Exception {
        return ok(sc);
    }
}));

When using the second solution, the chunks aren't appearing incrementally in the browser, and I wanted them to do that. Thanks in advance.

Answer 1

You only have to wrap your result in async if your computation happens in a Promise (Future in 2.1), e.g. when using an Akka actor. The result type is then AsyncResult.

Since Chunks (defined in play.mvc.Results.java) internally uses an Enumerator that pushes the callback's content to an Iteratee, it should be non-blocking.