Setting media type (json for eg) manually not working for certain cases.

[chirans]

As a continuation of discussion we had in Google group, please find the following observations:-

The below response handling doesn't work when I use it with use(new Jackson());

response.status(Status.OK).type(MediaType.json).send("{\"status\":\"failed\", \"msg\" : \"" + msg + "\"}");

But it works if I comment use(new Jackson()); out, not sure if this is expected.

Unfortunately, setting MediaType json manually doesn't work in deferred API and hence I'd need to resort to use(new Jackson()); to send JSON response from a deferred API by returning map (Jackson would convert to JSON)

[jknack]

There two issues here:

1-- writing raw json doesn't work bc Jackson outputs String, primitives or similar as valid JSON. There are a lot of discussion around this... but there is no formal/unique solution.

For this specific use case I suggest you to write a custom render, like:

    /** Raw JSON renderer .*/
    renderer((value, ctx) -> {
      if (value instanceof String && ctx.accepts(MediaType.json)) {
        ctx.send(value.toString());
      }
    });

    use(new Jackson());

So, here you test for a String output and application/json and write directly.

Please note the custom renderer is on top of the Jackson module. Renderers in jooby are executed in the order they were provided.

2-- We do have a bug while returning results from Deferred API, this is now fixed and this is now possible:

    get("/482/raw", promise(deferred -> {
      exec.execute(deferred.run(() -> Results.json("{\"status\":\"success\"}")));
    }));

[paul-hammant]

Would love a one-liner for this: stringsWillBeJson();