Should Strings returned from a Controller be wrapped in quotes when the Content-Type is application/json?

[mjohnston-il]

When I define a controller endpoint that returns a String object (or HttpResponse) and the @produces("application/json") annotation is present (or omitted completely - it's the default), the response that is written to the client is not a valid JSON response because the String isn't (necessarily) a quoted String. Is this something that Micronaut should handle automatically? A non-String object is automatically serialized to a JSON string, why wouldn't we wrap a String response with quotes to make it a valid JSON string?

Thoughts?

@Get("/echo")
@Produces(MediaType.APPLICATION_JSON)
fun echo(@QueryValue("ping")ping: String) : String {
    return ping
}

[yawkat]

The reason for the special behavior for String is that we want to allow users to return "raw" json without using our serialization logic. If you want to return a json scalar string, you could return a JsonNode instead.

[mjohnston-il]

I can understand that but it seems ... unintuitive. I would assume that using a different serializer and outputting already formatted JSON is a fairly uncommon case. Couldn't that be handled with a marker annotation telling the system to not escape the String? I realize that for backwards compatibility reasons it might be too late to make a change here regardless.

[yawkat]

It might be possible. But you are right in that it wouldn't be backwards-compatible.