Google Cloud Endpoints allowed method's return types
I'm developing a REST API using Cloud Endpoints. I know that as per the documentation each API method should return an entity that is then automatically converted to a valid JSON string.
However, I'm dealing with an authentication library that in some cases returns a JSON which should be passed back to the client as a response.
Sticking with the default approach, meaning returning an entity, would still be possible, but it would involve a number of obnoxious intermediate steps, like parsing the JSON and filling the right fields of the entity to be returned according to the JSON content.
I was wondering if there is a more straightforward way to instruct the API to directly return the JSON string, instead of converting it to an entity just to have it translated back to the source JSON.