Response validation modifies payload

[hueniverse]

Unlike input validation, responses should not be modified to comply with validation rules (e.g. casting a string to a number).

[worklez]

Would it be a valid use case to allow response objects to be stripped by validator? Consider following scenario:

1. Server is configured with validation: { stripUnknown: true }
2. Route config has its response: { schema: Joi... } specified
3. Request handler retrieves a doc which has more keys than needed for the response, but otherwise its satisfies the schema; and calls reply(doc).

As of now, validation would succeed but the response would contain full set of keys, including those not matched by the validator.

This commit Qey@0bb2152 enables response modifications but they're not restricted to stripping.

[hueniverse]

Open a new issue requesting this feature. I'll consider it.