Advanced use of to_xml and to_json

Hello,

I'm working on a Rails app which has a REST API. I manage two formats
JSON and XML.
Very often to simplify the use if the API, I'm making includes. But when
you add params to to_json and to_xml like :only, :except, it's not only
applied on the root object but on all the objects included.

Do you know libs or methods to answer to these different problems:
* Tell never return a user password in the API
* Tell always include a relationship or a method in each user serialized
in the API
* Serialize objects depending on context. For exemple, when a user ask
for the user list, he should see its complete profile, a partial profile
of its friends and just the name of others...
* Don't have to copy paste the parameters for xml and json

Thank you very much,
Camille Roux

Hi Camille,