Designing and Building an API converter

[samuelmarks at gmail.com]

How would I go about building an API converter?

I have multiple different APIs with different schemas serialised in XML or JSON which I need to output as a standardised schema.

Other features needed:
- Authentication (i.e.: can't get/set data unless you're from a certain DNS xor have the correct user+pass)
- Role/Scope limitation (i.e.: you can't access everything in our database, only what your role allows for)

Is this the sort of problem I would use Slumber (http://slumber.in/) for?

Or would there be a different library you'd recommend?

Thanks for all suggestions,

Alec Taylor