Interceptors: path filtering

[marloncarvalho]

We should be able to define the paths that trigger an interceptor. For example, an interceptor should be executed only in paths starting with 'api/private/'.

[marloncarvalho]

It can be accomplished in an interceptor checking the URI. For example, chain.request.uri.indexOf('api/private') > -1. I'm not sure whether we should implement it or not.