OpenStack-SDK-PHP/Design/JSON-schema

We've discussed several times the best way to define services in the SDK. These are our three options:

1. JSON-schema 2. Guzzle's DSL 3. Hand-coding everything

Based on our discussions, we seem to have agreed that JSON schemas were the best options, because:

- It's a standard format that lots of APIs use, including: OpenStack Glance, OpenStack Keystone (future), Google Discovery API, Heroku - It's being implemented into OpenStack common soon - It avoids duplication - It allows us to RAPIDLY implement new features. For example, I defined the Compute API in 1 day. To do that in normal code would have take 3-5 days. - As we add new features, we don't need to write new unit tests because the parsing feature is already fully tested - It's more scalable and responsive

A parsing feature should:

- Validate data according to a schema - Consume remote schemas (from an API) or local schema files - Parse data into models objects for users to use