On Thu, Feb 5, 2015 at 12:04 PM, Brion Vibber <bvibber@wikimedia.org> wrote:
    • Versioning? What if we add or remove a field from the response? We should version this. Can we do this easily?

In RESTBase we generally use mime type versioning like this:

application/json; profile=mediawiki.org/specs/app_page_bundle/1.0.0

This is specced in the Swagger spec & enforced by RESTBase. On version mismatch from stored content, the backend service is called to re-generate or upgrade the content, which is then saved back. It can be passed the stored content to make re-generation more efficient.

If needed, clients could also signal the content-type they expect with an accept header. The details of how things would then be upgraded / downgraded would need to be worked out in case you really need this. In general, you can go a long way by only adding properties while remaining backwards-compatible with the old properties.

We also distinguish stability per end point:

  • experimental end points can change at any time (effectively private, use at your own risk)
  • unstable end points can change, but we make an effort to avoid breakage and notify users
  • any change to stable end points will increment the major API version (/v1/) following semver
The mobile API should probably be marked as experimental, as it is primarily intended as an API for apps we control.

Gabriel