Paginating over cloud DBs

[samholman]

As per http://docs.rackspacecloud.com/cdb/api/v1.0/cdb-devguide/content/pagination.html, cloud DB list operations (instances, databases, users) return pages (of 20 by default).

The \OpenCloud\Collection class seems to make no reference to pagination so there doesn't seem to be any current means of fetching the full set.

[gecampbell]

You know, I never realized that Cloud DB was paginated by default. I'll take a look at this.

[gecampbell]

I have a prototype implementation for Instances. I've modified the Collection class to support a new API method, NextPage() that returns the object for the next page. I'm not perfectly happy with it; it requires the user to know if the collection could be paginated and to write code to handle it. I may try to rethink this so that it's transparent to the user (e.g., maybe have the Next() method automatically retrieve the NextPage() if it's at the end of a collection).

[gecampbell]

A coworker pointed out that making it transparent to the user may not be the best idea, since there's still overhead in the network call and thus it won't actually be transparent from a performance standpoint. So I'll leave the implementation like it is for the moment. It should work with any Collection where the JSON includes links[rel=next].href.