Sync and Datastore APIs reach 3.0 beta

Dropbox has released the 3.0 beta of its Sync and Datastore APIs for Android, iOS, and OS X. The update brings a range of additions to the Datastore API alongside a smaller set of changes to the Sync API. This is a major release with breaking changes, so developers should review the full changelog before upgrading.

Datastore metadata and sizing improvements

The Datastore API now exposes additional metadata on datastore objects. A title field lets developers attach a user-friendly name, while mtime reports the last modification time. Developers also get visibility into datastore size through three new properties:

  • size — current datastore size in bytes
  • recordCount — total number of records
  • unsyncedChangesSize — size in bytes of changes queued for upload on the next sync call

Record-level size information is now available as well, calculated by summing the size of all field values plus the base size of an empty record.

More flexible datastore IDs

Developers can now create datastores using meaningful local identifiers like "settings", rather than relying only on the default datastore ID "default". In addition, the maximum length for datastore, table, record, and field IDs has been increased to 64 characters. The release also includes fixes for edge cases in syncing and conflict resolution.

Preview: local datastores

An experimental preview introduces local datastores, which let apps use datastore functionality without requiring a Dropbox login upfront. Users can start working immediately and sign in later to sync data. Dropbox notes this feature is not production-ready and should be treated as a preview only.

Sync API and platform updates

On the Sync API side, 3.0 adds a configurable file-system cache size and batching of file-system operations for faster uploads. Android gains multiple account support, a feature already present on iOS and OS X, along with background thread errors for DbxDatastoreStatus. For iOS and OS X, DBDatastoreStatus and DBSyncStatus now include more detail, including background thread errors.

The beta SDKs are available for download, and feedback can be submitted through the Dropbox developer forum.