GSoC 2026 – Week 10: Hardening As-Of and Fixing Snapshot Consistency

Initiatives Google Summer of Code
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Project: Time-Travel Data Access and Versioning UI for istSOS Web Administration
Organization: OSGeo / istSOS4
Contributor: Bhudev Bhanpuriya
Mentors: Massimiliano Cannata, Daniele Strigaro, Claudio Primerano

I performed the following tasks during this week:

  • 1d9348b — Grey out row actions in Snapshot mode: Updated the Datastream Table so that edit and delete actions remain visible but are disabled in Snapshot mode, with appropriate read-only tooltips. Also fixed the table re-rendering issue when switching between live and snapshot modes and added the corresponding English and Italian translations.

  • 7bd11f0 — Unpin the Snapshot chart window: Changed the Snapshot chart window from a strict restriction to a default anchor. The chart now opens on [as_of − 7d, as_of] when observations are available and falls back to the latest observation when the snapshot window is empty. Also extracted shared observation-window calculations into a reusable utility.

  • 1756980 — Resolve Snapshots server-side: Fixed a major issue where $as_of requests made from the browser failed because the Docker API hostname could not be resolved and the backend did not provide CORS headers. Snapshot reads now go through Next.js route handlers and are resolved server-side. Also added endpoint validation, explicit error handling, and fixed Datastream Table refresh behavior when changing or leaving Snapshot mode.

  • 5882589 — Build the timeline from version validity: Updated the Timeline Scrubber to reconstruct version history using systemTimeValidity instead of relying only on the /Commits endpoint, allowing historical versions to be correctly traversed even when the commit endpoint only exposes the current version.

  • e989610 — Fix Snapshot timestamp boundaries: Fixed an issue caused by the difference between the backend’s microsecond timestamp precision and the second-level precision used by $as_of. Added safe earliest and latest valid snapshot boundaries so timeline navigation, commit ticks, and recovery actions resolve to timestamps that the backend can successfully handle.

  • Verification and testing: Verified the complete implementation using tsc --noEmit, automated assertions for timestamp boundary handling, and integration tests against a running istSOS4 backend. Snapshot resolution, authentication/token forwarding, version traversal, and API boundary behavior were tested successfully.

Details can be found in:

What do I plan to do next week?

  • Address any additional review comments and backend issues identified during testing.

  • Continue the frontend implementation of the from_to temporal navigation workflow.

  • Integrate the approved from_to design with the existing temporal navigation architecture.

  • Begin connecting the from_to workflow with the relevant backend APIs.

Am I blocked on anything?

No, currently I do not have any blocking issues.

Note: This report covers the work completed during Week 10. I missed posting the update last week, so I’m sharing it now for completeness.

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Regards,

Bhudev Bhanpuriya (GitHub)