Jonas c5fd4de09b Implement labeling frontend and the backend support it needs
Add a framework-free HTML/CSS/JS labeling UI: set/session/status
filters, a frame browser, drag-to-draw/move/resize bounding boxes with
a per-set class picker, per-frame status control, and Left/Right frame
navigation. No login - a locally cached username is sent for
attribution only, matching the backend's get-or-create user model.

Backend additions the frontend needed: serve frame images from a
configurable FRAMES_ROOT via a /images static mount, permissive CORS
(internal tool, not publicly exposed), and a GET /sets/{id}/frames
endpoint returning frames joined with their per-set label status
(defaulting missing rows to unlabeled) for the frame browser.

Verified the full call chain end-to-end against a running backend +
static frontend server (set/class creation, frame ingest, image
serving, label CRUD, status updates, CORS preflight) - every field
name the JS reads matches the API responses. 18/18 backend tests
pass. Not yet verified: actual interactive browser use (no browser
tooling available here) - try drag-to-draw/resize locally.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
2026-07-16 11:34:26 +02:00
..

Labeling Tool — Backend

API + data model for the bounding-box labeling tool. See CLAUDE.md §3.2 for the full requirements this is built against.

Status: core data model + CRUD API implemented (sets, hierarchical classes, frames, labels, per-frame/per-set status). Not yet implemented: dataset versioning/promotion (enemy-v1, enemy-v2, ...) — deferred since it needs its own design pass (snapshot semantics: labels are editable at any time, but a promoted dataset version must stay reproducible). Also not yet implemented: any frontend, auth/login (see below), or the active-learning auto-label workflow.

Stack

  • FastAPI + SQLAlchemy (2.0), SQLite by default (./labeling.db), swappable via the DATABASE_URL env var (e.g. to Postgres later without code changes — one Postgres-compatible ORM).
  • Multi-user, no auth yet: labels/status changes take a plain created_by / updated_by username string, resolved via get-or-create (users.py). There's no login flow — attribution only, since there's no UI yet that would need real auth.

Data model

  • LabelSet — a label set (Enemy, Items, Traps, ...), one per detector model.
  • MainClass / SubClass — the per-set Main → Sub class hierarchy (e.g. EnemyBat, Snake), created ad hoc via the API, no migration needed to add classes.
  • Frame — one labelable image, identified by (session_name, frame_index) — matches the recording tool's frame-extraction output 1:1.
  • Label — one bounding box (x, y, width, height in pixel space), scoped to a frame + set + sub-class.
  • FrameSetStatus — per-frame, per-set label state (unlabeled / auto_labeled / reviewed).

Setup

python -m venv .venv
source .venv/bin/activate
pip install -e ".[dev]"

Run

spelunkai-labeling-backend
# or: uvicorn spelunkai_labeling_backend.main:create_app --factory --reload

Interactive API docs at http://127.0.0.1:8000/docs once running.

Testing

pytest

Each test gets a fully isolated app + SQLite file via create_app(database_url=...) (see tests/conftest.py) — no shared state between tests, no real server needed.