fix: return S3-URLs for snapshots

src/routers/analytics.py

@@ -527,6 +527,25 @@ def _ensure_detection_visible(db: Session, detection: OccupancyObservation, user
     )
 
 
+def _available_artifact_url(
+    metadata: dict[str, Any],
+    variant: str,
+) -> str | None:
+    snapshots = metadata.get("snapshots")
+    if not isinstance(snapshots, dict):
+        return None
+
+    artifact = snapshots.get(variant)
+    if not isinstance(artifact, dict):
+        return None
+
+    url = artifact.get("url")
+    if not isinstance(url, str) or not url.strip():
+        return None
+
+    return url
+
+
 # ---------------------------------------------------------------------------
 # Time and aggregation helpers
 # ---------------------------------------------------------------------------
@@ -800,6 +819,9 @@ def _serialize_detection_run(
         error_code=_to_str_or_none(_metadata_value(metadata, "error_code")),
         error_message=_to_str_or_none(_metadata_value(metadata, "error_message", "error")),
         has_feedback=observation.observation_id in feedback_ids,
+        raw_snapshot_url=_available_artifact_url(metadata, "raw"),
+        annotated_snapshot_url=_available_artifact_url(metadata, "annotated"),
+        yolo_labels_url=_available_artifact_url(metadata, "labels"),
     )
 
 

src/routers/cameras.py

@@ -533,12 +533,7 @@ def _stored_snapshot_response(
 # GET /cameras/{camera_id}/snapshot
 # ---------------------------------------------------------------------------
 
-@router.get(
-    "/{camera_id}/snapshot",
-    response_class=Response,
-    responses=SNAPSHOT_IMAGE_RESPONSES,
-)
-def get_camera_snapshot(
+def _legacy_get_snapshot(
     camera_id: int,
     current_user: Annotated[User, require("cameras.view")],
     db: Annotated[Session, Depends(get_db)],

src/schemas/analytics.py

@@ -151,6 +151,9 @@ class DetectionRun(BaseModel):
     error_code: str | None
     error_message: str | None
     has_feedback: bool
+    raw_snapshot_url: str | None
+    annotated_snapshot_url: str | None
+    yolo_labels_url: str | None
 
 
 class DetectionRunListResponse(BaseModel):

tests/test_snapshot_routes.py

@@ -1,15 +1,17 @@
 from __future__ import annotations
 
+from datetime import datetime, timezone
 import os
 import unittest
 
 os.environ.setdefault("DATABASE_URL", "sqlite://")
 
+from src.db_models import OccupancyObservation  # noqa: E402
 from src.routers import analytics, cameras  # noqa: E402
 
 
 class SnapshotRouteContractTests(unittest.TestCase):
-    def test_snapshot_is_exposed_by_cameras_only(self):
+    def test_separate_detection_artifact_endpoints_remain_removed(self):
         analytics_paths = {route.path for route in analytics.router.routes}
         camera_paths = {route.path for route in cameras.router.routes}
 
@@ -21,7 +23,54 @@ def test_snapshot_is_exposed_by_cameras_only(self):
             "/admin/analytics/detections/{detection_run_id}/labels",
             analytics_paths,
         )
-        self.assertIn("/cameras/{camera_id}/snapshot", camera_paths)
+        self.assertNotIn("/cameras/{camera_id}/snapshot", camera_paths)
+
+    def test_detection_response_keeps_public_s3_artifact_urls(self):
+        raw_url = "https://s3.example.test/detections/42/raw.jpg"
+        annotated_url = "https://s3.example.test/detections/42/annotated.jpg"
+        labels_url = "https://s3.example.test/detections/42/labels.txt"
+        observed_at = datetime(2026, 7, 23, 12, 0, tzinfo=timezone.utc)
+        detection = OccupancyObservation(
+            observation_id=42,
+            zone_id=9,
+            camera_id=17,
+            source_type="detector",
+            capacity=8,
+            occupied=3,
+            confidence=0.9,
+            observed_at=observed_at,
+            ingested_at=observed_at,
+            metadata_json={
+                "snapshots": {
+                    "raw": {"url": raw_url},
+                    "annotated": {"url": annotated_url},
+                    "labels": {"url": labels_url},
+                }
+            },
+        )
+
+        result = analytics._serialize_detection_run(
+            db=None,  # type: ignore[arg-type]
+            observation=detection,
+            feedback_ids=set(),
+        )
+
+        self.assertEqual(result.raw_snapshot_url, raw_url)
+        self.assertEqual(result.annotated_snapshot_url, annotated_url)
+        self.assertEqual(result.yolo_labels_url, labels_url)
+
+    def test_invalid_or_missing_s3_artifact_urls_are_null(self):
+        metadata = {
+            "snapshots": {
+                "raw": {"url": "   "},
+                "annotated": {"object_key": "annotated.jpg"},
+                "labels": "https://s3.example.test/labels.txt",
+            }
+        }
+
+        self.assertIsNone(analytics._available_artifact_url(metadata, "raw"))
+        self.assertIsNone(analytics._available_artifact_url(metadata, "annotated"))
+        self.assertIsNone(analytics._available_artifact_url(metadata, "labels"))
 
 
 if __name__ == "__main__":