fix: make screenshot retry idempotent

apps/api/app/routers/submissions.py

@@ -19,7 +19,7 @@ from ..dependencies import Db
 from ..importer import normalize
 from ..models import Bait, BaitKind, CatchReport, Fish, ModerationStatus, SourceType, Spot, SubmissionAttempt, Waterbody
 from ..schemas import CatchReportAccepted, CatchReportCreate
-from ..storage import ScreenshotError, upload_screenshot
+from ..storage import ScreenshotError, delete_screenshot, upload_screenshot
 from ..submission_security import check_rate_limit
 from ..tackle_components import replace_tackle_components
 from rf4_research.gear_components import from_catch_fields
@@ -77,21 +77,31 @@ def create_catch_report(payload: CatchReportCreate, request: Request, db: Db, id
 
 @router.post("/api/v1/catch-reports/{report_id}/screenshot", status_code=204, response_class=Response)
 def add_screenshot(report_id: UUID, db: Db, screenshot: UploadFile = File(), upload_token: Annotated[str | None, Header(alias="X-Upload-Token")] = None) -> Response:
-    report = db.get(CatchReport, report_id)
+    report_query = select(CatchReport).where(CatchReport.id == report_id)
+    if db.bind is not None and db.bind.dialect.name == "postgresql":
+        report_query = report_query.with_for_update()
+    report = db.scalar(report_query)
     if report is None or report.source_type != SourceType.user or report.moderation_status != ModerationStatus.pending:
         raise HTTPException(status_code=404, detail="pending catch report not found")
     supplied_hash = hashlib.sha256((upload_token or "").encode()).hexdigest()
     if not report.screenshot_upload_token_hash or not hmac.compare_digest(report.screenshot_upload_token_hash, supplied_hash):
         raise HTTPException(status_code=401, detail="invalid screenshot upload token")
     if report.screenshot_key:
-        raise HTTPException(status_code=409, detail="screenshot already uploaded")
+        return Response(status_code=204)
     raw = screenshot.file.read(settings.screenshot_max_bytes + 1)
     try:
         report.screenshot_key = upload_screenshot(raw, filename=screenshot.filename, content_type=screenshot.content_type)
     except ScreenshotError as exc:
         raise HTTPException(status_code=422, detail=str(exc)) from exc
-    report.screenshot_upload_token_hash = None
-    db.commit()
+    try:
+        db.commit()
+    except Exception as exc:
+        db.rollback()
+        try:
+            delete_screenshot(report.screenshot_key)
+        except Exception:
+            logger.exception("failed to remove orphaned screenshot", extra={"screenshot_key": report.screenshot_key})
+        raise HTTPException(status_code=503, detail="screenshot could not be saved; please retry") from exc
     return Response(status_code=204)
 
 

apps/api/tests/test_api.py

@@ -528,14 +528,21 @@ def test_admin_can_start_and_list_official_import(monkeypatch) -> None:
 
 def test_pending_report_accepts_one_validated_screenshot(monkeypatch) -> None:
     created = client.post("/api/v1/catch-reports", json={"fish_slug": "pike", "waterbody_slug": "test-lake", "x": 91, "y": 92, "weight_g": 4200}).json()
-    monkeypatch.setattr("app.routers.submissions.upload_screenshot", lambda raw, **metadata: "reports/test.jpg" if raw == b"image-bytes" and metadata == {"filename": "catch.jpg", "content_type": "image/jpeg"} else "unexpected")
+    uploaded: list[bytes] = []
+    def fake_upload(raw, **metadata):
+        if raw == b"image-bytes" and metadata == {"filename": "catch.jpg", "content_type": "image/jpeg"}:
+            uploaded.append(raw)
+            return "reports/test.jpg"
+        return "unexpected"
+    monkeypatch.setattr("app.routers.submissions.upload_screenshot", fake_upload)
     upload_url = f"/api/v1/catch-reports/{created['id']}/screenshot"
     assert client.post(upload_url, files={"screenshot": ("catch.jpg", b"image-bytes", "image/jpeg")}).status_code == 401
     assert client.post(upload_url, headers={"X-Upload-Token": "wrong"}, files={"screenshot": ("catch.jpg", b"image-bytes", "image/jpeg")}).status_code == 401
     response = client.post(upload_url, headers={"X-Upload-Token": created["screenshot_upload_token"]}, files={"screenshot": ("catch.jpg", b"image-bytes", "image/jpeg")})
     assert response.status_code == 204
     reused = client.post(upload_url, headers={"X-Upload-Token": created["screenshot_upload_token"]}, files={"screenshot": ("catch.jpg", b"image-bytes", "image/jpeg")})
-    assert reused.status_code == 401
+    assert reused.status_code == 204
+    assert uploaded == [b"image-bytes"]
 
 
 def test_idempotency_replay_survives_completed_screenshot(monkeypatch) -> None:

apps/web/src/pages/api/report-screenshot.ts

@@ -12,7 +12,10 @@ export const POST: APIRoute = async ({ request, redirect, cookies }) => {
   try {
     const upload = new FormData(); upload.set("screenshot", screenshot);
     const response = await fetch(`${base}/api/v1/catch-reports/${reportId}/screenshot`, { method: "POST", headers:{"X-Upload-Token":uploadToken}, body: upload, signal: AbortSignal.timeout(60_000) });
-    if (response.ok) cookies.delete(cookieName, {path:"/"});
+    if (response.ok) {
+      cookies.delete(cookieName, {path:"/"});
+      cookies.delete("rf4-idempotency-key", {path:"/"});
+    }
     return redirect(response.ok ? "/report?state=screenshot_sent" : `/report?state=screenshot_error&report_id=${encodeURIComponent(reportId)}`, 303);
   } catch (err) {
     const isTimeout = err instanceof DOMException && err.name === "TimeoutError" ||