feat(api): add backend

routes and WebSockets

services/api/app/ws/broadcaster.py

@@ -0,0 +1,41 @@
+from __future__ import annotations
+
+import asyncio
+from contextlib import suppress
+from datetime import timezone
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.db.session import SessionLocal
+from app.repositories.audio_repository import AudioRepository
+from app.ws.manager import manager
+
+
+def _iso_z(dt) -> str:
+    # dt ожидается timezone-aware
+    return dt.astimezone(timezone.utc).isoformat().replace("+00:00", "Z")
+
+
+async def audio_live_broadcaster(poll_interval_sec: float = 0.2) -> None:
+    last_time = None
+
+    while True:
+        try:
+            async with SessionLocal() as db:  # AsyncSession
+                repo = AudioRepository(db)
+                rows = await repo.latest(1)
+                if rows:
+                    row = rows[0]
+                    if last_time is None or row.time > last_time:
+                        last_time = row.time
+                        await manager.broadcast_json(
+                            {
+                                "time": _iso_z(row.time),
+                                "rms_db": float(row.rms_db),
+                                "freq_hz": int(row.frequency_hz),
+                            }
+                        )
+        except Exception:
+            # чтобы WS не умирал из-за временных проблем с БД
+            pass
+
+        await asyncio.sleep(poll_interval_sec)