Initial web ui and control for robot

webui/backend/main.py

@@ -0,0 +1,105 @@
+import asyncio
+import logging
+from contextlib import asynccontextmanager
+from pathlib import Path
+
+from fastapi import FastAPI, WebSocket, WebSocketDisconnect
+from fastapi.responses import FileResponse, JSONResponse
+
+from ros_node import get_node, start_ros, stop_ros
+
+logging.basicConfig(level=logging.INFO)
+logger = logging.getLogger(__name__)
+
+STATIC_DIR = Path(__file__).parent / 'static'
+
+
+class ConnectionManager:
+    def __init__(self) -> None:
+        self.connections: list[WebSocket] = []
+        self._loop: asyncio.AbstractEventLoop | None = None
+
+    def set_loop(self, loop: asyncio.AbstractEventLoop) -> None:
+        self._loop = loop
+
+    async def connect(self, ws: WebSocket) -> None:
+        await ws.accept()
+        self.connections.append(ws)
+
+    def disconnect(self, ws: WebSocket) -> None:
+        if ws in self.connections:
+            self.connections.remove(ws)
+
+    def broadcast_from_thread(self, data: dict) -> None:
+        if self._loop and self._loop.is_running():
+            asyncio.run_coroutine_threadsafe(self._broadcast(data), self._loop)
+
+    async def _broadcast(self, data: dict) -> None:
+        dead = []
+        for ws in self.connections:
+            try:
+                await ws.send_json(data)
+            except Exception:
+                dead.append(ws)
+        for ws in dead:
+            self.disconnect(ws)
+
+
+manager = ConnectionManager()
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    manager.set_loop(asyncio.get_event_loop())
+    node = start_ros()
+    node.on_joint_states_callbacks.append(manager.broadcast_from_thread)
+    node.on_ultrasonic_callbacks.append(manager.broadcast_from_thread)
+    yield
+    stop_ros()
+
+
+app = FastAPI(lifespan=lifespan)
+
+
+@app.websocket('/ws')
+async def websocket_endpoint(ws: WebSocket):
+    await manager.connect(ws)
+    node = get_node()
+    try:
+        while True:
+            data = await ws.receive_json()
+            msg_type = data.get('type')
+            if msg_type == 'cmd_vel':
+                node.publish_cmd_vel(data.get('linear_x', 0.0), data.get('angular_z', 0.0))
+            elif msg_type == 'joint_command':
+                node.publish_joint_command(data.get('pan', 0.0), data.get('tilt', 0.0))
+    except WebSocketDisconnect:
+        pass
+    except Exception as e:
+        logger.error('WebSocket error: %s', e)
+    finally:
+        manager.disconnect(ws)
+        try:
+            node.publish_cmd_vel(0.0, 0.0)
+        except Exception:
+            pass
+
+
+@app.get('/{full_path:path}')
+async def serve_spa(full_path: str):
+    index = STATIC_DIR / 'index.html'
+    if not index.exists():
+        return JSONResponse(
+            {'detail': 'Frontend not built. In dev mode open http://localhost:5173'},
+            status_code=404,
+        )
+    candidate = (STATIC_DIR / full_path).resolve()
+    static_root = STATIC_DIR.resolve()
+    if str(candidate).startswith(str(static_root)) and full_path and candidate.is_file():
+        return FileResponse(candidate)
+    return FileResponse(index)
+
+
+if __name__ == '__main__':
+    import uvicorn
+    uvicorn.run(app, host='0.0.0.0', port=8080)