feat: add ue_scene websocket integration

Reviewed-on: #8

backend/app/api/v1/websocket.py

@@ -1,7 +1,6 @@
 """WebSocket API endpoints"""
 
 import asyncio
-import json
 import logging
 from datetime import UTC, datetime
 from typing import Optional
@@ -12,9 +11,20 @@ from jose import jwt, JWTError
 from app.core.config import settings
 from app.core.time import to_iso8601_utc
 from app.core.websocket.manager import manager
+from app.core.websocket.ue_scene import expand_scene_payload_for_transport, ue_scene_state_store
+from app.db.session import async_session_factory
 
 logger = logging.getLogger(__name__)
 router = APIRouter()
+SUPPORTED_CHANNELS = [
+    "gpu_clusters",
+    "submarine_cables",
+    "ixp_nodes",
+    "alerts",
+    "dashboard",
+    "datasource_tasks",
+    "ue_scene",
+]
 
 
 async def authenticate_token(token: str) -> Optional[dict]:
@@ -50,18 +60,12 @@ async def websocket_endpoint(
         await websocket.send_json(
             {
                 "type": "connection_established",
+                "timestamp": to_iso8601_utc(datetime.now(UTC)),
                 "data": {
                     "connection_id": f"conn_{user_id}",
                     "server_version": settings.VERSION,
                     "heartbeat_interval": 30,
-                    "supported_channels": [
+                    "supported_channels": SUPPORTED_CHANNELS,
-                        "gpu_clusters",
-                        "submarine_cables",
-                        "ixp_nodes",
-                        "alerts",
-                        "dashboard",
-                        "datasource_tasks",
-                    ],
                 },
             }
         )
@@ -74,26 +78,79 @@ async def websocket_endpoint(
                     await websocket.send_json(
                         {
                             "type": "heartbeat",
+                            "timestamp": to_iso8601_utc(datetime.now(UTC)),
                             "data": {"action": "pong", "timestamp": to_iso8601_utc(datetime.now(UTC))},
                         }
                     )
                 elif data.get("type") == "subscribe":
-                    channels = data.get("data", {}).get("channels", [])
+                    requested_channels = data.get("data", {}).get("channels", [])
+                    channels = manager.subscribe(websocket, requested_channels)
                     await websocket.send_json(
                         {
                             "type": "subscription_confirmed",
+                            "timestamp": to_iso8601_utc(datetime.now(UTC)),
                             "data": {"action": "subscribe", "channels": channels},
                         }
                     )
+                elif data.get("type") == "sync_request":
+                    sync_data = data.get("data", {})
+                    channel = sync_data.get("channel")
+                    if channel == "ue_scene":
+                        async with async_session_factory() as session:
+                            scene_payloads = await ue_scene_state_store.get_sync_payloads(
+                                session,
+                                last_sequence=sync_data.get("last_sequence"),
+                                reason=sync_data.get("reason"),
+                            )
+                        for scene_payload in scene_payloads:
+                            for transport_payload in expand_scene_payload_for_transport(scene_payload):
+                                await websocket.send_json(
+                                    {
+                                        "type": "data_frame",
+                                        "channel": "ue_scene",
+                                        "timestamp": to_iso8601_utc(datetime.now(UTC)),
+                                        "data": transport_payload,
+                                    }
+                                )
+                    else:
+                        await websocket.send_json(
+                            {
+                                "type": "error",
+                                "timestamp": to_iso8601_utc(datetime.now(UTC)),
+                                "data": {
+                                    "message": f"Unsupported sync channel: {channel}",
+                                },
+                            }
+                        )
                 elif data.get("type") == "control_frame":
                     await websocket.send_json(
-                        {"type": "control_acknowledged", "data": {"received": True}}
+                        {
+                            "type": "control_acknowledged",
+                            "timestamp": to_iso8601_utc(datetime.now(UTC)),
+                            "data": {
+                                "target": data.get("data", {}).get("target"),
+                                "command": data.get("data", {}).get("command"),
+                                "accepted": True,
+                            },
+                        }
                     )
                 else:
-                    await websocket.send_json({"type": "ack", "data": {"received": True}})
+                    await websocket.send_json(
+                        {
+                            "type": "ack",
+                            "timestamp": to_iso8601_utc(datetime.now(UTC)),
+                            "data": {"received": True},
+                        }
+                    )
 
             except asyncio.TimeoutError:
-                await websocket.send_json({"type": "heartbeat", "data": {"action": "ping"}})
+                await websocket.send_json(
+                    {
+                        "type": "heartbeat",
+                        "timestamp": to_iso8601_utc(datetime.now(UTC)),
+                        "data": {"action": "ping"},
+                    }
+                )
 
     except WebSocketDisconnect:
         pass

backend/app/core/websocket/broadcaster.py

@@ -1,11 +1,12 @@
-"""Data broadcaster for WebSocket connections"""
+"""Data broadcaster for WebSocket connections."""
 
 import asyncio
 from datetime import UTC, datetime
-from typing import Dict, Any, Optional
+from typing import Any, Dict
 
 from app.core.time import to_iso8601_utc
 from app.core.websocket.manager import manager
+from app.db.session import async_session_factory
 
 
 
@@ -45,6 +46,30 @@ class DataBroadcaster:
                 pass
             await asyncio.sleep(interval)
 
+    async def broadcast_ue_scene(self, interval: int = 5) -> None:
+        """Broadcast UE scene updates for nDisplay primary nodes."""
+        from app.core.websocket.ue_scene import expand_scene_payload_for_transport, ue_scene_state_store
+
+        while self.running:
+            try:
+                async with async_session_factory() as session:
+                    scene_payloads = await ue_scene_state_store.get_broadcast_payloads(session)
+
+                for scene_data in scene_payloads:
+                    for transport_payload in expand_scene_payload_for_transport(scene_data):
+                        await manager.broadcast(
+                            {
+                                "type": "data_frame",
+                                "channel": "ue_scene",
+                                "timestamp": to_iso8601_utc(datetime.now(UTC)),
+                                "data": transport_payload,
+                            },
+                            channel="ue_scene",
+                        )
+            except Exception:
+                pass
+            await asyncio.sleep(interval)
+
     async def broadcast_alert(self, alert: Dict[str, Any]):
         """Broadcast an alert to all connected clients"""
         await manager.broadcast(
@@ -75,7 +100,7 @@ class DataBroadcaster:
                 "timestamp": to_iso8601_utc(datetime.now(UTC)),
                 "payload": data,
             },
-            channel=channel if channel in manager.active_connections else "all",
+            channel=channel,
         )
 
     async def broadcast_datasource_task_update(self, data: Dict[str, Any]):
@@ -95,6 +120,7 @@ class DataBroadcaster:
         if not self.running:
             self.running = True
             self.tasks["dashboard"] = asyncio.create_task(self.broadcast_stats(5))
+            self.tasks["ue_scene"] = asyncio.create_task(self.broadcast_ue_scene(5))
 
     def stop(self):
         """Stop all broadcasters"""

backend/app/core/websocket/manager.py

@@ -1,9 +1,7 @@
-"""WebSocket Connection Manager"""
+"""WebSocket connection manager with channel subscriptions."""
+
+from typing import Dict, Optional, Set
 
-import json
-import asyncio
-from typing import Dict, Set, Optional
-from datetime import datetime
 from fastapi import WebSocket
 import redis.asyncio as redis
 
@@ -11,17 +9,25 @@ from app.core.config import settings
 
 
 class ConnectionManager:
-    """Manages WebSocket connections"""
+    """Manage user connections and channel subscriptions."""
 
-    def __init__(self):
+    def __init__(self) -> None:
-        self.active_connections: Dict[str, Set[WebSocket]] = {}  # user_id -> connections
+        self.user_connections: Dict[str, Set[WebSocket]] = {}
+        self.socket_users: Dict[WebSocket, str] = {}
+        self.channel_connections: Dict[str, Set[WebSocket]] = {}
+        self.socket_channels: Dict[WebSocket, Set[str]] = {}
         self.redis_client: Optional[redis.Redis] = None
 
-    async def connect(self, websocket: WebSocket, user_id: str):
+    @property
+    def active_connections(self) -> Dict[str, Set[WebSocket]]:
+        """Compatibility alias for existing callers."""
+        return self.user_connections
+
+    async def connect(self, websocket: WebSocket, user_id: str) -> None:
         await websocket.accept()
-        if user_id not in self.active_connections:
+        self.user_connections.setdefault(user_id, set()).add(websocket)
-            self.active_connections[user_id] = set()
+        self.socket_users[websocket] = user_id
-        self.active_connections[user_id].add(websocket)
+        self.socket_channels.setdefault(websocket, set())
 
         if self.redis_client is None:
             redis_url = settings.REDIS_URL
@@ -35,32 +41,69 @@ class ConnectionManager:
                     decode_responses=True,
                 )
 
-    def disconnect(self, websocket: WebSocket, user_id: str):
+    def disconnect(self, websocket: WebSocket, user_id: str) -> None:
-        if user_id in self.active_connections:
+        self.unsubscribe(websocket, list(self.socket_channels.get(websocket, set())))
-            self.active_connections[user_id].discard(websocket)
-            if not self.active_connections[user_id]:
-                del self.active_connections[user_id]
 
-    async def send_personal_message(self, message: dict, user_id: str):
+        if user_id in self.user_connections:
-        if user_id in self.active_connections:
+            self.user_connections[user_id].discard(websocket)
-            for connection in self.active_connections[user_id]:
+            if not self.user_connections[user_id]:
-                try:
+                del self.user_connections[user_id]
-                    await connection.send_json(message)
-                except Exception:
-                    pass
 
-    async def broadcast(self, message: dict, channel: str = "all"):
+        self.socket_users.pop(websocket, None)
+        self.socket_channels.pop(websocket, None)
+
+    def subscribe(self, websocket: WebSocket, channels: list[str]) -> list[str]:
+        subscribed_channels: list[str] = []
+        socket_channel_set = self.socket_channels.setdefault(websocket, set())
+
+        for channel in channels:
+            normalized_channel = channel.strip()
+            if not normalized_channel:
+                continue
+            self.channel_connections.setdefault(normalized_channel, set()).add(websocket)
+            socket_channel_set.add(normalized_channel)
+            subscribed_channels.append(normalized_channel)
+
+        return subscribed_channels
+
+    def unsubscribe(self, websocket: WebSocket, channels: list[str]) -> None:
+        socket_channel_set = self.socket_channels.setdefault(websocket, set())
+
+        for channel in channels:
+            normalized_channel = channel.strip()
+            if not normalized_channel:
+                continue
+            if normalized_channel in self.channel_connections:
+                self.channel_connections[normalized_channel].discard(websocket)
+                if not self.channel_connections[normalized_channel]:
+                    del self.channel_connections[normalized_channel]
+            socket_channel_set.discard(normalized_channel)
+
+    async def send_personal_message(self, message: dict, user_id: str) -> None:
+        for connection in list(self.user_connections.get(user_id, set())):
+            try:
+                await connection.send_json(message)
+            except Exception:
+                self.disconnect(connection, user_id)
+
+    async def broadcast(self, message: dict, channel: str = "all") -> None:
         if channel == "all":
-            for user_id in self.active_connections:
+            targets = list(self.socket_users.keys())
-                await self.send_personal_message(message, user_id)
         else:
-            await self.send_personal_message(message, channel)
+            targets = list(self.channel_connections.get(channel, set()))
 
-    async def close_all(self):
+        for connection in targets:
-        for user_id in self.active_connections:
+            try:
-            for connection in self.active_connections[user_id]:
+                await connection.send_json(message)
-                await connection.close()
+            except Exception:
-        self.active_connections.clear()
+                user_id = self.socket_users.get(connection)
+                if user_id is not None:
+                    self.disconnect(connection, user_id)
+
+    async def close_all(self) -> None:
+        for websocket, user_id in list(self.socket_users.items()):
+            await websocket.close()
+            self.disconnect(websocket, user_id)
 
 
 manager = ConnectionManager()

backend/app/core/websocket/ue_scene.py

@@ -0,0 +1,562 @@
+"""UE scene state built from visualization aggregate output."""
+
+import asyncio
+import json
+import zlib
+from datetime import UTC, datetime
+from typing import TYPE_CHECKING, Any, Dict, List
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.core.time import to_iso8601_utc
+from app.models.bgp_anomaly import BGPAnomaly
+from app.models.bgp_incident import BGPIncident
+
+if TYPE_CHECKING:
+    from app.models.collected_data import CollectedData
+
+DEFAULT_LAYER_ORDER = (
+    "satellites",
+    "supercomputers",
+    "gpu_clusters",
+    "submarine_cables",
+    "landing_points",
+    "bgp_anomalies",
+    "bgp_incidents",
+    "bgp_collectors",
+    "alerts",
+)
+
+FULL_RESYNC_REASONS = {"initial_connect", "manual_resync", "profile_changed"}
+UE_SCENE_LAYER_CHUNK_ITEM_LIMITS = {
+    "satellites": 500,
+    "supercomputers": 200,
+    "gpu_clusters": 100,
+    "submarine_cables": 25,
+    "landing_points": 250,
+    "bgp_anomalies": 100,
+    "bgp_incidents": 100,
+    "bgp_collectors": 100,
+    "alerts": 100,
+}
+
+
+def _default_display_profile() -> Dict[str, Any]:
+    return {
+        "profile_id": "polarized-wall-a",
+        "stereo_mode": "polarized",
+        "screen_width_m": 3.0,
+        "screen_height_m": 2.0,
+        "target_refresh_hz": 120,
+    }
+
+
+def _default_camera_state() -> Dict[str, Any]:
+    return {
+        "mode": "auto_cruise",
+        "path_id": "global_overview",
+        "fov": 42.0,
+    }
+
+
+def _stable_json(value: Any) -> str:
+    return json.dumps(value, ensure_ascii=True, sort_keys=True, separators=(",", ":"))
+
+
+def _entity_type_for_layer(layer_name: str) -> str:
+    return {
+        "satellites": "satellite",
+        "supercomputers": "supercomputer",
+        "gpu_clusters": "gpu_cluster",
+        "submarine_cables": "submarine_cable",
+        "landing_points": "landing_point",
+        "bgp_anomalies": "bgp_anomaly",
+        "bgp_incidents": "bgp_incident",
+        "bgp_collectors": "bgp_collector",
+        "alerts": "alert",
+    }[layer_name]
+
+
+def _default_visual_for_layer(layer_name: str) -> Dict[str, Any]:
+    visuals = {
+        "satellites": {"style": "satellite_marker", "size": 0.7, "color": "#9BDBFF"},
+        "supercomputers": {"style": "supercomputer_marker", "size": 1.2, "color": "#FF6B6B"},
+        "gpu_clusters": {"style": "pulse_marker", "size": 1.0, "color": "#FF8C42"},
+        "submarine_cables": {"style": "cable_arc", "width": 2.0, "color": "#4ECDC4"},
+        "landing_points": {"style": "landing_point_marker", "size": 0.8, "color": "#45B7D1"},
+        "bgp_anomalies": {"style": "anomaly_marker", "size": 1.0, "color": "#FFB703"},
+        "bgp_incidents": {"style": "incident_marker", "size": 1.2, "color": "#E63946"},
+        "bgp_collectors": {"style": "collector_marker", "size": 0.9, "color": "#7B9ACC"},
+        "alerts": {"style": "alert_marker", "size": 1.0, "color": "#FFD166"},
+    }
+    return visuals[layer_name]
+
+
+def _empty_scene_layers() -> Dict[str, Dict[str, Any]]:
+    return {
+        layer_name: {"revision": 0, "items": {}}
+        for layer_name in DEFAULT_LAYER_ORDER
+    }
+
+
+def _empty_changes() -> Dict[str, Dict[str, List[Any]]]:
+    return {
+        layer_name: {"added": [], "updated": [], "removed": []}
+        for layer_name in DEFAULT_LAYER_ORDER
+    }
+
+
+def _point_geo(coordinates: List[Any]) -> Dict[str, Any]:
+    lng = coordinates[0] if len(coordinates) > 0 else None
+    lat = coordinates[1] if len(coordinates) > 1 else None
+    alt = coordinates[2] if len(coordinates) > 2 else 0.0
+    return {"lat": lat, "lng": lng, "alt": alt}
+
+
+def _path_geo(geometry_type: str, coordinates: Any) -> Dict[str, Any]:
+    if geometry_type == "LineString":
+        return {
+            "path": [
+                {"lat": point[1], "lng": point[0], "alt": point[2] if len(point) > 2 else 0.0}
+                for point in coordinates
+                if isinstance(point, list) and len(point) >= 2
+            ]
+        }
+
+    if geometry_type == "MultiLineString":
+        return {
+            "segments": [
+                [
+                    {"lat": point[1], "lng": point[0], "alt": point[2] if len(point) > 2 else 0.0}
+                    for point in line
+                    if isinstance(point, list) and len(point) >= 2
+                ]
+                for line in coordinates
+                if isinstance(line, list)
+            ]
+        }
+
+    return {}
+
+
+def _item_identifier(layer_name: str, feature: Dict[str, Any], index: int) -> str:
+    properties = feature.get("properties") or {}
+    feature_id = feature.get("id") or properties.get("id") or properties.get("source_id")
+    return f"{layer_name}:{feature_id or index}"
+
+
+def _item_revision(item: Dict[str, Any]) -> int:
+    return zlib.crc32(_stable_json(item).encode("utf-8")) & 0xFFFFFFFF
+
+
+def _layer_revision(items: Dict[str, Dict[str, Any]]) -> int:
+    if not items:
+        return 0
+    joined = "|".join(
+        f"{item_id}:{items[item_id]['revision']}"
+        for item_id in sorted(items)
+    )
+    return zlib.crc32(joined.encode("utf-8")) & 0xFFFFFFFF
+
+
+def _serialize_feature(layer_name: str, feature: Dict[str, Any], index: int) -> Dict[str, Any]:
+    properties = dict(feature.get("properties") or {})
+    geometry = feature.get("geometry") or {}
+    geometry_type = geometry.get("type", "")
+    coordinates = geometry.get("coordinates") or []
+    item_id = _item_identifier(layer_name, feature, index)
+
+    geo: Dict[str, Any] = {}
+    if geometry_type == "Point":
+        geo = _point_geo(coordinates)
+    elif geometry_type in {"LineString", "MultiLineString"}:
+        geo = _path_geo(geometry_type, coordinates)
+
+    title = (
+        properties.get("name")
+        or properties.get("Name")
+        or properties.get("title")
+        or item_id
+    )
+    subtitle_parts = [
+        properties.get("city"),
+        properties.get("country"),
+        properties.get("region"),
+    ]
+    item = {
+        "id": item_id,
+        "entity_type": _entity_type_for_layer(layer_name),
+        "geo": geo,
+        "visual": {
+            **_default_visual_for_layer(layer_name),
+            **({"color": properties["color"]} if properties.get("color") else {}),
+        },
+        "metrics": properties,
+        "labels": {
+            "title": title,
+            "subtitle": ", ".join([part for part in subtitle_parts if part]),
+        },
+        "status": {
+            "health": properties.get("status", "normal"),
+            "alert_level": properties.get("severity", "none"),
+        },
+    }
+    item["revision"] = _item_revision(item)
+    return item
+
+
+async def build_visualization_scene_state(db: AsyncSession) -> Dict[str, Any]:
+    from app.api.v1.visualization import (
+        _build_landing_point_cable_maps,
+        _filter_known_records,
+        _load_current_collected_data_by_sources,
+        build_anomaly_geography_hints,
+        build_incident_geography_hints,
+        convert_bgp_anomalies_to_geojson,
+        convert_bgp_collectors_to_geojson,
+        convert_bgp_incidents_to_geojson,
+        convert_cable_to_geojson,
+        convert_gpu_cluster_to_geojson,
+        convert_landing_point_to_geojson,
+        convert_satellite_to_geojson,
+        convert_supercomputer_to_geojson,
+    )
+    from app.services.bgp_collectors import build_bgp_collector_coverage
+
+    records_by_source = await _load_current_collected_data_by_sources(
+        db,
+        [
+            "arcgis_cables",
+            "arcgis_landing_points",
+            "arcgis_cable_landing_relation",
+            "celestrak_tle",
+            "top500",
+            "epoch_ai_gpu",
+        ],
+    )
+
+    cables_records = records_by_source.get("arcgis_cables", [])
+    landing_point_records = records_by_source.get("arcgis_landing_points", [])
+    relation_records = records_by_source.get("arcgis_cable_landing_relation", [])
+    satellites_records = _filter_known_records(records_by_source.get("celestrak_tle", []))
+    supercomputer_records = _filter_known_records(records_by_source.get("top500", []))
+    gpu_records = _filter_known_records(records_by_source.get("epoch_ai_gpu", []))
+    bgp_anomalies_result = await db.execute(
+        select(BGPAnomaly)
+        .where(BGPAnomaly.status == "active")
+        .order_by(BGPAnomaly.created_at.desc())
+        .limit(200)
+    )
+    bgp_anomalies = list(bgp_anomalies_result.scalars().all())
+    bgp_anomaly_geography_hints = await build_anomaly_geography_hints(db, bgp_anomalies)
+    bgp_incidents_result = await db.execute(
+        select(BGPIncident)
+        .where(BGPIncident.status == "active")
+        .order_by(BGPIncident.created_at.desc())
+        .limit(100)
+    )
+    bgp_incidents = list(bgp_incidents_result.scalars().all())
+    bgp_incident_geography_hints = await build_incident_geography_hints(db, bgp_incidents)
+    bgp_collector_coverage = await build_bgp_collector_coverage(
+        db,
+        source_filter=("ris_live_bgp", "bgpstream_bgp"),
+    )
+    bgp_coverage_by_collector = {
+        item["collector"]: item
+        for item in bgp_collector_coverage
+        if item.get("collector")
+    }
+
+    city_to_cable_ids_map, cable_id_to_name_map = _build_landing_point_cable_maps(
+        relation_records,
+        cables_records,
+    )
+
+    aggregate = {
+        "satellites": convert_satellite_to_geojson(satellites_records),
+        "supercomputers": convert_supercomputer_to_geojson(supercomputer_records),
+        "gpu_clusters": convert_gpu_cluster_to_geojson(gpu_records),
+        "submarine_cables": convert_cable_to_geojson(cables_records),
+        "landing_points": convert_landing_point_to_geojson(
+            landing_point_records,
+            city_to_cable_ids_map,
+            cable_id_to_name_map,
+        ),
+        "bgp_anomalies": convert_bgp_anomalies_to_geojson(
+            bgp_anomalies,
+            bgp_anomaly_geography_hints,
+        ),
+        "bgp_incidents": convert_bgp_incidents_to_geojson(
+            bgp_incidents,
+            bgp_incident_geography_hints,
+        ),
+        "bgp_collectors": convert_bgp_collectors_to_geojson(bgp_coverage_by_collector),
+        "alerts": {"type": "FeatureCollection", "features": []},
+    }
+
+    layers = _empty_scene_layers()
+    total_records = 0
+    for layer_name in DEFAULT_LAYER_ORDER:
+        feature_collection = aggregate.get(layer_name) or {"features": []}
+        items = {
+            item["id"]: item
+            for index, feature in enumerate(feature_collection.get("features", []), start=1)
+            for item in [_serialize_feature(layer_name, feature, index)]
+        }
+        layers[layer_name]["items"] = items
+        layers[layer_name]["revision"] = _layer_revision(items)
+        total_records += len(items)
+
+    timestamp = to_iso8601_utc(datetime.now(UTC))
+    state_hash = zlib.crc32(
+        _stable_json(
+            {
+                layer_name: {
+                    item_id: item["revision"]
+                    for item_id, item in layers[layer_name]["items"].items()
+                }
+                for layer_name in DEFAULT_LAYER_ORDER
+            }
+        ).encode("utf-8")
+    ) & 0xFFFFFFFF
+
+    return {
+        "generated_at": timestamp,
+        "state_hash": state_hash,
+        "total_records": total_records,
+        "layers": layers,
+    }
+
+
+def _changes_exist(changes: Dict[str, Dict[str, List[Any]]]) -> bool:
+    return any(
+        layer_changes["added"] or layer_changes["updated"] or layer_changes["removed"]
+        for layer_changes in changes.values()
+    )
+
+
+def build_incremental_changes(
+    previous_state: Dict[str, Any],
+    current_state: Dict[str, Any],
+) -> Dict[str, Dict[str, List[Any]]]:
+    changes = _empty_changes()
+
+    for layer_name in DEFAULT_LAYER_ORDER:
+        previous_items = previous_state["layers"][layer_name]["items"]
+        current_items = current_state["layers"][layer_name]["items"]
+        previous_ids = set(previous_items)
+        current_ids = set(current_items)
+
+        for added_id in sorted(current_ids - previous_ids):
+            changes[layer_name]["added"].append(current_items[added_id])
+
+        for removed_id in sorted(previous_ids - current_ids):
+            changes[layer_name]["removed"].append(removed_id)
+
+        for common_id in sorted(previous_ids & current_ids):
+            if _stable_json(previous_items[common_id]) != _stable_json(current_items[common_id]):
+                changes[layer_name]["updated"].append(current_items[common_id])
+
+    return changes
+
+
+def _full_payload_from_state(state: Dict[str, Any], sequence: int) -> Dict[str, Any]:
+    return {
+        "update_type": "full",
+        "sequence": sequence,
+        "cluster_time": state["generated_at"],
+        "display_profile": _default_display_profile(),
+        "camera_state": _default_camera_state(),
+        "payload": {
+            "meta": {
+                "generated_at": state["generated_at"],
+                "total_records": state["total_records"],
+                "state_hash": state["state_hash"],
+            },
+            "layers": {
+                layer_name: {
+                    "revision": layer_data["revision"],
+                    "items": [
+                        layer_data["items"][item_id]
+                        for item_id in sorted(layer_data["items"])
+                    ],
+                }
+                for layer_name, layer_data in state["layers"].items()
+            },
+        },
+    }
+
+
+def _incremental_payload(
+    *,
+    current_state: Dict[str, Any],
+    sequence: int,
+    base_sequence: int,
+    changes: Dict[str, Dict[str, List[Any]]],
+) -> Dict[str, Any]:
+    return {
+        "update_type": "incremental",
+        "sequence": sequence,
+        "base_sequence": base_sequence,
+        "cluster_time": current_state["generated_at"],
+        "changes": changes,
+        "meta": {
+            "generated_at": current_state["generated_at"],
+            "total_records": current_state["total_records"],
+            "state_hash": current_state["state_hash"],
+        },
+    }
+
+
+def _noop_incremental_payload(state: Dict[str, Any], sequence: int) -> Dict[str, Any]:
+    return _incremental_payload(
+        current_state=state,
+        sequence=sequence,
+        base_sequence=sequence,
+        changes=_empty_changes(),
+    )
+
+
+def expand_scene_payload_for_transport(scene_payload: Dict[str, Any]) -> List[Dict[str, Any]]:
+    """Split oversized scene payloads into smaller transport-safe chunks."""
+    update_type = scene_payload.get("update_type")
+    if update_type != "full":
+        return [scene_payload]
+
+    payload = scene_payload.get("payload") or {}
+    layers = payload.get("layers") or {}
+    if not layers:
+        return [scene_payload]
+
+    chunks: List[Dict[str, Any]] = []
+    for layer_name in DEFAULT_LAYER_ORDER:
+        layer_data = layers.get(layer_name) or {}
+        items = list(layer_data.get("items") or [])
+        if not items:
+            continue
+
+        chunk_size = UE_SCENE_LAYER_CHUNK_ITEM_LIMITS.get(layer_name, 100)
+        total_layer_chunks = max(1, (len(items) + chunk_size - 1) // chunk_size)
+        for chunk_index, offset in enumerate(range(0, len(items), chunk_size), start=1):
+            chunk_items = items[offset : offset + chunk_size]
+            chunks.append(
+                {
+                    **scene_payload,
+                    "payload": {
+                        "meta": {
+                            **(payload.get("meta") or {}),
+                            "chunked": True,
+                            "layer_name": layer_name,
+                            "layer_chunk_index": chunk_index,
+                            "layer_chunk_count": total_layer_chunks,
+                        },
+                        "layers": {
+                            layer_name: {
+                                "revision": layer_data.get("revision", 0),
+                                "items": chunk_items,
+                            }
+                        },
+                    },
+                }
+            )
+
+    if not chunks:
+        return [scene_payload]
+
+    total_chunks = len(chunks)
+    for transport_index, chunk in enumerate(chunks, start=1):
+        chunk_payload = chunk.setdefault("payload", {})
+        chunk_meta = chunk_payload.setdefault("meta", {})
+        chunk_meta["transport_chunk_index"] = transport_index
+        chunk_meta["transport_chunk_count"] = total_chunks
+
+    return chunks
+
+
+class UeSceneStateStore:
+    """Maintain cached ue_scene state and a bounded incremental replay history."""
+
+    def __init__(self, history_limit: int = 20) -> None:
+        self.history_limit = history_limit
+        self.sequence = 0
+        self.state: Dict[str, Any] | None = None
+        self.history: List[Dict[str, Any]] = []
+        self.lock = asyncio.Lock()
+
+    async def _refresh_locked(self, db: AsyncSession) -> List[Dict[str, Any]]:
+        current_state = await build_visualization_scene_state(db)
+
+        if self.state is None:
+            self.sequence = 1
+            self.state = current_state
+            return [_full_payload_from_state(self.state, self.sequence)]
+
+        if current_state["state_hash"] == self.state["state_hash"]:
+            self.state = current_state
+            return []
+
+        previous_sequence = self.sequence
+        previous_state = self.state
+        self.sequence += 1
+        self.state = current_state
+        changes = build_incremental_changes(previous_state, current_state)
+        incremental = _incremental_payload(
+            current_state=current_state,
+            sequence=self.sequence,
+            base_sequence=previous_sequence,
+            changes=changes,
+        )
+        self.history.append(incremental)
+        if len(self.history) > self.history_limit:
+            self.history = self.history[-self.history_limit :]
+        return [incremental]
+
+    async def get_broadcast_payloads(self, db: AsyncSession) -> List[Dict[str, Any]]:
+        async with self.lock:
+            payloads = await self._refresh_locked(db)
+            return [payload for payload in payloads if payload["update_type"] == "full" or _changes_exist(payload.get("changes", {}))]
+
+    async def get_sync_payloads(
+        self,
+        db: AsyncSession,
+        *,
+        last_sequence: int | None,
+        reason: str | None,
+    ) -> List[Dict[str, Any]]:
+        async with self.lock:
+            await self._refresh_locked(db)
+            if self.state is None:
+                return []
+
+            normalized_reason = (reason or "").strip()
+            if last_sequence is None or normalized_reason in FULL_RESYNC_REASONS:
+                return [_full_payload_from_state(self.state, self.sequence)]
+
+            if last_sequence == self.sequence:
+                return [_noop_incremental_payload(self.state, self.sequence)]
+
+            if last_sequence > self.sequence:
+                return [_full_payload_from_state(self.state, self.sequence)]
+
+            replay_payloads = [
+                payload
+                for payload in self.history
+                if payload["base_sequence"] >= last_sequence
+                and payload["sequence"] > last_sequence
+            ]
+            if replay_payloads:
+                expected_base = last_sequence
+                ordered_payloads: List[Dict[str, Any]] = []
+                for payload in replay_payloads:
+                    if payload["base_sequence"] != expected_base:
+                        return [_full_payload_from_state(self.state, self.sequence)]
+                    ordered_payloads.append(payload)
+                    expected_base = payload["sequence"]
+                if ordered_payloads and ordered_payloads[-1]["sequence"] == self.sequence:
+                    return ordered_payloads
+
+            return [_full_payload_from_state(self.state, self.sequence)]
+
+
+ue_scene_state_store = UeSceneStateStore()

backend/tests/test_websocket_scene.py

@@ -0,0 +1,150 @@
+import pytest
+
+from app.core.websocket.manager import ConnectionManager
+from app.core.websocket.ue_scene import (
+    UeSceneStateStore,
+    _item_revision,
+    build_incremental_changes,
+)
+
+
+class _FakeSession:
+    pass
+
+
+class _FakeWebSocket:
+    def __init__(self):
+        self.accepted = False
+        self.messages = []
+
+    async def accept(self):
+        self.accepted = True
+
+    async def send_json(self, message):
+        self.messages.append(message)
+
+    async def close(self):
+        return None
+
+
+def _scene_item(item_id: str, title: str, *, lat: float = 0.0, lng: float = 0.0):
+    item = {
+        "id": item_id,
+        "entity_type": "gpu_cluster",
+        "geo": {"lat": lat, "lng": lng, "alt": 0.0},
+        "visual": {"style": "pulse_marker", "size": 1.0, "color": "#FF8C42"},
+        "metrics": {"name": title},
+        "labels": {"title": title, "subtitle": ""},
+        "status": {"health": "normal", "alert_level": "none"},
+    }
+    item["revision"] = _item_revision(item)
+    return item
+
+
+def _scene_state(state_hash: int, items_by_layer: dict[str, dict[str, dict]]):
+    base_layers = {
+        "satellites": {"revision": 0, "items": {}},
+        "supercomputers": {"revision": 0, "items": {}},
+        "gpu_clusters": {"revision": 0, "items": {}},
+        "submarine_cables": {"revision": 0, "items": {}},
+        "landing_points": {"revision": 0, "items": {}},
+        "alerts": {"revision": 0, "items": {}},
+    }
+    for layer_name, items in items_by_layer.items():
+        base_layers[layer_name]["items"] = items
+        base_layers[layer_name]["revision"] = len(items)
+    return {
+        "generated_at": "2026-04-17T00:00:00Z",
+        "state_hash": state_hash,
+        "total_records": sum(len(items) for items in items_by_layer.values()),
+        "layers": base_layers,
+    }
+
+
+def test_build_incremental_changes_detects_add_update_remove():
+    previous_state = _scene_state(
+        1,
+        {
+            "gpu_clusters": {
+                "gpu:a": _scene_item("gpu:a", "A"),
+                "gpu:b": _scene_item("gpu:b", "B"),
+            }
+        },
+    )
+    current_state = _scene_state(
+        2,
+        {
+            "gpu_clusters": {
+                "gpu:b": _scene_item("gpu:b", "B Updated"),
+                "gpu:c": _scene_item("gpu:c", "C"),
+            }
+        },
+    )
+
+    changes = build_incremental_changes(previous_state, current_state)
+
+    assert changes["gpu_clusters"]["added"][0]["id"] == "gpu:c"
+    assert changes["gpu_clusters"]["updated"][0]["id"] == "gpu:b"
+    assert changes["gpu_clusters"]["removed"] == ["gpu:a"]
+
+
+@pytest.mark.asyncio
+async def test_state_store_replays_incremental_history(monkeypatch):
+    state_list = [
+        _scene_state(1, {"gpu_clusters": {"gpu:a": _scene_item("gpu:a", "A")}}),
+        _scene_state(
+            2,
+            {"gpu_clusters": {"gpu:a": _scene_item("gpu:a", "A"), "gpu:b": _scene_item("gpu:b", "B")}},
+        ),
+        _scene_state(
+            3,
+            {"gpu_clusters": {"gpu:a": _scene_item("gpu:a", "A Updated"), "gpu:b": _scene_item("gpu:b", "B")}},
+        ),
+    ]
+    state_index = {"value": 0}
+
+    async def _fake_build_visualization_scene_state(_db):
+        current_index = state_index["value"]
+        if current_index < len(state_list) - 1:
+            state_index["value"] += 1
+        return state_list[current_index]
+
+    monkeypatch.setattr(
+        "app.core.websocket.ue_scene.build_visualization_scene_state",
+        _fake_build_visualization_scene_state,
+    )
+
+    store = UeSceneStateStore(history_limit=5)
+    session = _FakeSession()
+
+    first_payloads = await store.get_broadcast_payloads(session)
+    second_payloads = await store.get_broadcast_payloads(session)
+    third_payloads = await store.get_broadcast_payloads(session)
+    replay_payloads = await store.get_sync_payloads(
+        session,
+        last_sequence=1,
+        reason="sequence_gap",
+    )
+
+    assert first_payloads[0]["update_type"] == "full"
+    assert second_payloads[0]["update_type"] == "incremental"
+    assert third_payloads[0]["sequence"] == 3
+    assert [payload["sequence"] for payload in replay_payloads] == [2, 3]
+
+
+@pytest.mark.asyncio
+async def test_connection_manager_broadcasts_to_subscribed_channel_only():
+    manager = ConnectionManager()
+    ws_dashboard = _FakeWebSocket()
+    ws_scene = _FakeWebSocket()
+
+    await manager.connect(ws_dashboard, "user-dashboard")
+    await manager.connect(ws_scene, "user-scene")
+
+    manager.subscribe(ws_dashboard, ["dashboard"])
+    manager.subscribe(ws_scene, ["ue_scene"])
+
+    await manager.broadcast({"type": "data_frame", "channel": "ue_scene"}, channel="ue_scene")
+
+    assert ws_dashboard.messages == []
+    assert ws_scene.messages == [{"type": "data_frame", "channel": "ue_scene"}]

docs/ue-ndisplay-websocket-protocol.md

@@ -0,0 +1,352 @@
+# UE nDisplay WebSocket 协议草案
+
+## 目的
+
+本协议定义后端到 UE `nDisplay` 集群运行时之间的场景同步契约。
+
+设计目标：
+
+- 由 UE 主节点单点接入后端
+- 使用全量快照重建完整场景
+- 使用增量更新降低同步成本
+- 支持控制帧和显示配置
+- 支持序列号、重放和重同步
+
+## 适用范围
+
+该协议建立在通用 WebSocket 协议之上，参考 [websocket_protocol.md](/D:/work/planet/planet/websocket_protocol.md:1)。
+
+新增的核心内容是 `ue_scene` 频道。
+
+## 连接模型
+
+### 客户端
+
+- UE 主节点连接 `ws://<backend-host>:8000/ws?token=<access_token>`
+- UE 渲染节点不直接连接后端场景通道
+
+### 订阅
+
+UE 主节点建议订阅：
+
+- `ue_scene`
+- `alerts`
+- `dashboard`
+
+## 协议规则
+
+- 每次场景更新都带单调递增的 `sequence`
+- 增量更新必须包含 `base_sequence`
+- UE 如果发现序列断裂，应先发 `sync_request`
+- 服务端优先返回可重放的增量历史；无法重放时返回全量快照
+- 后端始终发送地理坐标，UE 本地负责转成球体世界坐标
+- 控制消息与场景消息分离
+
+## 消息类型
+
+### `connection_established`
+
+服务端 -> 客户端
+
+```json
+{
+  "type": "connection_established",
+  "timestamp": "2026-04-17T02:30:00.000Z",
+  "data": {
+    "connection_id": "conn_primary_node_01",
+    "server_version": "0.19.0",
+    "heartbeat_interval": 30,
+    "supported_channels": [
+      "ue_scene",
+      "alerts",
+      "dashboard",
+      "datasource_tasks"
+    ]
+  }
+}
+```
+
+### `subscribe`
+
+客户端 -> 服务端
+
+```json
+{
+  "type": "subscribe",
+  "timestamp": "2026-04-17T02:30:01.000Z",
+  "data": {
+    "channels": ["ue_scene", "alerts"]
+  }
+}
+```
+
+### `sync_request`
+
+客户端 -> 服务端
+
+```json
+{
+  "type": "sync_request",
+  "timestamp": "2026-04-17T02:30:05.000Z",
+  "data": {
+    "channel": "ue_scene",
+    "reason": "initial_connect",
+    "last_sequence": null
+  }
+}
+```
+
+`reason` 常见值：
+
+- `initial_connect`
+- `sequence_gap`
+- `manual_resync`
+- `profile_changed`
+
+### `data_frame` 全量快照
+
+服务端 -> 客户端
+
+```json
+{
+  "type": "data_frame",
+  "channel": "ue_scene",
+  "timestamp": "2026-04-17T02:30:06.000Z",
+  "data": {
+    "update_type": "full",
+    "sequence": 12,
+    "cluster_time": "2026-04-17T02:30:06.000Z",
+    "display_profile": {
+      "profile_id": "polarized-wall-a",
+      "stereo_mode": "polarized",
+      "screen_width_m": 3.0,
+      "screen_height_m": 2.0,
+      "target_refresh_hz": 120
+    },
+    "camera_state": {
+      "mode": "auto_cruise",
+      "path_id": "global_overview",
+      "fov": 42.0
+    },
+    "payload": {
+      "meta": {
+        "generated_at": "2026-04-17T02:30:06.000Z",
+        "total_records": 20800,
+        "state_hash": 123456789
+      },
+      "layers": {
+        "satellites": {
+          "revision": 111,
+          "items": []
+        },
+        "supercomputers": {
+          "revision": 222,
+          "items": []
+        },
+        "gpu_clusters": {
+          "revision": 333,
+          "items": []
+        },
+        "submarine_cables": {
+          "revision": 444,
+          "items": []
+        },
+        "landing_points": {
+          "revision": 555,
+          "items": []
+        },
+        "alerts": {
+          "revision": 0,
+          "items": []
+        }
+      }
+    }
+  }
+}
+```
+
+### `data_frame` 增量更新
+
+服务端 -> 客户端
+
+```json
+{
+  "type": "data_frame",
+  "channel": "ue_scene",
+  "timestamp": "2026-04-17T02:31:00.000Z",
+  "data": {
+    "update_type": "incremental",
+    "sequence": 13,
+    "base_sequence": 12,
+    "cluster_time": "2026-04-17T02:31:00.000Z",
+    "meta": {
+      "generated_at": "2026-04-17T02:31:00.000Z",
+      "total_records": 20805,
+      "state_hash": 123456790
+    },
+    "changes": {
+      "gpu_clusters": {
+        "added": [],
+        "updated": [],
+        "removed": []
+      },
+      "submarine_cables": {
+        "added": [],
+        "updated": [],
+        "removed": []
+      }
+    }
+  }
+}
+```
+
+### `control_frame`
+
+客户端 -> 服务端
+
+```json
+{
+  "type": "control_frame",
+  "timestamp": "2026-04-17T02:32:00.000Z",
+  "data": {
+    "target": "ue_scene",
+    "command": "set_camera_mode",
+    "arguments": {
+      "mode": "manual",
+      "camera_id": "operator_cam_1"
+    }
+  }
+}
+```
+
+常见命令：
+
+- `set_camera_mode`
+- `set_camera_path`
+- `focus_entity`
+- `set_layer_visibility`
+- `set_alert_filter`
+- `set_display_profile`
+- `pause_auto_cruise`
+- `resume_auto_cruise`
+
+### `control_acknowledged`
+
+服务端 -> 客户端
+
+```json
+{
+  "type": "control_acknowledged",
+  "timestamp": "2026-04-17T02:32:00.050Z",
+  "data": {
+    "target": "ue_scene",
+    "command": "set_camera_mode",
+    "accepted": true
+  }
+}
+```
+
+### `heartbeat`
+
+双向
+
+```json
+{
+  "type": "heartbeat",
+  "timestamp": "2026-04-17T02:32:30.000Z",
+  "data": {
+    "action": "ping"
+  }
+}
+```
+
+服务端返回：
+
+```json
+{
+  "type": "heartbeat",
+  "timestamp": "2026-04-17T02:32:30.020Z",
+  "data": {
+    "action": "pong"
+  }
+}
+```
+
+## 场景实体结构
+
+每个场景实体建议包含：
+
+- `id`
+- `entity_type`
+- `revision`
+- `geo`
+- `visual`
+- `metrics`
+- `labels`
+- `status`
+
+示例：
+
+```json
+{
+  "id": "gpu_clusters:123",
+  "entity_type": "gpu_cluster",
+  "revision": 987654321,
+  "geo": {
+    "lat": 35.9327,
+    "lng": -84.3107,
+    "alt": 0.0
+  },
+  "visual": {
+    "style": "pulse_marker",
+    "size": 1.0,
+    "color": "#FF8C42"
+  },
+  "metrics": {
+    "name": "Frontier"
+  },
+  "labels": {
+    "title": "Frontier",
+    "subtitle": "Oak Ridge, US"
+  },
+  "status": {
+    "health": "normal",
+    "alert_level": "none"
+  }
+}
+```
+
+## 同步策略
+
+UE 主节点建议这样处理：
+
+1. 保存本地最后一次成功应用的 `sequence`
+2. 收到增量帧时检查 `base_sequence`
+3. 若 `base_sequence` 不等于本地序列，则立即发 `sync_request`
+4. 如果服务端能重放缺失增量，则按顺序依次应用
+5. 如果服务端无法重放，则接收并应用新的全量快照
+6. 场景更新应在主节点原子提交，再交给集群同步显示
+
+## 服务端重同步规则
+
+服务端建议行为：
+
+- `initial_connect`：直接返回全量快照
+- `manual_resync`：直接返回全量快照
+- `profile_changed`：直接返回全量快照
+- `sequence_gap`：优先尝试从历史缓存中回放增量
+- 如果历史缓存不完整：回退到全量快照
+- 如果客户端已是最新序列：返回空变化增量或保持静默
+
+## 集群职责约束
+
+- 只有 UE 主节点接收后端场景同步消息
+- 渲染节点不直接重放后端消息
+- 服务端表达的是场景意图，而不是每个节点的底层渲染状态
+
+## 推荐的后端扩展
+
+- 为 `ue_scene` 增加更多真实可视化层
+- 将告警/BGP 事件并入统一场景层
+- 为控制命令增加真正的状态持久化与回执
+- 为主节点断线重连补状态恢复策略

scripts/test_ue_scene_ws.ps1

@@ -0,0 +1,134 @@
+param(
+    [string]$BaseUrl = "http://localhost:8000",
+    [string]$Username,
+    [string]$Password,
+    [int]$ReadMessageCount = 5
+)
+
+Set-StrictMode -Version Latest
+$ErrorActionPreference = "Stop"
+
+if ([string]::IsNullOrWhiteSpace($Username) -or [string]::IsNullOrWhiteSpace($Password)) {
+    throw "Missing username/password. Pass -Username and -Password."
+}
+
+Add-Type -AssemblyName System.Net.Http
+
+function Read-WebSocketMessage {
+    param(
+        [System.Net.WebSockets.ClientWebSocket]$Socket
+    )
+
+    $buffer = New-Object byte[] 8192
+    $segment = [System.ArraySegment[byte]]::new($buffer)
+    $builder = New-Object System.Text.StringBuilder
+
+    do {
+        $result = $Socket.ReceiveAsync($segment, [Threading.CancellationToken]::None).GetAwaiter().GetResult()
+        if ($result.MessageType -eq [System.Net.WebSockets.WebSocketMessageType]::Close) {
+            return $null
+        }
+
+        $builder.Append([System.Text.Encoding]::UTF8.GetString($buffer, 0, $result.Count)) | Out-Null
+    } while (-not $result.EndOfMessage)
+
+    return $builder.ToString()
+}
+
+$loginUri = "$BaseUrl/api/v1/auth/login"
+$loginBody = "username=$([uri]::EscapeDataString($Username))&password=$([uri]::EscapeDataString($Password))"
+
+Write-Host "Requesting access token from $loginUri ..."
+$tokenResponse = Invoke-RestMethod `
+    -Method Post `
+    -Uri $loginUri `
+    -ContentType "application/x-www-form-urlencoded" `
+    -Body $loginBody
+
+if (-not $tokenResponse.access_token) {
+    throw "Login succeeded but access_token missing."
+}
+
+$accessToken = [string]$tokenResponse.access_token
+Write-Host "Token acquired. Expires in: $($tokenResponse.expires_in)"
+
+$wsBase = $BaseUrl -replace "^http", "ws"
+$wsUri = "$wsBase/ws?token=$accessToken"
+
+$socket = [System.Net.WebSockets.ClientWebSocket]::new()
+$socket.Options.KeepAliveInterval = [TimeSpan]::FromSeconds(20)
+
+Write-Host "Connecting WebSocket: $wsUri"
+$socket.ConnectAsync([Uri]$wsUri, [Threading.CancellationToken]::None).GetAwaiter().GetResult()
+Write-Host "WebSocket connected."
+
+try {
+    $initial = Read-WebSocketMessage -Socket $socket
+    if ($null -ne $initial) {
+        Write-Host ""
+        Write-Host "=== connection_established ==="
+        Write-Host $initial
+    }
+
+    $subscribeFrame = @{
+        type = "subscribe"
+        data = @{
+            channels = @("ue_scene")
+        }
+    } | ConvertTo-Json -Depth 8 -Compress
+
+    $subscribeBytes = [System.Text.Encoding]::UTF8.GetBytes($subscribeFrame)
+    $subscribeSegment = [System.ArraySegment[byte]]::new($subscribeBytes)
+    $socket.SendAsync(
+        $subscribeSegment,
+        [System.Net.WebSockets.WebSocketMessageType]::Text,
+        $true,
+        [Threading.CancellationToken]::None
+    ).GetAwaiter().GetResult()
+
+    $subAck = Read-WebSocketMessage -Socket $socket
+    if ($null -ne $subAck) {
+        Write-Host ""
+        Write-Host "=== subscription_confirmed ==="
+        Write-Host $subAck
+    }
+
+    $syncFrame = @{
+        type = "sync_request"
+        data = @{
+            channel = "ue_scene"
+            reason = "initial_connect"
+            last_sequence = $null
+        }
+    } | ConvertTo-Json -Depth 8 -Compress
+
+    $syncBytes = [System.Text.Encoding]::UTF8.GetBytes($syncFrame)
+    $syncSegment = [System.ArraySegment[byte]]::new($syncBytes)
+    $socket.SendAsync(
+        $syncSegment,
+        [System.Net.WebSockets.WebSocketMessageType]::Text,
+        $true,
+        [Threading.CancellationToken]::None
+    ).GetAwaiter().GetResult()
+
+    for ($i = 1; $i -le $ReadMessageCount; $i++) {
+        $message = Read-WebSocketMessage -Socket $socket
+        if ($null -eq $message) {
+            break
+        }
+
+        Write-Host ""
+        Write-Host "=== message $i ==="
+        Write-Host $message
+    }
+}
+finally {
+    if ($socket.State -eq [System.Net.WebSockets.WebSocketState]::Open) {
+        $socket.CloseAsync(
+            [System.Net.WebSockets.WebSocketCloseStatus]::NormalClosure,
+            "done",
+            [Threading.CancellationToken]::None
+        ).GetAwaiter().GetResult()
+    }
+    $socket.Dispose()
+}

unreal/Content/Blueprints/BP_GlobeController_WebSocket_Guide.md

@@ -0,0 +1,264 @@
+# BP_GlobeController 接 `ue_scene` 数据接口指南
+
+## 这份文档解决什么问题
+
+这份文档专门讲：
+
+1. 后端 `ue_scene` 已经准备好之后，如何先在本机验证接口
+2. UE 展示端接接口时，消息应该怎么走
+3. `BP_GlobeController` 后续该预留哪些函数和状态
+
+适合当前阶段：
+
+- 你已经有 `Earth_Globe`
+- 你已经有一个能展示地球的 Demo
+- 现在要开始把后端的 `ue_scene` 数据接进来
+
+## 当前后端入口
+
+后端 WebSocket 入口在：
+
+- [backend/app/api/v1/websocket.py](/D:/work/planet/planet/backend/app/api/v1/websocket.py:1)
+
+`ue_scene` 数据构建在：
+
+- [backend/app/core/websocket/ue_scene.py](/D:/work/planet/planet/backend/app/core/websocket/ue_scene.py:1)
+
+协议草案在：
+
+- [docs/ue-ndisplay-websocket-protocol.md](/D:/work/planet/planet/docs/ue-ndisplay-websocket-protocol.md:1)
+
+## 先不要直接进 UE
+
+建议先做一件事：
+
+先在本机验证这条链路是通的：
+
+1. 登录后端拿 `access_token`
+2. 用这个 token 连接 `/ws`
+3. 订阅 `ue_scene`
+4. 发送 `sync_request`
+5. 确认后端回了 `full` 快照
+
+这一步跑通后，再把同样的消息流程搬到 UE。
+
+## 本机验证脚本
+
+仓库里已经补了测试脚本：
+
+- [scripts/test_ue_scene_ws.ps1](/D:/work/planet/planet/scripts/test_ue_scene_ws.ps1)
+
+### 用法
+
+```powershell
+powershell -ExecutionPolicy Bypass -File scripts/test_ue_scene_ws.ps1 `
+  -BaseUrl http://localhost:8000 `
+  -Username 你的用户名 `
+  -Password 你的密码 `
+  -ReadMessageCount 3
+```
+
+### 预期输出
+
+你应该能看到这些消息：
+
+1. `connection_established`
+2. `subscription_confirmed`
+3. 至少一条 `data_frame`
+
+其中第一条 `data_frame` 里：
+
+- `channel = ue_scene`
+- `update_type = full`
+
+如果这一步失败，不要先去 UE 里找问题。
+
+## 连接顺序
+
+UE 主节点后续接接口时，顺序就是下面这样：
+
+1. 登录拿 token
+2. 连接 `ws://<host>:8000/ws?token=<access_token>`
+3. 收到 `connection_established`
+4. 发 `subscribe`
+5. 发 `sync_request`
+6. 收 `data_frame`
+7. 应用 `full`
+8. 后续继续应用 `incremental`
+
+## WebSocket 地址
+
+```text
+ws://localhost:8000/ws?token=<access_token>
+```
+
+## `subscribe` 消息
+
+```json
+{
+  "type": "subscribe",
+  "data": {
+    "channels": ["ue_scene"]
+  }
+}
+```
+
+## `sync_request` 消息
+
+```json
+{
+  "type": "sync_request",
+  "data": {
+    "channel": "ue_scene",
+    "reason": "initial_connect",
+    "last_sequence": null
+  }
+}
+```
+
+## 你在 UE 里要接收的重点字段
+
+### 1. `data.update_type`
+
+可能是：
+
+- `full`
+- `incremental`
+
+### 2. `data.sequence`
+
+每次场景更新都会递增。
+
+UE 主节点要保存自己最近一次成功应用的 `sequence`。
+
+### 3. `data.payload.layers`
+
+`full` 快照时，场景实体都在这里。
+
+重点层包括：
+
+- `satellites`
+- `supercomputers`
+- `gpu_clusters`
+- `submarine_cables`
+- `landing_points`
+- `alerts`
+
+### 4. `data.changes`
+
+`incremental` 更新时，变化都在这里。
+
+每一层会包含：
+
+- `added`
+- `updated`
+- `removed`
+
+## `BP_GlobeController` 建议先预留的变量
+
+### `LastSequence`
+
+- 类型：整数
+- 用途：记录最近一次成功应用的序列号
+
+### `SceneConnected`
+
+- 类型：布尔
+- 用途：当前是否已连上后端 WebSocket
+
+### `PendingFullSync`
+
+- 类型：布尔
+- 用途：是否正在等待全量快照
+
+### `CurrentSceneHash`
+
+- 类型：字符串
+- 用途：记录当前已应用场景的 `state_hash`
+
+## `BP_GlobeController` 建议先预留的函数
+
+### `ConnectWebSocket`
+
+负责：
+
+- 建立连接
+- 进入已连接状态
+
+### `SendSubscribe`
+
+负责：
+
+- 订阅 `ue_scene`
+
+### `SendSyncRequest`
+
+负责：
+
+- 请求 `full` 快照
+
+### `HandleMessage`
+
+负责：
+
+- 解析服务端返回的原始 JSON
+
+### `ApplyFullScene`
+
+负责：
+
+- 清理旧场景数据
+- 按 `layers` 重建当前场景
+
+### `ApplyIncrementalScene`
+
+负责：
+
+- 处理 `added`
+- 处理 `updated`
+- 处理 `removed`
+
+### `GeoToWorld`
+
+负责：
+
+- 把 `lat/lng/alt` 转成球面世界坐标
+
+## 第一个可落地目标
+
+不要一上来就把所有层都接进来。
+
+建议第一阶段只做：
+
+1. 连接成功
+2. 收到 `full`
+3. 先只解析 `gpu_clusters`
+4. 在地球上生成几个测试点位
+
+这样最容易判断问题在哪：
+
+- 是连接没通
+- 还是 JSON 没解析对
+- 还是地理坐标映射有问题
+
+## 当前阶段建议
+
+对于你现在这个 Demo，建议下一步按这个顺序：
+
+1. 先跑 [scripts/test_ue_scene_ws.ps1](/D:/work/planet/planet/scripts/test_ue_scene_ws.ps1:1)
+2. 确认后端确实回 `ue_scene`
+3. 再在 UE 里接登录和 WebSocket
+4. 先只落 `ApplyFullScene`
+5. 最后再接 `ApplyIncrementalScene`
+
+## 一个现实提醒
+
+UE 原生 `WebSockets` 插件更适合 C++ 层接入，不是最友好的纯蓝图体验。
+
+所以如果你下一步要我继续带着落地，我建议走这条路线：
+
+1. 先把协议和测试跑通
+2. 再补一个 UE 侧最小 C++ WebSocket 接收层
+3. 最后把消息转给 `BP_GlobeController`
+
+这样会比纯蓝图硬接稳定很多。

unreal/Source/Planet/Planet.Build.cs

@@ -0,0 +1,22 @@
+using UnrealBuildTool;
+
+public class Planet : ModuleRules
+{
+    public Planet(ReadOnlyTargetRules Target) : base(Target)
+    {
+        PCHUsage = PCHUsageMode.UseExplicitOrSharedPCHs;
+
+        PublicDependencyModuleNames.AddRange(
+            new[]
+            {
+                "Core",
+                "CoreUObject",
+                "Engine",
+                "HTTP",
+                "Json",
+                "JsonUtilities",
+                "WebSockets",
+            }
+        );
+    }
+}

unreal/Source/Planet/Private/UeSceneWebSocketClient.cpp

@@ -0,0 +1,677 @@
+#include "UeSceneWebSocketClient.h"
+
+#include "Dom/JsonObject.h"
+#include "Dom/JsonValue.h"
+#include "HttpModule.h"
+#include "JsonObjectConverter.h"
+#include "Serialization/JsonReader.h"
+#include "Serialization/JsonSerializer.h"
+#include "WebSocketsModule.h"
+
+namespace
+{
+constexpr double GeoPointMergeTolerance = 1e-4;
+
+bool TryParseGeoPoint(const TSharedPtr<FJsonObject>& PointObject, FVector& OutGeoPoint)
+{
+    if (!PointObject.IsValid())
+    {
+        return false;
+    }
+
+    double Latitude = 0.0;
+    double Longitude = 0.0;
+    double Altitude = 0.0;
+    if (!PointObject->TryGetNumberField(TEXT("lat"), Latitude)
+        || !PointObject->TryGetNumberField(TEXT("lng"), Longitude))
+    {
+        return false;
+    }
+
+    PointObject->TryGetNumberField(TEXT("alt"), Altitude);
+    OutGeoPoint = FVector(Longitude, Latitude, Altitude);
+    return true;
+}
+
+FString ResolveCableName(const TSharedPtr<FJsonObject>& ItemObject)
+{
+    FString CableName;
+
+    const TSharedPtr<FJsonObject>* LabelsObject = nullptr;
+    if (ItemObject->TryGetObjectField(TEXT("labels"), LabelsObject)
+        && LabelsObject != nullptr
+        && LabelsObject->IsValid())
+    {
+        (*LabelsObject)->TryGetStringField(TEXT("title"), CableName);
+    }
+
+    if (CableName.IsEmpty())
+    {
+        ItemObject->TryGetStringField(TEXT("id"), CableName);
+    }
+
+    return CableName;
+}
+
+bool AreGeoPointsConnected(const FVector& A, const FVector& B)
+{
+    return FMath::Abs(A.X - B.X) <= GeoPointMergeTolerance
+        && FMath::Abs(A.Y - B.Y) <= GeoPointMergeTolerance
+        && FMath::Abs(A.Z - B.Z) <= GeoPointMergeTolerance;
+}
+
+void AppendMergedSegment(
+    TArray<TArray<FVector>>& MergedSegments,
+    const TArray<FVector>& IncomingSegment
+)
+{
+    if (IncomingSegment.Num() < 2)
+    {
+        return;
+    }
+
+    if (MergedSegments.Num() == 0)
+    {
+        MergedSegments.Add(IncomingSegment);
+        return;
+    }
+
+    TArray<FVector>& LastMergedSegment = MergedSegments.Last();
+    if (LastMergedSegment.Num() == 0)
+    {
+        LastMergedSegment = IncomingSegment;
+        return;
+    }
+
+    if (AreGeoPointsConnected(LastMergedSegment.Last(), IncomingSegment[0]))
+    {
+        for (int32 Index = 1; Index < IncomingSegment.Num(); ++Index)
+        {
+            LastMergedSegment.Add(IncomingSegment[Index]);
+        }
+        return;
+    }
+
+    MergedSegments.Add(IncomingSegment);
+}
+}
+
+UUeSceneWebSocketClient::UUeSceneWebSocketClient()
+{
+    PrimaryComponentTick.bCanEverTick = false;
+}
+
+void UUeSceneWebSocketClient::BeginPlay()
+{
+    Super::BeginPlay();
+}
+
+void UUeSceneWebSocketClient::EndPlay(const EEndPlayReason::Type EndPlayReason)
+{
+    DisconnectFromBackend();
+    Super::EndPlay(EndPlayReason);
+}
+
+void UUeSceneWebSocketClient::ConnectToBackend()
+{
+    if (Username.IsEmpty() || Password.IsEmpty())
+    {
+        EmitError(TEXT("Username / Password 不能为空。"));
+        return;
+    }
+
+    RequestAccessToken();
+}
+
+void UUeSceneWebSocketClient::DisconnectFromBackend()
+{
+    if (Socket.IsValid())
+    {
+        Socket->Close();
+        Socket.Reset();
+    }
+
+    PendingFullScene.Reset();
+    OnConnectedChanged.Broadcast(false);
+}
+
+void UUeSceneWebSocketClient::SendSubscribe()
+{
+    TSharedRef<FJsonObject> Root = MakeShared<FJsonObject>();
+    Root->SetStringField(TEXT("type"), TEXT("subscribe"));
+
+    TSharedRef<FJsonObject> Data = MakeShared<FJsonObject>();
+    TArray<TSharedPtr<FJsonValue>> Channels;
+    for (const FString& Channel : DefaultChannels)
+    {
+        Channels.Add(MakeShared<FJsonValueString>(Channel));
+    }
+    Data->SetArrayField(TEXT("channels"), Channels);
+    Root->SetObjectField(TEXT("data"), Data);
+
+    FString Payload;
+    TSharedRef<TJsonWriter<>> Writer = TJsonWriterFactory<>::Create(&Payload);
+    FJsonSerializer::Serialize(Root, Writer);
+    SendJsonString(Payload);
+}
+
+void UUeSceneWebSocketClient::SendInitialSyncRequest()
+{
+    SendSyncRequest(TEXT("initial_connect"), INDEX_NONE);
+}
+
+void UUeSceneWebSocketClient::SendSyncRequest(const FString& Reason, int32 InLastSequence)
+{
+    TSharedRef<FJsonObject> Root = MakeShared<FJsonObject>();
+    Root->SetStringField(TEXT("type"), TEXT("sync_request"));
+
+    TSharedRef<FJsonObject> Data = MakeShared<FJsonObject>();
+    Data->SetStringField(TEXT("channel"), TEXT("ue_scene"));
+    Data->SetStringField(TEXT("reason"), Reason);
+    if (InLastSequence >= 0)
+    {
+        Data->SetNumberField(TEXT("last_sequence"), InLastSequence);
+    }
+    Root->SetObjectField(TEXT("data"), Data);
+
+    FString Payload;
+    TSharedRef<TJsonWriter<>> Writer = TJsonWriterFactory<>::Create(&Payload);
+    FJsonSerializer::Serialize(Root, Writer);
+    SendJsonString(Payload);
+}
+
+void UUeSceneWebSocketClient::RequestAccessToken()
+{
+    TSharedRef<IHttpRequest, ESPMode::ThreadSafe> Request = FHttpModule::Get().CreateRequest();
+    Request->SetURL(BuildHttpUrl(TEXT("/api/v1/auth/login")));
+    Request->SetVerb(TEXT("POST"));
+    Request->SetHeader(TEXT("Content-Type"), TEXT("application/x-www-form-urlencoded"));
+    Request->SetContentAsString(
+        FString::Printf(TEXT("username=%s&password=%s"), *Username, *Password)
+    );
+    Request->OnProcessRequestComplete().BindUObject(
+        this, &UUeSceneWebSocketClient::HandleLoginResponse
+    );
+    Request->ProcessRequest();
+}
+
+void UUeSceneWebSocketClient::HandleLoginResponse(
+    FHttpRequestPtr Request,
+    FHttpResponsePtr Response,
+    bool bSucceeded
+)
+{
+    if (!bSucceeded || !Response.IsValid())
+    {
+        EmitError(TEXT("登录请求失败。"));
+        return;
+    }
+
+    if (Response->GetResponseCode() < 200 || Response->GetResponseCode() >= 300)
+    {
+        EmitError(FString::Printf(TEXT("登录失败，HTTP %d"), Response->GetResponseCode()));
+        return;
+    }
+
+    TSharedPtr<FJsonObject> Root;
+    TSharedRef<TJsonReader<>> Reader = TJsonReaderFactory<>::Create(Response->GetContentAsString());
+    if (!FJsonSerializer::Deserialize(Reader, Root) || !Root.IsValid())
+    {
+        EmitError(TEXT("登录响应 JSON 解析失败。"));
+        return;
+    }
+
+    AccessToken = Root->GetStringField(TEXT("access_token"));
+    if (AccessToken.IsEmpty())
+    {
+        EmitError(TEXT("登录响应里没有 access_token。"));
+        return;
+    }
+
+    OpenWebSocket();
+}
+
+void UUeSceneWebSocketClient::OpenWebSocket()
+{
+    if (!FModuleManager::Get().IsModuleLoaded(TEXT("WebSockets")))
+    {
+        FModuleManager::Get().LoadModule(TEXT("WebSockets"));
+    }
+
+    Socket = FWebSocketsModule::Get().CreateWebSocket(BuildWsUrl());
+    BindSocketEvents();
+    Socket->Connect();
+}
+
+void UUeSceneWebSocketClient::BindSocketEvents()
+{
+    if (!Socket.IsValid())
+    {
+        return;
+    }
+
+    Socket->OnConnected().AddLambda([this]()
+    {
+        OnConnectedChanged.Broadcast(true);
+    });
+
+    Socket->OnConnectionError().AddLambda([this](const FString& Error)
+    {
+        EmitError(FString::Printf(TEXT("WebSocket 连接失败: %s"), *Error));
+    });
+
+    Socket->OnClosed().AddLambda([this](int32 StatusCode, const FString& Reason, bool bWasClean)
+    {
+        OnConnectedChanged.Broadcast(false);
+    });
+
+    Socket->OnMessage().AddLambda([this](const FString& Message)
+    {
+        OnRawMessage.Broadcast(Message);
+        TryBroadcastSceneFrame(Message);
+    });
+}
+
+void UUeSceneWebSocketClient::EmitError(const FString& ErrorMessage)
+{
+    OnError.Broadcast(ErrorMessage);
+}
+
+void UUeSceneWebSocketClient::TryBroadcastSceneFrame(const FString& Message)
+{
+    TSharedPtr<FJsonObject> Root;
+    TSharedRef<TJsonReader<>> Reader = TJsonReaderFactory<>::Create(Message);
+    if (!FJsonSerializer::Deserialize(Reader, Root) || !Root.IsValid())
+    {
+        return;
+    }
+
+    FString Type;
+    if (!Root->TryGetStringField(TEXT("type"), Type) || Type != TEXT("data_frame"))
+    {
+        return;
+    }
+
+    FString Channel;
+    if (!Root->TryGetStringField(TEXT("channel"), Channel) || Channel != TEXT("ue_scene"))
+    {
+        return;
+    }
+
+    const TSharedPtr<FJsonObject>* DataObject = nullptr;
+    if (!Root->TryGetObjectField(TEXT("data"), DataObject) || DataObject == nullptr || !DataObject->IsValid())
+    {
+        return;
+    }
+    TSharedPtr<FJsonObject> EffectiveDataObject = *DataObject;
+
+    FString UpdateType = TEXT("unknown");
+    EffectiveDataObject->TryGetStringField(TEXT("update_type"), UpdateType);
+
+    int32 Sequence = 0;
+    EffectiveDataObject->TryGetNumberField(TEXT("sequence"), Sequence);
+
+    int32 TotalRecords = 0;
+    const TSharedPtr<FJsonObject>* PayloadObject = nullptr;
+    if (EffectiveDataObject->TryGetObjectField(TEXT("payload"), PayloadObject) && PayloadObject != nullptr && PayloadObject->IsValid())
+    {
+        const TSharedPtr<FJsonObject>* MetaObject = nullptr;
+        if ((*PayloadObject)->TryGetObjectField(TEXT("meta"), MetaObject) && MetaObject != nullptr && MetaObject->IsValid())
+        {
+            (*MetaObject)->TryGetNumberField(TEXT("total_records"), TotalRecords);
+        }
+    }
+
+    if (UpdateType == TEXT("full"))
+    {
+        TSharedPtr<FJsonObject> AssembledDataObject;
+        if (!TryAssembleFullScene(EffectiveDataObject, Sequence, TotalRecords, AssembledDataObject))
+        {
+            return;
+        }
+        if (AssembledDataObject.IsValid())
+        {
+            EffectiveDataObject = AssembledDataObject;
+        }
+    }
+
+    LastSequence = Sequence;
+    OnSceneFrame.Broadcast(UpdateType, Sequence, TotalRecords);
+    BroadcastScenePayload(UpdateType, Sequence, EffectiveDataObject);
+}
+
+bool UUeSceneWebSocketClient::TryAssembleFullScene(
+    const TSharedPtr<FJsonObject>& DataObject,
+    int32 Sequence,
+    int32 TotalRecords,
+    TSharedPtr<FJsonObject>& OutAssembledDataObject
+)
+{
+    OutAssembledDataObject = nullptr;
+
+    const TSharedPtr<FJsonObject>* PayloadObject = nullptr;
+    if (!DataObject->TryGetObjectField(TEXT("payload"), PayloadObject) || PayloadObject == nullptr || !PayloadObject->IsValid())
+    {
+        EmitError(TEXT("Full scene payload is missing."));
+        return false;
+    }
+
+    const TSharedPtr<FJsonObject>* MetaObject = nullptr;
+    if (!(*PayloadObject)->TryGetObjectField(TEXT("meta"), MetaObject) || MetaObject == nullptr || !MetaObject->IsValid())
+    {
+        EmitError(TEXT("Full scene meta is missing."));
+        return false;
+    }
+
+    bool bChunked = false;
+    (*MetaObject)->TryGetBoolField(TEXT("chunked"), bChunked);
+    if (!bChunked)
+    {
+        OutAssembledDataObject = DataObject;
+        PendingFullScene.Reset();
+        return true;
+    }
+
+    int32 TransportChunkIndex = 0;
+    int32 TransportChunkCount = 0;
+    int32 LayerChunkIndex = 0;
+    int32 LayerChunkCount = 0;
+    FString LayerName;
+    (*MetaObject)->TryGetNumberField(TEXT("transport_chunk_index"), TransportChunkIndex);
+    (*MetaObject)->TryGetNumberField(TEXT("transport_chunk_count"), TransportChunkCount);
+    (*MetaObject)->TryGetNumberField(TEXT("layer_chunk_index"), LayerChunkIndex);
+    (*MetaObject)->TryGetNumberField(TEXT("layer_chunk_count"), LayerChunkCount);
+    (*MetaObject)->TryGetStringField(TEXT("layer_name"), LayerName);
+
+    if (TransportChunkIndex <= 0 || TransportChunkCount <= 0 || LayerChunkIndex <= 0 || LayerChunkCount <= 0 || LayerName.IsEmpty())
+    {
+        EmitError(TEXT("Chunked full scene metadata is incomplete."));
+        PendingFullScene.Reset();
+        return false;
+    }
+
+    if (PendingFullScene.Sequence != Sequence)
+    {
+        PendingFullScene.Reset();
+        PendingFullScene.Sequence = Sequence;
+        PendingFullScene.ExpectedTransportChunkCount = TransportChunkCount;
+        PendingFullScene.TotalRecords = TotalRecords;
+        PendingFullScene.DisplayProfile = DataObject->GetObjectField(TEXT("display_profile"));
+        PendingFullScene.CameraState = DataObject->GetObjectField(TEXT("camera_state"));
+        PendingFullScene.Meta = MakeShared<FJsonObject>(*MetaObject->Get());
+        DataObject->TryGetStringField(TEXT("cluster_time"), PendingFullScene.ClusterTime);
+    }
+
+    if (PendingFullScene.Sequence != Sequence || PendingFullScene.ExpectedTransportChunkCount != TransportChunkCount)
+    {
+        EmitError(TEXT("Chunked full scene sequence mismatch."));
+        PendingFullScene.Reset();
+        return false;
+    }
+
+    if (PendingFullScene.ReceivedTransportChunkIndices.Contains(TransportChunkIndex))
+    {
+        return false;
+    }
+
+    PendingFullScene.ReceivedTransportChunkIndices.Add(TransportChunkIndex);
+
+    const TSharedPtr<FJsonObject>* LayersObject = nullptr;
+    if (!(*PayloadObject)->TryGetObjectField(TEXT("layers"), LayersObject) || LayersObject == nullptr || !LayersObject->IsValid())
+    {
+        EmitError(TEXT("Chunked full scene layers are missing."));
+        PendingFullScene.Reset();
+        return false;
+    }
+
+    const TSharedPtr<FJsonObject>* LayerDataObject = nullptr;
+    if (!(*LayersObject)->TryGetObjectField(LayerName, LayerDataObject) || LayerDataObject == nullptr || !LayerDataObject->IsValid())
+    {
+        EmitError(TEXT("Chunked full scene layer payload is missing."));
+        PendingFullScene.Reset();
+        return false;
+    }
+
+    FLayerChunkAccumulator& LayerAccumulator = PendingFullScene.Layers.FindOrAdd(LayerName);
+    if (LayerAccumulator.ExpectedChunkCount == 0)
+    {
+        LayerAccumulator.ExpectedChunkCount = LayerChunkCount;
+        LayerDataObject->Get()->TryGetNumberField(TEXT("revision"), LayerAccumulator.Revision);
+    }
+    else if (LayerAccumulator.ExpectedChunkCount != LayerChunkCount)
+    {
+        EmitError(TEXT("Layer chunk count changed while assembling full scene."));
+        PendingFullScene.Reset();
+        return false;
+    }
+
+    if (LayerAccumulator.ReceivedChunkIndices.Contains(LayerChunkIndex))
+    {
+        return false;
+    }
+
+    const TArray<TSharedPtr<FJsonValue>>* LayerItems = nullptr;
+    if (!LayerDataObject->Get()->TryGetArrayField(TEXT("items"), LayerItems) || LayerItems == nullptr)
+    {
+        EmitError(TEXT("Chunked full scene items are missing."));
+        PendingFullScene.Reset();
+        return false;
+    }
+
+    LayerAccumulator.ReceivedChunkIndices.Add(LayerChunkIndex);
+    LayerAccumulator.Items.Append(*LayerItems);
+
+    if (PendingFullScene.ReceivedTransportChunkIndices.Num() != PendingFullScene.ExpectedTransportChunkCount)
+    {
+        return false;
+    }
+
+    for (const TPair<FString, FLayerChunkAccumulator>& LayerPair : PendingFullScene.Layers)
+    {
+        if (LayerPair.Value.ReceivedChunkIndices.Num() != LayerPair.Value.ExpectedChunkCount)
+        {
+            return false;
+        }
+    }
+
+    TSharedRef<FJsonObject> AssembledDataObject = MakeShared<FJsonObject>();
+    AssembledDataObject->SetStringField(TEXT("update_type"), TEXT("full"));
+    AssembledDataObject->SetNumberField(TEXT("sequence"), Sequence);
+    AssembledDataObject->SetStringField(TEXT("cluster_time"), PendingFullScene.ClusterTime);
+    if (PendingFullScene.DisplayProfile.IsValid())
+    {
+        AssembledDataObject->SetObjectField(TEXT("display_profile"), PendingFullScene.DisplayProfile);
+    }
+    if (PendingFullScene.CameraState.IsValid())
+    {
+        AssembledDataObject->SetObjectField(TEXT("camera_state"), PendingFullScene.CameraState);
+    }
+
+    TSharedRef<FJsonObject> AssembledPayloadObject = MakeShared<FJsonObject>();
+    TSharedRef<FJsonObject> AssembledMetaObject = PendingFullScene.Meta.IsValid()
+        ? MakeShared<FJsonObject>(*PendingFullScene.Meta.Get())
+        : MakeShared<FJsonObject>();
+    AssembledMetaObject->SetBoolField(TEXT("chunked"), false);
+    AssembledMetaObject->RemoveField(TEXT("layer_name"));
+    AssembledMetaObject->RemoveField(TEXT("layer_chunk_index"));
+    AssembledMetaObject->RemoveField(TEXT("layer_chunk_count"));
+    AssembledMetaObject->RemoveField(TEXT("transport_chunk_index"));
+    AssembledMetaObject->RemoveField(TEXT("transport_chunk_count"));
+    AssembledPayloadObject->SetObjectField(TEXT("meta"), AssembledMetaObject);
+
+    TSharedRef<FJsonObject> AssembledLayersObject = MakeShared<FJsonObject>();
+    for (TPair<FString, FLayerChunkAccumulator>& LayerPair : PendingFullScene.Layers)
+    {
+        TSharedRef<FJsonObject> LayerObject = MakeShared<FJsonObject>();
+        LayerObject->SetNumberField(TEXT("revision"), LayerPair.Value.Revision);
+        LayerObject->SetArrayField(TEXT("items"), LayerPair.Value.Items);
+        AssembledLayersObject->SetObjectField(LayerPair.Key, LayerObject);
+    }
+    AssembledPayloadObject->SetObjectField(TEXT("layers"), AssembledLayersObject);
+    AssembledDataObject->SetObjectField(TEXT("payload"), AssembledPayloadObject);
+
+    OutAssembledDataObject = AssembledDataObject;
+    PendingFullScene.Reset();
+    return true;
+}
+
+void UUeSceneWebSocketClient::BroadcastScenePayload(
+    const FString& UpdateType,
+    int32 Sequence,
+    const TSharedPtr<FJsonObject>& DataObject
+)
+{
+    FString PayloadJson;
+    TSharedRef<TJsonWriter<>> Writer = TJsonWriterFactory<>::Create(&PayloadJson);
+    if (FJsonSerializer::Serialize(DataObject.ToSharedRef(), Writer))
+    {
+        OnScenePayload.Broadcast(UpdateType, Sequence, PayloadJson);
+    }
+
+    BroadcastLegacySubmarineCableEvents(DataObject);
+}
+
+void UUeSceneWebSocketClient::BroadcastLegacySubmarineCableEvents(
+    const TSharedPtr<FJsonObject>& DataObject
+)
+{
+    if (!DataObject.IsValid())
+    {
+        return;
+    }
+
+    const TSharedPtr<FJsonObject>* PayloadObject = nullptr;
+    if (!DataObject->TryGetObjectField(TEXT("payload"), PayloadObject)
+        || PayloadObject == nullptr
+        || !PayloadObject->IsValid())
+    {
+        return;
+    }
+
+    const TSharedPtr<FJsonObject>* LayersObject = nullptr;
+    if (!(*PayloadObject)->TryGetObjectField(TEXT("layers"), LayersObject)
+        || LayersObject == nullptr
+        || !LayersObject->IsValid())
+    {
+        return;
+    }
+
+    const TSharedPtr<FJsonObject>* CableLayerObject = nullptr;
+    if (!(*LayersObject)->TryGetObjectField(TEXT("submarine_cables"), CableLayerObject)
+        || CableLayerObject == nullptr
+        || !CableLayerObject->IsValid())
+    {
+        return;
+    }
+
+    const TArray<TSharedPtr<FJsonValue>>* CableItems = nullptr;
+    if (!(*CableLayerObject)->TryGetArrayField(TEXT("items"), CableItems) || CableItems == nullptr)
+    {
+        return;
+    }
+
+    for (const TSharedPtr<FJsonValue>& CableItemValue : *CableItems)
+    {
+        const TSharedPtr<FJsonObject> CableItemObject = CableItemValue.IsValid()
+            ? CableItemValue->AsObject()
+            : nullptr;
+        if (!CableItemObject.IsValid())
+        {
+            continue;
+        }
+
+        const FString CableName = ResolveCableName(CableItemObject);
+
+        const TSharedPtr<FJsonObject>* GeoObject = nullptr;
+        if (!CableItemObject->TryGetObjectField(TEXT("geo"), GeoObject)
+            || GeoObject == nullptr
+            || !GeoObject->IsValid())
+        {
+            continue;
+        }
+
+        const TArray<TSharedPtr<FJsonValue>>* SegmentArray = nullptr;
+        if ((*GeoObject)->TryGetArrayField(TEXT("segments"), SegmentArray) && SegmentArray != nullptr)
+        {
+            TArray<TArray<FVector>> MergedSegments;
+            for (const TSharedPtr<FJsonValue>& SegmentValue : *SegmentArray)
+            {
+                const TArray<TSharedPtr<FJsonValue>>* SegmentPoints = nullptr;
+                if (!SegmentValue.IsValid() || !SegmentValue->TryGetArray(SegmentPoints) || SegmentPoints == nullptr)
+                {
+                    continue;
+                }
+
+                TArray<FVector> GeoPoints;
+                GeoPoints.Reserve(SegmentPoints->Num());
+
+                for (const TSharedPtr<FJsonValue>& PointValue : *SegmentPoints)
+                {
+                    FVector GeoPoint = FVector::ZeroVector;
+                    if (PointValue.IsValid() && TryParseGeoPoint(PointValue->AsObject(), GeoPoint))
+                    {
+                        GeoPoints.Add(GeoPoint);
+                    }
+                }
+
+                AppendMergedSegment(MergedSegments, GeoPoints);
+            }
+
+            for (const TArray<FVector>& MergedSegment : MergedSegments)
+            {
+                if (MergedSegment.Num() >= 2)
+                {
+                    OnSubmarineCableReceived.Broadcast(CableName, MergedSegment);
+                }
+            }
+
+            continue;
+        }
+
+        const TArray<TSharedPtr<FJsonValue>>* PathArray = nullptr;
+        if (!(*GeoObject)->TryGetArrayField(TEXT("path"), PathArray) || PathArray == nullptr)
+        {
+            continue;
+        }
+
+        TArray<FVector> GeoPoints;
+        GeoPoints.Reserve(PathArray->Num());
+        for (const TSharedPtr<FJsonValue>& PointValue : *PathArray)
+        {
+            FVector GeoPoint = FVector::ZeroVector;
+            if (PointValue.IsValid() && TryParseGeoPoint(PointValue->AsObject(), GeoPoint))
+            {
+                GeoPoints.Add(GeoPoint);
+            }
+        }
+
+        if (GeoPoints.Num() >= 2)
+        {
+            OnSubmarineCableReceived.Broadcast(CableName, GeoPoints);
+        }
+    }
+}
+
+FString UUeSceneWebSocketClient::BuildWsUrl() const
+{
+    FString WsBase = BackendBaseUrl;
+    WsBase = WsBase.Replace(TEXT("http://"), TEXT("ws://"));
+    WsBase = WsBase.Replace(TEXT("https://"), TEXT("wss://"));
+    return FString::Printf(TEXT("%s/ws?token=%s"), *WsBase, *AccessToken);
+}
+
+FString UUeSceneWebSocketClient::BuildHttpUrl(const FString& Path) const
+{
+    return FString::Printf(TEXT("%s%s"), *BackendBaseUrl, *Path);
+}
+
+void UUeSceneWebSocketClient::SendJsonString(const FString& JsonPayload)
+{
+    if (!Socket.IsValid() || !Socket->IsConnected())
+    {
+        EmitError(TEXT("WebSocket 尚未连接。"));
+        return;
+    }
+
+    Socket->Send(JsonPayload);
+}

unreal/Source/Planet/Public/UeSceneWebSocketClient.h

@@ -0,0 +1,159 @@
+#pragma once
+
+#include "CoreMinimal.h"
+#include "Components/ActorComponent.h"
+#include "Interfaces/IHttpRequest.h"
+#include "Interfaces/IHttpResponse.h"
+#include "IWebSocket.h"
+#include "UeSceneWebSocketClient.generated.h"
+
+DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FUeSceneRawMessageEvent, const FString&, Message);
+DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FUeSceneConnectedEvent, bool, bConnected);
+DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FUeSceneErrorEvent, const FString&, ErrorMessage);
+DECLARE_DYNAMIC_MULTICAST_DELEGATE_ThreeParams(
+    FUeSceneFrameEvent,
+    const FString&,
+    UpdateType,
+    int32,
+    Sequence,
+    int32,
+    TotalRecords
+);
+DECLARE_DYNAMIC_MULTICAST_DELEGATE_ThreeParams(
+    FUeScenePayloadEvent,
+    const FString&,
+    UpdateType,
+    int32,
+    Sequence,
+    const FString&,
+    PayloadJson
+);
+DECLARE_DYNAMIC_MULTICAST_DELEGATE_TwoParams(
+    FUeSceneSubmarineCableEvent,
+    const FString&,
+    CableName,
+    const TArray<FVector>&,
+    GeoPoints
+);
+
+UCLASS(ClassGroup=(Planet), meta=(BlueprintSpawnableComponent))
+class PLANET_API UUeSceneWebSocketClient : public UActorComponent
+{
+    GENERATED_BODY()
+
+public:
+    UUeSceneWebSocketClient();
+
+    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Planet|Backend")
+    FString BackendBaseUrl = TEXT("http://127.0.0.1:8000");
+
+    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Planet|Backend")
+    FString Username;
+
+    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Planet|Backend")
+    FString Password;
+
+    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Planet|Backend")
+    TArray<FString> DefaultChannels = {TEXT("ue_scene")};
+
+    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Planet|Backend")
+    int32 LastSequence = INDEX_NONE;
+
+    UPROPERTY(BlueprintAssignable, Category="Planet|Backend")
+    FUeSceneConnectedEvent OnConnectedChanged;
+
+    UPROPERTY(BlueprintAssignable, Category="Planet|Backend")
+    FUeSceneRawMessageEvent OnRawMessage;
+
+    UPROPERTY(BlueprintAssignable, Category="Planet|Backend")
+    FUeSceneErrorEvent OnError;
+
+    UPROPERTY(BlueprintAssignable, Category="Planet|Backend")
+    FUeSceneFrameEvent OnSceneFrame;
+
+    UPROPERTY(BlueprintAssignable, Category="Planet|Backend")
+    FUeScenePayloadEvent OnScenePayload;
+
+    UPROPERTY(BlueprintAssignable, Category="Planet|Backend|Legacy")
+    FUeSceneSubmarineCableEvent OnSubmarineCableReceived;
+
+    UFUNCTION(BlueprintCallable, Category="Planet|Backend")
+    void ConnectToBackend();
+
+    UFUNCTION(BlueprintCallable, Category="Planet|Backend")
+    void DisconnectFromBackend();
+
+    UFUNCTION(BlueprintCallable, Category="Planet|Backend")
+    void SendSubscribe();
+
+    UFUNCTION(BlueprintCallable, Category="Planet|Backend")
+    void SendInitialSyncRequest();
+
+    UFUNCTION(BlueprintCallable, Category="Planet|Backend")
+    void SendSyncRequest(const FString& Reason, int32 InLastSequence);
+
+protected:
+    virtual void BeginPlay() override;
+    virtual void EndPlay(const EEndPlayReason::Type EndPlayReason) override;
+
+private:
+    struct FLayerChunkAccumulator
+    {
+        int32 Revision = 0;
+        int32 ExpectedChunkCount = 0;
+        TSet<int32> ReceivedChunkIndices;
+        TArray<TSharedPtr<FJsonValue>> Items;
+    };
+
+    struct FFullSceneAssemblyState
+    {
+        int32 Sequence = INDEX_NONE;
+        int32 ExpectedTransportChunkCount = 0;
+        int32 TotalRecords = 0;
+        FString ClusterTime;
+        TSharedPtr<FJsonObject> DisplayProfile;
+        TSharedPtr<FJsonObject> CameraState;
+        TSharedPtr<FJsonObject> Meta;
+        TMap<FString, FLayerChunkAccumulator> Layers;
+        TSet<int32> ReceivedTransportChunkIndices;
+
+        void Reset()
+        {
+            Sequence = INDEX_NONE;
+            ExpectedTransportChunkCount = 0;
+            TotalRecords = 0;
+            ClusterTime.Reset();
+            DisplayProfile.Reset();
+            CameraState.Reset();
+            Meta.Reset();
+            Layers.Reset();
+            ReceivedTransportChunkIndices.Reset();
+        }
+    };
+
+    FString AccessToken;
+    TSharedPtr<IWebSocket> Socket;
+    FFullSceneAssemblyState PendingFullScene;
+
+    void RequestAccessToken();
+    void HandleLoginResponse(FHttpRequestPtr Request, FHttpResponsePtr Response, bool bSucceeded);
+    void OpenWebSocket();
+    void BindSocketEvents();
+    void EmitError(const FString& ErrorMessage);
+    void TryBroadcastSceneFrame(const FString& Message);
+    bool TryAssembleFullScene(
+        const TSharedPtr<FJsonObject>& DataObject,
+        int32 Sequence,
+        int32 TotalRecords,
+        TSharedPtr<FJsonObject>& OutAssembledDataObject
+    );
+    void BroadcastScenePayload(
+        const FString& UpdateType,
+        int32 Sequence,
+        const TSharedPtr<FJsonObject>& DataObject
+    );
+    void BroadcastLegacySubmarineCableEvents(const TSharedPtr<FJsonObject>& DataObject);
+    FString BuildWsUrl() const;
+    FString BuildHttpUrl(const FString& Path) const;
+    void SendJsonString(const FString& JsonPayload);
+};

unreal/UE57_WebSocket_Integration.md

@@ -0,0 +1,189 @@
+# UE5.7 连接 `ue_scene` 数据接口实操
+
+## 目标
+
+把当前后端的 `ue_scene` WebSocket 数据接到 UE5.7 工程里。
+
+当前后端入口：
+
+- [backend/app/api/v1/websocket.py](/D:/work/planet/planet/backend/app/api/v1/websocket.py:1)
+- [backend/app/core/websocket/ue_scene.py](/D:/work/planet/planet/backend/app/core/websocket/ue_scene.py:1)
+
+本次补的 UE 侧最小 C++ 文件：
+
+- [Planet.Build.cs](/D:/work/planet/planet/unreal/Source/Planet/Planet.Build.cs:1)
+- [UeSceneWebSocketClient.h](/D:/work/planet/planet/unreal/Source/Planet/Public/UeSceneWebSocketClient.h:1)
+- [UeSceneWebSocketClient.cpp](/D:/work/planet/planet/unreal/Source/Planet/Private/UeSceneWebSocketClient.cpp:1)
+
+## 这一步先做什么
+
+先做最小闭环：
+
+1. UE 登录后端拿 token
+2. UE 连接 `/ws`
+3. UE 订阅 `ue_scene`
+4. UE 发送 `sync_request`
+5. UE 收到原始 JSON
+
+先不急着做完整场景生成。
+
+## 第 1 步：把代码放进你的 UE5.7 工程
+
+你的真实 UE 工程里应该有：
+
+```text
+YourProject/
+  Source/
+    YourProject/
+```
+
+把这里的示例代码内容按模块名改进去：
+
+- `Planet.Build.cs`
+- `UeSceneWebSocketClient.h`
+- `UeSceneWebSocketClient.cpp`
+
+如果你的工程模块名不是 `Planet`，要把：
+
+- `PLANET_API`
+
+改成你自己的模块导出宏。
+
+## 第 2 步：启用插件
+
+在 UE5.7 编辑器里启用：
+
+- `WebSockets`
+- `HTTP`
+- `Json Blueprint Utilities`（可选）
+
+启用后重启编辑器。
+
+## 第 3 步：重新生成并编译工程
+
+如果你是 Visual Studio 工作流：
+
+1. 右键 `.uproject`
+2. 选择“生成 Visual Studio 项目文件”
+3. 打开 `.sln`
+4. 编译 `Development Editor`
+
+## 第 4 步：把组件挂到 `BP_GlobeController`
+
+编译成功后：
+
+1. 打开 `BP_GlobeController`
+2. 点击 `添加`
+3. 搜索：
+   - `Ue Scene Web Socket Client`
+4. 把这个组件挂进去
+
+## 第 5 步：填写后端参数
+
+选中这个组件，在 `细节` 面板里填写：
+
+- `Backend Base Url`：`http://127.0.0.1:8000`
+- `Username`：你的后端用户名
+- `Password`：你的后端密码
+
+默认频道已经是：
+
+- `ue_scene`
+
+## 第 6 步：在蓝图里接事件
+
+在 `BP_GlobeController` 里接这几个事件：
+
+### `On Connected Changed`
+
+连接成功后：
+
+1. 调 `Send Subscribe`
+2. 再调 `Send Initial Sync Request`
+
+### `On Raw Message`
+
+先不要急着解析全部结构。
+
+第一步只做：
+
+1. 把原始 JSON 打印出来
+2. 或保存到字符串变量
+
+这样先确认 UE 确实收到后端消息。
+
+### `On Error`
+
+把错误字符串打印到屏幕和日志里。
+
+## 蓝图推荐连法
+
+### 开始游戏时
+
+1. `开始游戏时`
+2. 调组件的 `Connect To Backend`
+
+### 连接成功后
+
+1. `On Connected Changed`
+2. `分支`
+3. 如果 `bConnected = true`
+4. 调 `Send Subscribe`
+5. 调 `Send Initial Sync Request`
+
+### 收消息后
+
+1. `On Raw Message`
+2. `打印字符串`
+
+## 第 7 步：先验证消息类型
+
+你应该先在屏幕或输出日志里确认这些消息已经进来了：
+
+1. `connection_established`
+2. `subscription_confirmed`
+3. `data_frame`
+
+其中 `data_frame` 的第一条应是：
+
+- `channel = ue_scene`
+- `update_type = full`
+
+## 第 8 步：再接 JSON 解析
+
+当前这一步不建议纯蓝图手搓整个 JSON 结构。
+
+更稳的是：
+
+1. 先在 C++ 里加一个简单解析层
+2. 只抽出 `type`
+3. 只抽出 `data.update_type`
+4. 只抽出 `payload.layers.gpu_clusters.items`
+
+先把 `gpu_clusters` 画出来，再扩到别的层。
+
+## 当前阶段建议
+
+先完成这 3 件事就够了：
+
+1. UE 能成功连接后端
+2. UE 能收到 `full` 快照
+3. UE 能把原始 JSON 打印出来
+
+做到这一步，我们再继续补：
+
+- JSON 结构体
+- `ApplyFullScene`
+- `ApplyIncrementalScene`
+- `GeoToWorld`
+
+## 一句最重要的提醒
+
+现在先别在 UE 里同时做：
+
+- WebSocket 连接
+- 全量 JSON 解析
+- 点位生成
+- 海缆生成
+
+一步一步来，先确认“连通”，再做“可视化”。这样最不容易卡死。