feat(map): add cached public station navigation

station-navigation/server.py

@@ -0,0 +1,230 @@
+"""Public hydrogen station navigation service.
+
+This process deliberately has a smaller API boundary than the operations map:
+it retrieves only station directory fields and never exposes vehicle records or
+hydrogen-volume fields.
+"""
+
+import hashlib
+from http.server import HTTPServer, SimpleHTTPRequestHandler
+import json
+import os
+from pathlib import Path
+from socketserver import ThreadingMixIn
+import threading
+import time
+from urllib.error import HTTPError, URLError
+from urllib.parse import urlparse
+from urllib.request import Request, urlopen
+
+
+ROOT = Path(__file__).resolve().parent
+# Production deliberately reuses the operations map's visual assets.  Keeping
+# this configurable lets the standalone release live under its own directory.
+VEHICLE_MAP_ROOT = Path(os.getenv("VEHICLE_MAP_ASSET_ROOT", str(ROOT.parent / "vehicle-map")))
+HOST = os.getenv("STATION_NAVIGATION_HOST", "0.0.0.0")
+PORT = int(os.getenv("STATION_NAVIGATION_PORT", "20804"))
+OPEN_PLATFORM_BASE_URL = os.getenv("OPEN_PLATFORM_BASE_URL", "https://open.d.lnoneos.com").rstrip("/")
+OPEN_PLATFORM_APP_KEY = os.getenv("OPEN_PLATFORM_APP_KEY", "").strip()
+UPSTREAM_TIMEOUT_SECONDS = float(os.getenv("UPSTREAM_TIMEOUT_SECONDS", "15"))
+STATION_CACHE_SECONDS = int(os.getenv("STATION_NAVIGATION_CACHE_SECONDS", "120"))
+_cache_lock = threading.Lock()
+_cache = {}
+
+
+def _static_asset_version():
+    digest = hashlib.sha256()
+    for filename in ("app.js", "styles.css"):
+        digest.update((ROOT / filename).read_bytes())
+    digest.update((VEHICLE_MAP_ROOT / "styles.css").read_bytes())
+    return digest.hexdigest()[:16]
+
+
+STATIC_ASSET_VERSION = _static_asset_version()
+
+
+class ThreadingHTTPServer(ThreadingMixIn, HTTPServer):
+    daemon_threads = True
+    allow_reuse_address = True
+
+
+def _json_bytes(value):
+    return json.dumps(value, ensure_ascii=False, separators=(",", ":")).encode("utf-8")
+
+
+def _post_open_platform(path, body):
+    if not OPEN_PLATFORM_APP_KEY:
+        raise RuntimeError("OPEN_PLATFORM_APP_KEY is not configured")
+    request = Request(
+        OPEN_PLATFORM_BASE_URL + path,
+        data=_json_bytes(body),
+        method="POST",
+        headers={
+            "Authorization": "Bearer " + OPEN_PLATFORM_APP_KEY,
+            "Content-Type": "application/json",
+            "Accept": "application/json",
+            "User-Agent": "lingniu-station-navigation/1.0",
+        },
+    )
+    try:
+        with urlopen(request, timeout=UPSTREAM_TIMEOUT_SECONDS) as response:
+            payload = json.load(response)
+    except HTTPError as exc:
+        detail = exc.read(2048).decode("utf-8", errors="replace")
+        raise RuntimeError(f"open platform returned HTTP {exc.code}: {detail}") from exc
+    except URLError as exc:
+        raise RuntimeError(f"open platform unavailable: {exc.reason}") from exc
+    if payload.get("code") != "SUCCESS":
+        raise RuntimeError(f"open platform rejected request: {payload.get('code')} {payload.get('message')}")
+    return payload.get("data") or []
+
+
+def _cached(key, ttl_seconds, loader):
+    now = time.time()
+    with _cache_lock:
+        cached = _cache.get(key)
+        if cached and now - cached[0] < ttl_seconds:
+            return cached[1]
+    value = loader()
+    with _cache_lock:
+        _cache[key] = (now, value)
+    return value
+
+
+def _public_station(station):
+    """Positive allowlist: do not add operational or hydrogen fields here."""
+    fields = (
+        "id", "name", "shortName", "province", "city", "district", "address",
+        "longitude", "latitude", "cooperative",
+    )
+    return {field: station.get(field) for field in fields if station.get(field) is not None}
+
+
+def _load_station_directory():
+    stations = _post_open_platform("/api/v1/hydrogen-stations/query", {})
+    directory = [_public_station(station) for station in stations]
+    return {
+        "status": "ok",
+        "asOf": time.strftime("%Y-%m-%d %H:%M:%S", time.localtime()),
+        "summary": {
+            "totalStations": len(directory),
+            "cooperativeStations": sum(1 for station in directory if station.get("cooperative")),
+        },
+        "stations": directory,
+    }
+
+
+def _prewarm_station_directory_cache():
+    """Fetch the public directory after startup so first navigation is warm."""
+    try:
+        _cached("station-directory", STATION_CACHE_SECONDS, _load_station_directory)
+    except Exception as exc:  # The request path will retry without blocking startup.
+        print(f"station navigation cache warmup deferred: {exc}")
+
+
+class StationNavigationHandler(SimpleHTTPRequestHandler):
+    server_version = "LingniuStationNavigation/1.0"
+
+    def do_GET(self):
+        path = urlparse(self.path).path
+        if path in {"/", "/index.html"}:
+            self._serve_index()
+            return
+        if path == "/api/health":
+            self._write_json(200, {
+                "status": "ok",
+                "service": "station-navigation",
+                "openPlatformConfigured": bool(OPEN_PLATFORM_APP_KEY),
+            })
+            return
+        if path == "/api/stations":
+            try:
+                self._write_json(200, _cached("station-directory", STATION_CACHE_SECONDS, _load_station_directory))
+            except Exception as exc:
+                self.log_error("station directory refresh failed: %s", exc)
+                self._write_json(502, {
+                    "status": "error",
+                    "code": "UPSTREAM_UNAVAILABLE",
+                    "message": "加氢站数据暂时不可用，请稍后重试",
+                })
+            return
+        if path == "/assets/logo_light.svg":
+            self._serve_logo()
+            return
+        if path == "/assets/vehicle-map.css":
+            self._serve_vehicle_map_styles()
+            return
+        if path.startswith("/api/"):
+            self._write_json(404, {"status": "error", "code": "NOT_FOUND"})
+            return
+        super().do_GET()
+
+    def _serve_index(self):
+        try:
+            template = (ROOT / "index.html").read_text(encoding="utf-8")
+            body = template.replace("__ASSET_VERSION__", STATIC_ASSET_VERSION).encode("utf-8")
+        except OSError as exc:
+            self.log_error("index template unavailable: %s", exc)
+            self.send_error(500, "Station navigation is temporarily unavailable")
+            return
+        self.send_response(200)
+        self.send_header("Content-Type", "text/html; charset=utf-8")
+        self.send_header("Content-Length", str(len(body)))
+        self.send_header("Cache-Control", "no-cache")
+        self.end_headers()
+        self.wfile.write(body)
+
+    def _serve_logo(self):
+        try:
+            body = (VEHICLE_MAP_ROOT / "logo_light.svg").read_bytes()
+        except OSError:
+            self.send_error(404)
+            return
+        self.send_response(200)
+        self.send_header("Content-Type", "image/svg+xml")
+        self.send_header("Content-Length", str(len(body)))
+        self.send_header("Cache-Control", "public, max-age=86400")
+        self.end_headers()
+        self.wfile.write(body)
+
+    def _serve_vehicle_map_styles(self):
+        try:
+            body = (VEHICLE_MAP_ROOT / "styles.css").read_bytes()
+        except OSError:
+            self.send_error(404)
+            return
+        self.send_response(200)
+        self.send_header("Content-Type", "text/css; charset=utf-8")
+        self.send_header("Content-Length", str(len(body)))
+        self.send_header("Cache-Control", "no-cache")
+        self.end_headers()
+        self.wfile.write(body)
+
+    def end_headers(self):
+        if self.path == "/" or self.path.split("?", 1)[0].endswith((".html", ".css", ".js", ".svg")):
+            self.send_header("Cache-Control", "no-cache")
+        self.send_header("X-Content-Type-Options", "nosniff")
+        self.send_header("Referrer-Policy", "strict-origin-when-cross-origin")
+        self.send_header("X-Frame-Options", "SAMEORIGIN")
+        super().end_headers()
+
+    def _write_json(self, status, payload):
+        body = _json_bytes(payload)
+        self.send_response(status)
+        self.send_header("Content-Type", "application/json; charset=utf-8")
+        self.send_header("Cache-Control", "no-store")
+        self.send_header("Content-Length", str(len(body)))
+        self.end_headers()
+        self.wfile.write(body)
+
+
+if __name__ == "__main__":
+    server = ThreadingHTTPServer((HOST, PORT), StationNavigationHandler)
+    threading.Thread(target=_prewarm_station_directory_cache, daemon=True).start()
+    print(f"Lingniu Station Navigation listening on http://{HOST}:{PORT}")
+    try:
+        server.serve_forever()
+    except KeyboardInterrupt:
+        pass
+    finally:
+        server.server_close()