274 lines
10 KiB
Python
274 lines
10 KiB
Python
"""Public hydrogen station navigation service.
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This process deliberately has a smaller API boundary than the operations map:
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it retrieves only station directory fields and never exposes vehicle records or
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hydrogen-volume fields.
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"""
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import hashlib
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from http.server import HTTPServer, SimpleHTTPRequestHandler
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import json
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import os
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from pathlib import Path
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from socketserver import ThreadingMixIn
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import threading
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import time
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from urllib.error import HTTPError, URLError
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from urllib.parse import urlparse
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from urllib.request import Request, urlopen
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ROOT = Path(__file__).resolve().parent
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# Production deliberately reuses the operations map's visual assets. Keeping
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# this configurable lets the standalone release live under its own directory.
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VEHICLE_MAP_ROOT = Path(os.getenv("VEHICLE_MAP_ASSET_ROOT", str(ROOT.parent / "vehicle-map")))
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HOST = os.getenv("STATION_NAVIGATION_HOST", "0.0.0.0")
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PORT = int(os.getenv("STATION_NAVIGATION_PORT", "20804"))
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OPEN_PLATFORM_BASE_URL = os.getenv("OPEN_PLATFORM_BASE_URL", "https://open.d.lnoneos.com").rstrip("/")
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OPEN_PLATFORM_APP_KEY = os.getenv("OPEN_PLATFORM_APP_KEY", "").strip()
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UPSTREAM_TIMEOUT_SECONDS = float(os.getenv("UPSTREAM_TIMEOUT_SECONDS", "15"))
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STATION_CACHE_SECONDS = int(os.getenv("STATION_NAVIGATION_CACHE_SECONDS", "120"))
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VEHICLE_MAP_INTERNAL_BASE_URL = os.getenv("VEHICLE_MAP_INTERNAL_BASE_URL", "http://127.0.0.1:20800").rstrip("/")
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_cache_lock = threading.Lock()
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_cache = {}
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_cache_load_locks = {}
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_cache_refreshing = set()
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def _static_asset_version():
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digest = hashlib.sha256()
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for filename in ("app.js", "styles.css"):
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digest.update((ROOT / filename).read_bytes())
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digest.update((VEHICLE_MAP_ROOT / "styles.css").read_bytes())
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return digest.hexdigest()[:16]
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STATIC_ASSET_VERSION = _static_asset_version()
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class ThreadingHTTPServer(ThreadingMixIn, HTTPServer):
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daemon_threads = True
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allow_reuse_address = True
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def _json_bytes(value):
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return json.dumps(value, ensure_ascii=False, separators=(",", ":")).encode("utf-8")
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def _post_open_platform(path, body):
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if not OPEN_PLATFORM_APP_KEY:
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raise RuntimeError("OPEN_PLATFORM_APP_KEY is not configured")
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request = Request(
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OPEN_PLATFORM_BASE_URL + path,
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data=_json_bytes(body),
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method="POST",
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headers={
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"Authorization": "Bearer " + OPEN_PLATFORM_APP_KEY,
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"Content-Type": "application/json",
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"Accept": "application/json",
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"User-Agent": "lingniu-station-navigation/1.0",
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},
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)
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try:
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with urlopen(request, timeout=UPSTREAM_TIMEOUT_SECONDS) as response:
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payload = json.load(response)
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except HTTPError as exc:
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detail = exc.read(2048).decode("utf-8", errors="replace")
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raise RuntimeError(f"open platform returned HTTP {exc.code}: {detail}") from exc
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except URLError as exc:
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raise RuntimeError(f"open platform unavailable: {exc.reason}") from exc
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if payload.get("code") != "SUCCESS":
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raise RuntimeError(f"open platform rejected request: {payload.get('code')} {payload.get('message')}")
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return payload.get("data") or []
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def _refresh_cached_value(key, loader):
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try:
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value = loader()
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except Exception as exc:
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print("{} cache background refresh deferred: {}".format(key, exc))
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else:
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with _cache_lock:
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_cache[key] = (time.time(), value)
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finally:
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with _cache_lock:
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_cache_refreshing.discard(key)
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def _start_cache_refresh(key, loader):
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threading.Thread(target=_refresh_cached_value, args=(key, loader), daemon=True).start()
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def _cached(key, ttl_seconds, loader):
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now = time.time()
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refresh_in_background = False
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with _cache_lock:
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cached = _cache.get(key)
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if cached and now - cached[0] < ttl_seconds:
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return cached[1]
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if cached:
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if key not in _cache_refreshing:
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_cache_refreshing.add(key)
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refresh_in_background = True
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stale_value = cached[1]
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else:
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stale_value = None
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load_lock = _cache_load_locks.setdefault(key, threading.Lock())
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if cached:
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if refresh_in_background:
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_start_cache_refresh(key, loader)
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return stale_value
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with load_lock:
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with _cache_lock:
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cached = _cache.get(key)
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if cached:
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return _cached(key, ttl_seconds, loader)
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value = loader()
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with _cache_lock:
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_cache[key] = (time.time(), value)
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return value
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def _load_station_directory():
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"""Use the operations map's GPS-resolved public station directory.
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The map service owns reverse-geocoding and its persistent cache, keeping
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the public navigation view and the operations view on identical boundaries.
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"""
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request = Request(
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VEHICLE_MAP_INTERNAL_BASE_URL + "/api/stations",
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headers={"Accept": "application/json", "User-Agent": "lingniu-station-navigation/1.0"},
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)
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try:
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with urlopen(request, timeout=UPSTREAM_TIMEOUT_SECONDS) as response:
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payload = json.load(response)
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except (HTTPError, URLError, ValueError) as exc:
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raise RuntimeError("vehicle map station directory unavailable: {}".format(exc)) from exc
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if payload.get("status") != "ok" or not isinstance(payload.get("stations"), list):
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raise RuntimeError("vehicle map returned an invalid station directory")
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return payload
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def _prewarm_station_directory_cache():
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"""Fetch the public directory after startup so first navigation is warm."""
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try:
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_cached("station-directory", STATION_CACHE_SECONDS, _load_station_directory)
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except Exception as exc: # The request path will retry without blocking startup.
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print(f"station navigation cache warmup deferred: {exc}")
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class StationNavigationHandler(SimpleHTTPRequestHandler):
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server_version = "LingniuStationNavigation/1.0"
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def do_GET(self):
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path = urlparse(self.path).path
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if path in {"/", "/index.html"}:
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self._serve_index()
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return
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if path == "/api/health":
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self._write_json(200, {
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"status": "ok",
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"service": "station-navigation",
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"openPlatformConfigured": bool(OPEN_PLATFORM_APP_KEY),
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})
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return
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if path == "/api/stations":
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try:
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payload = _cached("station-directory", STATION_CACHE_SECONDS, _load_station_directory)
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except Exception as exc:
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self.log_error("station directory refresh failed: %s", exc)
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self._write_json(502, {
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"status": "error",
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"code": "UPSTREAM_UNAVAILABLE",
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"message": "加氢站数据暂时不可用，请稍后重试",
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})
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return
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self._write_json(200, payload)
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return
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if path == "/assets/logo_light.svg":
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self._serve_logo()
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return
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if path == "/assets/vehicle-map.css":
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self._serve_vehicle_map_styles()
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return
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if path.startswith("/api/"):
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self._write_json(404, {"status": "error", "code": "NOT_FOUND"})
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return
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super().do_GET()
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def _serve_index(self):
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try:
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template = (ROOT / "index.html").read_text(encoding="utf-8")
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body = template.replace("__ASSET_VERSION__", STATIC_ASSET_VERSION).encode("utf-8")
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except OSError as exc:
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self.log_error("index template unavailable: %s", exc)
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self.send_error(500, "Station navigation is temporarily unavailable")
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return
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self.send_response(200)
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self.send_header("Content-Type", "text/html; charset=utf-8")
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self.send_header("Content-Length", str(len(body)))
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self.send_header("Cache-Control", "no-cache")
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self.end_headers()
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self.wfile.write(body)
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def _serve_logo(self):
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try:
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body = (VEHICLE_MAP_ROOT / "logo_light.svg").read_bytes()
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except OSError:
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self.send_error(404)
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return
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self.send_response(200)
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self.send_header("Content-Type", "image/svg+xml")
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self.send_header("Content-Length", str(len(body)))
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self.send_header("Cache-Control", "public, max-age=86400")
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self.end_headers()
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self.wfile.write(body)
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def _serve_vehicle_map_styles(self):
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try:
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body = (VEHICLE_MAP_ROOT / "styles.css").read_bytes()
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except OSError:
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self.send_error(404)
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return
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self.send_response(200)
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self.send_header("Content-Type", "text/css; charset=utf-8")
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self.send_header("Content-Length", str(len(body)))
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self.send_header("Cache-Control", "no-cache")
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self.end_headers()
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self.wfile.write(body)
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def end_headers(self):
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if self.path == "/" or self.path.split("?", 1)[0].endswith((".html", ".css", ".js", ".svg")):
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self.send_header("Cache-Control", "no-cache")
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self.send_header("X-Content-Type-Options", "nosniff")
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self.send_header("Referrer-Policy", "strict-origin-when-cross-origin")
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self.send_header("X-Frame-Options", "SAMEORIGIN")
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super().end_headers()
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def _write_json(self, status, payload):
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body = _json_bytes(payload)
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self.send_response(status)
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self.send_header("Content-Type", "application/json; charset=utf-8")
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self.send_header("Cache-Control", "no-store")
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self.send_header("Content-Length", str(len(body)))
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self.end_headers()
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try:
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self.wfile.write(body)
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except (BrokenPipeError, ConnectionResetError):
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self.log_message("client disconnected before JSON response completed")
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if __name__ == "__main__":
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# Python 3.6 on ECS predates SimpleHTTPRequestHandler(directory=...).
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# Resolve static assets from this release directory before serving.
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os.chdir(str(ROOT))
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server = ThreadingHTTPServer((HOST, PORT), StationNavigationHandler)
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threading.Thread(target=_prewarm_station_directory_cache, daemon=True).start()
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print(f"Lingniu Station Navigation listening on http://{HOST}:{PORT}")
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try:
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server.serve_forever()
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except KeyboardInterrupt:
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pass
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finally:
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server.server_close()
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