Fix map loading and tab navigation v0.4.1

app/main.py

@@ -11,6 +11,7 @@ import time
 import urllib.error
 import urllib.parse
 import urllib.request
+from collections import OrderedDict
 from datetime import datetime
 from pathlib import Path
 from typing import Annotated, Any
@@ -21,12 +22,15 @@ from fastapi.staticfiles import StaticFiles
 
 APP_NAME = os.getenv("APP_NAME", "Photo Date Editor")
 APP_URL = os.getenv("APP_URL", "http://localhost:8080")
-APP_VERSION = "0.4.0"
+APP_VERSION = "0.4.1"
 MAX_UPLOAD_MB = int(os.getenv("MAX_UPLOAD_MB", "150"))
 MAX_UPLOAD_BYTES = MAX_UPLOAD_MB * 1024 * 1024
 LOG_LEVEL = os.getenv("LOG_LEVEL", "INFO").upper()
 
-MAP_TILE_URL = os.getenv("MAP_TILE_URL", "https://tile.openstreetmap.org/{z}/{x}/{y}.png")
+MAP_TILE_SOURCE_URL = os.getenv(
+    "MAP_TILE_SOURCE_URL",
+    os.getenv("MAP_TILE_URL", "https://tile.openstreetmap.org/{z}/{x}/{y}.png"),
+)
 MAP_ATTRIBUTION = os.getenv(
     "MAP_ATTRIBUTION",
     '&copy; <a href="https://www.openstreetmap.org/copyright">OpenStreetMap contributors</a>',
@@ -43,6 +47,9 @@ GEOCODER_USER_AGENT = os.getenv(
 _geocode_lock = asyncio.Lock()
 _geocode_cache: dict[str, list[dict[str, Any]]] = {}
 _last_geocode_request = 0.0
+_tile_cache: OrderedDict[str, tuple[bytes, str]] = OrderedDict()
+_tile_cache_limit = 512
+_tile_lock = asyncio.Lock()
 
 logging.basicConfig(
     level=getattr(logging, LOG_LEVEL, logging.INFO),
@@ -68,7 +75,7 @@ def config() -> dict[str, str | int | float]:
         "appUrl": APP_URL,
         "version": APP_VERSION,
         "maxUploadMb": MAX_UPLOAD_MB,
-        "mapTileUrl": MAP_TILE_URL,
+        "mapTileUrl": "/api/map/tiles/{z}/{x}/{y}.png",
         "mapAttribution": MAP_ATTRIBUTION,
         "defaultMapLat": DEFAULT_MAP_LAT,
         "defaultMapLon": DEFAULT_MAP_LON,
@@ -77,6 +84,59 @@ def config() -> dict[str, str | int | float]:
 
 
 
+def _fetch_map_tile(z: int, x: int, y: int) -> tuple[bytes, str]:
+    tile_url = (
+        MAP_TILE_SOURCE_URL
+        .replace("{z}", str(z))
+        .replace("{x}", str(x))
+        .replace("{y}", str(y))
+    )
+    request = urllib.request.Request(
+        tile_url,
+        headers={
+            "User-Agent": GEOCODER_USER_AGENT,
+            "Accept": "image/avif,image/webp,image/png,image/*,*/*;q=0.8",
+        },
+    )
+    with urllib.request.urlopen(request, timeout=20) as response:
+        content_type = response.headers.get_content_type() or "image/png"
+        return response.read(), content_type
+
+
+@app.get("/api/map/tiles/{z}/{x}/{y}.png", include_in_schema=False)
+async def map_tile(z: int, x: int, y: int) -> Response:
+    if not 0 <= z <= 19:
+        raise HTTPException(status_code=404, detail="Unsupported map zoom level.")
+    limit = 1 << z
+    if not 0 <= x < limit or not 0 <= y < limit:
+        raise HTTPException(status_code=404, detail="Invalid map tile coordinates.")
+
+    cache_key = f"{z}/{x}/{y}"
+    cached = _tile_cache.get(cache_key)
+    if cached is not None:
+        _tile_cache.move_to_end(cache_key)
+        payload, content_type = cached
+        return Response(payload, media_type=content_type, headers={"Cache-Control": "public, max-age=86400"})
+
+    async with _tile_lock:
+        cached = _tile_cache.get(cache_key)
+        if cached is None:
+            try:
+                cached = await asyncio.to_thread(_fetch_map_tile, z, x, y)
+            except (urllib.error.URLError, TimeoutError) as exc:
+                logger.warning("Map tile request failed for %s: %s", cache_key, exc)
+                raise HTTPException(status_code=502, detail="The map tile service could not be reached.") from exc
+            _tile_cache[cache_key] = cached
+            if len(_tile_cache) > _tile_cache_limit:
+                _tile_cache.popitem(last=False)
+        else:
+            _tile_cache.move_to_end(cache_key)
+
+    payload, content_type = cached
+    return Response(payload, media_type=content_type, headers={"Cache-Control": "public, max-age=86400"})
+
+
+
 def _fetch_geocode_results(query: str) -> list[dict[str, Any]]:
     parameters = urllib.parse.urlencode(
         {