Create geocoding.py

services/geocoding.py

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+from __future__ import annotations
+from typing import Optional, Dict
+import os
+import requests
+from functools import lru_cache
+
+# Nominatimの利用規約に従ってUAと連絡先を付与
+def _ua() -> Dict[str, str]:
+    email = os.getenv("GEOCODING_EMAIL") or os.getenv("CONTACT_EMAIL") or "example@example.com"
+    return {"User-Agent": f"HF-Space-Trip-Planner/1.0 (contact: {email})"}
+
+@lru_cache(maxsize=512)
+def geocode_city(city: str) -> Optional[Dict[str, object]]:
+    """
+    文字列の都市名から緯度経度を取得（Nominatim / OpenStreetMap）。
+    成功時: {"lat": float, "lon": float, "display_name": str}
+    失敗時: None
+    """
+    if not city or not str(city).strip():
+        return None
+
+    q = str(city).strip()
+    url = "https://nominatim.openstreetmap.org/search"
+    params = {
+        "q": q,
+        "format": "jsonv2",
+        "addressdetails": 1,
+        "limit": 1,
+    }
+    try:
+        r = requests.get(url, params=params, headers=_ua(), timeout=20)
+        r.raise_for_status()
+        items = r.json()
+        if not items:
+            return None
+        j = items[0]
+        lat = float(j["lat"])
+        lon = float(j["lon"])
+        name = j.get("display_name") or q
+        return {"lat": lat, "lon": lon, "display_name": name}
+    except Exception:
+        return None