83 lines
2.9 KiB
Python
83 lines
2.9 KiB
Python
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"""Offline generator for backend/cities.json — the finite set of cities that get
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crawlable climate pages (/climate/<slug>). Run occasionally to refresh the list:
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python gen_cities.py [N] # default N=500 top metros by population
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It reuses the GeoNames index that places.py already downloads/parses (calling
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places._load() synchronously fills places._data), takes the top-N places by
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population, and assigns each a stable, unique, URL-safe slug. Committing the output
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keeps the routable city set explicit and reviewable, and decouples page-serving
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from the async place-name loader.
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"""
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import json
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import os
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import re
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import sys
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import unicodedata
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import places
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OUT_PATH = os.path.join(os.path.dirname(__file__), "cities.json")
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# GeoNames entry tuple layout (see places._load): the fields we keep.
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_NAME, _ADMIN1, _COUNTRY, _CC, _LAT, _LON, _POP = 1, 2, 3, 4, 5, 6, 7
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def slugify(*parts: str) -> str:
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"""ASCII, lowercase, hyphenated slug from name/admin/country parts."""
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text = " ".join(p for p in parts if p)
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text = unicodedata.normalize("NFKD", text).encode("ascii", "ignore").decode()
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text = re.sub(r"[^a-zA-Z0-9]+", "-", text).strip("-").lower()
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return re.sub(r"-{2,}", "-", text)
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def build(n: int = 500) -> list[dict]:
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places._load() # synchronous parse; fills places._data (entries are pop-desc)
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if not places._data:
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raise SystemExit("GeoNames index failed to load (see logs); cannot generate cities.")
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entries = places._data[0]
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out: list[dict] = []
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seen_slugs: set[str] = set()
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for e in entries:
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if len(out) >= n:
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break
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name, admin1, country, cc = e[_NAME], e[_ADMIN1], e[_COUNTRY], e[_CC]
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# Drop admin1 from the slug when it just repeats the city name
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# (e.g. Tokyo/Tokyo, Singapore/Singapore) to avoid "tokyo-tokyo-jp".
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admin_part = admin1 if admin1 and slugify(admin1) != slugify(name) else ""
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base = slugify(name, admin_part, cc or "")
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if not base:
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continue
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slug = base
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i = 2
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while slug in seen_slugs: # disambiguate the rare collision
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slug = f"{base}-{i}"
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i += 1
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seen_slugs.add(slug)
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out.append({
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"slug": slug,
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"name": name,
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"admin1": admin1,
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"country": country,
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"country_code": cc,
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"lat": round(e[_LAT], 5),
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"lon": round(e[_LON], 5),
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"population": e[_POP],
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})
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return out
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def main() -> None:
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n = int(sys.argv[1]) if len(sys.argv) > 1 else 500
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cities = build(n)
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with open(OUT_PATH, "w", encoding="utf-8") as f:
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json.dump(cities, f, ensure_ascii=False, indent=0, separators=(",", ":"))
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f.write("\n")
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print(f"wrote {len(cities)} cities -> {OUT_PATH}")
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print("sample:", ", ".join(c["slug"] for c in cities[:8]))
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if __name__ == "__main__":
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main()
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