Files
planet/backend/app/services/location/resolvers/nominatim.py
linkong e1984c7a35 release: bump version to 0.49.0
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-05-08 17:42:27 +08:00

293 lines
9.0 KiB
Python

"""Nominatim-backed online geocoder.
The actual HTTP call is encapsulated in :func:`build_default_nominatim_geocoder`
which returns an ``lru_cache``-wrapped function. Domain modules typically:
1. Build a default geocoder via :func:`build_default_nominatim_geocoder`.
2. Re-export it under a stable module-level name (e.g. ``_geocode_online``).
3. Pass a *late-binding lambda* (``lambda q: _geocode_online(q)``) to
:class:`NominatimResolver`.
This ensures tests that ``monkeypatch.setattr(module, "_geocode_online", ...)``
can swap the geocoder behavior without touching pipeline construction.
"""
from __future__ import annotations
import time
from functools import lru_cache
from typing import Any, Callable
import httpx
from ..models import LocationCandidate, LocationQuery, ResolverOutput
from ..text import (
coerce_str,
normalize_country_text,
normalize_text,
parse_float,
)
NOMINATIM_SEARCH_URL = "https://nominatim.openstreetmap.org/search"
DEFAULT_USER_AGENT = "planet-earth-location-resolver/1.0"
DEFAULT_MIN_INTERVAL_SECONDS = 1.1
DEFAULT_TIMEOUT_SECONDS = 8.0
def build_default_nominatim_geocoder(
*,
user_agent: str = DEFAULT_USER_AGENT,
min_interval_seconds: float = DEFAULT_MIN_INTERVAL_SECONDS,
timeout_seconds: float = DEFAULT_TIMEOUT_SECONDS,
cache_size: int = 512,
) -> Callable[[str], dict[str, Any] | None]:
"""Return a cached, rate-limited Nominatim geocoder."""
last_request_at = [0.0]
@lru_cache(maxsize=cache_size)
def geocode(query: str) -> dict[str, Any] | None:
if not query:
return None
elapsed = time.monotonic() - last_request_at[0]
if elapsed < min_interval_seconds:
time.sleep(min_interval_seconds - elapsed)
last_request_at[0] = time.monotonic()
response = httpx.get(
NOMINATIM_SEARCH_URL,
params={
"q": query,
"format": "jsonv2",
"limit": 1,
"addressdetails": 1,
},
headers={"User-Agent": user_agent},
timeout=timeout_seconds,
)
response.raise_for_status()
payload = response.json()
if not isinstance(payload, list) or not payload:
return None
result = payload[0]
if not isinstance(result, dict):
return None
return result
return geocode
_DEFAULT_SITE_CATEGORIES = frozenset(
{
"amenity",
"office",
"building",
"industrial",
"research",
"university",
"education",
"tourism",
"shop",
"man_made",
"campus",
"research_institute",
}
)
def interpret_geocode_result(
result: dict[str, Any],
*,
matched_fields: tuple[str, ...],
context_country: str | None,
site_categories: frozenset[str] = _DEFAULT_SITE_CATEGORIES,
site_promoting_match_fields: frozenset[str] = frozenset(
{"site", "operator", "name"}
),
) -> tuple[float, float, dict[str, Any], str] | None:
"""Validate a Nominatim raw result. Returns (lat, lon, address, classification)."""
latitude = parse_float(result.get("lat"))
longitude = parse_float(result.get("lon"))
if latitude in (None, 0.0) or longitude in (None, 0.0):
return None
address = result.get("address") if isinstance(result.get("address"), dict) else {}
if not isinstance(address, dict):
address = {}
has_city_level = bool(
address.get("city")
or address.get("town")
or address.get("village")
or address.get("municipality")
or address.get("hamlet")
or address.get("suburb")
)
osm_class = str(result.get("class") or "").lower()
osm_type = str(result.get("type") or "").lower()
is_site_like = osm_class in site_categories or osm_type in site_categories
if not has_city_level and not is_site_like:
return None
if context_country:
normalized_context = normalize_text(normalize_country_text(context_country))
normalized_result = normalize_text(
normalize_country_text(address.get("country"))
)
if (
normalized_context
and normalized_result
and normalized_context != normalized_result
):
return None
classification = (
"site"
if (
is_site_like
and has_city_level
and any(field in site_promoting_match_fields for field in matched_fields)
)
else "city"
)
return float(latitude), float(longitude), address, classification
def _candidate_from_geocode(
*,
query: LocationQuery,
geocode_query: str,
matched_fields: tuple[str, ...],
raw_result: dict[str, Any],
interpret: Callable[..., tuple[float, float, dict[str, Any], str] | None],
source: str,
site_confidence: float,
city_confidence: float,
) -> LocationCandidate | None:
interpreted = interpret(
raw_result,
matched_fields=matched_fields,
context_country=query.country,
)
if not interpreted:
return None
latitude, longitude, address, classification = interpreted
city = (
address.get("city")
or address.get("town")
or address.get("village")
or address.get("municipality")
or query.city
or None
)
region = address.get("state") or address.get("region")
country = address.get("country") or query.country or None
display_name = raw_result.get("display_name") or geocode_query
confidence = city_confidence if classification == "city" else site_confidence
extra = query.extra or {}
suggested_registry_entry = {
"canonical_name": (
(query.aliases[0] if query.aliases else None)
or query.name
or display_name
),
"aliases": list(
{
value
for value in [
query.name,
*query.aliases,
coerce_str(extra.get("operator")),
coerce_str(extra.get("site")),
]
if value
}
),
"operator": coerce_str(extra.get("operator")) or None,
"site": coerce_str(extra.get("site"))
or coerce_str(extra.get("organization"))
or None,
"country": country,
"city": city,
"region": region,
"latitude": latitude,
"longitude": longitude,
"precision": classification,
"confidence": confidence,
"source_note": (
f"Resolved via Nominatim query '{geocode_query}'{display_name}"
),
}
return LocationCandidate(
latitude=latitude,
longitude=longitude,
display_name=display_name,
precision=classification,
confidence=confidence,
query=geocode_query,
source=source,
source_note=f"Nominatim search result: {display_name}",
matched_fields=matched_fields,
needs_confirmation=True,
city=city,
region=region,
country=country,
matched_location_name=display_name,
location_verified_at=None,
suggested_registry_entry=suggested_registry_entry,
)
class NominatimResolver:
"""Run a domain-specific query plan against Nominatim."""
def __init__(
self,
*,
query_plan_builder: Callable[
[LocationQuery], list[tuple[str, tuple[str, ...]]]
],
geocoder: Callable[[str], dict[str, Any] | None],
name: str = "nominatim_online_geocode",
site_confidence: float = 0.72,
city_confidence: float = 0.62,
interpret: Callable[..., tuple[float, float, dict[str, Any], str] | None] = (
interpret_geocode_result
),
) -> None:
self.name = name
self._query_plan_builder = query_plan_builder
self._geocoder = geocoder
self._site_confidence = site_confidence
self._city_confidence = city_confidence
self._interpret = interpret
def resolve(self, query: LocationQuery) -> ResolverOutput:
plan = self._query_plan_builder(query)
candidates: list[LocationCandidate] = []
attempted: list[str] = []
for geocode_query, matched_fields in plan:
attempted.append(geocode_query)
try:
raw_result = self._geocoder(geocode_query)
except Exception:
continue
if not raw_result:
continue
candidate = _candidate_from_geocode(
query=query,
geocode_query=geocode_query,
matched_fields=matched_fields,
raw_result=raw_result,
interpret=self._interpret,
source=self.name,
site_confidence=self._site_confidence,
city_confidence=self._city_confidence,
)
if candidate is not None:
candidates.append(candidate)
return ResolverOutput(
candidates=tuple(candidates),
attempted_queries=tuple(attempted),
)