prop/lib/microwaveprop/geocoder.ex
Graham McIntire 99e7560601
Drop gridmap.org dependency, resolve callsigns locally
Instead of shelling out to https://gridmap.org/locate/:callsign for
callsign → lat/lon lookups, ports the resolver pipeline from gridmap-web
into this project so the whole flow runs in-process.

New modules:

- Microwaveprop.Qrz — cache facade over the QRZ.com XML callsign API.
  Looks up from qrz_callsigns first, falls back to a live fetch, and
  upserts the result with a configurable cache_ttl_hours (default
  168h / 7 days).
- Microwaveprop.Qrz.Client — HTTP/XML client against
  https://xmldata.qrz.com/xml/current/. Holds the session key in an
  Agent, transparently re-logs-in on :session_expired, and parses
  responses via xmerl.
- Microwaveprop.Qrz.Callsign — Ecto schema for the qrz_callsigns
  cache table, binary_id primary key per project convention.
- Microwaveprop.Qrz.Record — slim struct with only the 11 fields
  we actually consume (identity, name, grid, address, lat/lon).
  The full XML payload stays in the raw :data jsonb column for
  anyone who wants the other ~40 QRZ fields.
- Microwaveprop.Geocoder — Req-based client against the Google Maps
  Geocoding API. Only called as a fallback when QRZ has no explicit
  <lat>/<lon> for the callsign.
- Microwaveprop.CallsignLocation — orchestrator. Reads the
  callsign_locations cache, on miss calls Qrz then either uses QRZ's
  coords directly or geocodes the formatted address, snaps to an
  8-char Maidenhead grid via Microwaveprop.Radio.Maidenhead, and
  upserts the result.

Microwaveprop.Radio.CallsignClient.locate/1 is rewritten to delegate
to CallsignLocation.lookup/1 and shape the response back to the
existing {:ok, %{callsign, gridsquare, lat, lon}} contract so the
callers in PathLive and RoverLive don't change.

Wiring:

- priv/repo/migrations/20260413000000_create_qrz_callsigns_and_callsign_locations.exs
  creates qrz_callsigns and callsign_locations with unique indexes
  on :callsign.
- Microwaveprop.Qrz.Client added to the application supervision tree
  so the session Agent is started.
- :xmerl added to extra_applications so the release bundles it.
- config/test.exs wires Req.Test plugs for Microwaveprop.Qrz.Client
  and Microwaveprop.Geocoder, forces cache_ttl_hours: 0 so the cache
  never short-circuits test-level stubs, and supplies dummy QRZ
  credentials.
- config/runtime.exs pulls QRZ_USERNAME / QRZ_PASSWORD / QRZ_AGENT
  and GOOGLE_API_KEY from the environment so prod and dev can
  configure both upstream keys out of band.

Tests (ported verbatim from gridmap-web):

- test/microwaveprop/qrz/callsign_test.exs — schema/changeset
- test/microwaveprop/qrz_test.exs — cache hit, cache miss, TTL
  behavior, upsert on stale, error passthrough, case-insensitive
  input
- test/microwaveprop/geocoder_test.exs — success, zero results,
  request denied, transport error
- test/microwaveprop/callsign_location_test.exs — end-to-end flow
  including the QRZ-lat/lon shortcut and the missing-address error
  path

All 1294 tests still pass. Credo strict clean.
2026-04-12 17:43:29 -05:00

40 lines
1.3 KiB
Elixir

defmodule Microwaveprop.Geocoder do
@moduledoc """
Thin wrapper around the Google Maps Geocoding API. Only used as a
fallback when QRZ's own `<lat>` / `<lon>` fields are missing on a
callsign record.
"""
@spec geocode(String.t()) :: {:ok, %{lat: float(), lon: float()}} | {:error, String.t()}
def geocode(address) do
case Req.get(client(), url: "/maps/api/geocode/json", params: [address: address, key: api_key()]) do
{:ok, %{status: 200, body: %{"status" => "OK", "results" => [first | _]}}} ->
%{"geometry" => %{"location" => %{"lat" => lat, "lng" => lon}}} = first
{:ok, %{lat: lat, lon: lon}}
{:ok, %{status: 200, body: %{"status" => "ZERO_RESULTS"}}} ->
{:error, "No results found"}
{:ok, %{status: 200, body: %{"status" => status}}} ->
{:error, "Geocoding failed: #{status}"}
{:error, reason} ->
{:error, "Geocoding request failed: #{inspect(reason)}"}
end
end
defp client do
config = Application.get_env(:microwaveprop, __MODULE__, [])
[base_url: "https://maps.googleapis.com"]
|> Req.new()
|> Req.Request.register_options([:plug, :api_key])
|> Req.merge(config)
end
defp api_key do
:microwaveprop
|> Application.get_env(__MODULE__, [])
|> Keyword.get(:api_key, "")
end
end