mobilizon/lib/service/geospatial/nominatim.ex

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Elixir
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defmodule Mobilizon.Service.Geospatial.Nominatim do
@moduledoc """
[Nominatim](https://wiki.openstreetmap.org/wiki/Nominatim) backend.
"""
alias Mobilizon.Service.Geospatial.Provider
alias Mobilizon.Addresses.Address
require Logger
@behaviour Provider
@endpoint Application.get_env(:mobilizon, __MODULE__) |> get_in([:endpoint])
@api_key Application.get_env(:mobilizon, __MODULE__) |> get_in([:api_key])
@impl Provider
@doc """
Nominatim implementation for `c:Mobilizon.Service.Geospatial.Provider.geocode/3`.
"""
@spec geocode(String.t(), keyword()) :: list(Address.t())
def geocode(lon, lat, options \\ []) do
url = build_url(:geocode, %{lon: lon, lat: lat}, options)
Logger.debug("Asking Nominatim for geocode with #{url}")
with {:ok, %HTTPoison.Response{status_code: 200, body: body}} <-
HTTPoison.get(url),
{:ok, body} <- Poison.decode(body) do
[process_data(body)]
end
end
@impl Provider
@doc """
Nominatim implementation for `c:Mobilizon.Service.Geospatial.Provider.search/2`.
"""
@spec search(String.t(), keyword()) :: list(Address.t())
def search(q, options \\ []) do
url = build_url(:search, %{q: q}, options)
Logger.debug("Asking Nominatim for addresses with #{url}")
with {:ok, %HTTPoison.Response{status_code: 200, body: body}} <-
HTTPoison.get(url),
{:ok, body} <- Poison.decode(body) do
Enum.map(body, fn entry -> process_data(entry) end)
end
end
@spec build_url(atom(), map(), list()) :: String.t()
defp build_url(method, args, options) do
limit = Keyword.get(options, :limit, 10)
lang = Keyword.get(options, :lang, "en")
endpoint = Keyword.get(options, :endpoint, @endpoint)
api_key = Keyword.get(options, :api_key, @api_key)
url =
case method do
:search ->
"#{endpoint}/search?format=jsonv2&q=#{URI.encode(args.q)}&limit=#{limit}&accept-language=#{
lang
}&addressdetails=1"
:geocode ->
"#{endpoint}/reverse?format=jsonv2&lat=#{args.lat}&lon=#{args.lon}&addressdetails=1"
end
if is_nil(api_key), do: url, else: url <> "&key=#{api_key}"
end
@spec process_data(map()) :: Address.t()
defp process_data(%{"address" => address} = body) do
%Address{
addressCountry: Map.get(address, "country"),
addressLocality: Map.get(address, "city"),
addressRegion: Map.get(address, "state"),
description: Map.get(body, "display_name"),
floor: Map.get(address, "floor"),
geom: [Map.get(body, "lon"), Map.get(body, "lat")] |> Provider.coordinates(),
postalCode: Map.get(address, "postcode"),
streetAddress: street_address(address)
}
end
@spec street_address(map()) :: String.t()
defp street_address(body) do
if Map.has_key?(body, "house_number") do
Map.get(body, "house_number") <> " " <> Map.get(body, "road")
else
Map.get(body, "road")
end
end
end