Add GeoSpatial backends for geocoding

Signed-off-by: Thomas Citharel <tcit@tcit.fr> Geospatial Backend Signed-off-by: Thomas Citharel <tcit@tcit.fr>
2019-03-12 11:52:28 +01:00
parent f7284740e3
commit 98b7618338
29 changed files with 1301 additions and 1 deletions
--- a/lib/service/geospatial/nominatim.ex
+++ b/lib/service/geospatial/nominatim.ex
@@ -0,0 +1,89 @@
+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