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/google_maps.ex
+++ b/lib/service/geospatial/google_maps.ex
@@ -0,0 +1,126 @@
+defmodule Mobilizon.Service.Geospatial.GoogleMaps do
+  @moduledoc """
+  Google Maps [Geocoding service](https://developers.google.com/maps/documentation/geocoding/intro)
+
+  Note: Endpoint is hardcoded to Google Maps API
+  """
+  alias Mobilizon.Service.Geospatial.Provider
+  alias Mobilizon.Addresses.Address
+  require Logger
+
+  @behaviour Provider
+
+  @api_key Application.get_env(:mobilizon, __MODULE__) |> get_in([:api_key])
+
+  @components [
+    "street_number",
+    "route",
+    "locality",
+    "administrative_area_level_1",
+    "country",
+    "postal_code"
+  ]
+
+  @api_key_missing_message "API Key required to use Google Maps"
+
+  @impl Provider
+  @doc """
+  Google Maps 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 Google Maps for reverse geocode with #{url}")
+
+    with {:ok, %HTTPoison.Response{status_code: 200, body: body}} <-
+           HTTPoison.get(url),
+         {:ok, %{"results" => results, "status" => "OK"}} <- Poison.decode(body) do
+      Enum.map(results, &process_data/1)
+    else
+      {:ok, %{"status" => "REQUEST_DENIED", "error_message" => error_message}} ->
+        raise ArgumentError, message: to_string(error_message)
+    end
+  end
+
+  @impl Provider
+  @doc """
+  Google Maps 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 Google Maps for addresses with #{url}")
+
+    with {:ok, %HTTPoison.Response{status_code: 200, body: body}} <-
+           HTTPoison.get(url),
+         {:ok, %{"results" => results, "status" => "OK"}} <- Poison.decode(body) do
+      Enum.map(results, fn entry -> process_data(entry) end)
+    else
+      {:ok, %{"status" => "REQUEST_DENIED", "error_message" => error_message}} ->
+        raise ArgumentError, message: to_string(error_message)
+    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")
+    api_key = Keyword.get(options, :api_key, @api_key)
+    if is_nil(api_key), do: raise(ArgumentError, message: @api_key_missing_message)
+
+    url =
+      "https://maps.googleapis.com/maps/api/geocode/json?limit=#{limit}&key=#{api_key}&language=#{
+        lang
+      }"
+
+    case method do
+      :search ->
+        url <> "&address=#{URI.encode(args.q)}"
+
+      :geocode ->
+        url <> "&latlng=#{args.lat},#{args.lon}"
+    end
+  end
+
+  defp process_data(%{
+         "formatted_address" => description,
+         "geometry" => %{"location" => %{"lat" => lat, "lng" => lon}},
+         "address_components" => components
+       }) do
+    components =
+      @components
+      |> Enum.reduce(%{}, fn component, acc ->
+        Map.put(acc, component, extract_component(components, component))
+      end)
+
+    %Address{
+      addressCountry: Map.get(components, "country"),
+      addressLocality: Map.get(components, "locality"),
+      addressRegion: Map.get(components, "administrative_area_level_1"),
+      description: description,
+      floor: nil,
+      geom: [lon, lat] |> Provider.coordinates(),
+      postalCode: Map.get(components, "postal_code"),
+      streetAddress: street_address(components)
+    }
+  end
+
+  defp extract_component(components, key) do
+    case components
+         |> Enum.filter(fn component -> key in component["types"] end)
+         |> Enum.map(& &1["long_name"]) do
+      [] -> nil
+      component -> hd(component)
+    end
+  end
+
+  defp street_address(body) do
+    if Map.has_key?(body, "street_number") && !is_nil(Map.get(body, "street_number")) do
+      Map.get(body, "street_number") <> " " <> Map.get(body, "route")
+    else
+      Map.get(body, "route")
+    end
+  end
+end