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/photon.ex
+++ b/lib/service/geospatial/photon.ex
@@ -0,0 +1,87 @@
+defmodule Mobilizon.Service.Geospatial.Photon do
+  @moduledoc """
+  [Photon](https://photon.komoot.de) backend.
+  """
+  alias Mobilizon.Service.Geospatial.Provider
+  require Logger
+  alias Mobilizon.Addresses.Address
+
+  @behaviour Provider
+
+  @endpoint Application.get_env(:mobilizon, __MODULE__) |> get_in([:endpoint])
+
+  @impl Provider
+  @doc """
+  Photon implementation for `c:Mobilizon.Service.Geospatial.Provider.geocode/3`.
+
+  Note: It seems results are quite wrong.
+  """
+  @spec geocode(number(), number(), keyword()) :: list(Address.t())
+  def geocode(lon, lat, options \\ []) do
+    url = build_url(:geocode, %{lon: lon, lat: lat}, options)
+    Logger.debug("Asking photon for reverse geocoding with #{url}")
+
+    with {:ok, %HTTPoison.Response{status_code: 200, body: body}} <-
+           HTTPoison.get(url),
+         {:ok, %{"features" => features}} <- Poison.decode(body) do
+      processData(features)
+    end
+  end
+
+  @impl Provider
+  @doc """
+  Photon 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 photon for addresses with #{url}")
+
+    with {:ok, %HTTPoison.Response{status_code: 200, body: body}} <-
+           HTTPoison.get(url),
+         {:ok, %{"features" => features}} <- Poison.decode(body) do
+      processData(features)
+    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")
+    coords = Keyword.get(options, :coords, nil)
+    endpoint = Keyword.get(options, :endpoint, @endpoint)
+
+    case method do
+      :search ->
+        url = "#{endpoint}/api/?q=#{URI.encode(args.q)}&lang=#{lang}&limit=#{limit}"
+        if is_nil(coords), do: url, else: url <> "&lat=#{coords.lat}&lon=#{coords.lon}"
+
+      :geocode ->
+        "#{endpoint}/reverse?lon=#{args.lon}&lat=#{args.lat}&lang=#{lang}&limit=#{limit}"
+    end
+  end
+
+  defp processData(features) do
+    features
+    |> Enum.map(fn %{"geometry" => geometry, "properties" => properties} ->
+      %Address{
+        addressCountry: Map.get(properties, "country"),
+        addressLocality: Map.get(properties, "city"),
+        addressRegion: Map.get(properties, "state"),
+        description: Map.get(properties, "name") || streetAddress(properties),
+        floor: Map.get(properties, "floor"),
+        geom: Map.get(geometry, "coordinates") |> Provider.coordinates(),
+        postalCode: Map.get(properties, "postcode"),
+        streetAddress: properties |> streetAddress()
+      }
+    end)
+  end
+
+  defp streetAddress(properties) do
+    if Map.has_key?(properties, "housenumber") do
+      Map.get(properties, "housenumber") <> " " <> Map.get(properties, "street")
+    else
+      Map.get(properties, "street")
+    end
+  end
+end