mobilizon/lib/service/geospatial/google_maps.ex

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Elixir
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defmodule Mobilizon.Service.Geospatial.GoogleMaps do
@moduledoc """
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Google Maps [Geocoding service](https://developers.google.com/maps/documentation/geocoding/intro).
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Note: Endpoint is hardcoded to Google Maps API.
"""
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alias Mobilizon.Addresses.Address
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alias Mobilizon.Service.Geospatial.Provider
require Logger
@behaviour Provider
@api_key Application.get_env(:mobilizon, __MODULE__) |> get_in([:api_key])
@fetch_place_details (Application.get_env(:mobilizon, __MODULE__)
|> get_in([:fetch_place_details])) in [true, "true", "True"]
@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, fn entry -> process_data(entry, options) end)
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
results |> Enum.map(fn entry -> process_data(entry, options) end)
else
{:ok, %{"status" => "REQUEST_DENIED", "error_message" => error_message}} ->
raise ArgumentError, message: to_string(error_message)
{:ok, %{"results" => [], "status" => "ZERO_RESULTS"}} ->
[]
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
}"
uri =
case method do
:search ->
url <> "&address=#{args.q}"
:geocode ->
url <> "&latlng=#{args.lat},#{args.lon}&result_type=street_address"
:place_details ->
"https://maps.googleapis.com/maps/api/place/details/json?key=#{api_key}&placeid=#{
args.place_id
}"
end
URI.encode(uri)
end
defp process_data(
%{
"formatted_address" => description,
"geometry" => %{"location" => %{"lat" => lat, "lng" => lon}},
"address_components" => components,
"place_id" => place_id
},
options
) do
components =
@components
|> Enum.reduce(%{}, fn component, acc ->
Map.put(acc, component, extract_component(components, component))
end)
description =
if Keyword.get(options, :fetch_place_details, @fetch_place_details) == true do
do_fetch_place_details(place_id, options) || description
else
description
end
%Address{
country: Map.get(components, "country"),
locality: Map.get(components, "locality"),
region: Map.get(components, "administrative_area_level_1"),
description: description,
floor: nil,
geom: [lon, lat] |> Provider.coordinates(),
postal_code: Map.get(components, "postal_code"),
street: street_address(components),
origin_id: "gm:" <> to_string(place_id)
}
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
defp do_fetch_place_details(place_id, options) do
url = build_url(:place_details, %{place_id: place_id}, options)
Logger.debug("Asking Google Maps for details with #{url}")
with {:ok, %HTTPoison.Response{status_code: 200, body: body}} <-
HTTPoison.get(url),
{:ok, %{"result" => %{"name" => name}, "status" => "OK"}} <- Poison.decode(body) do
name
else
{:ok, %{"status" => "REQUEST_DENIED", "error_message" => error_message}} ->
raise ArgumentError, message: to_string(error_message)
{:ok, %{"status" => "INVALID_REQUEST"}} ->
raise ArgumentError, message: "Invalid Request"
{:ok, %{"results" => [], "status" => "ZERO_RESULTS"}} ->
nil
end
end
end