feat: optionally use OpenTripPlanner for nearby transit (#41)

* feat: optionally use OpenTripPlanner for nearby transit

* fix: don't use OTP's wacky route pattern data

* fix Nearby.parse/1 typespec

* refactor: don't parse source as a single-use atom

* feat: ignore massport stops

* test: add OTP parsing parent stations

Author: boringcactus

config/runtime.exs

@@ -17,6 +17,10 @@ if config_env() != :test do
     app_id: System.get_env("ALGOLIA_APP_ID"),
     search_key: System.get_env("ALGOLIA_SEARCH_KEY"),
     base_url: System.get_env("ALGOLIA_READ_URL")
+
+  # open_trip_planner_client configuration in disguise
+  config :mobile_app_backend,
+    otp_url: System.get_env("OTP_URL")
 end
 
 # ## Using releases

config/test.exs

@@ -14,7 +14,8 @@ config :logger, level: :warning
 config :phoenix, :plug_init_mode, :runtime
 
 config :mobile_app_backend,
-  base_url: "https://api-dev.mbtace.com/"
+  base_url: "https://api-dev.mbtace.com/",
+  otp_url: "http://otp.example.com/"
 
 config :mobile_app_backend, MobileAppBackend.Search.Algolia,
   app_id: "fake_app",

lib/mobile_app_backend_web/controllers/nearby_controller.ex

@@ -2,17 +2,28 @@ defmodule MobileAppBackendWeb.NearbyController do
   use MobileAppBackendWeb, :controller
 
   def show(conn, params) do
+    params = Map.merge(%{"source" => "otp", "radius" => "0.5"}, params)
+    latitude = String.to_float(Map.fetch!(params, "latitude"))
+    longitude = String.to_float(Map.fetch!(params, "longitude"))
+    radius = String.to_float(Map.fetch!(params, "radius"))
+
     {:ok, stops} =
-      MBTAV3API.Stop.get_all(
-        filter: [
-          latitude: String.to_float(params["latitude"]),
-          longitude: String.to_float(params["longitude"]),
-          location_type: [0, 1],
-          radius: miles_to_degrees(0.5)
-        ],
-        include: :parent_station,
-        sort: {:distance, :asc}
-      )
+      case Map.fetch!(params, "source") do
+        "v3" ->
+          MBTAV3API.Stop.get_all(
+            filter: [
+              latitude: latitude,
+              longitude: longitude,
+              location_type: [0, 1],
+              radius: miles_to_degrees(radius)
+            ],
+            include: :parent_station,
+            sort: {:distance, :asc}
+          )
+
+        "otp" ->
+          OpenTripPlannerClient.nearby(latitude, longitude, miles_to_meters(radius))
+      end
 
     stop_ids = MapSet.new(stops, & &1.id)
 
@@ -46,6 +57,8 @@ defmodule MobileAppBackendWeb.NearbyController do
     })
   end
 
+  defp miles_to_meters(miles), do: round(miles * 1_609.344)
+
   # The V3 API does not actually calculate distance,
   # and it just pretends latitude degrees and longitude degrees are equally sized.
   # See https://github.com/mbta/api/blob/1671ba02d4669827fb2a58966d8c3ab39c939b0e/apps/api_web/lib/api_web/controllers/stop_controller.ex#L27-L31.

lib/open_trip_planner_client.ex

@@ -0,0 +1,74 @@
+defmodule OpenTripPlannerClient do
+  @moduledoc """
+  Fetches data from the OpenTripPlanner API.
+
+  ## Configuration
+
+  ```elixir
+  config :mobile_app_backend,
+    otp_url: "http://localhost:8080"
+  ```
+  """
+
+  require Logger
+
+  alias OpenTripPlannerClient.Nearby
+
+  @doc """
+  Fetches stops within the given number of meters of the given position.
+  """
+  @spec nearby(float(), float(), integer(), Keyword.t()) ::
+          {:ok, [MBTAV3API.Stop.t()]} | {:error, term()}
+  def nearby(latitude, longitude, radius, opts \\ []) do
+    root_url =
+      Keyword.get(opts, :root_url, Application.fetch_env!(:mobile_app_backend, :otp_url))
+
+    request =
+      Nearby.request(latitude, longitude, radius)
+      |> Req.update(base_url: root_url, url: "/otp/routers/default/index/graphql")
+
+    case send_request(request) do
+      {:ok, body} -> Nearby.parse(body)
+      {:error, error} -> {:error, error}
+    end
+  end
+
+  @spec send_request(Req.Request.t()) :: {:ok, term()} | {:error, term()}
+  defp send_request(request) do
+    with {:ok, response} <- log_response(request),
+         %{status: 200, body: body} <- response do
+      {:ok, body}
+    else
+      %{status: _} = response ->
+        {:error, response}
+
+      error ->
+        error
+    end
+  end
+
+  @spec log_response(Req.Request.t()) :: {:ok, Req.Response.t()} | {:error, term()}
+  defp log_response(request) do
+    {duration, response} =
+      :timer.tc(
+        MobileAppBackend.HTTP,
+        :request,
+        [request]
+      )
+
+    _ =
+      Logger.info(fn ->
+        "#{__MODULE__}.otp_response query=#{inspect(request.options[:graphql])} #{status_text(response)} duration=#{duration / :timer.seconds(1)}"
+      end)
+
+    response
+  end
+
+  defp status_text({:ok, %{status: code}}) do
+    "status=#{code}"
+  end
+
+  defp status_text({:error, error}) do
+    "status=error error=#{inspect(error)}"
+  end
+end

lib/open_trip_planner_client/nearby.ex

@@ -0,0 +1,111 @@
+defmodule OpenTripPlannerClient.Nearby do
+  @spec request(float(), float(), integer()) :: Req.Request.t()
+  def request(latitude, longitude, radius) do
+    Req.new(method: :post)
+    |> AbsintheClient.attach(
+      graphql: {graphql_query(), %{latitude: latitude, longitude: longitude, radius: radius}}
+    )
+  end
+
+  @spec parse(map()) :: {:ok, [MBTAV3API.Stop.t()]} | {:error, term()}
+  def parse(data) do
+    with {:ok, edges} <- get_edges(data),
+         {:ok, stops} <- parse_edges(edges) do
+      {:ok, stops}
+    else
+      {:error, error} -> {:error, error}
+    end
+  end
+
+  defp graphql_query do
+    """
+    query NearbyQuery($latitude: Float!, $longitude: Float!, $radius: Int!) {
+      nearest(lat: $latitude, lon: $longitude, maxDistance: $radius, filterByPlaceTypes: [STOP]) {
+        edges {
+          node {
+            place {
+              ... on Stop {
+                ...stopDetails
+                parentStation {
+                  ...stopDetails
+                }
+              }
+            }
+            distance
+          }
+        }
+      }
+    }
+
+    fragment stopDetails on Stop {
+      gtfsId
+      lat
+      lon
+      name
+    }
+    """
+  end
+
+  @spec get_edges(map()) :: {:ok, list(map())} | {:error, term()}
+  defp get_edges(data) do
+    case data do
+      %{"data" => %{"nearest" => %{"edges" => edges}}} -> {:ok, edges}
+      _ -> {:error, :bad_format}
+    end
+  end
+
+  @spec parse_edges(list(map())) :: {:ok, list(MBTAV3API.Stop.t())} | {:error, term()}
+  defp parse_edges(edges) do
+    edges
+    |> Enum.reduce({:ok, []}, fn
+      edge, {:ok, reversed_stops} ->
+        with {:ok, stop} <- get_stop(edge),
+             {:ok, stop} <- parse_stop(stop) do
+          {:ok, [stop | reversed_stops]}
+        else
+          :ignore -> {:ok, reversed_stops}
+          {:error, error} -> {:error, error}
+        end
+
+      _edge, {:error, error} ->
+        {:error, error}
+    end)
+    |> case do
+      {:ok, reversed_stops} -> {:ok, Enum.reverse(reversed_stops)}
+      {:error, error} -> {:error, error}
+    end
+  end
+
+  @spec get_stop(map()) :: {:ok, map()} | {:error, term()}
+  defp get_stop(edge) do
+    case edge do
+      %{"node" => %{"place" => stop}} -> {:ok, stop}
+      _ -> {:error, :bad_format}
+    end
+  end
+
+  @spec parse_stop(map()) :: {:ok, MBTAV3API.Stop.t()} | :ignore | {:error, term()}
+  defp parse_stop(place) do
+    case place do
+      %{"lat" => latitude, "lon" => longitude, "gtfsId" => "mbta-ma-us:" <> id, "name" => name} ->
+        {:ok,
+         %MBTAV3API.Stop{
+           id: id,
+           latitude: latitude,
+           longitude: longitude,
+           name: name,
+           parent_station:
+             with {:ok, parent_station} when not is_nil(parent_station) <-
+                    Map.fetch(place, "parentStation"),
+                  {:ok, parent_station} <- parse_stop(parent_station) do
+               parent_station
+             else
+               _ -> nil
+             end
+         }}
+
+      %{"gtfsId" => "2272_2274:" <> _} ->
+        :ignore
+    end
+  end
+end

mix.exs

@@ -68,10 +68,11 @@ defmodule MobileAppBackend.MixProject do
       {:dialyxir, "~> 1.4", only: [:dev, :test], runtime: false},
       {:mox, "~> 1.0", only: :test},
       {:uniq, "~> 0.6", only: :test},
-      {:req, "~> 0.4.8"},
+      {:req, "~> 0.3"},
       {:sentry, "~> 10.0"},
       {:timex, "~> 3.7"},
-      {:lcov_ex, "~> 0.3", only: [:test], runtime: false}
+      {:lcov_ex, "~> 0.3", only: [:test], runtime: false},
+      {:absinthe_client, "~> 0.1.0"}
     ]
   end
 

mix.lock

@@ -1,4 +1,5 @@
 %{
+  "absinthe_client": {:hex, :absinthe_client, "0.1.0", "a3bafc1dff141073a2a7fd926942fb10afb4d45295f0b6df46f6f1955ececaac", [:mix], [{:castore, ">= 0.0.0", [hex: :castore, repo: "hexpm", optional: false]}, {:req, "~> 0.3.0", [hex: :req, repo: "hexpm", optional: false]}, {:slipstream, "~> 1.0", [hex: :slipstream, repo: "hexpm", optional: false]}], "hexpm", "a7ec3e13da9b463cb024dba4733c2fa31a0690a3bfa897b9df6bdd544a4d6f91"},
   "bunt": {:hex, :bunt, "0.2.1", "e2d4792f7bc0ced7583ab54922808919518d0e57ee162901a16a1b6664ef3b14", [:mix], [], "hexpm", "a330bfb4245239787b15005e66ae6845c9cd524a288f0d141c148b02603777a5"},
   "castore": {:hex, :castore, "1.0.5", "9eeebb394cc9a0f3ae56b813459f990abb0a3dedee1be6b27fdb50301930502f", [:mix], [], "hexpm", "8d7c597c3e4a64c395980882d4bca3cebb8d74197c590dc272cfd3b6a6310578"},
   "certifi": {:hex, :certifi, "2.12.0", "2d1cca2ec95f59643862af91f001478c9863c2ac9cb6e2f89780bfd8de987329", [:rebar3], [], "hexpm", "ee68d85df22e554040cdb4be100f33873ac6051387baf6a8f6ce82272340ff1c"},
@@ -28,6 +29,7 @@
   "mime": {:hex, :mime, "2.0.5", "dc34c8efd439abe6ae0343edbb8556f4d63f178594894720607772a041b04b02", [:mix], [], "hexpm", "da0d64a365c45bc9935cc5c8a7fc5e49a0e0f9932a761c55d6c52b142780a05c"},
   "mimerl": {:hex, :mimerl, "1.2.0", "67e2d3f571088d5cfd3e550c383094b47159f3eee8ffa08e64106cdf5e981be3", [:rebar3], [], "hexpm", "f278585650aa581986264638ebf698f8bb19df297f66ad91b18910dfc6e19323"},
   "mint": {:hex, :mint, "1.5.2", "4805e059f96028948870d23d7783613b7e6b0e2fb4e98d720383852a760067fd", [:mix], [{:castore, "~> 0.1.0 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:hpax, "~> 0.1.1", [hex: :hpax, repo: "hexpm", optional: false]}], "hexpm", "d77d9e9ce4eb35941907f1d3df38d8f750c357865353e21d335bdcdf6d892a02"},
+  "mint_web_socket": {:hex, :mint_web_socket, "1.0.3", "aab42fff792a74649916236d0b01f560a0b3f03ca5dea693c230d1c44736b50e", [:mix], [{:mint, ">= 1.4.1 and < 2.0.0-0", [hex: :mint, repo: "hexpm", optional: false]}], "hexpm", "ca3810ca44cc8532e3dce499cc17f958596695d226bb578b2fbb88c09b5954b0"},
   "mox": {:hex, :mox, "1.1.0", "0f5e399649ce9ab7602f72e718305c0f9cdc351190f72844599545e4996af73c", [:mix], [], "hexpm", "d44474c50be02d5b72131070281a5d3895c0e7a95c780e90bc0cfe712f633a13"},
   "nimble_options": {:hex, :nimble_options, "1.1.0", "3b31a57ede9cb1502071fade751ab0c7b8dbe75a9a4c2b5bbb0943a690b63172", [:mix], [], "hexpm", "8bbbb3941af3ca9acc7835f5655ea062111c9c27bcac53e004460dfd19008a99"},
   "nimble_pool": {:hex, :nimble_pool, "1.0.0", "5eb82705d138f4dd4423f69ceb19ac667b3b492ae570c9f5c900bb3d2f50a847", [:mix], [], "hexpm", "80be3b882d2d351882256087078e1b1952a28bf98d0a287be87e4a24a710b67a"},
@@ -43,8 +45,9 @@
   "plug_cowboy": {:hex, :plug_cowboy, "2.6.2", "753611b23b29231fb916b0cdd96028084b12aff57bfd7b71781bd04b1dbeb5c9", [:mix], [{:cowboy, "~> 2.7", [hex: :cowboy, repo: "hexpm", optional: false]}, {:cowboy_telemetry, "~> 0.3", [hex: :cowboy_telemetry, repo: "hexpm", optional: false]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}], "hexpm", "951ed2433df22f4c97b85fdb145d4cee561f36b74854d64c06d896d7cd2921a7"},
   "plug_crypto": {:hex, :plug_crypto, "2.0.0", "77515cc10af06645abbfb5e6ad7a3e9714f805ae118fa1a70205f80d2d70fe73", [:mix], [], "hexpm", "53695bae57cc4e54566d993eb01074e4d894b65a3766f1c43e2c61a1b0f45ea9"},
   "ranch": {:hex, :ranch, "1.8.0", "8c7a100a139fd57f17327b6413e4167ac559fbc04ca7448e9be9057311597a1d", [:make, :rebar3], [], "hexpm", "49fbcfd3682fab1f5d109351b61257676da1a2fdbe295904176d5e521a2ddfe5"},
-  "req": {:hex, :req, "0.4.8", "2b754a3925ddbf4ad78c56f30208ced6aefe111a7ea07fb56c23dccc13eb87ae", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:ezstd, "~> 1.0", [hex: :ezstd, repo: "hexpm", optional: true]}, {:finch, "~> 0.9", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 1.6 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "7146e51d52593bb7f20d00b5308a5d7d17d663d6e85cd071452b613a8277100c"},
+  "req": {:hex, :req, "0.3.12", "f84c2f9e7cc71c81d7cbeacf7c61e763e53ab5f3065703792a4ab264b4f22672", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:ezstd, "~> 1.0", [hex: :ezstd, repo: "hexpm", optional: true]}, {:finch, "~> 0.9", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 1.6 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "c91103d4d1c8edeba90c84e0ba223a59865b673eaab217bfd17da3aa54ab136c"},
   "sentry": {:hex, :sentry, "10.1.0", "5d73c23deb5d95f3027fbb09801bd8e787065be61f0065418aed3961becbbe9f", [:mix], [{:hackney, "~> 1.8", [hex: :hackney, repo: "hexpm", optional: true]}, {:jason, "~> 1.1", [hex: :jason, repo: "hexpm", optional: true]}, {:nimble_options, "~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:plug, "~> 1.6", [hex: :plug, repo: "hexpm", optional: true]}, {:plug_cowboy, "~> 2.3", [hex: :plug_cowboy, repo: "hexpm", optional: true]}], "hexpm", "f4319e7491133046912b4cf7cbe6f5226b309275d1a6d05386cce2ac7f97b2d2"},
+  "slipstream": {:hex, :slipstream, "1.1.0", "e3581e9bc73036e4283b33447475499d18c813c7662aa6b86e131633a7e912f3", [:mix], [{:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:mint_web_socket, "~> 0.2 or ~> 1.0", [hex: :mint_web_socket, repo: "hexpm", optional: false]}, {:nimble_options, "~> 0.1 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "66eb1ac7c43573511b5bad90c24c128bb4e69f588bff65d0c409adf4c7eb02e6"},
   "sobelow": {:hex, :sobelow, "0.13.0", "218afe9075904793f5c64b8837cc356e493d88fddde126a463839351870b8d1e", [:mix], [{:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "cd6e9026b85fc35d7529da14f95e85a078d9dd1907a9097b3ba6ac7ebbe34a0d"},
   "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.7", "354c321cf377240c7b8716899e182ce4890c5938111a1296add3ec74cf1715df", [:make, :mix, :rebar3], [], "hexpm", "fe4c190e8f37401d30167c8c405eda19469f34577987c76dde613e838bbc67f8"},
   "tailwind": {:hex, :tailwind, "0.2.2", "9e27288b568ede1d88517e8c61259bc214a12d7eed271e102db4c93fcca9b2cd", [:mix], [{:castore, ">= 0.0.0", [hex: :castore, repo: "hexpm", optional: false]}], "hexpm", "ccfb5025179ea307f7f899d1bb3905cd0ac9f687ed77feebc8f67bdca78565c4"},

priv/test_data/018d3879-36f2-709a-b94f-1c2cba8612fb.json

@@ -0,0 +1 @@
+{"data":{"nearest":{"edges":[{"node":{"distance":354,"place":{"gtfsId":"mbta-ma-us:67120","lat":42.28101,"lon":-71.177035,"name":"Millennium Park","parentStation":null}}},{"node":{"distance":618,"place":{"gtfsId":"mbta-ma-us:129","lat":42.278959,"lon":-71.175667,"name":"Rivermoor St @ Charles Park Rd","parentStation":null}}},{"node":{"distance":627,"place":{"gtfsId":"mbta-ma-us:137","lat":42.278907,"lon":-71.175492,"name":"Charles Park Rd @ Rivermoor St","parentStation":null}}}]}}}

priv/test_data/018d3c77-9e37-7ec8-b618-b1d5ec8fc4ba.json

@@ -0,0 +1 @@
+{"data":{"nearest":{"edges":[{"node":{"distance":44,"place":{"gtfsId":"mbta-ma-us:7097","lat":42.374518,"lon":-71.029532,"name":"Airport","parentStation":{"gtfsId":"mbta-ma-us:place-aport","lat":42.374262,"lon":-71.030395,"name":"Airport"}}}},{"node":{"distance":44,"place":{"gtfsId":"mbta-ma-us:7096","lat":42.374693,"lon":-71.029333,"name":"Airport","parentStation":{"gtfsId":"mbta-ma-us:place-aport","lat":42.374262,"lon":-71.030395,"name":"Airport"}}}},{"node":{"distance":44,"place":{"gtfsId":"mbta-ma-us:70048","lat":42.374262,"lon":-71.030395,"name":"Airport","parentStation":{"gtfsId":"mbta-ma-us:place-aport","lat":42.374262,"lon":-71.030395,"name":"Airport"}}}},{"node":{"distance":44,"place":{"gtfsId":"mbta-ma-us:70047","lat":42.374262,"lon":-71.030395,"name":"Airport","parentStation":{"gtfsId":"mbta-ma-us:place-aport","lat":42.374262,"lon":-71.030395,"name":"Airport"}}}},{"node":{"distance":69,"place":{"gtfsId":"2272_2274:52","lat":42.373908,"lon":-71.030087,"name":"Blue Line - MBTA","parentStation":null}}},{"node":{"distance":80,"place":{"gtfsId":"2272_2274:41","lat":42.37374,"lon":-71.03005,"name":"Blue Line - MBTA","parentStation":null}}}]}}}