feat: set up GraphQL API

lib/mobile_app_backend_web/endpoint.ex

@@ -41,7 +41,7 @@ defmodule MobileAppBackendWeb.Endpoint do
   plug Plug.Telemetry, event_prefix: [:phoenix, :endpoint]
 
   plug Plug.Parsers,
-    parsers: [:urlencoded, :multipart, :json],
+    parsers: [:urlencoded, :multipart, :json, Absinthe.Plug.Parser],
     pass: ["*/*"],
     json_decoder: Phoenix.json_library()
 

lib/mobile_app_backend_web/resolvers/route.ex

@@ -0,0 +1,7 @@
+defmodule MobileAppBackendWeb.Resolvers.Route do
+  def by_stop(%Stops.Stop{id: stop_id}, _args, _resolution) do
+    {:ok,
+     Routes.Repo.by_stop_with_route_pattern(stop_id)
+     |> Enum.map(fn {route, route_patterns} -> Map.put(route, :route_patterns, route_patterns) end)}
+  end
+end

lib/mobile_app_backend_web/resolvers/stop.ex

@@ -0,0 +1,8 @@
+defmodule MobileAppBackendWeb.Resolvers.Stop do
+  def find_stop(_parent, %{id: id}, _resolution) do
+    case Stops.Api.by_gtfs_id(id) do
+      {:ok, stop} when not is_nil(stop) -> {:ok, stop}
+      x -> {:error, x}
+    end
+  end
+end

lib/mobile_app_backend_web/router.ex

@@ -31,6 +31,16 @@ defmodule MobileAppBackendWeb.Router do
     get("/route/by-stop/:stop_id", RouteController, :by_stop)
   end
 
+  scope "/graphql" do
+    pipe_through :api
+
+    forward "/graphiql", Absinthe.Plug.GraphiQL,
+      schema: MobileAppBackendWeb.Schema,
+      interface: :playground
+
+    forward "/", Absinthe.Plug, schema: MobileAppBackendWeb.Schema
+  end
+
   # Enable LiveDashboard and Swoosh mailbox preview in development
   if Application.compile_env(:mobile_app_backend, :dev_routes) do
     # If you want to use the LiveDashboard in production, you should put

lib/mobile_app_backend_web/schema.ex

@@ -0,0 +1,15 @@
+defmodule MobileAppBackendWeb.Schema do
+  use Absinthe.Schema
+  import_types(MobileAppBackendWeb.Schema.RouteTypes)
+  import_types(MobileAppBackendWeb.Schema.StopTypes)
+
+  alias MobileAppBackendWeb.Resolvers
+
+  query do
+    @desc "Get a stop by ID"
+    field :stop, :stop do
+      arg(:id, non_null(:id))
+      resolve(&Resolvers.Stop.find_stop/3)
+    end
+  end
+end

lib/mobile_app_backend_web/schema/route_types.ex

@@ -0,0 +1,16 @@
+defmodule MobileAppBackendWeb.Schema.RouteTypes do
+  use Absinthe.Schema.Notation
+
+  object :route do
+    field(:id, non_null(:id))
+    field(:name, non_null(:string))
+    field(:long_name, non_null(:string))
+
+    field(:route_patterns, list_of(:route_pattern))
+  end
+
+  object :route_pattern do
+    field(:id, non_null(:id))
+    field(:name, non_null(:string))
+  end
+end

lib/mobile_app_backend_web/schema/stop_types.ex

@@ -0,0 +1,16 @@
+defmodule MobileAppBackendWeb.Schema.StopTypes do
+  use Absinthe.Schema.Notation
+
+  alias MobileAppBackendWeb.Resolvers
+
+  object :stop do
+    field(:id, non_null(:id))
+    field(:name, non_null(:string))
+    field(:latitude, non_null(:float))
+    field(:longitude, non_null(:float))
+
+    field :routes, list_of(:route) do
+      resolve(&Resolvers.Route.by_stop/3)
+    end
+  end
+end

mix.exs

@@ -65,7 +65,9 @@ defmodule MobileAppBackend.MixProject do
       {:bypass, "~> 2.1", only: :test},
       {:httpoison, "~> 1.5"},
       {:sentry, "~> 7.0"},
-      {:con_cache, "~> 0.12.0"}
+      {:con_cache, "~> 0.12.0"},
+      {:absinthe, "~> 1.7"},
+      {:absinthe_plug, "~> 1.5"}
     ]
   end
 

mix.lock

@@ -1,4 +1,6 @@
 %{
+  "absinthe": {:hex, :absinthe, "1.7.6", "0b897365f98d068cfcb4533c0200a8e58825a4aeeae6ec33633ebed6de11773b", [:mix], [{:dataloader, "~> 1.0.0 or ~> 2.0", [hex: :dataloader, repo: "hexpm", optional: true]}, {:decimal, "~> 1.0 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: true]}, {:nimble_parsec, "~> 1.2.2 or ~> 1.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}, {:opentelemetry_process_propagator, "~> 0.2.1", [hex: :opentelemetry_process_propagator, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "e7626951ca5eec627da960615b51009f3a774765406ff02722b1d818f17e5778"},
+  "absinthe_plug": {:hex, :absinthe_plug, "1.5.8", "38d230641ba9dca8f72f1fed2dfc8abd53b3907d1996363da32434ab6ee5d6ab", [:mix], [{:absinthe, "~> 1.5", [hex: :absinthe, repo: "hexpm", optional: false]}, {:plug, "~> 1.4", [hex: :plug, repo: "hexpm", optional: false]}], "hexpm", "bbb04176647b735828861e7b2705465e53e2cf54ccf5a73ddd1ebd855f996e5a"},
   "bunt": {:hex, :bunt, "0.2.1", "e2d4792f7bc0ced7583ab54922808919518d0e57ee162901a16a1b6664ef3b14", [:mix], [], "hexpm", "a330bfb4245239787b15005e66ae6845c9cd524a288f0d141c148b02603777a5"},
   "bypass": {:hex, :bypass, "2.1.0", "909782781bf8e20ee86a9cabde36b259d44af8b9f38756173e8f5e2e1fabb9b1", [:mix], [{:plug, "~> 1.7", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.0", [hex: :plug_cowboy, repo: "hexpm", optional: false]}, {:ranch, "~> 1.3", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm", "d9b5df8fa5b7a6efa08384e9bbecfe4ce61c77d28a4282f79e02f1ef78d96b80"},
   "castore": {:hex, :castore, "1.0.4", "ff4d0fb2e6411c0479b1d965a814ea6d00e51eb2f58697446e9c41a97d940b28", [:mix], [], "hexpm", "9418c1b8144e11656f0be99943db4caf04612e3eaecefb5dae9a2a87565584f8"},
@@ -31,6 +33,7 @@
   "mimerl": {:hex, :mimerl, "1.2.0", "67e2d3f571088d5cfd3e550c383094b47159f3eee8ffa08e64106cdf5e981be3", [:rebar3], [], "hexpm", "f278585650aa581986264638ebf698f8bb19df297f66ad91b18910dfc6e19323"},
   "mint": {:hex, :mint, "1.5.1", "8db5239e56738552d85af398798c80648db0e90f343c8469f6c6d8898944fb6f", [: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", "4a63e1e76a7c3956abd2c72f370a0d0aecddc3976dea5c27eccbecfa5e7d5b1e"},
   "nimble_options": {:hex, :nimble_options, "1.0.2", "92098a74df0072ff37d0c12ace58574d26880e522c22801437151a159392270e", [:mix], [], "hexpm", "fd12a8db2021036ce12a309f26f564ec367373265b53e25403f0ee697380f1b8"},
+  "nimble_parsec": {:hex, :nimble_parsec, "1.4.0", "51f9b613ea62cfa97b25ccc2c1b4216e81df970acd8e16e8d1bdc58fef21370d", [:mix], [], "hexpm", "9c565862810fb383e9838c1dd2d7d2c437b3d13b267414ba6af33e50d2d1cf28"},
   "nimble_pool": {:hex, :nimble_pool, "1.0.0", "5eb82705d138f4dd4423f69ceb19ac667b3b492ae570c9f5c900bb3d2f50a847", [:mix], [], "hexpm", "80be3b882d2d351882256087078e1b1952a28bf98d0a287be87e4a24a710b67a"},
   "parse_trans": {:hex, :parse_trans, "3.4.1", "6e6aa8167cb44cc8f39441d05193be6e6f4e7c2946cb2759f015f8c56b76e5ff", [:rebar3], [], "hexpm", "620a406ce75dada827b82e453c19cf06776be266f5a67cff34e1ef2cbb60e49a"},
   "phoenix": {:hex, :phoenix, "1.7.10", "02189140a61b2ce85bb633a9b6fd02dff705a5f1596869547aeb2b2b95edd729", [:mix], [{:castore, ">= 0.0.0", [hex: :castore, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:phoenix_pubsub, "~> 2.1", [hex: :phoenix_pubsub, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.6", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:plug_crypto, "~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:websock_adapter, "~> 0.5.3", [hex: :websock_adapter, repo: "hexpm", optional: false]}], "hexpm", "cf784932e010fd736d656d7fead6a584a4498efefe5b8227e9f383bf15bb79d0"},