Associations

lib/scoreboard/games/games.ex

@@ -8,6 +8,14 @@ defmodule Scoreboard.Games do
 
   alias Scoreboard.Games.Player
 
+  def data() do
+    Dataloader.Ecto.new(Scoreboard.Repo, query: &query/2)
+  end
+
+  def query(queryable, _params) do
+    queryable
+  end
+
   def get(queryable, id) do
     case Repo.get(queryable, id) do
       nil ->

lib/scoreboard_web/schema.ex

@@ -1,24 +1,40 @@
 defmodule ScoreboardWeb.Schema do
   use Absinthe.Schema
+  import Absinthe.Resolution.Helpers, only: [dataloader: 1]
   alias Scoreboard.Games
 
+  def context(ctx) do
+    loader =
+      Dataloader.new |> Dataloader.add_source(:games, Games.data())
+
+    Map.put(ctx, :loader, loader)
+  end
+
+  def plugins do
+    [Absinthe.Middleware.Dataloader] ++ Absinthe.Plugin.defaults()
+  end
+
   @desc "A Game"
   object :game do
     field(:id, non_null(:id))
     field(:name, non_null(:string))
+    field(:scores, list_of(:score), resolve: dataloader(:games))
   end
 
   @desc "A Player"
   object :player do
     field(:id, non_null(:id))
     field(:name, non_null(:string))
+    field(:scores, list_of(:score), resolve: dataloader(:games))
   end
 
-  # @desc "A Score."
-  # object :score do
-  #   field(:id, non_null(:id))
-  #   field(:total, non_null(:integer))
-  # end
+  @desc "A Score."
+  object :score do
+    field(:id, non_null(:id))
+    field(:total, non_null(:integer))
+    field(:player, :player, resolve: dataloader(:games))
+    field(:game, :game, resolve: dataloader(:games))
+  end
 
   query do
     field :game, :game do

mix.exs

@@ -39,7 +39,8 @@ defmodule Scoreboard.Mixfile do
       {:postgrex, ">= 0.0.0"},
       {:gettext, "~> 0.11"},
       {:absinthe, "~> 1.4"},
-      {:cowboy, "~> 1.0"}
+      {:cowboy, "~> 1.0"},
+      {:dataloader, "~> 1.0.0"}
     ]
   end
 

mix.lock

@@ -3,6 +3,7 @@
   "connection": {:hex, :connection, "1.0.4", "a1cae72211f0eef17705aaededacac3eb30e6625b04a6117c1b2db6ace7d5976", [:mix], [], "hexpm"},
   "cowboy": {:hex, :cowboy, "1.1.2", "61ac29ea970389a88eca5a65601460162d370a70018afe6f949a29dca91f3bb0", [:rebar3], [{:cowlib, "~> 1.0.2", [hex: :cowlib, repo: "hexpm", optional: false]}, {:ranch, "~> 1.3.2", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm"},
   "cowlib": {:hex, :cowlib, "1.0.2", "9d769a1d062c9c3ac753096f868ca121e2730b9a377de23dec0f7e08b1df84ee", [:make], [], "hexpm"},
+  "dataloader": {:hex, :dataloader, "1.0.2", "90e788dc507bb80f7281f2d3d6c6e4bb1d18709c8351392365b6a0950bfe9f7d", [:mix], [{:ecto, ">= 0.0.0", [hex: :ecto, repo: "hexpm", optional: true]}], "hexpm"},
   "db_connection": {:hex, :db_connection, "1.1.3", "89b30ca1ef0a3b469b1c779579590688561d586694a3ce8792985d4d7e575a61", [:mix], [{:connection, "~> 1.0.2", [hex: :connection, repo: "hexpm", optional: false]}, {:poolboy, "~> 1.5", [hex: :poolboy, repo: "hexpm", optional: true]}, {:sbroker, "~> 1.0", [hex: :sbroker, repo: "hexpm", optional: true]}], "hexpm"},
   "decimal": {:hex, :decimal, "1.5.0", "b0433a36d0e2430e3d50291b1c65f53c37d56f83665b43d79963684865beab68", [:mix], [], "hexpm"},
   "ecto": {:hex, :ecto, "2.2.10", "e7366dc82f48f8dd78fcbf3ab50985ceeb11cb3dc93435147c6e13f2cda0992e", [:mix], [{:db_connection, "~> 1.1", [hex: :db_connection, repo: "hexpm", optional: true]}, {:decimal, "~> 1.2", [hex: :decimal, repo: "hexpm", optional: false]}, {:mariaex, "~> 0.8.0", [hex: :mariaex, repo: "hexpm", optional: true]}, {:poison, "~> 2.2 or ~> 3.0", [hex: :poison, repo: "hexpm", optional: true]}, {:poolboy, "~> 1.5", [hex: :poolboy, repo: "hexpm", optional: false]}, {:postgrex, "~> 0.13.0", [hex: :postgrex, repo: "hexpm", optional: true]}, {:sbroker, "~> 1.0", [hex: :sbroker, repo: "hexpm", optional: true]}], "hexpm"},

test/scoreboard_web/schema_test.exs

@@ -1,7 +1,7 @@
 defmodule Scoreboard.SchemaTest do
   use Scoreboard.DataCase
 
-  alias Scoreboard.Games.{Game, Player}
+  alias Scoreboard.Games.{Game, Player, Score}
   alias Scoreboard.Repo
 
   setup do
@@ -11,8 +11,8 @@ defmodule Scoreboard.SchemaTest do
     %{game: game, player: player}
   end
 
-  describe "scores" do
-    test "We can get our fake data", context do
+  describe("top level queries") do
+    test("We can get our fake data", context) do
       document = """
       {
         game(id: "#{context.game.id}") {
@@ -33,4 +33,35 @@ defmodule Scoreboard.SchemaTest do
       assert get_in(data, ["player", "name"]) == context.player.name
     end
   end
+
+  describe("nested queries") do
+    test("We can query associations", context) do
+      score = Repo.insert!(%Score{game_id: context.game.id, player_id: context.player.id, total: 101})
+
+      document = """
+      {
+        game(id: "#{context.game.id}") {
+          id
+          name
+          scores {
+            total
+            player {
+              id
+              name
+            }
+          }
+        }
+      }
+      """
+
+      result = Absinthe.run(document, ScoreboardWeb.Schema)
+
+      assert {:ok, %{data: data}} = result
+      assert get_in(data, ["game", "name"]) == context.game.name
+
+      first = fn :get, data, next -> data |> hd() |> next.() end
+      assert get_in(data, ["game", "scores", first, "total"]) == score.total
+      assert get_in(data, ["game", "scores", first, "player", "name"]) == context.player.name
+    end
+  end
 end