GenServer post

lib/example.ex

@@ -1,18 +1,7 @@
-defmodule Example do
-  @moduledoc """
-  Documentation for Example.
-  """
+defmodule EX.Application do
+  use Application
 
-  @doc """
-  Hello world.
-
-  ## Examples
-
-      iex> Example.hello
-      :world
-
-  """
-  def hello do
-    :world
+  def start(_type, _args) do
+    EX.Worker.start_link(name: EX.Worker)
   end
 end

lib/worker.ex

@@ -0,0 +1,32 @@
+defmodule EX.Worker do
+  use GenServer
+
+  def start_link(args) do
+    GenServer.start_link(__MODULE__, :ok, args)
+  end
+
+  @impl GenServer
+  def init(:ok) do
+    state = Shortener.new()
+    {:ok, state}
+  end
+
+  def get(pid, hash) do
+    GenServer.call(pid, {:get, hash})
+  end
+
+  def put(pid, hash, url) do
+    GenServer.cast(pid, {:put, hash, url})
+  end
+
+  @impl GenServer
+  def handle_call({:get, hash}, _timeout, state) do
+    {:reply, Shortener.get_url(state, hash), state}
+  end
+
+  @impl GenServer
+  def handle_cast({:put, hash, url}, state) do
+    new_state = Shortener.create_short_url(state, hash, url)
+    {:noreply, new_state}
+  end
+end

mix.exs

@@ -14,7 +14,8 @@ defmodule Example.MixProject do
   # Run "mix help compile.app" to learn about applications.
   def application do
     [
-      extra_applications: [:logger]
+      extra_applications: [:logger],
+      mod: {EX.Application, []}
     ]
   end
 

test/worker_test.exs

@@ -0,0 +1,16 @@
+defmodule EX.WorkerTest do
+  use ExUnit.Case, async: true
+
+  setup do
+    pid = start_supervised!(EX.Worker)
+    %{pid: pid}
+  end
+
+  test "get and put work", %{pid: pid} do
+    assert EX.Worker.get(pid, "x") === :undefined
+
+    EX.Worker.put(pid, "x", "google.com")
+
+    assert EX.Worker.get(pid, "x") === "google.com"
+  end
+end