Add the API to show the Links model or models.

lib/link_shortener_web/controllers/api/v1/links_controller.ex

@@ -0,0 +1,17 @@
+defmodule LinkShortenerWeb.Api.V1.LinksController do
+  use LinkShortenerWeb, :controller
+
+  alias LinkShortener.Links
+
+  action_fallback LinkShortenerWeb.FallbackController
+
+  def index(conn, _params) do
+    links = Links.get_all({})
+    render(conn, "index.json", links: links)
+  end
+
+  def show(conn, %{"id" => id}) do
+    link = Links.get_one(id)
+    render(conn, "show.json", links: link)
+  end
+end

lib/link_shortener_web/controllers/fallback_controller.ex

@@ -0,0 +1,24 @@
+defmodule LinkShortenerWeb.FallbackController do
+  @moduledoc """
+  Translates controller action results into valid `Plug.Conn` responses.
+
+  See `Phoenix.Controller.action_fallback/1` for more details.
+  """
+  use LinkShortenerWeb, :controller
+
+  # This clause handles errors returned by Ecto's insert/update/delete.
+  def call(conn, {:error, %Ecto.Changeset{} = changeset}) do
+    conn
+    |> put_status(:unprocessable_entity)
+    |> put_view(LinkShortenerWeb.ChangesetView)
+    |> render("error.json", changeset: changeset)
+  end
+
+  # This clause is an example of how to handle resources that cannot be found.
+  def call(conn, {:error, :not_found}) do
+    conn
+    |> put_status(:not_found)
+    |> put_view(LinkShortenerWeb.ErrorView)
+    |> render(:"404")
+  end
+end