Correctly return 404s in /images endpoint

lib/music_library/records.ex

@@ -68,13 +68,13 @@ defmodule MusicLibrary.Records do
     Repo.one!(q)
   end
 
-  def get_cover!(id) do
+  def get_cover(id) do
     q =
       from r in Record,
         where: r.id == ^id,
         select: %{cover_data: r.cover_data, cover_hash: r.cover_hash}
 
-    Repo.one!(q)
+    Repo.one(q)
   end
 
   def search_release_group(query, opts \\ []) do

lib/music_library_web/controllers/image_controller.ex

@@ -4,9 +4,11 @@ defmodule MusicLibraryWeb.ImageController do
   alias MusicLibrary.Records
 
   def show(conn, %{"record_id" => record_id}) do
-    case Records.get_cover!(record_id) do
+    case Records.get_cover(record_id) do
       nil ->
-        send_resp(conn, 404, "Not found")
+        conn
+        |> put_status(:not_found)
+        |> text("Not found")
 
       %{cover_data: cover_data, cover_hash: etag} ->
         case get_req_header(conn, "if-none-match") do