Cache images for 24 hours

lib/music_library_web/controllers/cover_controller.ex

@@ -13,11 +13,16 @@ defmodule MusicLibraryWeb.CoverController do
       %{cover_data: cover_data, cover_hash: etag} ->
         case get_req_header(conn, "if-none-match") do
           [^etag] ->
-            send_resp(conn, 304, "")
+            conn
+            # 24 hours
+            |> put_resp_header("cache-control", "public, max-age=86400")
+            |> send_resp(304, "")
 
           _ ->
             conn
             |> put_resp_content_type("image/jpeg", "utf-8")
+            # 24 hours
+            |> put_resp_header("cache-control", "public, max-age=86400")
             |> put_resp_header("etag", etag)
             |> send_resp(200, cover_data)
         end

test/music_library_web/controllers/cover_controller_test.exs

@@ -22,6 +22,7 @@ defmodule MusicLibraryWeb.CoverControllerTest do
 
       assert conn.status == 200
       assert get_resp_header(conn, "content-type") == ["image/jpeg; charset=utf-8"]
+      assert get_resp_header(conn, "cache-control") == ["public, max-age=86400"]
       assert get_resp_header(conn, "etag") == [record.cover_hash]
 
       assert conn.resp_body == record.cover_data
@@ -35,6 +36,7 @@ defmodule MusicLibraryWeb.CoverControllerTest do
 
       assert conn.status == 200
       assert get_resp_header(conn, "content-type") == ["image/jpeg; charset=utf-8"]
+      assert get_resp_header(conn, "cache-control") == ["public, max-age=86400"]
       assert get_resp_header(conn, "etag") == [record.cover_hash]
 
       assert conn.resp_body == record.cover_data
@@ -48,6 +50,7 @@ defmodule MusicLibraryWeb.CoverControllerTest do
 
       assert conn.status == 304
       assert get_resp_header(conn, "content-type") == []
+      assert get_resp_header(conn, "cache-control") == ["public, max-age=86400"]
       assert get_resp_header(conn, "etag") == []
 
       assert conn.resp_body == <<>>