Cache transformations

lib/music_library/application.ex

@@ -5,8 +5,12 @@ defmodule MusicLibrary.Application do
 
   use Application
 
+  alias MusicLibrary.Assets
+
   @impl true
   def start(_type, _args) do
+    _ = Assets.Cache.new()
+
     children = [
       MusicLibraryWeb.Telemetry,
       MusicLibrary.Vault,

lib/music_library/assets/cache.ex

@@ -0,0 +1,16 @@
+defmodule MusicLibrary.Assets.Cache do
+  def new do
+    :ets.new(__MODULE__, [:named_table, :public, read_concurrency: true])
+  end
+
+  def set(payload, format, content) do
+    :ets.insert(__MODULE__, {{payload, format}, content})
+  end
+
+  def get(payload, format) do
+    case :ets.lookup(__MODULE__, {payload, format}) do
+      [{{^payload, ^format}, content}] -> {:found, content}
+      [] -> :not_found
+    end
+  end
+end

lib/music_library/records/cover.ex

@@ -6,18 +6,25 @@ defmodule MusicLibrary.Records.Cover do
 
   @external_resource fallback_path
 
-  @size 2000
+  @default_size 2000
+  @default_format "image/jpeg"
 
   def fallback_data, do: unquote(fallback_data)
 
-  def resize(cover_data, size \\ @size) do
+  def resize(cover_data, size \\ @default_size, format \\ @default_format) do
     {:ok, thumb} = Operation.thumbnail_buffer(cover_data, size)
-    Image.write_to_buffer(thumb, ".jpg")
+    Image.write_to_buffer(thumb, extension(format))
   end
 
-  def correct_size?(cover_data) do
-    {:ok, image} = Image.new_from_buffer(cover_data)
-
-    Image.width(image) == @size
+  def convert(cover_data, data_format, target_format) do
+    if data_format == target_format do
+      {:ok, cover_data}
+    else
+      {:ok, image} = Image.new_from_buffer(cover_data)
+      Image.write_to_buffer(image, extension(target_format))
+    end
   end
+
+  defp extension("image/jpeg"), do: ".jpg"
+  defp extension("image/webp"), do: ".webp"
 end