add customizable asset delete callbacks

lib/beacon/config.ex

@@ -152,6 +152,10 @@ defmodule Beacon.Config do
              [
                {identifier :: atom(), fun :: (Ecto.Schema.t(), Beacon.MediaLibrary.UploadMetadata.t() -> {:cont, any()} | {:halt, Exception.t()})}
              ]}
+          | {:soft_delete_asset,
+             [
+               {identifier :: atom(), fun :: (Ecto.Schema.t() -> {:cont, any()} | {:halt, Exception.t()})}
+             ]}
 
   @typedoc """
   Add extra fields to pages.

lib/beacon/lifecycle/asset.ex

@@ -48,4 +48,20 @@ defmodule Beacon.Lifecycle.Asset do
   end
 
   def variant_480w(asset, _metadata), do: {:cont, asset}
+
+  def delete_uploaded_asset(%MediaLibrary.Asset{site: site, media_type: media_type} = asset) do
+    config =
+      site
+      |> Beacon.Config.fetch!()
+      |> Beacon.Config.config_for_media_type(media_type)
+      |> Enum.into(%{})
+
+    if Map.get(config, :delete_asset_callbacks) do
+      Enum.reduce(config.delete_asset_callbacks, asset, fn
+        callback, asset -> callback.(asset)
+      end)
+    end
+
+    {:cont, asset}
+  end
 end

lib/beacon/media_library.ex

@@ -343,8 +343,12 @@ defmodule Beacon.MediaLibrary do
       )
 
     case update do
-      {1, _} -> {:ok, repo(asset).reload(asset)}
-      _ -> :error
+      {1, _} ->
+        Lifecycle.Asset.delete_uploaded_asset(asset)
+        {:ok, repo(asset).reload(asset)}
+
+      _ ->
+        :error
     end
   end
 end