Delete attachments asynchronously

lib/pleroma/workers/attachments_cleanup_worker.ex

@@ -0,0 +1,87 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Workers.AttachmentsCleanupWorker do
+  import Ecto.Query
+
+  alias Pleroma.Object
+  alias Pleroma.Repo
+
+  use Pleroma.Workers.WorkerHelper, queue: "attachments_cleanup"
+
+  @impl Oban.Worker
+  def perform(
+        %{"object" => %{"data" => %{"attachment" => [_ | _] = attachments, "actor" => actor}}},
+        _job
+      ) do
+    hrefs =
+      Enum.flat_map(attachments, fn attachment ->
+        Enum.map(attachment["url"], & &1["href"])
+      end)
+
+    names = Enum.map(attachments, & &1["name"])
+
+    uploader = Pleroma.Config.get([Pleroma.Upload, :uploader])
+
+    # find all objects for copies of the attachments, name and actor doesn't matter here
+    delete_ids =
+      from(o in Object,
+        where:
+          fragment(
+            "to_jsonb(array(select jsonb_array_elements((?)#>'{url}') ->> 'href' where jsonb_typeof((?)#>'{url}') = 'array'))::jsonb \\?| (?)",
+            o.data,
+            o.data,
+            ^hrefs
+          )
+      )
+      # The query above can be time consumptive on large instances until we refactor how uploads are stored
+      |> Repo.all(timout: :infinity)
+      # we should delete 1 object for any given attachment, but don't delete files if
+      # there are more than 1 object for it
+      |> Enum.reduce(%{}, fn %{
+                               id: id,
+                               data: %{
+                                 "url" => [%{"href" => href}],
+                                 "actor" => obj_actor,
+                                 "name" => name
+                               }
+                             },
+                             acc ->
+        Map.update(acc, href, %{id: id, count: 1}, fn val ->
+          case obj_actor == actor and name in names do
+            true ->
+              # set id of the actor's object that will be deleted
+              %{val | id: id, count: val.count + 1}
+
+            false ->
+              # another actor's object, just increase count to not delete file
+              %{val | count: val.count + 1}
+          end
+        end)
+      end)
+      |> Enum.map(fn {href, %{id: id, count: count}} ->
+        # only delete files that have single instance
+        with 1 <- count do
+          prefix =
+            case Pleroma.Config.get([Pleroma.Upload, :base_url]) do
+              nil -> "media"
+              _ -> ""
+            end
+
+          base_url = Pleroma.Config.get([__MODULE__, :base_url], Pleroma.Web.base_url())
+
+          file_path = String.trim_leading(href, "#{base_url}/#{prefix}")
+
+          uploader.delete_file(file_path)
+        end
+
+        id
+      end)
+
+    from(o in Object, where: o.id in ^delete_ids)
+    |> Repo.delete_all()
+  end
+
+  def perform(%{"object" => _object}, _job), do: :ok
+end