pleroma/lib/pleroma/upload/filter/dedupe.ex

# Pleroma: A lightweight social networking server
# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only

defmodule Pleroma.Upload.Filter.Dedupe do
  @behaviour Pleroma.Upload.Filter
  alias Pleroma.Upload

  def filter(%Upload{name: name, tempfile: tempfile} = upload) do
    extension =
      name
      |> String.split(".")
      |> List.last()

    shasum =
      :crypto.hash(:sha256, File.read!(tempfile))
      |> Base.encode16(case: :lower)

    filename = shasum <> "." <> extension
    {:ok, %Upload{upload | id: shasum, path: filename}}
  end

  def filter(_), do: :ok
end