1 files changed, 40 insertions, 0 deletions
diff --git a/lib/pleroma/uploaders/uploader.ex b/lib/pleroma/uploaders/uploader.ex
new file mode 100644
index 000000000..afda5609e
--- /dev/null
+++ b/lib/pleroma/uploaders/uploader.ex
@@ -0,0 +1,40 @@
+defmodule Pleroma.Uploaders.Uploader do
+  @moduledoc """
+  Defines the contract to put and get an uploaded file to any backend.
+  """
+
+  @doc """
+  Instructs how to get the file from the backend.
+
+  Used by `Pleroma.Plugs.UploadedMedia`.
+  """
+  @type get_method :: {:static_dir, directory :: String.t()} | {:url, url :: String.t()}
+  @callback get_file(file :: String.t()) :: {:ok, get_method()}
+
+  @doc """
+  Put a file to the backend.
+
+  Returns:
+
+  * `:ok` which assumes `{:ok, upload.path}`
+  * `{:ok, spec}` where spec is:
+    * `{:file, filename :: String.t}` to handle reads with `get_file/1` (recommended)
+
+    This allows to correctly proxy or redirect requests to the backend, while allowing to migrate backends without breaking any URL.
+  * `{url, url :: String.t}` to bypass `get_file/2` and use the `url` directly in the activity.
+  * `{:error, String.t}` error information if the file failed to be saved to the backend.
+
+
+  """
+  @callback put_file(Pleroma.Upload.t()) ::
+              :ok | {:ok, {:file | :url, String.t()}} | {:error, String.t()}
+
+  @spec put_file(module(), Pleroma.Upload.t()) ::
+          {:ok, {:file | :url, String.t()}} | {:error, String.t()}
+  def put_file(uploader, upload) do
+    case uploader.put_file(upload) do
+      :ok -> {:ok, {:file, upload.path}}
+      other -> other
+    end
+  end
+end