Add backend failure handling with :ok | :error so the uploader can handle it.

defaulting to :ok, since that's the currently level of error handling.

lib/pleroma/uploaders/local.ex

@@ -17,7 +17,7 @@ defmodule Pleroma.Uploaders.Local do
       File.cp!(tmpfile, result_file)
     end
 
-    url_path
+    {:ok, url_path}
   end
 
   def upload_path do

lib/pleroma/uploaders/s3.ex

@@ -19,6 +19,6 @@ defmodule Pleroma.Uploaders.S3 do
       ])
       |> ExAws.request()
 
-    "#{public_endpoint}/#{bucket}/#{s3_name}"
+    {:ok, "#{public_endpoint}/#{bucket}/#{s3_name}"}
   end
 end

lib/pleroma/uploaders/swift/swift.ex

@@ -11,20 +11,18 @@ defmodule Pleroma.Uploaders.Swift.Client do
   end
 
   def upload_file(filename, body, content_type) do
+    object_url = Keyword.fetch!(@settings, :object_url)
     token = Pleroma.Uploaders.Swift.Keystone.get_token()
 
     case put("#{filename}", body, "X-Auth-Token": token, "Content-Type": content_type) do
       {:ok, %HTTPoison.Response{status_code: 201}} ->
-        # lgtm
-        ""
+        {:ok, "#{object_url}/#{filename}"}
 
       {:ok, %HTTPoison.Response{status_code: 401}} ->
-        # bad token
-        ""
+        {:error, "Unauthorized, Bad Token"}
 
       {:error, _} ->
-        # bad news
-        ""
+        {:error, "Swift Upload Error"}
     end
   end
 end

lib/pleroma/uploaders/swift/uploader.ex

@@ -1,15 +1,10 @@
 defmodule Pleroma.Uploaders.Swift do
   @behaviour Pleroma.Uploaders.Uploader
 
-  @settings Application.get_env(:pleroma, Pleroma.Uploaders.Swift)
-
   def put_file(name, uuid, tmp_path, content_type, _should_dedupe) do
     {:ok, file_data} = File.read(tmp_path)
     remote_name = "#{uuid}/#{name}"
 
     Pleroma.Uploaders.Swift.Client.upload_file(remote_name, file_data, content_type)
-
-    object_url = Keyword.fetch!(@settings, :object_url)
-    "#{object_url}/#{remote_name}"
   end
 end

lib/pleroma/uploaders/uploader.ex

@@ -14,13 +14,5 @@ defmodule Pleroma.Uploaders.Uploader do
               file :: File.t(),
               content_type :: String.t(),
               should_dedupe :: Boolean.t()
-            ) :: String.t()
-
-  @callback put_file(
-              name :: String.t(),
-              uuid :: String.t(),
-              image_data :: String.t(),
-              content_type :: String.t(),
-              should_dedupe :: String.t()
-            ) :: String.t()
+            ) :: {:ok, String.t()} | {:error, String.t()}
 end