Fixed local MastoFE authentication / `force_login` option.

lib/pleroma/web/controller_helper.ex

@@ -7,7 +7,7 @@ defmodule Pleroma.Web.ControllerHelper do
 
   # As in MastoAPI, per https://api.rubyonrails.org/classes/ActiveModel/Type/Boolean.html
   @falsy_param_values [false, 0, "0", "f", "F", "false", "FALSE", "off", "OFF"]
-  def truthy_param?(nil), do: nil
+  def truthy_param?(blank_value) when blank_value in [nil, ""], do: nil
   def truthy_param?(value), do: value not in @falsy_param_values
 
   def oauth_scopes(params, default) do

lib/pleroma/web/mastodon_api/mastodon_api_controller.ex

@@ -1249,16 +1249,22 @@ defp get_user_flavour(_) do
     "glitch"
   end
 
-  def login(conn, %{"code" => code}) do
+  def login(%{assigns: %{user: %User{}}} = conn, _params) do
+    redirect(conn, to: local_mastodon_root_path(conn))
+  end
+
+  @doc "Local Mastodon FE login init action"
+  def login(conn, %{"code" => auth_token}) do
     with {:ok, app} <- get_or_make_app(),
-         %Authorization{} = auth <- Repo.get_by(Authorization, token: code, app_id: app.id),
+         %Authorization{} = auth <- Repo.get_by(Authorization, token: auth_token, app_id: app.id),
          {:ok, token} <- Token.exchange_token(app, auth) do
       conn
       |> put_session(:oauth_token, token.token)
-      |> redirect(to: "/web/getting-started")
+      |> redirect(to: local_mastodon_root_path(conn))
     end
   end
 
+  @doc "Local Mastodon FE callback action"
   def login(conn, _) do
     with {:ok, app} <- get_or_make_app() do
       path =
@@ -1276,6 +1282,8 @@ def login(conn, _) do
     end
   end
 
+  defp local_mastodon_root_path(conn), do: mastodon_api_path(conn, :index, ["getting-started"])
+
   defp get_or_make_app do
     find_attrs = %{client_name: @local_mastodon_name, redirect_uris: "."}
     scopes = ["read", "write", "follow", "push"]

lib/pleroma/web/oauth/oauth_controller.ex

@@ -239,7 +239,7 @@ defp get_app_from_request(conn, params) do
   end
 
   # Special case: Local MastodonFE
-  defp redirect_uri(conn, "."), do: mastodon_api_url(conn, :index, [])
+  defp redirect_uri(conn, "."), do: mastodon_api_url(conn, :login)
 
   defp redirect_uri(_conn, redirect_uri), do: redirect_uri
 end