Respond with a 404 Not implemented JSON error message

when requested API is not implemented

lib/pleroma/web/router.ex

@@ -710,6 +710,7 @@ defmodule Pleroma.Web.Router do
   scope "/", Fallback do
     get("/registration/:token", RedirectController, :registration_page)
     get("/:maybe_nickname_or_id", RedirectController, :redirector_with_meta)
+    get("/api*path", RedirectController, :api_not_implemented)
     get("/*path", RedirectController, :redirector)
 
     options("/*path", RedirectController, :empty)
@@ -721,6 +722,12 @@ defmodule Fallback.RedirectController do
   alias Pleroma.User
   alias Pleroma.Web.Metadata
 
+  def api_not_implemented(conn, _params) do
+    conn
+    |> put_status(404)
+    |> json(%{error: "Not implemented"})
+  end
+
   def redirector(conn, _params, code \\ 200) do
     conn
     |> put_resp_content_type("text/html")