Statically serve the generated files

See #2350

lib/ask/survey_results.ex

@@ -365,8 +365,8 @@ defmodule Ask.SurveyResults do
   end
 
   defp write_to_file(file_type, survey, rows) do
-    File.mkdir_p!(@target_dir)
-    target_file = file_path(survey, file_type, @target_dir)
+    File.mkdir_p!("./priv/static/" <> @target_dir)
+    target_file = "./priv/static/" <> file_path(survey, file_type, @target_dir)
     if File.exists?(target_file), do: File.rm!(target_file)
 
     # Poor man's mktemp. We only want to avoid having the file living at the stable

lib/ask_web/controllers/respondent_controller.ex

@@ -729,17 +729,11 @@ defmodule AskWeb.RespondentController do
     conn
   end
 
-  # FIXME: this function should return the proper file URL/path
-  defp generated_file_url(%{id: survey_id}, {:results, _filter}), do: "/?some-thingy"
-  defp generated_file_url(%{id: survey_id}, :disposition_history), do: "#dispositon_history"
-  defp generated_file_url(%{id: survey_id}, :incentives), do: "#incentives-#{survey_id}"
-  defp generated_file_url(%{id: survey_id}, :interactions), do: "#interactions-#{survey_id}"
-
   defp file_redirection(conn, survey, file_type) do
-    file_url = generated_file_url(survey, file_type)
+    file_url = SurveyResults.file_path(survey, file_type)
 
     render(conn, "file-redirect.json",
-      file_url: file_url
+      file_url: "/#{file_url}" # TODO: there may be better ways of avoiding relative URLs
     )
   end
 

lib/ask_web/router.ex

@@ -11,6 +11,10 @@ defmodule AskWeb.Router do
     plug :protect_from_forgery
     plug :put_secure_browser_headers
     plug Plug.Static, at: "files/", from: "assets/static/files/"
+
+    # FIXME: this is temporary. We have to apply access control here: https://elixirforum.com/t/how-can-you-hide-certain-static-assets-behind-a-require-authenticated-user-path/53106/6
+    plug Plug.Static, at: "generated_files/", from: "priv/static/generated_files/"
+
     plug Coherence.Authentication.Session, db_model: Ask.User
   end