How can I render an image file that's not in assets?

pejrich · June 1, 2018, 3:56am

I’m trying to build something like Imgur, so going to "/1" would show a page with the image/comments/etc. but "/1.jpg" would just render the image (for hotlinking). My images are held in "/uploads/DATE_UPLOADED/FILENAME", not in "/assets". If a user visits "/1.jpg", how could I render the file that’s sitting in "/uploads/1_6_2018/hawaii.jpg"? (already have the code to access the filepath/file from the ID, just not sure how to serve it so it can be hotlinked).

Kabie · June 1, 2018, 7:57am

A easy way I can think of is copy Plug.Static and change how path was build.

github.com

elixir-plug/plug/blob/master/lib/plug/static.ex#L393


  end


  defp path({app, from}, segments) when is_atom(app) and is_binary(from),
    do: Path.join([Application.app_dir(app), from | segments])


  defp path(from, segments), do: Path.join([from | segments])


  defp subset([h | expected], [h | actual]), do: subset(expected, actual)
  defp subset([], actual), do: actual
  defp subset(_, _), do: []


  defp invalid_path?(list) do
    invalid_path?(list, :binary.compile_pattern(["/", "\\", ":", "\0"]))
  end


  defp invalid_path?([h | _], _match) when h in [".", "..", ""], do: true
  defp invalid_path?([h | t], match), do: String.contains?(h, match) or invalid_path?(t)
  defp invalid_path?([], _match), do: false
end

OvermindDL1 · June 1, 2018, 6:47pm

I would just look it up in the DB (probably this is a good case for CacheX to be in front) to see which one to send out and then send_file it out.

You can also build a static list that nginx can use to dispatch directly to the right file instantly though, that is what I’d do for performance. Or maybe even symlinks!