defmodule Pleroma.Web.MediaProxy.MediaProxyController do use Pleroma.Web, :controller require Logger @httpoison Application.get_env(:pleroma, :httpoison) @max_body_length 25 * 1_048_576 @cache_control %{ default: "public, max-age=1209600", error: "public, must-revalidate, max-age=160" } # Content-types that will not be returned as content-disposition attachments # Override with :media_proxy, :safe_content_types in the configuration @safe_content_types [ "image/gif", "image/jpeg", "image/jpg", "image/png", "image/svg+xml", "audio/mpeg", "audio/mp3", "video/webm", "video/mp4" ] def remote(conn, params = %{"sig" => sig, "url" => url}) do config = Application.get_env(:pleroma, :media_proxy, []) with true <- Keyword.get(config, :enabled, false), {:ok, url} <- Pleroma.Web.MediaProxy.decode_url(sig, url), filename <- Path.basename(URI.parse(url).path), true <- if(Map.get(params, "filename"), do: filename == Path.basename(conn.request_path), else: true ), {:ok, content_type, body} <- proxy_request(url), safe_content_type <- Enum.member?( Keyword.get(config, :safe_content_types, @safe_content_types), content_type ) do conn |> put_resp_content_type(content_type) |> set_cache_header(:default) |> put_resp_header( "content-security-policy", "default-src 'none'; style-src 'unsafe-inline'; media-src data:; img-src 'self' data:" ) |> put_resp_header("x-xss-protection", "1; mode=block") |> put_resp_header("x-content-type-options", "nosniff") |> put_attachement_header(safe_content_type, filename) |> send_resp(200, body) else false -> send_error(conn, 404) {:error, :invalid_signature} -> send_error(conn, 403) {:error, {:http, _, url}} -> redirect_or_error(conn, url, Keyword.get(config, :redirect_on_failure, true)) end end defp proxy_request(link) do headers = [ {"user-agent", "Pleroma/MediaProxy; #{Pleroma.Web.base_url()} <#{ Application.get_env(:pleroma, :instance)[:email] }>"} ] options = @httpoison.process_request_options([:insecure, {:follow_redirect, true}]) ++ [{:pool, :default}] with {:ok, 200, headers, client} <- :hackney.request(:get, link, headers, "", options), headers = Enum.into(headers, Map.new()), {:ok, body} <- proxy_request_body(client), content_type <- proxy_request_content_type(headers, body) do {:ok, content_type, body} else {:ok, status, _, _} -> Logger.warn("MediaProxy: request failed, status #{status}, link: #{link}") {:error, {:http, :bad_status, link}} {:error, error} -> Logger.warn("MediaProxy: request failed, error #{inspect(error)}, link: #{link}") {:error, {:http, error, link}} end end defp set_cache_header(conn, key) do Plug.Conn.put_resp_header(conn, "cache-control", @cache_control[key]) end defp redirect_or_error(conn, url, true), do: redirect(conn, external: url) defp redirect_or_error(conn, url, _), do: send_error(conn, 502, "Media proxy error: " <> url) defp send_error(conn, code, body \\ "") do conn |> set_cache_header(:error) |> send_resp(code, body) end defp proxy_request_body(client), do: proxy_request_body(client, <<>>) defp proxy_request_body(client, body) when byte_size(body) < @max_body_length do case :hackney.stream_body(client) do {:ok, data} -> proxy_request_body(client, <>) :done -> {:ok, body} {:error, reason} -> {:error, reason} end end defp proxy_request_body(client, _) do :hackney.close(client) {:error, :body_too_large} end # TODO: the body is passed here as well because some hosts do not provide a content-type. # At some point we may want to use magic numbers to discover the content-type and reply a proper one. defp proxy_request_content_type(headers, _body) do headers["Content-Type"] || headers["content-type"] || "application/octet-stream" end defp put_attachement_header(conn, true, _), do: conn defp put_attachement_header(conn, false, filename) do put_resp_header(conn, "content-disposition", "attachment; filename='#{filename}'") end end