akkoma/lib/pleroma/web/media_proxy/media_proxy_controller.ex
Ivan Tashkinov cd234a5321 [#2497] Media preview proxy: preview bypass for small images
(basing on Content-Length and Content-Type).
2020-09-12 11:20:41 +03:00

190 lines
6.4 KiB
Elixir

# Pleroma: A lightweight social networking server
# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only
defmodule Pleroma.Web.MediaProxy.MediaProxyController do
use Pleroma.Web, :controller
alias Pleroma.Config
alias Pleroma.Helpers.MediaHelper
alias Pleroma.ReverseProxy
alias Pleroma.Web.MediaProxy
alias Plug.Conn
@min_content_length_for_preview 100 * 1024
def remote(conn, %{"sig" => sig64, "url" => url64}) do
with {_, true} <- {:enabled, MediaProxy.enabled?()},
{:ok, url} <- MediaProxy.decode_url(sig64, url64),
{_, false} <- {:in_banned_urls, MediaProxy.in_banned_urls(url)},
:ok <- MediaProxy.verify_request_path_and_url(conn, url) do
ReverseProxy.call(conn, url, media_proxy_opts())
else
{:enabled, false} ->
send_resp(conn, 404, Conn.Status.reason_phrase(404))
{:in_banned_urls, true} ->
send_resp(conn, 404, Conn.Status.reason_phrase(404))
{:error, :invalid_signature} ->
send_resp(conn, 403, Conn.Status.reason_phrase(403))
{:wrong_filename, filename} ->
redirect(conn, external: MediaProxy.build_url(sig64, url64, filename))
end
end
def preview(%Conn{} = conn, %{"sig" => sig64, "url" => url64}) do
with {_, true} <- {:enabled, MediaProxy.preview_enabled?()},
{:ok, url} <- MediaProxy.decode_url(sig64, url64) do
handle_preview(conn, url)
else
{:enabled, false} ->
send_resp(conn, 404, Conn.Status.reason_phrase(404))
{:error, :invalid_signature} ->
send_resp(conn, 403, Conn.Status.reason_phrase(403))
{:wrong_filename, filename} ->
redirect(conn, external: MediaProxy.build_preview_url(sig64, url64, filename))
end
end
defp handle_preview(conn, url) do
media_proxy_url = MediaProxy.url(url)
with {:ok, %{status: status} = head_response} when status in 200..299 <-
Pleroma.HTTP.request("head", media_proxy_url, [], [], pool: :media) do
content_type = Tesla.get_header(head_response, "content-type")
content_length = Tesla.get_header(head_response, "content-length")
content_length = content_length && String.to_integer(content_length)
handle_preview(content_type, content_length, conn, media_proxy_url)
else
# If HEAD failed, redirecting to media proxy URI doesn't make much sense; returning an error
{_, %{status: status}} ->
send_resp(conn, :failed_dependency, "Can't fetch HTTP headers (HTTP #{status}).")
{:error, :recv_response_timeout} ->
send_resp(conn, :failed_dependency, "HEAD request timeout.")
_ ->
send_resp(conn, :failed_dependency, "Can't fetch HTTP headers.")
end
end
defp handle_preview(
"image/" <> _ = _content_type,
_content_length,
%{params: %{"output_format" => "jpeg"}} = conn,
media_proxy_url
) do
handle_jpeg_preview(conn, media_proxy_url)
end
defp handle_preview("image/gif" = _content_type, _content_length, conn, media_proxy_url) do
redirect(conn, external: media_proxy_url)
end
defp handle_preview("image/" <> _ = _content_type, content_length, conn, media_proxy_url)
when is_integer(content_length) and content_length > 0 and
content_length < @min_content_length_for_preview do
redirect(conn, external: media_proxy_url)
end
defp handle_preview("image/png" <> _ = _content_type, _content_length, conn, media_proxy_url) do
handle_png_preview(conn, media_proxy_url)
end
defp handle_preview("image/" <> _ = _content_type, _content_length, conn, media_proxy_url) do
handle_jpeg_preview(conn, media_proxy_url)
end
defp handle_preview("video/" <> _ = _content_type, _content_length, conn, media_proxy_url) do
handle_video_preview(conn, media_proxy_url)
end
defp handle_preview(_unsupported_content_type, _content_length, conn, media_proxy_url) do
fallback_on_preview_error(conn, media_proxy_url)
end
defp handle_png_preview(conn, media_proxy_url) do
quality = Config.get!([:media_preview_proxy, :image_quality])
with {thumbnail_max_width, thumbnail_max_height} <- thumbnail_max_dimensions(),
{:ok, thumbnail_binary} <-
MediaHelper.image_resize(
media_proxy_url,
%{
max_width: thumbnail_max_width,
max_height: thumbnail_max_height,
quality: quality,
format: "png"
}
) do
conn
|> put_preview_response_headers(["image/png", "preview.png"])
|> send_resp(200, thumbnail_binary)
else
_ ->
fallback_on_preview_error(conn, media_proxy_url)
end
end
defp handle_jpeg_preview(conn, media_proxy_url) do
quality = Config.get!([:media_preview_proxy, :image_quality])
with {thumbnail_max_width, thumbnail_max_height} <- thumbnail_max_dimensions(),
{:ok, thumbnail_binary} <-
MediaHelper.image_resize(
media_proxy_url,
%{max_width: thumbnail_max_width, max_height: thumbnail_max_height, quality: quality}
) do
conn
|> put_preview_response_headers()
|> send_resp(200, thumbnail_binary)
else
_ ->
fallback_on_preview_error(conn, media_proxy_url)
end
end
defp handle_video_preview(conn, media_proxy_url) do
with {:ok, thumbnail_binary} <-
MediaHelper.video_framegrab(media_proxy_url) do
conn
|> put_preview_response_headers()
|> send_resp(200, thumbnail_binary)
else
_ ->
fallback_on_preview_error(conn, media_proxy_url)
end
end
defp fallback_on_preview_error(conn, media_proxy_url) do
redirect(conn, external: media_proxy_url)
end
defp put_preview_response_headers(
conn,
[content_type, filename] = _content_info \\ ["image/jpeg", "preview.jpg"]
) do
conn
|> put_resp_header("content-type", content_type)
|> put_resp_header("content-disposition", "inline; filename=\"#{filename}\"")
|> put_resp_header("cache-control", ReverseProxy.default_cache_control_header())
end
defp thumbnail_max_dimensions do
config = Config.get([:media_preview_proxy], [])
thumbnail_max_width = Keyword.fetch!(config, :thumbnail_max_width)
thumbnail_max_height = Keyword.fetch!(config, :thumbnail_max_height)
{thumbnail_max_width, thumbnail_max_height}
end
defp media_proxy_opts do
Config.get([:media_proxy, :proxy_opts], [])
end
end