+ def preview(%Conn{} = conn, %{"sig" => sig64, "url" => url64}) do
+ with {_, true} <- {:enabled, MediaProxy.preview_enabled?()},
+ {:ok, url} <- MediaProxy.decode_url(sig64, url64),
+ :ok <- MediaProxy.verify_request_path_and_url(conn, url) 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)
+ static = conn.params["static"] in ["true", true]
+
+ cond do
+ static and content_type == "image/gif" ->
+ handle_jpeg_preview(conn, media_proxy_url)
+
+ static ->
+ drop_static_param_and_redirect(conn)
+
+ content_type == "image/gif" ->
+ redirect(conn, external: media_proxy_url)
+
+ min_content_length_for_preview() > 0 and content_length > 0 and
+ content_length < min_content_length_for_preview() ->
+ redirect(conn, external: media_proxy_url)
+
+ true ->
+ handle_preview(content_type, conn, media_proxy_url)
+ end
+ 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/png" <> _ = _content_type, conn, media_proxy_url) do
+ handle_png_preview(conn, media_proxy_url)
+ end
+
+ defp handle_preview("image/" <> _ = _content_type, conn, media_proxy_url) do
+ handle_jpeg_preview(conn, media_proxy_url)
+ end
+
+ defp handle_preview("video/" <> _ = _content_type, conn, media_proxy_url) do
+ handle_video_preview(conn, media_proxy_url)
+ end
+
+ defp handle_preview(_unsupported_content_type, 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])
+ {thumbnail_max_width, thumbnail_max_height} = thumbnail_max_dimensions()
+
+ with {: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])
+ {thumbnail_max_width, thumbnail_max_height} = thumbnail_max_dimensions()