Support PNG previews to preserve alpha channels

[akkoma] / lib / pleroma / web / media_proxy / media_proxy_controller.ex

diff --git a/lib/pleroma/web/media_proxy/media_proxy_controller.ex b/lib/pleroma/web/media_proxy/media_proxy_controller.ex
index 583c177f2e609eee9b92d01bc114009723d121d5..94fae6cac571f7c1de9adddde1b9374ab695cf8e 100644 (file)
--- a/lib/pleroma/web/media_proxy/media_proxy_controller.ex
+++ b/lib/pleroma/web/media_proxy/media_proxy_controller.ex
@@ -15,8 +15,7 @@ defmodule Pleroma.Web.MediaProxy.MediaProxyController do
          {: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
-      proxy_opts = Config.get([:media_proxy, :proxy_opts], [])
-      ReverseProxy.call(conn, url, proxy_opts)
+      ReverseProxy.call(conn, url, media_proxy_opts())
     else
       {:enabled, false} ->
         send_resp(conn, 404, Plug.Conn.Status.reason_phrase(404))
@@ -51,7 +50,9 @@ defmodule Pleroma.Web.MediaProxy.MediaProxyController do
 
   defp handle_preview(conn, url) do
     with {:ok, %{status: status} = head_response} when status in 200..299 <-
-           Tesla.head(url, opts: [adapter: [timeout: preview_head_request_timeout()]]) do
+           Tesla.head(url,
+             opts: [adapter: [timeout: preview_head_request_timeout(), follow_redirect: true]]
+           ) do
       content_type = Tesla.get_header(head_response, "content-type")
       handle_preview(content_type, conn, url)
     else
@@ -66,6 +67,87 @@ defmodule Pleroma.Web.MediaProxy.MediaProxyController do
     end
   end
 
+  # TODO: find a workaround so avatar_static and banner_static can work.
+  # Those only permit GIFs for animation, so we have to permit a way to
+  # allow those to get real static variants.
+  defp handle_preview("image/gif" = _content_type, conn, url) do
+    mediaproxy_url = url |> MediaProxy.url()
+
+    redirect(conn, external: mediaproxy_url)
+  end
+
+  defp handle_preview("image/png" <> _ = _content_type, conn, url) do
+    handle_png_preview(conn, url)
+  end
+
+  defp handle_preview("image/" <> _ = _content_type, conn, url) do
+    handle_jpeg_preview(conn, url)
+  end
+
+  defp handle_preview("video/" <> _ = _content_type, conn, url) do
+    handle_video_preview(conn, url)
+  end
+
+  defp handle_preview(content_type, conn, _url) do
+    send_resp(conn, :unprocessable_entity, "Unsupported content type: #{content_type}.")
+  end
+
+  defp handle_png_preview(%{params: params} = conn, url) do
+    quality = Config.get!([:media_preview_proxy, :image_quality])
+
+    with {thumbnail_max_width, thumbnail_max_height} <- thumbnail_max_dimensions(params),
+         {:ok, thumbnail_binary} <-
+           MediaHelper.image_resize(
+             url,
+             %{
+               max_width: thumbnail_max_width,
+               max_height: thumbnail_max_height,
+               quality: quality,
+               format: "png"
+             }
+           ) do
+      conn
+      |> put_resp_header("content-type", "image/png")
+      |> put_resp_header("content-disposition", "inline; filename=\"preview.png\"")
+      |> send_resp(200, thumbnail_binary)
+    else
+      _ ->
+        send_resp(conn, :failed_dependency, "Can't handle preview.")
+    end
+  end
+
+  defp handle_jpeg_preview(%{params: params} = conn, url) do
+    quality = Config.get!([:media_preview_proxy, :image_quality])
+
+    with {thumbnail_max_width, thumbnail_max_height} <- thumbnail_max_dimensions(params),
+         {:ok, thumbnail_binary} <-
+           MediaHelper.image_resize(
+             url,
+             %{max_width: thumbnail_max_width, max_height: thumbnail_max_height, quality: quality}
+           ) do
+      conn
+      |> put_resp_header("content-type", "image/jpeg")
+      |> put_resp_header("content-disposition", "inline; filename=\"preview.jpg\"")
+      |> send_resp(200, thumbnail_binary)
+    else
+      _ ->
+        send_resp(conn, :failed_dependency, "Can't handle preview.")
+    end
+  end
+
+  defp handle_video_preview(conn, url) do
+    with {:ok, thumbnail_binary} <-
+           MediaHelper.video_framegrab(url) do
+      conn
+      |> put_resp_header("content-type", "image/jpeg")
+      |> put_resp_header("content-disposition", "inline; filename=\"preview.jpg\"")
+      |> send_resp(200, thumbnail_binary)
+    else
+      _ ->
+        send_resp(conn, :failed_dependency, "Can't handle preview.")
+    end
+  end
+
   defp thumbnail_max_dimensions(params) do
     config = Config.get([:media_preview_proxy], [])
 
@@ -86,35 +168,17 @@ defmodule Pleroma.Web.MediaProxy.MediaProxyController do
     {thumbnail_max_width, thumbnail_max_height}
   end
 
-  defp handle_preview("image/" <> _ = _content_type, %{params: params} = conn, url) do
-    with {thumbnail_max_width, thumbnail_max_height} <- thumbnail_max_dimensions(params),
-         media_proxy_url <- MediaProxy.url(url),
-         {:ok, thumbnail_binary} <-
-           MediaHelper.ffmpeg_resize_remote(
-             media_proxy_url,
-             %{max_width: thumbnail_max_width, max_height: thumbnail_max_height}
-           ) do
-      conn
-      |> put_resp_header("content-type", "image/jpeg")
-      |> send_resp(200, thumbnail_binary)
-    else
-      _ ->
-        send_resp(conn, :failed_dependency, "Can't handle image preview.")
-    end
-  end
-
-  defp handle_preview(content_type, conn, _url) do
-    send_resp(conn, :unprocessable_entity, "Unsupported content type: #{content_type}.")
+  defp preview_head_request_timeout do
+    Keyword.get(media_preview_proxy_opts(), :head_request_max_read_duration) ||
+      Keyword.get(media_proxy_opts(), :max_read_duration) ||
+      ReverseProxy.max_read_duration_default()
   end
 
-  defp preview_head_request_timeout do
-    Config.get([:media_preview_proxy, :proxy_opts, :head_request_max_read_duration]) ||
-      preview_timeout()
+  defp media_proxy_opts do
+    Config.get([:media_proxy, :proxy_opts], [])
   end
 
-  defp preview_timeout do
-    Config.get([:media_preview_proxy, :proxy_opts, :max_read_duration]) ||
-      Config.get([:media_proxy, :proxy_opts, :max_read_duration]) ||
-      ReverseProxy.max_read_duration_default()
+  defp media_preview_proxy_opts do
+    Config.get([:media_preview_proxy, :proxy_opts], [])
   end
 end