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# Pleroma: A lightweight social networking server
# Copyright © 2017-2021 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only
defmodule Pleroma.Web.Metadata.Providers.TwitterCard do
alias Pleroma.User
alias Pleroma.Web.MediaProxy
alias Pleroma.Web.Metadata
alias Pleroma.Web.Metadata.Providers.Provider
alias Pleroma.Web.Metadata.Utils
@behaviour Provider
@media_types ["image", "audio", "video"]
@impl Provider
def build_tags(%{activity_id: id, object: object, user: user}) do
attachments = build_attachments(id, object)
scrubbed_content = Utils.scrub_html_and_truncate(object)
[
title_tag(user),
{:meta, [property: "twitter:description", content: scrubbed_content], []}
] ++
if attachments == [] or Metadata.activity_nsfw?(object) do
[
image_tag(user),
{:meta, [property: "twitter:card", content: "summary"], []}
]
else
attachments
end
end
@impl Provider
def build_tags(%{user: user}) do
with truncated_bio = Utils.scrub_html_and_truncate(user.bio) do
[
title_tag(user),
{:meta, [property: "twitter:description", content: truncated_bio], []},
image_tag(user),
{:meta, [property: "twitter:card", content: "summary"], []}
]
end
end
defp title_tag(user) do
{:meta, [property: "twitter:title", content: Utils.user_name_string(user)], []}
end
def image_tag(user) do
{:meta, [property: "twitter:image", content: MediaProxy.preview_url(User.avatar_url(user))],
[]}
end
defp build_attachments(id, %{data: %{"attachment" => attachments}}) do
Enum.reduce(attachments, [], fn attachment, acc ->
rendered_tags =
Enum.reduce(attachment["url"], [], fn url, acc ->
case Utils.fetch_media_type(@media_types, url["mediaType"]) do
"audio" ->
[
{:meta, [property: "twitter:card", content: "player"], []},
{:meta, [property: "twitter:player:width", content: "480"], []},
{:meta, [property: "twitter:player:height", content: "80"], []},
{:meta, [property: "twitter:player", content: player_url(id)], []}
| acc
]
# Not using preview_url for this. It saves bandwidth, but the image dimensions will
# be wrong. We generate it on the fly and have no way to capture or analyze the
# image to get the dimensions. This can be an issue for apps/FEs rendering images
# in timelines too, but you can get clever with the aspect ratio metadata as a
# workaround.
"image" ->
[
{:meta, [property: "twitter:card", content: "summary_large_image"], []},
{:meta,
[
property: "twitter:player",
content: MediaProxy.url(url["href"])
], []}
| acc
]
|> maybe_add_dimensions(url)
"video" ->
# fallback to old placeholder values
height = url["height"] || 480
width = url["width"] || 480
[
{:meta, [property: "twitter:card", content: "player"], []},
{:meta, [property: "twitter:player", content: player_url(id)], []},
{:meta, [property: "twitter:player:width", content: "#{width}"], []},
{:meta, [property: "twitter:player:height", content: "#{height}"], []},
{:meta, [property: "twitter:player:stream", content: MediaProxy.url(url["href"])],
[]},
{:meta,
[property: "twitter:player:stream:content_type", content: url["mediaType"]], []}
| acc
]
_ ->
acc
end
end)
acc ++ rendered_tags
end)
end
defp build_attachments(_id, _object), do: []
defp player_url(id) do
Pleroma.Web.Router.Helpers.o_status_url(Pleroma.Web.Endpoint, :notice_player, id)
end
# Videos have problems without dimensions, but we used to not provide WxH for images.
# A default (read: incorrect) fallback for images is likely to cause rendering bugs.
defp maybe_add_dimensions(metadata, url) do
cond do
!is_nil(url["height"]) && !is_nil(url["width"]) ->
metadata ++
[
{:meta, [property: "twitter:player:width", content: "#{url["width"]}"], []},
{:meta, [property: "twitter:player:height", content: "#{url["height"]}"], []}
]
true ->
metadata
end
end
end
|
