pleroma/lib/pleroma/web/activity_pub/mrf/force_mentions_in_content.ex

81 lines
2.3 KiB
Elixir

# Pleroma: A lightweight social networking server
# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only
defmodule Pleroma.Web.ActivityPub.MRF.ForceMentionsInContent do
alias Pleroma.Formatter
alias Pleroma.User
@behaviour Pleroma.Web.ActivityPub.MRF.Policy
defp do_extract({:a, attrs, _}, acc) do
if Enum.find(attrs, fn {name, value} ->
name == "class" && value in ["mention", "u-url mention", "mention u-url"]
end) do
href = Enum.find(attrs, fn {name, _} -> name == "href" end) |> elem(1)
acc ++ [href]
else
acc
end
end
defp do_extract({_, _, children}, acc) do
do_extract(children, acc)
end
defp do_extract(nodes, acc) when is_list(nodes) do
Enum.reduce(nodes, acc, fn node, acc -> do_extract(node, acc) end)
end
defp do_extract(_, acc), do: acc
defp extract_mention_uris_from_content(content) do
{:ok, tree} = :fast_html.decode(content, format: [:html_atoms])
do_extract(tree, [])
end
@impl true
def filter(%{"type" => "Create", "object" => %{"type" => "Note", "tag" => tag}} = object) do
# image-only posts from pleroma apparently reach this MRF without the content field
content = object["object"]["content"] || ""
mention_users =
tag
|> Enum.filter(fn tag -> tag["type"] == "Mention" end)
|> Enum.map(& &1["href"])
|> Enum.reject(&is_nil/1)
|> Enum.map(fn ap_id_or_uri ->
case User.get_or_fetch_by_ap_id(ap_id_or_uri) do
{:ok, user} -> {ap_id_or_uri, user}
_ -> {ap_id_or_uri, User.get_by_uri(ap_id_or_uri)}
end
end)
|> Enum.reject(fn {_, user} -> user == nil end)
|> Enum.into(%{})
explicitly_mentioned_uris = extract_mention_uris_from_content(content)
added_mentions =
Enum.reduce(mention_users, "", fn {uri, user}, acc ->
unless uri in explicitly_mentioned_uris do
acc <> Formatter.mention_from_user(user)
else
acc
end
end)
content =
if added_mentions != "",
do: added_mentions <> " " <> content,
else: content
{:ok, put_in(object["object"]["content"], content)}
end
@impl true
def filter(object), do: {:ok, object}
@impl true
def describe, do: {:ok, %{}}
end