base policy

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

@@ -0,0 +1,59 @@
+defmodule Pleroma.Web.ActivityPub.MRF.TrackingLinkPolicy do
+  alias Pleroma.Object
+
+  @moduledoc "Rewrite tracking links to exclude their tracking parameters"
+  @behaviour Pleroma.Web.ActivityPub.MRF.Policy
+
+  # stolen directly from formatter
+  @link_regex ~r"((?:http(s)?:\/\/)?[\w.-]+(?:\.[\w\.-]+)+[\w\-\._~%:/?#[\]@!\$&'\(\)\*\+,;=.]+)|[0-9a-z+\-\.]+:[0-9a-z$-_.+!*'(),]+"ui
+  
+  # permit timestamp
+  @youtube %{
+    allowed_params: ["v", "t"],
+    domains: "youtube.com, "youtu.be", "www.youtube.com"
+  }
+  @youtube_allowed_params ["v", "t"]
+
+  def history_awareness, do: :auto
+
+  def filter(%{"content" => content} = object) do
+    # find all links
+    links = Regex.scan(@link_regex, content)
+    {:ok, object}
+  end
+
+  def filter(object), do: {:ok, object}
+
+  defp maybe_rewrite_link(link) do
+    url = URI.parse(link)
+    maybe_rewrite_link(url, @youtube)
+  end
+
+  defp maybe_rewrite_link(link, policy) do
+    if Enum.any?(policy.domains, fn domain -> link.host == domain end) do
+      # filter out params
+      link
+    else
+      link
+    end
+  end
+
+  def describe, do: {:ok, %{}}
+
+  @impl true
+  def config_description do
+    %{
+      key: :mrf_tracking_link,
+      related_policy: "Pleroma.Web.ActivityPub.MRF.TrackingLinkPolicy",
+      label: "Tracking Link Policy",
+      description: @moduledoc,
+      children: [
+        %{
+          key: :youtube,
+          type: :boolean,
+          description: "Rewrite youtube links?"
+        }
+      ]
+    }
+  end
+end