# Pleroma: A lightweight social networking server # Copyright © 2017-2021 Pleroma Authors <https://pleroma.social/> # SPDX-License-Identifier: AGPL-3.0-only defmodule Pleroma.Web.ActivityPub.Publisher do alias Pleroma.Activity alias Pleroma.Config alias Pleroma.Delivery alias Pleroma.HTTP alias Pleroma.Instances alias Pleroma.Object alias Pleroma.Repo alias Pleroma.User alias Pleroma.Web.ActivityPub.Relay alias Pleroma.Web.ActivityPub.Transmogrifier require Pleroma.Constants import Pleroma.Web.ActivityPub.Visibility @behaviour Pleroma.Web.Federator.Publisher require Logger @moduledoc """ ActivityPub outgoing federation module. """ @doc """ Determine if an activity can be represented by running it through Transmogrifier. """ def is_representable?(%Activity{} = activity) do with {:ok, _data} <- Transmogrifier.prepare_outgoing(activity.data) do true else _e -> false end end @doc """ Publish a single message to a peer. Takes a struct with the following parameters set: * `inbox`: the inbox to publish to * `json`: the JSON message body representing the ActivityPub message * `actor`: the actor which is signing the message * `id`: the ActivityStreams URI of the message """ def publish_one(%{inbox: inbox, json: json, actor: %User{} = actor, id: id} = params) do Logger.debug("Federating #{id} to #{inbox}") uri = %{path: path} = URI.parse(inbox) digest = "SHA-256=" <> (:crypto.hash(:sha256, json) |> Base.encode64()) date = Pleroma.Signature.signed_date() signature = Pleroma.Signature.sign(actor, %{ "(request-target)": "post #{path}", host: signature_host(uri), "content-length": byte_size(json), digest: digest, date: date }) with {:ok, %{status: code}} = result when code in 200..299 <- HTTP.post( inbox, json, [ {"Content-Type", "application/activity+json"}, {"Date", date}, {"signature", signature}, {"digest", digest} ] ) do if not Map.has_key?(params, :unreachable_since) || params[:unreachable_since] do Instances.set_reachable(inbox) end result else {_post_result, response} -> unless params[:unreachable_since], do: Instances.set_unreachable(inbox) {:error, response} end end def publish_one(%{actor_id: actor_id} = params) do actor = User.get_cached_by_id(actor_id) params |> Map.delete(:actor_id) |> Map.put(:actor, actor) |> publish_one() end defp signature_host(%URI{port: port, scheme: scheme, host: host}) do if port == URI.default_port(scheme) do host else "#{host}:#{port}" end end defp should_federate?(inbox, public) do if public do true else %{host: host} = URI.parse(inbox) quarantined_instances = Config.get([:instance, :quarantined_instances], []) |> Pleroma.Web.ActivityPub.MRF.instance_list_from_tuples() |> Pleroma.Web.ActivityPub.MRF.subdomains_regex() !Pleroma.Web.ActivityPub.MRF.subdomain_match?(quarantined_instances, host) end end @spec recipients(User.t(), Activity.t()) :: list(User.t()) | [] defp recipients(actor, activity) do followers = if actor.follower_address in activity.recipients do User.get_external_followers(actor) else [] end fetchers = with %Activity{data: %{"type" => "Delete"}} <- activity, %Object{id: object_id} <- Object.normalize(activity, fetch: false), fetchers <- User.get_delivered_users_by_object_id(object_id), _ <- Delivery.delete_all_by_object_id(object_id) do fetchers else _ -> [] end Pleroma.Web.Federator.Publisher.remote_users(actor, activity) ++ followers ++ fetchers end defp get_cc_ap_ids(ap_id, recipients) do host = Map.get(URI.parse(ap_id), :host) recipients |> Enum.filter(fn %User{ap_id: ap_id} -> Map.get(URI.parse(ap_id), :host) == host end) |> Enum.map(& &1.ap_id) end defp maybe_use_sharedinbox(%User{shared_inbox: nil, inbox: inbox}), do: inbox defp maybe_use_sharedinbox(%User{shared_inbox: shared_inbox}), do: shared_inbox @doc """ Determine a user inbox to use based on heuristics. These heuristics are based on an approximation of the ``sharedInbox`` rules in the [ActivityPub specification][ap-sharedinbox]. Please do not edit this function (or its children) without reading the spec, as editing the code is likely to introduce some breakage without some familiarity. [ap-sharedinbox]: https://www.w3.org/TR/activitypub/#shared-inbox-delivery """ def determine_inbox( %Activity{data: activity_data}, %User{inbox: inbox} = user ) do to = activity_data["to"] || [] cc = activity_data["cc"] || [] type = activity_data["type"] cond do type == "Delete" -> maybe_use_sharedinbox(user) Pleroma.Constants.as_public() in to || Pleroma.Constants.as_public() in cc -> maybe_use_sharedinbox(user) length(to) + length(cc) > 1 -> maybe_use_sharedinbox(user) true -> inbox end end @doc """ Publishes an activity with BCC to all relevant peers. """ def publish(%User{} = actor, %{data: %{"bcc" => bcc}} = activity) when is_list(bcc) and bcc != [] do public = is_public?(activity) {:ok, data} = Transmogrifier.prepare_outgoing(activity.data) recipients = recipients(actor, activity) inboxes = recipients |> Enum.filter(&User.ap_enabled?/1) |> Enum.map(fn actor -> actor.inbox end) |> Enum.filter(fn inbox -> should_federate?(inbox, public) end) |> Instances.filter_reachable() Repo.checkout(fn -> Enum.each(inboxes, fn {inbox, unreachable_since} -> %User{ap_id: ap_id} = Enum.find(recipients, fn actor -> actor.inbox == inbox end) # Get all the recipients on the same host and add them to cc. Otherwise, a remote # instance would only accept a first message for the first recipient and ignore the rest. cc = get_cc_ap_ids(ap_id, recipients) json = data |> Map.put("cc", cc) |> Jason.encode!() Pleroma.Web.Federator.Publisher.enqueue_one(__MODULE__, %{ inbox: inbox, json: json, actor_id: actor.id, id: activity.data["id"], unreachable_since: unreachable_since }) end) end) end # Publishes an activity to all relevant peers. def publish(%User{} = actor, %Activity{} = activity) do public = is_public?(activity) if public && Config.get([:instance, :allow_relay]) do Logger.debug(fn -> "Relaying #{activity.data["id"]} out" end) Relay.publish(activity) end {:ok, data} = Transmogrifier.prepare_outgoing(activity.data) json = Jason.encode!(data) recipients(actor, activity) |> Enum.filter(fn user -> User.ap_enabled?(user) end) |> Enum.map(fn %User{} = user -> determine_inbox(activity, user) end) |> Enum.uniq() |> Enum.filter(fn inbox -> should_federate?(inbox, public) end) |> Instances.filter_reachable() |> Enum.each(fn {inbox, unreachable_since} -> Pleroma.Web.Federator.Publisher.enqueue_one( __MODULE__, %{ inbox: inbox, json: json, actor_id: actor.id, id: activity.data["id"], unreachable_since: unreachable_since } ) end) end def gather_webfinger_links(%User{} = user) do [ %{"rel" => "self", "type" => "application/activity+json", "href" => user.ap_id}, %{ "rel" => "self", "type" => "application/ld+json; profile=\"https://www.w3.org/ns/activitystreams\"", "href" => user.ap_id }, %{ "rel" => "http://ostatus.org/schema/1.0/subscribe", "template" => "#{Pleroma.Web.Endpoint.url()}/ostatus_subscribe?acct={uri}" } ] end def gather_nodeinfo_protocol_names, do: ["activitypub"] end