distraction.party/lib/pleroma/web/activity_pub/publisher.ex
rinpatch 2c55f7d7cb Remove FedSockets
Current FedSocket implementation has a bunch of problems. It doesn't
have proper error handling (in case of an error the server just doesn't
respond until the connection is closed, while the client doesn't match
any error messages and just assumes there has been an error after 15s)
and the code is full of bad descisions (see: fetch registry which uses
uuids for no reason and waits for a response by recursively querying a
 ets table until the value changes, or double JSON encoding).

Sometime ago I almost completed rewriting fedsockets from scrach to
adress these issues. However, while doing so, I realized that fedsockets
 are just too overkill for what they were trying to accomplish, which is
 reduce the overhead of federation by not signing every message.
This could be done without reimplementing failure states and endpoint
 logic we already have with HTTP by, for example, using TLS cert auth,
or switching to a more performant signature algorithm. I opened
https://git.pleroma.social/pleroma/pleroma/-/issues/2262 for further
discussion on alternatives to fedsockets.

From discussions I had with other Pleroma developers it seems like they
 would approve the descision to remove them as well,
therefore I am submitting this patch.
2020-11-17 17:28:30 +03:00

281 lines
8 KiB
Elixir

# Pleroma: A lightweight social networking server
# Copyright © 2017-2020 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}} when code in 200..299 <-
result =
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.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),
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.base_url()}/ostatus_subscribe?acct={uri}"
}
]
end
def gather_nodeinfo_protocol_names, do: ["activitypub"]
end