6 files changed, 450 insertions, 0 deletions
diff --git a/lib/pleroma/web/streamer/ping.ex b/lib/pleroma/web/streamer/ping.ex
new file mode 100644
index 000000000..f77cbb95c
--- /dev/null
+++ b/lib/pleroma/web/streamer/ping.ex
@@ -0,0 +1,33 @@
+defmodule Pleroma.Web.Streamer.Ping do
+  use GenServer
+  require Logger
+
+  alias Pleroma.Web.Streamer.State
+  alias Pleroma.Web.Streamer.StreamerSocket
+
+  @keepalive_interval :timer.seconds(30)
+
+  def start_link(opts) do
+    ping_interval = Keyword.get(opts, :ping_interval, @keepalive_interval)
+    GenServer.start_link(__MODULE__, %{ping_interval: ping_interval}, name: __MODULE__)
+  end
+
+  def init(%{ping_interval: ping_interval} = args) do
+    Process.send_after(self(), :ping, ping_interval)
+    {:ok, args}
+  end
+
+  def handle_info(:ping, %{ping_interval: ping_interval} = state) do
+    State.get_sockets()
+    |> Map.values()
+    |> List.flatten()
+    |> Enum.each(fn %StreamerSocket{transport_pid: transport_pid} ->
+      Logger.debug("Sending keepalive ping")
+      send(transport_pid, {:text, ""})
+    end)
+
+    Process.send_after(self(), :ping, ping_interval)
+
+    {:noreply, state}
+  end
+end
diff --git a/lib/pleroma/web/streamer/state.ex b/lib/pleroma/web/streamer/state.ex
new file mode 100644
index 000000000..c48752d95
--- /dev/null
+++ b/lib/pleroma/web/streamer/state.ex
@@ -0,0 +1,78 @@
+defmodule Pleroma.Web.Streamer.State do
+  use GenServer
+  require Logger
+
+  alias Pleroma.Web.Streamer.StreamerSocket
+
+  @env Mix.env()
+
+  def start_link(_) do
+    GenServer.start_link(__MODULE__, %{sockets: %{}}, name: __MODULE__)
+  end
+
+  def add_socket(topic, socket) do
+    GenServer.call(__MODULE__, {:add, topic, socket})
+  end
+
+  def remove_socket(topic, socket) do
+    do_remove_socket(@env, topic, socket)
+  end
+
+  def get_sockets do
+    %{sockets: stream_sockets} = GenServer.call(__MODULE__, :get_state)
+    stream_sockets
+  end
+
+  def init(init_arg) do
+    {:ok, init_arg}
+  end
+
+  def handle_call(:get_state, _from, state) do
+    {:reply, state, state}
+  end
+
+  def handle_call({:add, topic, socket}, _from, %{sockets: sockets} = state) do
+    internal_topic = internal_topic(topic, socket)
+    stream_socket = StreamerSocket.from_socket(socket)
+
+    sockets_for_topic =
+      sockets
+      |> Map.get(internal_topic, [])
+      |> List.insert_at(0, stream_socket)
+      |> Enum.uniq()
+
+    state = put_in(state, [:sockets, internal_topic], sockets_for_topic)
+    Logger.debug("Got new conn for #{topic}")
+    {:reply, state, state}
+  end
+
+  def handle_call({:remove, topic, socket}, _from, %{sockets: sockets} = state) do
+    internal_topic = internal_topic(topic, socket)
+    stream_socket = StreamerSocket.from_socket(socket)
+
+    sockets_for_topic =
+      sockets
+      |> Map.get(internal_topic, [])
+      |> List.delete(stream_socket)
+
+    state = Kernel.put_in(state, [:sockets, internal_topic], sockets_for_topic)
+    {:reply, state, state}
+  end
+
+  defp do_remove_socket(:test, _, _) do
+    :ok
+  end
+
+  defp do_remove_socket(_env, topic, socket) do
+    GenServer.call(__MODULE__, {:remove, topic, socket})
+  end
+
+  defp internal_topic(topic, socket)
+       when topic in ~w[user user:notification direct] do
+    "#{topic}:#{socket.assigns[:user].id}"
+  end
+
+  defp internal_topic(topic, _) do
+    topic
+  end
+end
diff --git a/lib/pleroma/web/streamer/streamer.ex b/lib/pleroma/web/streamer/streamer.ex
new file mode 100644
index 000000000..8cf719277
--- /dev/null
+++ b/lib/pleroma/web/streamer/streamer.ex
@@ -0,0 +1,55 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.Streamer do
+  alias Pleroma.Web.Streamer.State
+  alias Pleroma.Web.Streamer.Worker
+
+  @timeout 60_000
+  @mix_env Mix.env()
+
+  def add_socket(topic, socket) do
+    State.add_socket(topic, socket)
+  end
+
+  def remove_socket(topic, socket) do
+    State.remove_socket(topic, socket)
+  end
+
+  def get_sockets do
+    State.get_sockets()
+  end
+
+  def stream(topics, items) do
+    if should_send?() do
+      Task.async(fn ->
+        :poolboy.transaction(
+          :streamer_worker,
+          &Worker.stream(&1, topics, items),
+          @timeout
+        )
+      end)
+    end
+  end
+
+  def supervisor, do: Pleroma.Web.Streamer.Supervisor
+
+  defp should_send? do
+    handle_should_send(@mix_env)
+  end
+
+  defp handle_should_send(:test) do
+    case Process.whereis(:streamer_worker) do
+      nil ->
+        false
+
+      pid ->
+        Process.alive?(pid)
+    end
+  end
+
+  defp handle_should_send(_) do
+    true
+  end
+end
diff --git a/lib/pleroma/web/streamer/streamer_socket.ex b/lib/pleroma/web/streamer/streamer_socket.ex
new file mode 100644
index 000000000..f006c0306
--- /dev/null
+++ b/lib/pleroma/web/streamer/streamer_socket.ex
@@ -0,0 +1,31 @@
+defmodule Pleroma.Web.Streamer.StreamerSocket do
+  defstruct transport_pid: nil, user: nil
+
+  alias Pleroma.User
+  alias Pleroma.Web.Streamer.StreamerSocket
+
+  def from_socket(%{
+        transport_pid: transport_pid,
+        assigns: %{user: nil}
+      }) do
+    %StreamerSocket{
+      transport_pid: transport_pid
+    }
+  end
+
+  def from_socket(%{
+        transport_pid: transport_pid,
+        assigns: %{user: %User{} = user}
+      }) do
+    %StreamerSocket{
+      transport_pid: transport_pid,
+      user: user
+    }
+  end
+
+  def from_socket(%{transport_pid: transport_pid}) do
+    %StreamerSocket{
+      transport_pid: transport_pid
+    }
+  end
+end
diff --git a/lib/pleroma/web/streamer/supervisor.ex b/lib/pleroma/web/streamer/supervisor.ex
new file mode 100644
index 000000000..6afe19323
--- /dev/null
+++ b/lib/pleroma/web/streamer/supervisor.ex
@@ -0,0 +1,33 @@
+defmodule Pleroma.Web.Streamer.Supervisor do
+  use Supervisor
+
+  def start_link(opts) do
+    Supervisor.start_link(__MODULE__, opts, name: __MODULE__)
+  end
+
+  def init(args) do
+    children = [
+      {Pleroma.Web.Streamer.State, args},
+      {Pleroma.Web.Streamer.Ping, args},
+      :poolboy.child_spec(:streamer_worker, poolboy_config())
+    ]
+
+    opts = [strategy: :one_for_one, name: Pleroma.Web.Streamer.Supervisor]
+    Supervisor.init(children, opts)
+  end
+
+  defp poolboy_config do
+    opts =
+      Pleroma.Config.get(:streamer,
+        workers: 3,
+        overflow_workers: 2
+      )
+
+    [
+      {:name, {:local, :streamer_worker}},
+      {:worker_module, Pleroma.Web.Streamer.Worker},
+      {:size, opts[:workers]},
+      {:max_overflow, opts[:overflow_workers]}
+    ]
+  end
+end
diff --git a/lib/pleroma/web/streamer/worker.ex b/lib/pleroma/web/streamer/worker.ex
new file mode 100644
index 000000000..5804508eb
--- /dev/null
+++ b/lib/pleroma/web/streamer/worker.ex
@@ -0,0 +1,220 @@
+defmodule Pleroma.Web.Streamer.Worker do
+  use GenServer
+
+  require Logger
+
+  alias Pleroma.Activity
+  alias Pleroma.Config
+  alias Pleroma.Conversation.Participation
+  alias Pleroma.Notification
+  alias Pleroma.Object
+  alias Pleroma.User
+  alias Pleroma.Web.ActivityPub.ActivityPub
+  alias Pleroma.Web.ActivityPub.Visibility
+  alias Pleroma.Web.CommonAPI
+  alias Pleroma.Web.Streamer.State
+  alias Pleroma.Web.Streamer.StreamerSocket
+  alias Pleroma.Web.StreamerView
+
+  def start_link(_) do
+    GenServer.start_link(__MODULE__, %{}, [])
+  end
+
+  def init(init_arg) do
+    {:ok, init_arg}
+  end
+
+  def stream(pid, topics, items) do
+    GenServer.call(pid, {:stream, topics, items})
+  end
+
+  def handle_call({:stream, topics, item}, _from, state) when is_list(topics) do
+    Enum.each(topics, fn t ->
+      do_stream(%{topic: t, item: item})
+    end)
+
+    {:reply, state, state}
+  end
+
+  def handle_call({:stream, topic, items}, _from, state) when is_list(items) do
+    Enum.each(items, fn i ->
+      do_stream(%{topic: topic, item: i})
+    end)
+
+    {:reply, state, state}
+  end
+
+  def handle_call({:stream, topic, item}, _from, state) do
+    do_stream(%{topic: topic, item: item})
+
+    {:reply, state, state}
+  end
+
+  defp do_stream(%{topic: "direct", item: item}) do
+    recipient_topics =
+      User.get_recipients_from_activity(item)
+      |> Enum.map(fn %{id: id} -> "direct:#{id}" end)
+
+    Enum.each(recipient_topics, fn user_topic ->
+      Logger.debug("Trying to push direct message to #{user_topic}\n\n")
+      push_to_socket(State.get_sockets(), user_topic, item)
+    end)
+  end
+
+  defp do_stream(%{topic: "participation", item: participation}) do
+    user_topic = "direct:#{participation.user_id}"
+    Logger.debug("Trying to push a conversation participation to #{user_topic}\n\n")
+
+    push_to_socket(State.get_sockets(), user_topic, participation)
+  end
+
+  defp do_stream(%{topic: "list", item: item}) do
+    # filter the recipient list if the activity is not public, see #270.
+    recipient_lists =
+      case Visibility.is_public?(item) do
+        true ->
+          Pleroma.List.get_lists_from_activity(item)
+
+        _ ->
+          Pleroma.List.get_lists_from_activity(item)
+          |> Enum.filter(fn list ->
+            owner = User.get_cached_by_id(list.user_id)
+
+            Visibility.visible_for_user?(item, owner)
+          end)
+      end
+
+    recipient_topics =
+      recipient_lists
+      |> Enum.map(fn %{id: id} -> "list:#{id}" end)
+
+    Enum.each(recipient_topics, fn list_topic ->
+      Logger.debug("Trying to push message to #{list_topic}\n\n")
+      push_to_socket(State.get_sockets(), list_topic, item)
+    end)
+  end
+
+  defp do_stream(%{topic: topic, item: %Notification{} = item})
+       when topic in ["user", "user:notification"] do
+    State.get_sockets()
+    |> Map.get("#{topic}:#{item.user_id}", [])
+    |> Enum.each(fn %StreamerSocket{transport_pid: transport_pid, user: socket_user} ->
+      with %User{} = user <- User.get_cached_by_ap_id(socket_user.ap_id),
+           true <- should_send?(user, item) do
+        send(transport_pid, {:text, StreamerView.render("notification.json", socket_user, item)})
+      end
+    end)
+  end
+
+  defp do_stream(%{topic: "user", item: item}) do
+    Logger.debug("Trying to push to users")
+
+    recipient_topics =
+      User.get_recipients_from_activity(item)
+      |> Enum.map(fn %{id: id} -> "user:#{id}" end)
+
+    Enum.each(recipient_topics, fn topic ->
+      push_to_socket(State.get_sockets(), topic, item)
+    end)
+  end
+
+  defp do_stream(%{topic: topic, item: item}) do
+    Logger.debug("Trying to push to #{topic}")
+    Logger.debug("Pushing item to #{topic}")
+    push_to_socket(State.get_sockets(), topic, item)
+  end
+
+  defp should_send?(%User{} = user, %Activity{} = item) do
+    blocks = user.info.blocks || []
+    mutes = user.info.mutes || []
+    reblog_mutes = user.info.muted_reblogs || []
+    domain_blocks = Pleroma.Web.ActivityPub.MRF.subdomains_regex(user.info.domain_blocks)
+
+    with parent when not is_nil(parent) <- Object.normalize(item),
+         true <- Enum.all?([blocks, mutes, reblog_mutes], &(item.actor not in &1)),
+         true <- Enum.all?([blocks, mutes], &(parent.data["actor"] not in &1)),
+         %{host: item_host} <- URI.parse(item.actor),
+         %{host: parent_host} <- URI.parse(parent.data["actor"]),
+         false <- Pleroma.Web.ActivityPub.MRF.subdomain_match?(domain_blocks, item_host),
+         false <- Pleroma.Web.ActivityPub.MRF.subdomain_match?(domain_blocks, parent_host),
+         true <- thread_containment(item, user),
+         false <- CommonAPI.thread_muted?(user, item) do
+      true
+    else
+      _ -> false
+    end
+  end
+
+  defp should_send?(%User{} = user, %Notification{activity: activity}) do
+    should_send?(user, activity)
+  end
+
+  def push_to_socket(topics, topic, %Activity{data: %{"type" => "Announce"}} = item) do
+    Enum.each(topics[topic] || [], fn %StreamerSocket{
+                                        transport_pid: transport_pid,
+                                        user: socket_user
+                                      } ->
+      # Get the current user so we have up-to-date blocks etc.
+      if socket_user do
+        user = User.get_cached_by_ap_id(socket_user.ap_id)
+
+        if should_send?(user, item) do
+          send(transport_pid, {:text, StreamerView.render("update.json", item, user)})
+        end
+      else
+        send(transport_pid, {:text, StreamerView.render("update.json", item)})
+      end
+    end)
+  end
+
+  def push_to_socket(topics, topic, %Participation{} = participation) do
+    Enum.each(topics[topic] || [], fn %StreamerSocket{transport_pid: transport_pid} ->
+      send(transport_pid, {:text, StreamerView.render("conversation.json", participation)})
+    end)
+  end
+
+  def push_to_socket(topics, topic, %Activity{
+        data: %{"type" => "Delete", "deleted_activity_id" => deleted_activity_id}
+      }) do
+    Enum.each(topics[topic] || [], fn %StreamerSocket{transport_pid: transport_pid} ->
+      send(
+        transport_pid,
+        {:text, %{event: "delete", payload: to_string(deleted_activity_id)} |> Jason.encode!()}
+      )
+    end)
+  end
+
+  def push_to_socket(_topics, _topic, %Activity{data: %{"type" => "Delete"}}), do: :noop
+
+  def push_to_socket(topics, topic, item) do
+    Enum.each(topics[topic] || [], fn %StreamerSocket{
+                                        transport_pid: transport_pid,
+                                        user: socket_user
+                                      } ->
+      # Get the current user so we have up-to-date blocks etc.
+      if socket_user do
+        user = User.get_cached_by_ap_id(socket_user.ap_id)
+        blocks = user.info.blocks || []
+        mutes = user.info.mutes || []
+
+        with true <- Enum.all?([blocks, mutes], &(item.actor not in &1)),
+             true <- thread_containment(item, user) do
+          send(transport_pid, {:text, StreamerView.render("update.json", item, user)})
+        end
+      else
+        send(transport_pid, {:text, StreamerView.render("update.json", item)})
+      end
+    end)
+  end
+
+  @spec thread_containment(Activity.t(), User.t()) :: boolean()
+  defp thread_containment(_activity, %User{info: %{skip_thread_containment: true}}), do: true
+
+  defp thread_containment(activity, user) do
+    if Config.get([:instance, :skip_thread_containment]) do
+      true
+    else
+      ActivityPub.contain_activity(activity, user)
+    end
+  end
+end