akkoma/lib/pleroma/web/mastodon_api/websocket_handler.ex

176 lines
5.4 KiB
Elixir

# Pleroma: A lightweight social networking server
# Copyright © 2017-2021 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only
defmodule Pleroma.Web.MastodonAPI.WebsocketHandler do
require Logger
alias Pleroma.Repo
alias Pleroma.User
alias Pleroma.Web.OAuth.Token
alias Pleroma.Web.Streamer
@behaviour :cowboy_websocket
# Client ping period.
@tick :timer.seconds(30)
# Cowboy timeout period.
@timeout :timer.seconds(60)
# Hibernate every X messages
@hibernate_every 100
def init(%{qs: qs} = req, state) do
with params <- Enum.into(:cow_qs.parse_qs(qs), %{}),
sec_websocket <- :cowboy_req.header("sec-websocket-protocol", req, nil),
access_token <- Map.get(params, "access_token"),
{:ok, user, oauth_token} <- authenticate_request(access_token, sec_websocket),
{:ok, topic} <- Streamer.get_topic(params["stream"], user, oauth_token, params) do
req =
if sec_websocket do
:cowboy_req.set_resp_header("sec-websocket-protocol", sec_websocket, req)
else
req
end
{:cowboy_websocket, req,
%{
user: user,
topic: topic,
count: 0,
timer: nil,
subscriptions: [],
oauth_token: oauth_token
}, %{idle_timeout: @timeout}}
else
{:error, :bad_topic} ->
Logger.debug("#{__MODULE__} bad topic #{inspect(req)}")
req = :cowboy_req.reply(404, req)
{:ok, req, state}
{:error, :unauthorized} ->
Logger.debug("#{__MODULE__} authentication error: #{inspect(req)}")
req = :cowboy_req.reply(401, req)
{:ok, req, state}
end
end
def websocket_init(state) do
Logger.debug(
"#{__MODULE__} accepted websocket connection for user #{(state.user || %{id: "anonymous"}).id}, topic #{state.topic}"
)
Streamer.add_socket(state.topic, state.user)
{:ok, %{state | timer: timer()}}
end
# Client's Pong frame.
def websocket_handle(:pong, state) do
if state.timer, do: Process.cancel_timer(state.timer)
{:ok, %{state | timer: timer()}}
end
# We only receive pings for now
def websocket_handle(:ping, state), do: {:ok, state}
def websocket_handle({:text, ping}, state) when ping in ~w[ping PING] do
if state.timer, do: Process.cancel_timer(state.timer)
{:reply, {:text, "pong"}, %{state | timer: timer()}}
end
def websocket_handle({:text, text}, state) do
with {:ok, json} <- Jason.decode(text) do
websocket_handle({:json, json}, state)
else
_ ->
Logger.error("#{__MODULE__} received text frame: #{text}")
{:ok, state}
end
end
def websocket_handle(
{:json, %{"type" => "subscribe", "stream" => stream_name}},
%{user: user, oauth_token: token} = state
) do
with {:ok, topic} <- Streamer.get_topic(stream_name, user, token, %{}) do
new_subscriptions =
[topic | Map.get(state, :subscriptions, [])]
|> Enum.uniq()
{:ok, _topic} = Streamer.add_socket(topic, user)
{:ok, Map.put(state, :subscriptions, new_subscriptions)}
else
_ ->
Logger.error("#{__MODULE__} received invalid topic: #{stream_name}")
{:ok, state}
end
end
def websocket_handle(frame, state) do
Logger.error("#{__MODULE__} received frame: #{inspect(frame)}")
{:ok, state}
end
def websocket_info({:render_with_user, view, template, item, topic}, state) do
user = %User{} = User.get_cached_by_ap_id(state.user.ap_id)
unless Streamer.filtered_by_user?(user, item) do
websocket_info({:text, view.render(template, item, user, topic)}, %{state | user: user})
else
{:ok, state}
end
end
def websocket_info({:text, message}, state) do
# If the websocket processed X messages, force an hibernate/GC.
# We don't hibernate at every message to balance CPU usage/latency with RAM usage.
if state.count > @hibernate_every do
{:reply, {:text, message}, %{state | count: 0}, :hibernate}
else
{:reply, {:text, message}, %{state | count: state.count + 1}}
end
end
# Ping tick. We don't re-queue a timer there, it is instead queued when :pong is received.
# As we hibernate there, reset the count to 0.
# If the client misses :pong, Cowboy will automatically timeout the connection after
# `@idle_timeout`.
def websocket_info(:tick, state) do
{:reply, :ping, %{state | timer: nil, count: 0}, :hibernate}
end
# State can be `[]` only in case we terminate before switching to websocket,
# we already log errors for these cases in `init/1`, so just do nothing here
def terminate(_reason, _req, []), do: :ok
def terminate(reason, _req, state) do
Logger.debug(
"#{__MODULE__} terminating websocket connection for user #{(state.user || %{id: "anonymous"}).id}, topic #{state.topic || "?"}: #{inspect(reason)}"
)
Streamer.remove_socket(state.topic)
:ok
end
# Public streams without authentication.
defp authenticate_request(nil, nil) do
{:ok, nil, nil}
end
# Authenticated streams.
defp authenticate_request(access_token, sec_websocket) do
token = access_token || sec_websocket
with true <- is_bitstring(token),
oauth_token = %Token{user_id: user_id} <- Repo.get_by(Token, token: token),
user = %User{} <- User.get_cached_by_id(user_id) do
{:ok, user, oauth_token}
else
_ -> {:error, :unauthorized}
end
end
defp timer do
Process.send_after(self(), :tick, @tick)
end
end