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

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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.MastodonAPI.WebsocketHandler do
require Logger
alias Pleroma.Repo
alias Pleroma.User
alias Pleroma.Web.OAuth.Token
alias Pleroma.Web.Streamer
@behaviour :cowboy_websocket
# Cowboy timeout period.
@timeout :timer.seconds(30)
# Hibernate every X messages
@hibernate_every 100
@streams [
"public",
"public:local",
"public:media",
"public:local:media",
"user",
"user:notification",
"direct",
"list",
"hashtag"
]
@anonymous_streams ["public", "public:local", "hashtag"]
def init(%{qs: qs} = req, state) do
with params <- :cow_qs.parse_qs(qs),
sec_websocket <- :cowboy_req.header("sec-websocket-protocol", req, nil),
access_token <- List.keyfind(params, "access_token", 0),
{_, stream} <- List.keyfind(params, "stream", 0),
{:ok, user} <- allow_request(stream, [access_token, sec_websocket]),
topic when is_binary(topic) <- expand_topic(stream, 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}, %{idle_timeout: @timeout}}
else
{:error, code} ->
Logger.debug("#{__MODULE__} denied connection: #{inspect(code)} - #{inspect(req)}")
{:ok, req} = :cowboy_req.reply(code, req)
{:ok, req, state}
error ->
Logger.debug("#{__MODULE__} denied connection: #{inspect(error)} - #{inspect(req)}")
{:ok, req} = :cowboy_req.reply(400, 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}
end
# We never receive messages.
def websocket_handle(_frame, state) do
{:ok, state}
end
def websocket_info({:render_with_user, view, template, item}, 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)}, %{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
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 allow_request(stream, [nil, nil]) when stream in @anonymous_streams do
{:ok, nil}
end
# Authenticated streams.
defp allow_request(stream, [access_token, sec_websocket]) when stream in @streams do
token =
with {"access_token", token} <- access_token do
token
else
_ -> sec_websocket
end
with true <- is_bitstring(token),
%Token{user_id: user_id} <- Repo.get_by(Token, token: token),
user = %User{} <- User.get_cached_by_id(user_id) do
{:ok, user}
else
_ -> {:error, 403}
end
end
# Not authenticated.
defp allow_request(stream, _) when stream in @streams, do: {:error, 403}
# No matching stream.
defp allow_request(_, _), do: {:error, 404}
defp expand_topic("hashtag", params) do
case List.keyfind(params, "tag", 0) do
{_, tag} -> "hashtag:#{tag}"
_ -> nil
end
end
defp expand_topic("list", params) do
case List.keyfind(params, "list", 0) do
{_, list} -> "list:#{list}"
_ -> nil
end
end
defp expand_topic(topic, _), do: topic
end