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lib/phoenix/endpoint/cowboy2_handler.ex

defmodule Phoenix.Endpoint.Cowboy2Handler do
@moduledoc false
if Code.ensure_loaded?(:cowboy_websocket) and
function_exported?(:cowboy_websocket, :behaviour_info, 1) do
@behaviour :cowboy_websocket
end
@connection Plug.Cowboy.Conn
@already_sent {:plug_conn, :sent}
# Note we keep the websocket state as [handler | state]
# to avoid conflicts with {endpoint, opts}.
def init(req, {endpoint, opts}) do
init(@connection.conn(req), endpoint, opts, true)
end
defp init(conn, endpoint, opts, retry?) do
try do
case endpoint.__handler__(conn, opts) do
{:websocket, conn, handler, opts} ->
case Phoenix.Transports.WebSocket.connect(conn, endpoint, handler, opts) do
{:ok, %Plug.Conn{adapter: {@connection, req}} = conn, state} ->
cowboy_opts =
opts
|> Enum.flat_map(fn
{:timeout, timeout} ->
[idle_timeout: timeout]
{:compress, _} = opt ->
[opt]
{:max_frame_size, _} = opt ->
[opt]
{:fullsweep_after, value} ->
:erlang.process_flag(:fullsweep_after, value)
[]
_other ->
[]
end)
|> Map.new()
{:cowboy_websocket, copy_resp_headers(conn, req), [handler | state], cowboy_opts}
{:error, %Plug.Conn{adapter: {@connection, req}} = conn} ->
{:ok, copy_resp_headers(conn, req), {handler, opts}}
end
{:plug, conn, handler, opts} ->
%{adapter: {@connection, req}} =
conn
|> handler.call(opts)
|> maybe_send(handler)
{:ok, req, {handler, opts}}
end
catch
kind, reason ->
case __STACKTRACE__ do
# Maybe the handler is not available because the code is being recompiled.
# Sync with the code reloader and retry once.
[{^endpoint, :__handler__, _, _} | _] when reason == :undef and retry? ->
Phoenix.CodeReloader.sync()
init(conn, endpoint, opts, false)
stacktrace ->
exit_on_error(kind, reason, stacktrace, {endpoint, :call, [conn, opts]})
end
after
receive do
@already_sent -> :ok
after
0 -> :ok
end
end
end
defp maybe_send(%Plug.Conn{state: :unset}, _plug), do: raise(Plug.Conn.NotSentError)
defp maybe_send(%Plug.Conn{state: :set} = conn, _plug), do: Plug.Conn.send_resp(conn)
defp maybe_send(%Plug.Conn{} = conn, _plug), do: conn
defp maybe_send(other, plug) do
raise "Cowboy2 adapter expected #{inspect(plug)} to return Plug.Conn but got: " <>
inspect(other)
end
defp exit_on_error(
:error,
%Plug.Conn.WrapperError{kind: kind, reason: reason, stack: stack},
_stack,
call
) do
exit_on_error(kind, reason, stack, call)
end
defp exit_on_error(:error, value, stack, call) do
exception = Exception.normalize(:error, value, stack)
:erlang.raise(:exit, {{exception, stack}, call}, [])
end
defp exit_on_error(:throw, value, stack, call) do
:erlang.raise(:exit, {{{:nocatch, value}, stack}, call}, [])
end
defp exit_on_error(:exit, value, _stack, call) do
:erlang.raise(:exit, {value, call}, [])
end
defp copy_resp_headers(%Plug.Conn{} = conn, req) do
Enum.reduce(conn.resp_headers, req, fn {key, val}, acc ->
:cowboy_req.set_resp_header(key, val, acc)
end)
end
defp handle_reply(handler, {:ok, state}), do: {:ok, [handler | state]}
defp handle_reply(handler, {:push, data, state}), do: {:reply, data, [handler | state]}
defp handle_reply(handler, {:reply, _status, data, state}),
do: {:reply, data, [handler | state]}
defp handle_reply(handler, {:stop, _reason, state}), do: {:stop, [handler | state]}
defp handle_control_frame(payload_with_opts, handler_state) do
[handler | state] = handler_state
reply =
if function_exported?(handler, :handle_control, 2) do
handler.handle_control(payload_with_opts, state)
else
{:ok, state}
end
handle_reply(handler, reply)
end
## Websocket callbacks
def websocket_init([handler | state]) do
{:ok, state} = handler.init(state)
{:ok, [handler | state]}
end
def websocket_handle({opcode, payload}, [handler | state]) when opcode in [:text, :binary] do
handle_reply(handler, handler.handle_in({payload, opcode: opcode}, state))
end
def websocket_handle({opcode, payload}, handler_state) when opcode in [:ping, :pong] do
handle_control_frame({payload, opcode: opcode}, handler_state)
end
def websocket_handle(opcode, handler_state) when opcode in [:ping, :pong] do
handle_control_frame({nil, opcode: opcode}, handler_state)
end
def websocket_handle(_other, handler_state) do
{:ok, handler_state}
end
def websocket_info(message, [handler | state]) do
handle_reply(handler, handler.handle_info(message, state))
end
def terminate(_reason, _req, {_handler, _state}) do
:ok
end
def terminate({:error, :closed}, _req, [handler | state]) do
handler.terminate(:closed, state)
end
def terminate({:remote, :closed}, _req, [handler | state]) do
handler.terminate(:closed, state)
end
def terminate({:remote, code, _}, _req, [handler | state])
when code in 1000..1003 or code in 1005..1011 or code == 1015 do
handler.terminate(:closed, state)
end
def terminate(:remote, _req, [handler | state]) do
handler.terminate(:closed, state)
end
def terminate(reason, _req, [handler | state]) do
handler.terminate(reason, state)
end
end