%% Copyright (c) 2011-2013, Loïc Hoguin <[email protected]>
%%
%% Permission to use, copy, modify, and/or distribute this software for any
%% purpose with or without fee is hereby granted, provided that the above
%% copyright notice and this permission notice appear in all copies.
%%
%% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
%% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
%% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
%% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
%% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
%% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
%% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
%% @doc Websocket protocol implementation.
%%
%% Cowboy supports versions 7 through 17 of the Websocket drafts.
%% It also supports RFC6455, the proposed standard for Websocket.
-module(cowboy_websocket).
%% API.
-export([upgrade/4]).
%% Internal.
-export([handler_loop/4]).
-type frame() :: close | ping | pong
| {text | binary | close | ping | pong, binary()}
| {close, 1000..4999, binary()}.
-export_type([frame/0]).
-type opcode() :: 0 | 1 | 2 | 8 | 9 | 10.
-type mask_key() :: 0..16#ffffffff.
%% The websocket_data/4 function may be called multiple times for a message.
%% The websocket_dispatch/4 function is only called once for each message.
-type frag_state() ::
undefined | %% no fragmentation has been seen.
{nofin, opcode()} | %% first fragment has been seen.
{nofin, opcode(), binary()} | %% first fragment has been unmasked.
{fin, opcode(), binary()}. %% last fragment has been seen.
-record(state, {
env :: cowboy_middleware:env(),
socket = undefined :: inet:socket(),
transport = undefined :: module(),
handler :: module(),
handler_opts :: any(),
key = undefined :: undefined | binary(),
timeout = infinity :: timeout(),
timeout_ref = undefined :: undefined | reference(),
messages = undefined :: undefined | {atom(), atom(), atom()},
hibernate = false :: boolean(),
frag_state = undefined :: frag_state()
}).
%% @doc Upgrade an HTTP request to the Websocket protocol.
%%
%% You do not need to call this function manually. To upgrade to the Websocket
%% protocol, you simply need to return <em>{upgrade, protocol, {@module}}</em>
%% in your <em>cowboy_http_handler:init/3</em> handler function.
-spec upgrade(Req, Env, module(), any())
-> {ok, Req, Env} | {error, 400, Req}
| {suspend, module(), atom(), [any()]}
when Req::cowboy_req:req(), Env::cowboy_middleware:env().
upgrade(Req, Env, Handler, HandlerOpts) ->
{_, ListenerPid} = lists:keyfind(listener, 1, Env),
ranch_listener:remove_connection(ListenerPid),
[Socket, Transport] = cowboy_req:get([socket, transport], Req),
State = #state{env=Env, socket=Socket, transport=Transport,
handler=Handler, handler_opts=HandlerOpts},
case catch websocket_upgrade(State, Req) of
{ok, State2, Req2} -> handler_init(State2, Req2);
{'EXIT', _Reason} -> upgrade_error(Req, Env)
end.
-spec websocket_upgrade(#state{}, Req)
-> {ok, #state{}, Req} when Req::cowboy_req:req().
websocket_upgrade(State, Req) ->
{ok, ConnTokens, Req2}
= cowboy_req:parse_header(<<"connection">>, Req),
true = lists:member(<<"upgrade">>, ConnTokens),
%% @todo Should probably send a 426 if the Upgrade header is missing.
{ok, [<<"websocket">>], Req3}
= cowboy_req:parse_header(<<"upgrade">>, Req2),
{Version, Req4} = cowboy_req:header(<<"sec-websocket-version">>, Req3),
IntVersion = list_to_integer(binary_to_list(Version)),
true = (IntVersion =:= 7) orelse (IntVersion =:= 8)
orelse (IntVersion =:= 13),
{Key, Req5} = cowboy_req:header(<<"sec-websocket-key">>, Req4),
false = Key =:= undefined,
{ok, State#state{key=Key},
cowboy_req:set_meta(websocket_version, IntVersion, Req5)}.
-spec handler_init(#state{}, Req)
-> {ok, Req, cowboy_middleware:env()} | {error, 400, Req}
| {suspend, module(), atom(), [any()]}
when Req::cowboy_req:req().
handler_init(State=#state{env=Env, transport=Transport,
handler=Handler, handler_opts=HandlerOpts}, Req) ->
try Handler:websocket_init(Transport:name(), Req, HandlerOpts) of
{ok, Req2, HandlerState} ->
websocket_handshake(State, Req2, HandlerState);
{ok, Req2, HandlerState, hibernate} ->
websocket_handshake(State#state{hibernate=true},
Req2, HandlerState);
{ok, Req2, HandlerState, Timeout} ->
websocket_handshake(State#state{timeout=Timeout},
Req2, HandlerState);
{ok, Req2, HandlerState, Timeout, hibernate} ->
websocket_handshake(State#state{timeout=Timeout,
hibernate=true}, Req2, HandlerState);
{shutdown, Req2} ->
cowboy_req:ensure_response(Req2, 400),
{ok, Req2, [{result, closed}|Env]}
catch Class:Reason ->
error_logger:error_msg(
"** Cowboy handler ~p terminating in ~p/~p~n"
" for the reason ~p:~p~n** Options were ~p~n"
"** Request was ~p~n** Stacktrace: ~p~n~n",
[Handler, websocket_init, 3, Class, Reason, HandlerOpts,
cowboy_req:to_list(Req),erlang:get_stacktrace()]),
upgrade_error(Req, Env)
end.
-spec upgrade_error(Req, Env) -> {ok, Req, Env} | {error, 400, Req}
when Req::cowboy_req:req(), Env::cowboy_middleware:env().
upgrade_error(Req, Env) ->
receive
{cowboy_req, resp_sent} ->
{ok, Req, [{result, closed}|Env]}
after 0 ->
{error, 400, Req}
end.
-spec websocket_handshake(#state{}, Req, any())
-> {ok, Req, cowboy_middleware:env()}
| {suspend, module(), atom(), [any()]}
when Req::cowboy_req:req().
websocket_handshake(State=#state{transport=Transport, key=Key},
Req, HandlerState) ->
Challenge = base64:encode(crypto:sha(
<< Key/binary, "258EAFA5-E914-47DA-95CA-C5AB0DC85B11" >>)),
{ok, Req2} = cowboy_req:upgrade_reply(
101,
[{<<"upgrade">>, <<"websocket">>},
{<<"sec-websocket-accept">>, Challenge}],
Req),
%% Flush the resp_sent message before moving on.
receive {cowboy_req, resp_sent} -> ok after 0 -> ok end,
State2 = handler_loop_timeout(State),
handler_before_loop(State2#state{key=undefined,
messages=Transport:messages()}, Req2, HandlerState, <<>>).
-spec handler_before_loop(#state{}, Req, any(), binary())
-> {ok, Req, cowboy_middleware:env()}
| {suspend, module(), atom(), [any()]}
when Req::cowboy_req:req().
handler_before_loop(State=#state{
socket=Socket, transport=Transport, hibernate=true},
Req, HandlerState, SoFar) ->
Transport:setopts(Socket, [{active, once}]),
{suspend, ?MODULE, handler_loop,
[State#state{hibernate=false}, Req, HandlerState, SoFar]};
handler_before_loop(State=#state{socket=Socket, transport=Transport},
Req, HandlerState, SoFar) ->
Transport:setopts(Socket, [{active, once}]),
handler_loop(State, Req, HandlerState, SoFar).
-spec handler_loop_timeout(#state{}) -> #state{}.
handler_loop_timeout(State=#state{timeout=infinity}) ->
State#state{timeout_ref=undefined};
handler_loop_timeout(State=#state{timeout=Timeout, timeout_ref=PrevRef}) ->
_ = case PrevRef of undefined -> ignore; PrevRef ->
erlang:cancel_timer(PrevRef) end,
TRef = erlang:start_timer(Timeout, self(), ?MODULE),
State#state{timeout_ref=TRef}.
%% @private
-spec handler_loop(#state{}, Req, any(), binary())
-> {ok, Req, cowboy_middleware:env()}
| {suspend, module(), atom(), [any()]}
when Req::cowboy_req:req().
handler_loop(State=#state{
socket=Socket, messages={OK, Closed, Error}, timeout_ref=TRef},
Req, HandlerState, SoFar) ->
receive
{OK, Socket, Data} ->
State2 = handler_loop_timeout(State),
websocket_data(State2, Req, HandlerState,
<< SoFar/binary, Data/binary >>);
{Closed, Socket} ->
handler_terminate(State, Req, HandlerState, {error, closed});
{Error, Socket, Reason} ->
handler_terminate(State, Req, HandlerState, {error, Reason});
{timeout, TRef, ?MODULE} ->
websocket_close(State, Req, HandlerState, {normal, timeout});
{timeout, OlderTRef, ?MODULE} when is_reference(OlderTRef) ->
handler_loop(State, Req, HandlerState, SoFar);
Message ->
handler_call(State, Req, HandlerState,
SoFar, websocket_info, Message, fun handler_before_loop/4)
end.
-spec websocket_data(#state{}, Req, any(), binary())
-> {ok, Req, cowboy_middleware:env()}
| {suspend, module(), atom(), [any()]}
when Req::cowboy_req:req().
%% No more data.
websocket_data(State, Req, HandlerState, <<>>) ->
handler_before_loop(State, Req, HandlerState, <<>>);
%% Incomplete.
websocket_data(State, Req, HandlerState, Data) when byte_size(Data) =:= 1 ->
handler_before_loop(State, Req, HandlerState, Data);
%% 7 bit payload length prefix exists
websocket_data(State, Req, HandlerState,
<< Fin:1, Rsv:3, Opcode:4, 1:1, PayloadLen:7, Rest/bits >>
= Data) when PayloadLen < 126 ->
websocket_data(State, Req, HandlerState,
Fin, Rsv, Opcode, PayloadLen, Rest, Data);
%% 7+16 bits payload length prefix exists
websocket_data(State, Req, HandlerState,
<< Fin:1, Rsv:3, Opcode:4, 1:1, 126:7, PayloadLen:16, Rest/bits >>
= Data) when PayloadLen > 125 ->
websocket_data(State, Req, HandlerState,
Fin, Rsv, Opcode, PayloadLen, Rest, Data);
%% 7+16 bits payload length prefix missing
websocket_data(State, Req, HandlerState,
<< _Fin:1, _Rsv:3, _Opcode:4, 1:1, 126:7, Rest/bits >>
= Data) when byte_size(Rest) < 2 ->
handler_before_loop(State, Req, HandlerState, Data);
%% 7+64 bits payload length prefix exists
websocket_data(State, Req, HandlerState,
<< Fin:1, Rsv:3, Opcode:4, 1:1, 127:7, 0:1, PayloadLen:63,
Rest/bits >> = Data) when PayloadLen > 16#FFFF ->
websocket_data(State, Req, HandlerState,
Fin, Rsv, Opcode, PayloadLen, Rest, Data);
%% 7+64 bits payload length prefix missing
websocket_data(State, Req, HandlerState,
<< _Fin:1, _Rsv:3, _Opcode:4, 1:1, 127:7, Rest/bits >>
= Data) when byte_size(Rest) < 8 ->
handler_before_loop(State, Req, HandlerState, Data);
%% Invalid payload length or mask bit was not set.
websocket_data(State, Req, HandlerState, _Data) ->
websocket_close(State, Req, HandlerState, {error, badframe}).
-spec websocket_data(#state{}, Req, any(), non_neg_integer(),
non_neg_integer(), non_neg_integer(),
non_neg_integer(), binary(), binary())
-> {ok, Req, cowboy_middleware:env()}
when Req::cowboy_req:req().
%% A fragmented message MUST start a non-zero opcode.
websocket_data(State=#state{frag_state=undefined}, Req, HandlerState,
_Fin=0, _Rsv=0, _Opcode=0, _PayloadLen, _Rest, _Buffer) ->
websocket_close(State, Req, HandlerState, {error, badframe});
%% A control message MUST NOT be fragmented.
websocket_data(State, Req, HandlerState, _Fin=0, _Rsv=0, Opcode,
_PayloadLen, _Rest, _Buffer) when Opcode >= 8 ->
websocket_close(State, Req, HandlerState, {error, badframe});
%% The opcode is only included in the first message fragment.
websocket_data(State=#state{frag_state=undefined}, Req, HandlerState,
_Fin=0, _Rsv=0, Opcode, PayloadLen, Rest, Data) ->
websocket_before_unmask(
State#state{frag_state={nofin, Opcode}}, Req, HandlerState,
Data, Rest, 0, PayloadLen);
%% non-control opcode when expecting control message or next fragment.
websocket_data(State=#state{frag_state={nofin, _, _}}, Req, HandlerState, _Fin,
_Rsv=0, Opcode, _Ln, _Rest, _Data) when Opcode > 0, Opcode < 8 ->
websocket_close(State, Req, HandlerState, {error, badframe});
%% If the first message fragment was incomplete, retry unmasking.
websocket_data(State=#state{frag_state={nofin, Opcode}}, Req, HandlerState,
_Fin=0, _Rsv=0, Opcode, PayloadLen, Rest, Data) ->
websocket_before_unmask(
State#state{frag_state={nofin, Opcode}}, Req, HandlerState,
Data, Rest, 0, PayloadLen);
%% if the opcode is zero and the fin flag is zero, unmask and await next.
websocket_data(State=#state{frag_state={nofin, _Opcode, _Payloads}}, Req,
HandlerState, _Fin=0, _Rsv=0, _Opcode2=0, PayloadLen, Rest,
Data) ->
websocket_before_unmask(
State, Req, HandlerState, Data, Rest, 0, PayloadLen);
%% when the last fragment is seen. Update the fragmentation status.
websocket_data(State=#state{frag_state={nofin, Opcode, Payloads}}, Req,
HandlerState, _Fin=1, _Rsv=0, _Opcode=0, PayloadLen, Rest,
Data) ->
websocket_before_unmask(
State#state{frag_state={fin, Opcode, Payloads}},
Req, HandlerState, Data, Rest, 0, PayloadLen);
%% control messages MUST NOT use 7+16 bits or 7+64 bits payload length prefixes
websocket_data(State, Req, HandlerState, _Fin, _Rsv, Opcode, PayloadLen,
_Rest, _Data) when Opcode >= 8, PayloadLen > 125 ->
websocket_close(State, Req, HandlerState, {error, badframe});
%% unfragmented message. unmask and dispatch the message.
websocket_data(State, Req, HandlerState, _Fin=1, _Rsv=0,
Opcode, PayloadLen, Rest, Data) ->
websocket_before_unmask(
State, Req, HandlerState, Data, Rest, Opcode, PayloadLen);
%% Something was wrong with the frame. Close the connection.
websocket_data(State, Req, HandlerState, _Fin, _Rsv, _Opcode,
_PayloadLen, _Rest, _Data) ->
websocket_close(State, Req, HandlerState, {error, badframe}).
%% Routing depending on whether unmasking is needed.
-spec websocket_before_unmask(#state{}, Req, any(), binary(),
binary(), opcode(), non_neg_integer() | undefined)
-> {ok, Req, cowboy_middleware:env()}
| {suspend, module(), atom(), [any()]}
when Req::cowboy_req:req().
websocket_before_unmask(State, Req, HandlerState, Data,
Rest, Opcode, PayloadLen) ->
case PayloadLen of
N when N + 4 > byte_size(Rest); N =:= undefined ->
%% @todo We probably should allow limiting frame length.
handler_before_loop(State, Req, HandlerState, Data);
_N ->
<< MaskKey:32, Payload:PayloadLen/binary, Rest2/bits >> = Rest,
websocket_unmask(State, Req, HandlerState, Rest2,
Opcode, Payload, MaskKey)
end.
%% Unmasking.
-spec websocket_unmask(#state{}, Req, any(), binary(),
opcode(), binary(), mask_key())
-> {ok, Req, cowboy_middleware:env()}
| {suspend, module(), atom(), [any()]}
when Req::cowboy_req:req().
websocket_unmask(State, Req, HandlerState, RemainingData,
Opcode, Payload, MaskKey) ->
websocket_unmask(State, Req, HandlerState, RemainingData,
Opcode, Payload, MaskKey, <<>>).
-spec websocket_unmask(#state{}, Req, any(), binary(),
opcode(), binary(), mask_key(), binary())
-> {ok, Req, cowboy_middleware:env()}
| {suspend, module(), atom(), [any()]}
when Req::cowboy_req:req().
websocket_unmask(State, Req, HandlerState, RemainingData,
Opcode, << O:32, Rest/bits >>, MaskKey, Acc) ->
T = O bxor MaskKey,
websocket_unmask(State, Req, HandlerState, RemainingData,
Opcode, Rest, MaskKey, << Acc/binary, T:32 >>);
websocket_unmask(State, Req, HandlerState, RemainingData,
Opcode, << O:24 >>, MaskKey, Acc) ->
<< MaskKey2:24, _:8 >> = << MaskKey:32 >>,
T = O bxor MaskKey2,
websocket_dispatch(State, Req, HandlerState, RemainingData,
Opcode, << Acc/binary, T:24 >>);
websocket_unmask(State, Req, HandlerState, RemainingData,
Opcode, << O:16 >>, MaskKey, Acc) ->
<< MaskKey2:16, _:16 >> = << MaskKey:32 >>,
T = O bxor MaskKey2,
websocket_dispatch(State, Req, HandlerState, RemainingData,
Opcode, << Acc/binary, T:16 >>);
websocket_unmask(State, Req, HandlerState, RemainingData,
Opcode, << O:8 >>, MaskKey, Acc) ->
<< MaskKey2:8, _:24 >> = << MaskKey:32 >>,
T = O bxor MaskKey2,
websocket_dispatch(State, Req, HandlerState, RemainingData,
Opcode, << Acc/binary, T:8 >>);
websocket_unmask(State, Req, HandlerState, RemainingData,
Opcode, <<>>, _MaskKey, Acc) ->
websocket_dispatch(State, Req, HandlerState, RemainingData,
Opcode, Acc).
%% Dispatching.
-spec websocket_dispatch(#state{}, Req, any(), binary(), opcode(), binary())
-> {ok, Req, cowboy_middleware:env()}
| {suspend, module(), atom(), [any()]}
when Req::cowboy_req:req().
%% First frame of a fragmented message unmasked. Expect intermediate or last.
websocket_dispatch(State=#state{frag_state={nofin, Opcode}}, Req, HandlerState,
RemainingData, 0, Payload) ->
websocket_data(State#state{frag_state={nofin, Opcode, Payload}},
Req, HandlerState, RemainingData);
%% Intermediate frame of a fragmented message unmasked. Add payload to buffer.
websocket_dispatch(State=#state{frag_state={nofin, Opcode, Payloads}}, Req,
HandlerState, RemainingData, 0, Payload) ->
websocket_data(State#state{frag_state={nofin, Opcode,
<<Payloads/binary, Payload/binary>>}}, Req, HandlerState,
RemainingData);
%% Last frame of a fragmented message unmasked. Dispatch to handler.
websocket_dispatch(State=#state{frag_state={fin, Opcode, Payloads}}, Req,
HandlerState, RemainingData, 0, Payload) ->
websocket_dispatch(State#state{frag_state=undefined}, Req, HandlerState,
RemainingData, Opcode, <<Payloads/binary, Payload/binary>>);
%% Text frame.
websocket_dispatch(State, Req, HandlerState, RemainingData, 1, Payload) ->
handler_call(State, Req, HandlerState, RemainingData,
websocket_handle, {text, Payload}, fun websocket_data/4);
%% Binary frame.
websocket_dispatch(State, Req, HandlerState, RemainingData, 2, Payload) ->
handler_call(State, Req, HandlerState, RemainingData,
websocket_handle, {binary, Payload}, fun websocket_data/4);
%% Close control frame.
%% @todo Handle the optional Payload.
websocket_dispatch(State, Req, HandlerState, _RemainingData, 8, _Payload) ->
websocket_close(State, Req, HandlerState, {normal, closed});
%% Ping control frame. Send a pong back and forward the ping to the handler.
websocket_dispatch(State=#state{socket=Socket, transport=Transport},
Req, HandlerState, RemainingData, 9, Payload) ->
Len = payload_length_to_binary(byte_size(Payload)),
Transport:send(Socket, << 1:1, 0:3, 10:4, 0:1, Len/bits, Payload/binary >>),
handler_call(State, Req, HandlerState, RemainingData,
websocket_handle, {ping, Payload}, fun websocket_data/4);
%% Pong control frame.
websocket_dispatch(State, Req, HandlerState, RemainingData, 10, Payload) ->
handler_call(State, Req, HandlerState, RemainingData,
websocket_handle, {pong, Payload}, fun websocket_data/4).
-spec handler_call(#state{}, Req, any(), binary(), atom(), any(), fun())
-> {ok, Req, cowboy_middleware:env()}
| {suspend, module(), atom(), [any()]}
when Req::cowboy_req:req().
handler_call(State=#state{handler=Handler, handler_opts=HandlerOpts}, Req,
HandlerState, RemainingData, Callback, Message, NextState) ->
try Handler:Callback(Message, Req, HandlerState) of
{ok, Req2, HandlerState2} ->
NextState(State, Req2, HandlerState2, RemainingData);
{ok, Req2, HandlerState2, hibernate} ->
NextState(State#state{hibernate=true},
Req2, HandlerState2, RemainingData);
{reply, Payload, Req2, HandlerState2}
when is_tuple(Payload) ->
case websocket_send(Payload, State) of
ok ->
State2 = handler_loop_timeout(State),
NextState(State2, Req2, HandlerState2, RemainingData);
shutdown ->
handler_terminate(State, Req2, HandlerState,
{normal, shutdown});
{error, _} = Error ->
handler_terminate(State, Req2, HandlerState2, Error)
end;
{reply, Payload, Req2, HandlerState2, hibernate}
when is_tuple(Payload) ->
case websocket_send(Payload, State) of
ok ->
State2 = handler_loop_timeout(State),
NextState(State2#state{hibernate=true},
Req2, HandlerState2, RemainingData);
shutdown ->
handler_terminate(State, Req2, HandlerState,
{normal, shutdown});
{error, _} = Error ->
handler_terminate(State, Req2, HandlerState2, Error)
end;
{reply, Payload, Req2, HandlerState2}
when is_list(Payload) ->
case websocket_send_many(Payload, State) of
ok ->
State2 = handler_loop_timeout(State),
NextState(State2, Req2, HandlerState2, RemainingData);
shutdown ->
handler_terminate(State, Req2, HandlerState,
{normal, shutdown});
{error, _} = Error ->
handler_terminate(State, Req2, HandlerState2, Error)
end;
{reply, Payload, Req2, HandlerState2, hibernate}
when is_list(Payload) ->
case websocket_send_many(Payload, State) of
ok ->
State2 = handler_loop_timeout(State),
NextState(State2#state{hibernate=true},
Req2, HandlerState2, RemainingData);
shutdown ->
handler_terminate(State, Req2, HandlerState,
{normal, shutdown});
{error, _} = Error ->
handler_terminate(State, Req2, HandlerState2, Error)
end;
{shutdown, Req2, HandlerState2} ->
websocket_close(State, Req2, HandlerState2, {normal, shutdown})
catch Class:Reason ->
PLReq = cowboy_req:to_list(Req),
error_logger:error_msg(
"** Cowboy handler ~p terminating in ~p/~p~n"
" for the reason ~p:~p~n** Message was ~p~n"
"** Options were ~p~n** Handler state was ~p~n"
"** Request was ~p~n** Stacktrace: ~p~n~n",
[Handler, Callback, 3, Class, Reason, Message, HandlerOpts,
HandlerState, PLReq, erlang:get_stacktrace()]),
websocket_close(State, Req, HandlerState, {error, handler})
end.
websocket_opcode(text) -> 1;
websocket_opcode(binary) -> 2;
websocket_opcode(close) -> 8;
websocket_opcode(ping) -> 9;
websocket_opcode(pong) -> 10.
-spec websocket_send(frame(), #state{})
-> ok | shutdown | {error, atom()}.
websocket_send(Type, #state{socket=Socket, transport=Transport})
when Type =:= close ->
Opcode = websocket_opcode(Type),
case Transport:send(Socket, << 1:1, 0:3, Opcode:4, 0:8 >>) of
ok -> shutdown;
Error -> Error
end;
websocket_send(Type, #state{socket=Socket, transport=Transport})
when Type =:= ping; Type =:= pong ->
Opcode = websocket_opcode(Type),
Transport:send(Socket, << 1:1, 0:3, Opcode:4, 0:8 >>);
websocket_send({close, Payload}, State) ->
websocket_send({close, 1000, Payload}, State);
websocket_send({Type = close, StatusCode, Payload}, #state{
socket=Socket, transport=Transport}) ->
Opcode = websocket_opcode(Type),
Len = 2 + iolist_size(Payload),
%% Control packets must not be > 125 in length.
true = Len =< 125,
BinLen = payload_length_to_binary(Len),
Transport:send(Socket,
[<< 1:1, 0:3, Opcode:4, 0:1, BinLen/bits, StatusCode:16 >>, Payload]),
shutdown;
websocket_send({Type, Payload}, #state{socket=Socket, transport=Transport}) ->
Opcode = websocket_opcode(Type),
Len = iolist_size(Payload),
%% Control packets must not be > 125 in length.
true = if Type =:= ping; Type =:= pong ->
Len =< 125;
true ->
true
end,
BinLen = payload_length_to_binary(Len),
Transport:send(Socket,
[<< 1:1, 0:3, Opcode:4, 0:1, BinLen/bits >>, Payload]).
-spec websocket_send_many([frame()], #state{})
-> ok | shutdown | {error, atom()}.
websocket_send_many([], _) ->
ok;
websocket_send_many([Frame|Tail], State) ->
case websocket_send(Frame, State) of
ok -> websocket_send_many(Tail, State);
shutdown -> shutdown;
Error -> Error
end.
-spec websocket_close(#state{}, Req, any(), {atom(), atom()})
-> {ok, Req, cowboy_middleware:env()}
when Req::cowboy_req:req().
websocket_close(State=#state{socket=Socket, transport=Transport},
Req, HandlerState, Reason) ->
Transport:send(Socket, << 1:1, 0:3, 8:4, 0:8 >>),
handler_terminate(State, Req, HandlerState, Reason).
-spec handler_terminate(#state{}, Req, any(), atom() | {atom(), atom()})
-> {ok, Req, cowboy_middleware:env()}
when Req::cowboy_req:req().
handler_terminate(#state{env=Env, handler=Handler, handler_opts=HandlerOpts},
Req, HandlerState, TerminateReason) ->
try
Handler:websocket_terminate(TerminateReason, Req, HandlerState)
catch Class:Reason ->
PLReq = cowboy_req:to_list(Req),
error_logger:error_msg(
"** Cowboy handler ~p terminating in ~p/~p~n"
" for the reason ~p:~p~n** Initial reason was ~p~n"
"** Options were ~p~n** Handler state was ~p~n"
"** Request was ~p~n** Stacktrace: ~p~n~n",
[Handler, websocket_terminate, 3, Class, Reason, TerminateReason,
HandlerOpts, HandlerState, PLReq, erlang:get_stacktrace()])
end,
{ok, Req, [{result, closed}|Env]}.
-spec payload_length_to_binary(0..16#7fffffffffffffff)
-> << _:7 >> | << _:23 >> | << _:71 >>.
payload_length_to_binary(N) ->
case N of
N when N =< 125 -> << N:7 >>;
N when N =< 16#ffff -> << 126:7, N:16 >>;
N when N =< 16#7fffffffffffffff -> << 127:7, N:64 >>
end.
