%% Copyright (c) 2011-2013, Loïc Hoguin %% %% 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). -behaviour(cowboy_sub_protocol). %% API. -export([upgrade/4]). %% Internal. -export([handler_loop/4]). -type close_code() :: 1000..4999. -export_type([close_code/0]). -type frame() :: close | ping | pong | {text | binary | close | ping | pong, binary()} | {close, close_code(), binary()}. -export_type([frame/0]). -type opcode() :: 0 | 1 | 2 | 8 | 9 | 10. -type mask_key() :: 0..16#ffffffff. -type frag_state() :: undefined | {nofin, opcode(), binary()} | {fin, opcode(), binary()}. -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(), utf8_state = <<>> :: binary() }). %% @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 {upgrade, protocol, {@module}} %% in your cowboy_http_handler:init/3 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. %% Only send an error reply if there is no resp_sent message. -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. %% All frames passing through this function are considered valid, %% with the only exception of text and close frames with a payload %% which may still contain errors. -spec websocket_data(#state{}, Req, any(), binary()) -> {ok, Req, cowboy_middleware:env()} | {suspend, module(), atom(), [any()]} when Req::cowboy_req:req(). %% RSV bits MUST be 0 unless an extension is negotiated %% that defines meanings for non-zero values. websocket_data(State, Req, HandlerState, << _:1, Rsv:3, _/bits >>) when Rsv =/= 0 -> websocket_close(State, Req, HandlerState, {error, badframe}); %% Invalid opcode. Note that these opcodes may be used by extensions. websocket_data(State, Req, HandlerState, << _:4, Opcode:4, _/bits >>) when Opcode > 2, Opcode =/= 8, Opcode =/= 9, Opcode =/= 10 -> websocket_close(State, Req, HandlerState, {error, badframe}); %% Control frames MUST NOT be fragmented. websocket_data(State, Req, HandlerState, << 0:1, _:3, Opcode:4, _/bits >>) when Opcode >= 8 -> websocket_close(State, Req, HandlerState, {error, badframe}); %% A frame MUST NOT use the zero opcode unless fragmentation was initiated. websocket_data(State=#state{frag_state=undefined}, Req, HandlerState, << _:4, 0:4, _/bits >>) -> websocket_close(State, Req, HandlerState, {error, badframe}); %% Non-control opcode when expecting control message or next fragment. websocket_data(State=#state{frag_state={nofin, _, _}}, Req, HandlerState, << _:4, Opcode:4, _/bits >>) when Opcode =/= 0, Opcode < 8 -> websocket_close(State, Req, HandlerState, {error, badframe}); %% Close control frame length MUST be 0 or >= 2. websocket_data(State, Req, HandlerState, << _:4, 8:4, _:1, 1:7, _/bits >>) -> websocket_close(State, Req, HandlerState, {error, badframe}); %% Close control frame with incomplete close code. Need more data. websocket_data(State, Req, HandlerState, Data = << _:4, 8:4, 1:1, Len:7, _/bits >>) when Len > 1, byte_size(Data) < 8 -> handler_before_loop(State, Req, HandlerState, Data); %% 7 bits payload length. websocket_data(State, Req, HandlerState, << Fin:1, _Rsv:3, Opcode:4, 1:1, Len:7, MaskKey:32, Rest/bits >>) when Len < 126 -> websocket_data(State, Req, HandlerState, Opcode, Len, MaskKey, Rest, Fin); %% 16 bits payload length. websocket_data(State, Req, HandlerState, << Fin:1, _Rsv:3, Opcode:4, 1:1, 126:7, Len:16, MaskKey:32, Rest/bits >>) when Len > 125, Opcode < 8 -> websocket_data(State, Req, HandlerState, Opcode, Len, MaskKey, Rest, Fin); %% 63 bits payload length. websocket_data(State, Req, HandlerState, << Fin:1, _Rsv:3, Opcode:4, 1:1, 127:7, 0:1, Len:63, MaskKey:32, Rest/bits >>) when Len > 16#ffff, Opcode < 8 -> websocket_data(State, Req, HandlerState, Opcode, Len, MaskKey, Rest, Fin); %% When payload length is over 63 bits, the most significant bit MUST be 0. websocket_data(State, Req, HandlerState, << _:8, 1:1, 127:7, 1:1, _:7, _/binary >>) -> websocket_close(State, Req, HandlerState, {error, badframe}); %% All frames sent from the client to the server are masked. websocket_data(State, Req, HandlerState, << _:8, 0:1, _/bits >>) -> websocket_close(State, Req, HandlerState, {error, badframe}); %% For the next two clauses, it can be one of the following: %% %% * The minimal number of bytes MUST be used to encode the length %% * All control frames MUST have a payload length of 125 bytes or less websocket_data(State, Req, HandlerState, << _:9, 126:7, _:48, _/bits >>) -> websocket_close(State, Req, HandlerState, {error, badframe}); websocket_data(State, Req, HandlerState, << _:9, 127:7, _:96, _/bits >>) -> websocket_close(State, Req, HandlerState, {error, badframe}); %% Need more data. websocket_data(State, Req, HandlerState, Data) -> handler_before_loop(State, Req, HandlerState, Data). %% Initialize or update fragmentation state. -spec websocket_data(#state{}, Req, any(), opcode(), non_neg_integer(), mask_key(), binary(), 0 | 1) -> {ok, Req, cowboy_middleware:env()} | {suspend, module(), atom(), [any()]} when Req::cowboy_req:req(). %% The opcode is only included in the first frame fragment. websocket_data(State=#state{frag_state=undefined}, Req, HandlerState, Opcode, Len, MaskKey, Data, 0) -> websocket_payload(State#state{frag_state={nofin, Opcode, <<>>}}, Req, HandlerState, 0, Len, MaskKey, <<>>, Data); %% Subsequent frame fragments. websocket_data(State=#state{frag_state={nofin, _, _}}, Req, HandlerState, 0, Len, MaskKey, Data, 0) -> websocket_payload(State, Req, HandlerState, 0, Len, MaskKey, <<>>, Data); %% Final frame fragment. websocket_data(State=#state{frag_state={nofin, Opcode, SoFar}}, Req, HandlerState, 0, Len, MaskKey, Data, 1) -> websocket_payload(State#state{frag_state={fin, Opcode, SoFar}}, Req, HandlerState, 0, Len, MaskKey, <<>>, Data); %% Unfragmented frame. websocket_data(State, Req, HandlerState, Opcode, Len, MaskKey, Data, 1) -> websocket_payload(State, Req, HandlerState, Opcode, Len, MaskKey, <<>>, Data). -spec websocket_payload(#state{}, Req, any(), opcode(), non_neg_integer(), mask_key(), binary(), binary()) -> {ok, Req, cowboy_middleware:env()} | {suspend, module(), atom(), [any()]} when Req::cowboy_req:req(). %% Close control frames with a payload MUST contain a valid close code. websocket_payload(State, Req, HandlerState, Opcode=8, Len, MaskKey, <<>>, << MaskedCode:2/binary, Rest/bits >>) -> Unmasked = << Code:16 >> = websocket_unmask(MaskedCode, MaskKey, <<>>), if Code < 1000; Code =:= 1004; Code =:= 1005; Code =:= 1006; (Code > 1011) and (Code < 3000); Code > 4999 -> websocket_close(State, Req, HandlerState, {error, badframe}); true -> websocket_payload(State, Req, HandlerState, Opcode, Len - 2, MaskKey, Unmasked, Rest) end; %% Text frames and close control frames MUST have a payload that is valid UTF-8. websocket_payload(State=#state{utf8_state=Incomplete}, Req, HandlerState, Opcode, Len, MaskKey, Unmasked, Data) when (byte_size(Data) < Len) andalso ((Opcode =:= 1) orelse ((Opcode =:= 8) andalso (Unmasked =/= <<>>))) -> Unmasked2 = websocket_unmask(Data, rotate_mask_key(MaskKey, byte_size(Unmasked)), <<>>), case is_utf8(<< Incomplete/binary, Unmasked2/binary >>) of false -> websocket_close(State, Req, HandlerState, {error, badencoding}); Utf8State -> websocket_payload_loop(State#state{utf8_state=Utf8State}, Req, HandlerState, Opcode, Len - byte_size(Data), MaskKey, << Unmasked/binary, Unmasked2/binary >>) end; websocket_payload(State=#state{utf8_state=Incomplete}, Req, HandlerState, Opcode, Len, MaskKey, Unmasked, Data) when Opcode =:= 1; (Opcode =:= 8) and (Unmasked =/= <<>>) -> << End:Len/binary, Rest/bits >> = Data, Unmasked2 = websocket_unmask(End, rotate_mask_key(MaskKey, byte_size(Unmasked)), <<>>), case is_utf8(<< Incomplete/binary, Unmasked2/binary >>) of <<>> -> websocket_dispatch(State#state{utf8_state= <<>>}, Req, HandlerState, Rest, Opcode, << Unmasked/binary, Unmasked2/binary >>); _ -> websocket_close(State, Req, HandlerState, {error, badencoding}) end; %% Fragmented text frames may cut payload in the middle of UTF-8 codepoints. websocket_payload(State=#state{frag_state={_, 1, _}, utf8_state=Incomplete}, Req, HandlerState, Opcode=0, Len, MaskKey, Unmasked, Data) when byte_size(Data) < Len -> Unmasked2 = websocket_unmask(Data, rotate_mask_key(MaskKey, byte_size(Unmasked)), <<>>), case is_utf8(<< Incomplete/binary, Unmasked2/binary >>) of false -> websocket_close(State, Req, HandlerState, {error, badencoding}); Utf8State -> websocket_payload_loop(State#state{utf8_state=Utf8State}, Req, HandlerState, Opcode, Len - byte_size(Data), MaskKey, << Unmasked/binary, Unmasked2/binary >>) end; websocket_payload(State=#state{frag_state={Fin, 1, _}, utf8_state=Incomplete}, Req, HandlerState, Opcode=0, Len, MaskKey, Unmasked, Data) -> << End:Len/binary, Rest/bits >> = Data, Unmasked2 = websocket_unmask(End, rotate_mask_key(MaskKey, byte_size(Unmasked)), <<>>), case is_utf8(<< Incomplete/binary, Unmasked2/binary >>) of <<>> -> websocket_dispatch(State#state{utf8_state= <<>>}, Req, HandlerState, Rest, Opcode, << Unmasked/binary, Unmasked2/binary >>); Utf8State when is_binary(Utf8State), Fin =:= nofin -> websocket_dispatch(State#state{utf8_state=Utf8State}, Req, HandlerState, Rest, Opcode, << Unmasked/binary, Unmasked2/binary >>); _ -> websocket_close(State, Req, HandlerState, {error, badencoding}) end; %% Other frames have a binary payload. websocket_payload(State, Req, HandlerState, Opcode, Len, MaskKey, Unmasked, Data) when byte_size(Data) < Len -> Unmasked2 = websocket_unmask(Data, rotate_mask_key(MaskKey, byte_size(Unmasked)), Unmasked), websocket_payload_loop(State, Req, HandlerState, Opcode, Len - byte_size(Data), MaskKey, Unmasked2); websocket_payload(State, Req, HandlerState, Opcode, Len, MaskKey, Unmasked, Data) -> << End:Len/binary, Rest/bits >> = Data, Unmasked2 = websocket_unmask(End, rotate_mask_key(MaskKey, byte_size(Unmasked)), Unmasked), websocket_dispatch(State, Req, HandlerState, Rest, Opcode, Unmasked2). -spec websocket_unmask(B, mask_key(), B) -> B when B::binary(). websocket_unmask(<<>>, _, Unmasked) -> Unmasked; websocket_unmask(<< O:32, Rest/bits >>, MaskKey, Acc) -> T = O bxor MaskKey, websocket_unmask(Rest, MaskKey, << Acc/binary, T:32 >>); websocket_unmask(<< O:24 >>, MaskKey, Acc) -> << MaskKey2:24, _:8 >> = << MaskKey:32 >>, T = O bxor MaskKey2, << Acc/binary, T:24 >>; websocket_unmask(<< O:16 >>, MaskKey, Acc) -> << MaskKey2:16, _:16 >> = << MaskKey:32 >>, T = O bxor MaskKey2, << Acc/binary, T:16 >>; websocket_unmask(<< O:8 >>, MaskKey, Acc) -> << MaskKey2:8, _:24 >> = << MaskKey:32 >>, T = O bxor MaskKey2, << Acc/binary, T:8 >>. %% Because we unmask on the fly we need to continue from the right mask byte. -spec rotate_mask_key(mask_key(), non_neg_integer()) -> mask_key(). rotate_mask_key(MaskKey, UnmaskedLen) -> Left = UnmaskedLen rem 4, Right = 4 - Left, (MaskKey bsl (Left * 8)) + (MaskKey bsr (Right * 8)). %% Returns <<>> if the argument is valid UTF-8, false if not, %% or the incomplete part of the argument if we need more data. -spec is_utf8(binary()) -> false | binary(). is_utf8(Valid = <<>>) -> Valid; is_utf8(<< _/utf8, Rest/binary >>) -> is_utf8(Rest); %% 2 bytes. Codepages C0 and C1 are invalid; fail early. is_utf8(<< 2#1100000:7, _/bits >>) -> false; is_utf8(Incomplete = << 2#110:3, _:5 >>) -> Incomplete; %% 3 bytes. is_utf8(Incomplete = << 2#1110:4, _:4 >>) -> Incomplete; is_utf8(Incomplete = << 2#1110:4, _:4, 2#10:2, _:6 >>) -> Incomplete; %% 4 bytes. Codepage F4 may have invalid values greater than 0x10FFFF. is_utf8(<< 2#11110100:8, 2#10:2, High:6, _/bits >>) when High >= 2#10000 -> false; is_utf8(Incomplete = << 2#11110:5, _:3 >>) -> Incomplete; is_utf8(Incomplete = << 2#11110:5, _:3, 2#10:2, _:6 >>) -> Incomplete; is_utf8(Incomplete = << 2#11110:5, _:3, 2#10:2, _:6, 2#10:2, _:6 >>) -> Incomplete; %% Invalid. is_utf8(_) -> false. -spec websocket_payload_loop(#state{}, Req, any(), opcode(), non_neg_integer(), mask_key(), binary()) -> {ok, Req, cowboy_middleware:env()} | {suspend, module(), atom(), [any()]} when Req::cowboy_req:req(). websocket_payload_loop(State=#state{socket=Socket, transport=Transport, messages={OK, Closed, Error}, timeout_ref=TRef}, Req, HandlerState, Opcode, Len, MaskKey, Unmasked) -> Transport:setopts(Socket, [{active, once}]), receive {OK, Socket, Data} -> State2 = handler_loop_timeout(State), websocket_payload(State2, Req, HandlerState, Opcode, Len, MaskKey, Unmasked, Data); {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) -> websocket_payload_loop(State, Req, HandlerState, Opcode, Len, MaskKey, Unmasked); Message -> handler_call(State, Req, HandlerState, <<>>, websocket_info, Message, fun (State2, Req2, HandlerState2, _) -> websocket_payload_loop(State2, Req2, HandlerState2, Opcode, Len, MaskKey, Unmasked) end) end. -spec websocket_dispatch(#state{}, Req, any(), binary(), opcode(), binary()) -> {ok, Req, cowboy_middleware:env()} | {suspend, module(), atom(), [any()]} when Req::cowboy_req:req(). %% Continuation frame. websocket_dispatch(State=#state{frag_state={nofin, Opcode, SoFar}}, Req, HandlerState, RemainingData, 0, Payload) -> websocket_data(State#state{frag_state={nofin, Opcode, << SoFar/binary, Payload/binary >>}}, Req, HandlerState, RemainingData); %% Last continuation frame. websocket_dispatch(State=#state{frag_state={fin, Opcode, SoFar}}, Req, HandlerState, RemainingData, 0, Payload) -> websocket_dispatch(State#state{frag_state=undefined}, Req, HandlerState, RemainingData, Opcode, << SoFar/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. websocket_dispatch(State, Req, HandlerState, _RemainingData, 8, <<>>) -> websocket_close(State, Req, HandlerState, {remote, closed}); websocket_dispatch(State, Req, HandlerState, _RemainingData, 8, << Code:16, Payload/bits >>) -> websocket_close(State, Req, HandlerState, {remote, Code, Payload}); %% 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 -> NextState(State, Req2, HandlerState2, RemainingData); shutdown -> handler_terminate(State, Req2, HandlerState2, {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 -> NextState(State#state{hibernate=true}, Req2, HandlerState2, RemainingData); shutdown -> handler_terminate(State, Req2, HandlerState2, {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 -> NextState(State, Req2, HandlerState2, RemainingData); shutdown -> handler_terminate(State, Req2, HandlerState2, {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 -> NextState(State#state{hibernate=true}, Req2, HandlerState2, RemainingData); shutdown -> handler_terminate(State, Req2, HandlerState2, {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()} | {remote, close_code(), binary()}) -> {ok, Req, cowboy_middleware:env()} when Req::cowboy_req:req(). websocket_close(State=#state{socket=Socket, transport=Transport}, Req, HandlerState, Reason) -> case Reason of {normal, _} -> Transport:send(Socket, << 1:1, 0:3, 8:4, 0:1, 2:7, 1000:16 >>); {error, badframe} -> Transport:send(Socket, << 1:1, 0:3, 8:4, 0:1, 2:7, 1002:16 >>); {error, badencoding} -> Transport:send(Socket, << 1:1, 0:3, 8:4, 0:1, 2:7, 1007:16 >>); {error, handler} -> Transport:send(Socket, << 1:1, 0:3, 8:4, 0:1, 2:7, 1011:16 >>); {remote, closed} -> Transport:send(Socket, << 1:1, 0:3, 8:4, 0:8 >>); {remote, Code, _} -> Transport:send(Socket, << 1:1, 0:3, 8:4, 0:1, 2:7, Code:16 >>) end, 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.