%% Copyright (c) 2011-2017, 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. %% 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). -export([upgrade/4]). -export([upgrade/5]). -export([takeover/7]). -export([handler_loop/3]). -type call_result(State) :: {ok, State} | {ok, State, hibernate} | {reply, cow_ws:frame() | [cow_ws:frame()], State} | {reply, cow_ws:frame() | [cow_ws:frame()], State, hibernate} | {stop, State}. -type terminate_reason() :: normal | stop | timeout | remote | {remote, cow_ws:close_code(), binary()} | {error, badencoding | badframe | closed | atom()} | {crash, error | exit | throw, any()}. -callback init(Req, any()) -> {ok | module(), Req, any()} | {module(), Req, any(), any()} when Req::cowboy_req:req(). -callback websocket_init(State) -> call_result(State) when State::any(). -optional_callbacks([websocket_init/1]). -callback websocket_handle({text | binary | ping | pong, binary()}, State) -> call_result(State) when State::any(). -callback websocket_info(any(), State) -> call_result(State) when State::any(). -callback terminate(any(), cowboy_req:req(), any()) -> ok. -optional_callbacks([terminate/3]). -type opts() :: #{ compress => boolean(), idle_timeout => timeout(), req_filter => fun((cowboy_req:req()) -> map()) }. -export_type([opts/0]). -record(state, { socket = undefined :: inet:socket() | undefined, transport = undefined :: module(), handler :: module(), key = undefined :: undefined | binary(), timeout = infinity :: timeout(), timeout_ref = undefined :: undefined | reference(), compress = false :: boolean(), messages = undefined :: undefined | {atom(), atom(), atom()}, hibernate = false :: boolean(), frag_state = undefined :: cow_ws:frag_state(), frag_buffer = <<>> :: binary(), utf8_state = 0 :: cow_ws:utf8_state(), extensions = #{} :: map(), req = #{} :: map() }). %% Stream process. -spec upgrade(Req, Env, module(), any()) -> {ok, Req, Env} when Req::cowboy_req:req(), Env::cowboy_middleware:env(). upgrade(Req, Env, Handler, HandlerState) -> upgrade(Req, Env, Handler, HandlerState, #{}). -spec upgrade(Req, Env, module(), any(), opts()) -> {ok, Req, Env} when Req::cowboy_req:req(), Env::cowboy_middleware:env(). %% @todo Immediately crash if a response has already been sent. %% @todo Error out if HTTP/2. upgrade(Req0, Env, Handler, HandlerState, Opts) -> Timeout = maps:get(idle_timeout, Opts, 60000), Compress = maps:get(compress, Opts, false), FilteredReq = case maps:get(req_filter, Opts, undefined) of undefined -> maps:with([method, version, scheme, host, port, path, qs, peer], Req0); FilterFun -> FilterFun(Req0) end, State0 = #state{handler=Handler, timeout=Timeout, compress=Compress, req=FilteredReq}, try websocket_upgrade(State0, Req0) of {ok, State, Req} -> websocket_handshake(State, Req, HandlerState, Env) catch _:_ -> %% @todo Probably log something here? %% @todo Test that we can have 2 /ws 400 status code in a row on the same connection. %% @todo Does this even work? {ok, cowboy_req:reply(400, Req0), Env} end. -spec websocket_upgrade(#state{}, Req) -> {ok, #state{}, Req} when Req::cowboy_req:req(). websocket_upgrade(State, Req) -> ConnTokens = cowboy_req:parse_header(<<"connection">>, Req), true = lists:member(<<"upgrade">>, ConnTokens), %% @todo Should probably send a 426 if the Upgrade header is missing. [<<"websocket">>] = cowboy_req:parse_header(<<"upgrade">>, Req), Version = cowboy_req:header(<<"sec-websocket-version">>, Req), IntVersion = binary_to_integer(Version), true = (IntVersion =:= 7) orelse (IntVersion =:= 8) orelse (IntVersion =:= 13), Key = cowboy_req:header(<<"sec-websocket-key">>, Req), false = Key =:= undefined, websocket_extensions(State#state{key=Key}, Req#{websocket_version => IntVersion}). -spec websocket_extensions(#state{}, Req) -> {ok, #state{}, Req} when Req::cowboy_req:req(). websocket_extensions(State=#state{compress=Compress}, Req) -> %% @todo We want different options for this. For example %% * compress everything auto %% * compress only text auto %% * compress only binary auto %% * compress nothing auto (but still enabled it) %% * disable compression case {Compress, cowboy_req:parse_header(<<"sec-websocket-extensions">>, Req)} of {true, Extensions} when Extensions =/= undefined -> websocket_extensions(State, Req, Extensions, []); _ -> {ok, State, Req} end. websocket_extensions(State, Req, [], []) -> {ok, State, Req}; websocket_extensions(State, Req, [], [<<", ">>|RespHeader]) -> {ok, State, cowboy_req:set_resp_header(<<"sec-websocket-extensions">>, lists:reverse(RespHeader), Req)}; websocket_extensions(State=#state{extensions=Extensions}, Req=#{pid := Pid}, [{<<"permessage-deflate">>, Params}|Tail], RespHeader) -> %% @todo Make deflate options configurable. Opts = #{level => best_compression, mem_level => 8, strategy => default}, case cow_ws:negotiate_permessage_deflate(Params, Extensions, Opts#{owner => Pid}) of {ok, RespExt, Extensions2} -> websocket_extensions(State#state{extensions=Extensions2}, Req, Tail, [<<", ">>, RespExt|RespHeader]); ignore -> websocket_extensions(State, Req, Tail, RespHeader) end; websocket_extensions(State=#state{extensions=Extensions}, Req=#{pid := Pid}, [{<<"x-webkit-deflate-frame">>, Params}|Tail], RespHeader) -> %% @todo Make deflate options configurable. Opts = #{level => best_compression, mem_level => 8, strategy => default}, case cow_ws:negotiate_x_webkit_deflate_frame(Params, Extensions, Opts#{owner => Pid}) of {ok, RespExt, Extensions2} -> websocket_extensions(State#state{extensions=Extensions2}, Req, Tail, [<<", ">>, RespExt|RespHeader]); ignore -> websocket_extensions(State, Req, Tail, RespHeader) end; websocket_extensions(State, Req, [_|Tail], RespHeader) -> websocket_extensions(State, Req, Tail, RespHeader). -spec websocket_handshake(#state{}, Req, any(), Env) -> {ok, Req, Env} when Req::cowboy_req:req(), Env::cowboy_middleware:env(). websocket_handshake(State=#state{key=Key}, Req=#{pid := Pid, streamid := StreamID}, HandlerState, Env) -> Challenge = base64:encode(crypto:hash(sha, << Key/binary, "258EAFA5-E914-47DA-95CA-C5AB0DC85B11" >>)), Headers = cowboy_req:response_headers(#{ <<"connection">> => <<"Upgrade">>, <<"upgrade">> => <<"websocket">>, <<"sec-websocket-accept">> => Challenge }, Req), Pid ! {{Pid, StreamID}, {switch_protocol, Headers, ?MODULE, {State, HandlerState}}}, {ok, Req, Env}. %% Connection process. %% @todo Keep parent and handle system messages. -spec takeover(pid(), ranch:ref(), inet:socket(), module(), any(), binary(), {#state{}, any()}) -> ok. takeover(_Parent, Ref, Socket, Transport, _Opts, Buffer, {State0=#state{handler=Handler}, HandlerState}) -> %% @todo We should have an option to disable this behavior. ranch:remove_connection(Ref), State1 = handler_loop_timeout(State0#state{socket=Socket, transport=Transport}), State = State1#state{key=undefined, messages=Transport:messages()}, case erlang:function_exported(Handler, websocket_init, 1) of true -> handler_call(State, HandlerState, Buffer, websocket_init, undefined, fun handler_before_loop/3); false -> handler_before_loop(State, HandlerState, Buffer) end. -spec handler_before_loop(#state{}, any(), binary()) %% @todo Yeah not env. -> {ok, cowboy_middleware:env()}. handler_before_loop(State=#state{ socket=Socket, transport=Transport, hibernate=true}, HandlerState, SoFar) -> Transport:setopts(Socket, [{active, once}]), proc_lib:hibernate(?MODULE, handler_loop, [State#state{hibernate=false}, HandlerState, SoFar]); handler_before_loop(State=#state{socket=Socket, transport=Transport}, HandlerState, SoFar) -> Transport:setopts(Socket, [{active, once}]), handler_loop(State, 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}. -spec handler_loop(#state{}, any(), binary()) -> {ok, cowboy_middleware:env()}. handler_loop(State=#state{socket=Socket, messages={OK, Closed, Error}, timeout_ref=TRef}, HandlerState, SoFar) -> receive {OK, Socket, Data} -> State2 = handler_loop_timeout(State), websocket_data(State2, HandlerState, << SoFar/binary, Data/binary >>); {Closed, Socket} -> terminate(State, HandlerState, {error, closed}); {Error, Socket, Reason} -> terminate(State, HandlerState, {error, Reason}); {timeout, TRef, ?MODULE} -> websocket_close(State, HandlerState, timeout); {timeout, OlderTRef, ?MODULE} when is_reference(OlderTRef) -> handler_loop(State, HandlerState, SoFar); Message -> handler_call(State, HandlerState, SoFar, websocket_info, Message, fun handler_before_loop/3) end. -spec websocket_data(#state{}, any(), binary()) -> {ok, cowboy_middleware:env()}. websocket_data(State=#state{frag_state=FragState, extensions=Extensions}, HandlerState, Data) -> case cow_ws:parse_header(Data, Extensions, FragState) of %% All frames sent from the client to the server are masked. {_, _, _, _, undefined, _} -> websocket_close(State, HandlerState, {error, badframe}); {Type, FragState2, Rsv, Len, MaskKey, Rest} -> websocket_payload(State#state{frag_state=FragState2}, HandlerState, Type, Len, MaskKey, Rsv, undefined, <<>>, 0, Rest); more -> handler_before_loop(State, HandlerState, Data); error -> websocket_close(State, HandlerState, {error, badframe}) end. websocket_payload(State=#state{frag_state=FragState, utf8_state=Incomplete, extensions=Extensions}, HandlerState, Type, Len, MaskKey, Rsv, CloseCode, Unmasked, UnmaskedLen, Data) -> case cow_ws:parse_payload(Data, MaskKey, Incomplete, UnmaskedLen, Type, Len, FragState, Extensions, Rsv) of {ok, CloseCode2, Payload, Utf8State, Rest} -> websocket_dispatch(State#state{utf8_state=Utf8State}, HandlerState, Type, << Unmasked/binary, Payload/binary >>, CloseCode2, Rest); {ok, Payload, Utf8State, Rest} -> websocket_dispatch(State#state{utf8_state=Utf8State}, HandlerState, Type, << Unmasked/binary, Payload/binary >>, CloseCode, Rest); {more, CloseCode2, Payload, Utf8State} -> websocket_payload_loop(State#state{utf8_state=Utf8State}, HandlerState, Type, Len - byte_size(Data), MaskKey, Rsv, CloseCode2, << Unmasked/binary, Payload/binary >>, UnmaskedLen + byte_size(Data)); {more, Payload, Utf8State} -> websocket_payload_loop(State#state{utf8_state=Utf8State}, HandlerState, Type, Len - byte_size(Data), MaskKey, Rsv, CloseCode, << Unmasked/binary, Payload/binary >>, UnmaskedLen + byte_size(Data)); Error = {error, _Reason} -> websocket_close(State, HandlerState, Error) end. websocket_payload_loop(State=#state{socket=Socket, transport=Transport, messages={OK, Closed, Error}, timeout_ref=TRef}, HandlerState, Type, Len, MaskKey, Rsv, CloseCode, Unmasked, UnmaskedLen) -> Transport:setopts(Socket, [{active, once}]), receive {OK, Socket, Data} -> State2 = handler_loop_timeout(State), websocket_payload(State2, HandlerState, Type, Len, MaskKey, Rsv, CloseCode, Unmasked, UnmaskedLen, Data); {Closed, Socket} -> terminate(State, HandlerState, {error, closed}); {Error, Socket, Reason} -> terminate(State, HandlerState, {error, Reason}); {timeout, TRef, ?MODULE} -> websocket_close(State, HandlerState, timeout); {timeout, OlderTRef, ?MODULE} when is_reference(OlderTRef) -> websocket_payload_loop(State, HandlerState, Type, Len, MaskKey, Rsv, CloseCode, Unmasked, UnmaskedLen); Message -> handler_call(State, HandlerState, <<>>, websocket_info, Message, fun (State2, HandlerState2, _) -> websocket_payload_loop(State2, HandlerState2, Type, Len, MaskKey, Rsv, CloseCode, Unmasked, UnmaskedLen) end) end. websocket_dispatch(State=#state{socket=Socket, transport=Transport, frag_state=FragState, frag_buffer=SoFar, extensions=Extensions}, HandlerState, Type0, Payload0, CloseCode0, RemainingData) -> case cow_ws:make_frame(Type0, Payload0, CloseCode0, FragState) of %% @todo Allow receiving fragments. {fragment, nofin, _, Payload} -> websocket_data(State#state{frag_buffer= << SoFar/binary, Payload/binary >>}, HandlerState, RemainingData); {fragment, fin, Type, Payload} -> handler_call(State#state{frag_state=undefined, frag_buffer= <<>>}, HandlerState, RemainingData, websocket_handle, {Type, << SoFar/binary, Payload/binary >>}, fun websocket_data/3); close -> websocket_close(State, HandlerState, remote); {close, CloseCode, Payload} -> websocket_close(State, HandlerState, {remote, CloseCode, Payload}); Frame = ping -> Transport:send(Socket, cow_ws:frame(pong, Extensions)), handler_call(State, HandlerState, RemainingData, websocket_handle, Frame, fun websocket_data/3); Frame = {ping, Payload} -> Transport:send(Socket, cow_ws:frame({pong, Payload}, Extensions)), handler_call(State, HandlerState, RemainingData, websocket_handle, Frame, fun websocket_data/3); Frame -> handler_call(State, HandlerState, RemainingData, websocket_handle, Frame, fun websocket_data/3) end. -spec handler_call(#state{}, any(), binary(), atom(), any(), fun()) -> no_return(). handler_call(State=#state{handler=Handler}, HandlerState, RemainingData, Callback, Message, NextState) -> try case Callback of websocket_init -> Handler:websocket_init(HandlerState); _ -> Handler:Callback(Message, HandlerState) end of {ok, HandlerState2} -> NextState(State, HandlerState2, RemainingData); {ok, HandlerState2, hibernate} -> NextState(State#state{hibernate=true}, HandlerState2, RemainingData); {reply, Payload, HandlerState2} -> case websocket_send(Payload, State) of ok -> NextState(State, HandlerState2, RemainingData); stop -> terminate(State, HandlerState2, stop); Error = {error, _} -> terminate(State, HandlerState2, Error) end; {reply, Payload, HandlerState2, hibernate} -> case websocket_send(Payload, State) of ok -> NextState(State#state{hibernate=true}, HandlerState2, RemainingData); stop -> terminate(State, HandlerState2, stop); Error = {error, _} -> terminate(State, HandlerState2, Error) end; {stop, HandlerState2} -> websocket_close(State, HandlerState2, stop) catch Class:Reason -> websocket_send_close(State, {crash, Class, Reason}), handler_terminate(State, HandlerState, {crash, Class, Reason}), erlang:raise(Class, Reason, erlang:get_stacktrace()) end. -spec websocket_send(cow_ws:frame(), #state{}) -> ok | stop | {error, atom()}. websocket_send(Frames, State) when is_list(Frames) -> websocket_send_many(Frames, State, []); websocket_send(Frame, #state{socket=Socket, transport=Transport, extensions=Extensions}) -> Res = Transport:send(Socket, cow_ws:frame(Frame, Extensions)), case is_close_frame(Frame) of true -> stop; false -> Res end. websocket_send_many([], #state{socket=Socket, transport=Transport}, Acc) -> Transport:send(Socket, lists:reverse(Acc)); websocket_send_many([Frame|Tail], State=#state{socket=Socket, transport=Transport, extensions=Extensions}, Acc0) -> Acc = [cow_ws:frame(Frame, Extensions)|Acc0], case is_close_frame(Frame) of true -> _ = Transport:send(Socket, lists:reverse(Acc)), stop; false -> websocket_send_many(Tail, State, Acc) end. is_close_frame(close) -> true; is_close_frame({close, _}) -> true; is_close_frame({close, _, _}) -> true; is_close_frame(_) -> false. -spec websocket_close(#state{}, any(), terminate_reason()) -> no_return(). websocket_close(State, HandlerState, Reason) -> websocket_send_close(State, Reason), terminate(State, HandlerState, Reason). websocket_send_close(#state{socket=Socket, transport=Transport, extensions=Extensions}, Reason) -> _ = case Reason of Normal when Normal =:= stop; Normal =:= timeout -> Transport:send(Socket, cow_ws:frame({close, 1000, <<>>}, Extensions)); {error, badframe} -> Transport:send(Socket, cow_ws:frame({close, 1002, <<>>}, Extensions)); {error, badencoding} -> Transport:send(Socket, cow_ws:frame({close, 1007, <<>>}, Extensions)); {crash, _, _} -> Transport:send(Socket, cow_ws:frame({close, 1011, <<>>}, Extensions)); remote -> Transport:send(Socket, cow_ws:frame(close, Extensions)); {remote, Code, _} -> Transport:send(Socket, cow_ws:frame({close, Code, <<>>}, Extensions)) end, ok. -spec terminate(#state{}, any(), terminate_reason()) -> no_return(). terminate(State, HandlerState, Reason) -> handler_terminate(State, HandlerState, Reason), exit(normal). handler_terminate(#state{handler=Handler, req=Req}, HandlerState, Reason) -> cowboy_handler:terminate(Reason, Req, HandlerState, Handler).