%% Copyright (c) 2015-2019, 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.
-module(gun_ws).
-export([check_options/1]).
-export([name/0]).
-export([opts_name/0]).
-export([has_keepalive/0]).
-export([init/4]).
-export([handle/4]).
-export([update_flow/4]).
-export([closing/4]).
-export([close/4]).
-export([send/4]).
-export([down/1]).
-record(payload, {
type = undefined :: cow_ws:frame_type(),
rsv = undefined :: cow_ws:rsv(),
len = undefined :: non_neg_integer(),
mask_key = undefined :: cow_ws:mask_key(),
close_code = undefined :: undefined | cow_ws:close_code(),
unmasked = <<>> :: binary(),
unmasked_len = 0 :: non_neg_integer()
}).
-record(ws_state, {
owner :: pid(),
stream_ref :: reference(),
socket :: inet:socket() | ssl:sslsocket(),
transport :: module(),
opts = #{} :: map(), %% @todo
buffer = <<>> :: binary(),
in = head :: head | #payload{} | close,
out = head :: head | close,
frag_state = undefined :: cow_ws:frag_state(),
utf8_state = 0 :: cow_ws:utf8_state(),
extensions = #{} :: cow_ws:extensions(),
flow :: integer() | infinity,
handler :: module(),
handler_state :: any()
}).
check_options(Opts) ->
do_check_options(maps:to_list(Opts)).
do_check_options([]) ->
ok;
do_check_options([{closing_timeout, infinity}|Opts]) ->
do_check_options(Opts);
do_check_options([{closing_timeout, T}|Opts]) when is_integer(T), T > 0 ->
do_check_options(Opts);
do_check_options([{compress, B}|Opts]) when B =:= true; B =:= false ->
do_check_options(Opts);
do_check_options([{default_protocol, M}|Opts]) when is_atom(M) ->
do_check_options(Opts);
do_check_options([{flow, InitialFlow}|Opts]) when is_integer(InitialFlow), InitialFlow > 0 ->
do_check_options(Opts);
do_check_options([Opt={protocols, L}|Opts]) when is_list(L) ->
case lists:usort(lists:flatten([[is_binary(B), is_atom(M)] || {B, M} <- L])) of
[true] -> do_check_options(Opts);
_ -> {error, {options, {ws, Opt}}}
end;
do_check_options([{user_opts, _}|Opts]) ->
do_check_options(Opts);
do_check_options([Opt|_]) ->
{error, {options, {ws, Opt}}}.
name() -> ws.
opts_name() -> ws_opts.
has_keepalive() -> false.
init(Owner, Socket, Transport, #{stream_ref := StreamRef, headers := Headers,
extensions := Extensions, flow := InitialFlow, handler := Handler, opts := Opts}) ->
{ok, HandlerState} = Handler:init(Owner, StreamRef, Headers, Opts),
#ws_state{owner=Owner, stream_ref=StreamRef,
socket=Socket, transport=Transport, opts=Opts, extensions=Extensions,
flow=InitialFlow, handler=Handler, handler_state=HandlerState}.
%% Do not handle anything if we received a close frame.
%% Initiate or terminate the closing state depending on whether we sent a close yet.
handle(_, State=#ws_state{in=close, out=close}, _, EvHandlerState) ->
{[{state, State}, close], EvHandlerState};
handle(_, State=#ws_state{in=close}, EvHandler, EvHandlerState) ->
closing(normal, State, EvHandler, EvHandlerState);
%% Shortcut for common case when Data is empty after processing a frame.
handle(<<>>, State=#ws_state{in=head}, _, EvHandlerState) ->
maybe_active(State, EvHandlerState);
handle(Data, State=#ws_state{owner=ReplyTo, stream_ref=StreamRef, buffer=Buffer,
in=head, frag_state=FragState, extensions=Extensions},
EvHandler, EvHandlerState0) ->
%% Send the event only if there was no data in the buffer.
%% If there is data in the buffer then we already sent the event.
EvHandlerState1 = case Buffer of
<<>> ->
EvHandler:ws_recv_frame_start(#{
stream_ref => StreamRef,
reply_to => ReplyTo,
frag_state => FragState,
extensions => Extensions
}, EvHandlerState0);
_ ->
EvHandlerState0
end,
Data2 = << Buffer/binary, Data/binary >>,
case cow_ws:parse_header(Data2, Extensions, FragState) of
{Type, FragState2, Rsv, Len, MaskKey, Rest} ->
EvHandlerState = EvHandler:ws_recv_frame_header(#{
stream_ref => StreamRef,
reply_to => ReplyTo,
frag_state => FragState2,
extensions => Extensions,
type => Type,
rsv => Rsv,
len => Len,
mask_key => MaskKey
}, EvHandlerState1),
handle(Rest, State#ws_state{buffer= <<>>,
in=#payload{type=Type, rsv=Rsv, len=Len, mask_key=MaskKey},
frag_state=FragState2}, EvHandler, EvHandlerState);
more ->
maybe_active(State#ws_state{buffer=Data2}, EvHandlerState1);
error ->
closing({error, badframe}, State, EvHandler, EvHandlerState1)
end;
handle(Data, State=#ws_state{in=In=#payload{type=Type, rsv=Rsv, len=Len, mask_key=MaskKey,
close_code=CloseCode, unmasked=Unmasked, unmasked_len=UnmaskedLen}, frag_state=FragState,
utf8_state=Utf8State, extensions=Extensions}, EvHandler, EvHandlerState) ->
case cow_ws:parse_payload(Data, MaskKey, Utf8State, UnmaskedLen, Type, Len, FragState, Extensions, Rsv) of
{ok, CloseCode2, Payload, Utf8State2, Rest} ->
dispatch(Rest, State#ws_state{in=head, utf8_state=Utf8State2}, Type,
<<Unmasked/binary, Payload/binary>>, CloseCode2,
EvHandler, EvHandlerState);
{ok, Payload, Utf8State2, Rest} ->
dispatch(Rest, State#ws_state{in=head, utf8_state=Utf8State2}, Type,
<<Unmasked/binary, Payload/binary>>, CloseCode,
EvHandler, EvHandlerState);
{more, CloseCode2, Payload, Utf8State2} ->
maybe_active(State#ws_state{in=In#payload{close_code=CloseCode2,
unmasked= <<Unmasked/binary, Payload/binary>>,
len=Len - byte_size(Data), unmasked_len=2 + byte_size(Data)}, utf8_state=Utf8State2},
EvHandlerState);
{more, Payload, Utf8State2} ->
maybe_active(State#ws_state{in=In#payload{unmasked= <<Unmasked/binary, Payload/binary>>,
len=Len - byte_size(Data), unmasked_len=UnmaskedLen + byte_size(Data)}, utf8_state=Utf8State2},
EvHandlerState);
Error = {error, _Reason} ->
closing(Error, State, EvHandler, EvHandlerState)
end.
maybe_active(State=#ws_state{flow=Flow}, EvHandlerState) ->
{[
{state, State},
{active, Flow > 0}
], EvHandlerState}.
dispatch(Rest, State0=#ws_state{owner=ReplyTo, stream_ref=StreamRef,
frag_state=FragState, extensions=Extensions, flow=Flow0,
handler=Handler, handler_state=HandlerState0},
Type, Payload, CloseCode, EvHandler, EvHandlerState0) ->
EvHandlerState1 = EvHandler:ws_recv_frame_end(#{
stream_ref => StreamRef,
reply_to => ReplyTo,
extensions => Extensions,
close_code => CloseCode,
payload => Payload
}, EvHandlerState0),
case cow_ws:make_frame(Type, Payload, CloseCode, FragState) of
ping ->
{[], EvHandlerState} = send(pong, State0, EvHandler, EvHandlerState1),
handle(Rest, State0, EvHandler, EvHandlerState);
{ping, Payload} ->
{[], EvHandlerState} = send({pong, Payload}, State0, EvHandler, EvHandlerState1),
handle(Rest, State0, EvHandler, EvHandlerState);
pong ->
handle(Rest, State0, EvHandler, EvHandlerState1);
{pong, _} ->
handle(Rest, State0, EvHandler, EvHandlerState1);
Frame ->
{ok, Dec, HandlerState} = Handler:handle(Frame, HandlerState0),
Flow = case Flow0 of
infinity -> infinity;
_ -> Flow0 - Dec
end,
State1 = State0#ws_state{flow=Flow, handler_state=HandlerState},
State = case Frame of
close -> State1#ws_state{in=close};
{close, _, _} -> State1#ws_state{in=close};
{fragment, fin, _, _} -> State1#ws_state{frag_state=undefined};
_ -> State1
end,
handle(Rest, State, EvHandler, EvHandlerState1)
end.
update_flow(State=#ws_state{flow=Flow0}, _ReplyTo, _StreamRef, Inc) ->
Flow = case Flow0 of
infinity -> infinity;
_ -> Flow0 + Inc
end,
[
{state, State#ws_state{flow=Flow}},
{active, Flow > 0}
].
%% The user already sent the close frame; do nothing.
closing(_, State=#ws_state{out=close}, _, EvHandlerState) ->
{closing(State), EvHandlerState};
closing(Reason, State, EvHandler, EvHandlerState) ->
Code = case Reason of
normal -> 1000;
owner_down -> 1001;
shutdown -> 1001;
{error, badframe} -> 1002;
{error, badencoding} -> 1007
end,
send({close, Code, <<>>}, State, EvHandler, EvHandlerState).
closing(#ws_state{opts=Opts}) ->
Timeout = maps:get(closing_timeout, Opts, 15000),
{closing, Timeout}.
close(_, _, _, EvHandlerState) ->
EvHandlerState.
%% Send one frame.
send(Frame, State=#ws_state{owner=ReplyTo, stream_ref=StreamRef,
socket=Socket, transport=Transport, in=In, extensions=Extensions},
EvHandler, EvHandlerState0) when not is_list(Frame) ->
WsSendFrameEvent = #{
stream_ref => StreamRef,
reply_to => ReplyTo,
extensions => Extensions,
frame => Frame
},
EvHandlerState1 = EvHandler:ws_send_frame_start(WsSendFrameEvent, EvHandlerState0),
Transport:send(Socket, cow_ws:masked_frame(Frame, Extensions)),
EvHandlerState = EvHandler:ws_send_frame_end(WsSendFrameEvent, EvHandlerState1),
if
Frame =:= close; element(1, Frame) =:= close ->
{[
{state, State#ws_state{out=close}},
%% We can close immediately if we already received a close frame.
case In of
close -> close;
_ -> closing(State)
end
], EvHandlerState};
true ->
{[], EvHandlerState}
end;
%% Send many frames.
send([], _, _, EvHandlerState) ->
{[], EvHandlerState};
send([Frame|Tail], State, EvHandler, EvHandlerState0) ->
case send(Frame, State, EvHandler, EvHandlerState0) of
{[], EvHandlerState} ->
send(Tail, State, EvHandler, EvHandlerState);
Other ->
Other
end.
%% Websocket has no concept of streams.
down(_) ->
{[], []}.
