%% Copyright (c) 2011, 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(cowboy_http_websocket).
-export([upgrade/3]).
-include("include/http.hrl").
-record(state, {
handler :: module(),
opts :: term(),
origin = undefined :: undefined | string(),
challenge = undefined :: undefined | binary(),
timeout = infinity :: timeout(),
messages = undefined :: undefined | {atom(), atom(), atom()}
}).
-spec upgrade(Handler::module(), Opts::term(), Req::#http_req{}) -> ok.
upgrade(Handler, Opts, Req) ->
case catch websocket_upgrade(#state{handler=Handler, opts=Opts}, Req) of
{ok, State, Req2} -> handler_init(State, Req2);
{'EXIT', _Reason} -> upgrade_error(Req)
end.
-spec websocket_upgrade(State::#state{}, Req::#http_req{})
-> {ok, State::#state{}, Req::#http_req{}}.
websocket_upgrade(State, Req=#http_req{socket=Socket, transport=Transport}) ->
{"Upgrade", Req2} = cowboy_http_req:header('Connection', Req),
{"WebSocket", Req3} = cowboy_http_req:header('Upgrade', Req2),
{Origin, Req4} = cowboy_http_req:header("Origin", Req3),
{Key1, Req5} = cowboy_http_req:header("Sec-Websocket-Key1", Req4),
{Key2, Req6} = cowboy_http_req:header("Sec-Websocket-Key2", Req5),
false = lists:member(undefined, [Origin, Key1, Key2]),
Transport:setopts(Socket, [binary]),
{ok, Key3, Req7} = cowboy_http_req:body(8, Req6),
Challenge = challenge(Key1, Key2, Key3),
{ok, State#state{origin=Origin, challenge=Challenge}, Req7}.
-spec challenge(Key1::string(), Key2::string(), Key3::binary()) -> binary().
challenge(Key1, Key2, Key3) ->
IntKey1 = key_to_integer(Key1),
IntKey2 = key_to_integer(Key2),
erlang:md5(<< IntKey1:32, IntKey2:32, Key3/binary >>).
-spec key_to_integer(Key::string()) -> integer().
key_to_integer(Key) ->
Number = list_to_integer([C || C <- Key, C >= $0, C =< $9]),
Spaces = length([C || C <- Key, C =:= 32]),
Number div Spaces.
-spec handler_init(State::#state{}, Req::#http_req{}) -> ok.
handler_init(State=#state{handler=Handler, opts=Opts},
Req=#http_req{transport=Transport}) ->
case catch Handler:websocket_init(Transport:name(), Req, Opts) of
{ok, Req2, HandlerState} ->
websocket_handshake(State, Req2, HandlerState);
{ok, Req2, HandlerState, Timeout} ->
websocket_handshake(State#state{timeout=Timeout},
Req2, HandlerState);
{'EXIT', _Reason} ->
upgrade_error(Req)
end.
-spec upgrade_error(Req::#http_req{}) -> ok.
upgrade_error(Req=#http_req{socket=Socket, transport=Transport}) ->
{ok, _Req} = cowboy_http_req:reply(400, [], [],
Req#http_req{resp_state=waiting}),
Transport:close(Socket).
-spec websocket_handshake(State::#state{}, Req::#http_req{},
HandlerState::term()) -> ok.
websocket_handshake(State=#state{origin=Origin, challenge=Challenge},
Req=#http_req{transport=Transport, raw_host=Host, raw_path=Path},
HandlerState) ->
Location = websocket_location(Transport:name(), Host, Path),
{ok, Req2} = cowboy_http_req:reply(
"101 WebSocket Protocol Handshake",
[{"Connection", "Upgrade"},
{"Upgrade", "WebSocket"},
{"Sec-WebSocket-Location", Location},
{"Sec-WebSocket-Origin", Origin}],
Challenge, Req#http_req{resp_state=waiting}),
handler_loop(State#state{messages=Transport:messages()},
Req2, HandlerState, <<>>).
-spec websocket_location(TransName::atom(), Host::string(), Path::string())
-> string().
websocket_location(ssl, Host, Path) ->
"wss://" ++ Host ++ Path;
websocket_location(_Any, Host, Path) ->
"ws://" ++ Host ++ Path.
-spec handler_loop(State::#state{}, Req::#http_req{},
HandlerState::term(), SoFar::binary()) -> ok.
handler_loop(State=#state{messages={OK, Closed, Error}, timeout=Timeout},
Req=#http_req{socket=Socket, transport=Transport},
HandlerState, SoFar) ->
Transport:setopts(Socket, [{active, once}]),
receive
{OK, Socket, Data} ->
websocket_data(State, 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});
Message ->
handler_call(State, Req, HandlerState,
SoFar, Message, fun handler_loop/4)
after Timeout ->
websocket_close(State, Req, HandlerState, {normal, timeout})
end.
-spec websocket_data(State::#state{}, Req::#http_req{},
HandlerState::term(), Data::binary()) -> ok.
websocket_data(State, Req, HandlerState, << 255, 0, _Rest/bits >>) ->
websocket_close(State, Req, HandlerState, {normal, closed});
websocket_data(State, Req, HandlerState, Data) when byte_size(Data) < 3 ->
handler_loop(State, Req, HandlerState, Data);
websocket_data(State, Req, HandlerState, Data) ->
websocket_frame(State, Req, HandlerState, Data, binary:first(Data)).
%% We do not support any frame type other than 0 yet. Just like the specs.
-spec websocket_frame(State::#state{}, Req::#http_req{},
HandlerState::term(), Data::binary(), FrameType::byte()) -> ok.
websocket_frame(State, Req, HandlerState, Data, 0) ->
case binary:match(Data, << 255 >>) of
{Pos, 1} ->
Pos2 = Pos - 1,
<< 0, Frame:Pos2/binary, 255, Rest/bits >> = Data,
handler_call(State, Req, HandlerState,
Rest, {websocket, Frame}, fun websocket_data/4);
nomatch ->
%% @todo We probably should allow limiting frame length.
handler_loop(State, Req, HandlerState, Data)
end;
websocket_frame(State, Req, HandlerState, _Data, _FrameType) ->
websocket_close(State, Req, HandlerState, {error, badframe}).
-spec handler_call(State::#state{}, Req::#http_req{}, HandlerState::term(),
RemainingData::binary(), Message::term(), NextState::fun()) -> ok.
handler_call(State=#state{handler=Handler}, Req, HandlerState,
RemainingData, Message, NextState) ->
case catch Handler:websocket_handle(Message, Req, HandlerState) of
{ok, Req2, HandlerState2} ->
NextState(State, Req2, HandlerState2, RemainingData);
{reply, Data, Req2, HandlerState2} ->
websocket_send(Data, Req2),
NextState(State, Req2, HandlerState2, RemainingData);
{shutdown, Req2, HandlerState2} ->
websocket_close(State, Req2, HandlerState2, {normal, shutdown});
{'EXIT', _Reason} ->
websocket_close(State, Req, HandlerState, {error, handler})
end.
-spec websocket_send(Data::binary(), Req::#http_req{}) -> ok.
websocket_send(Data, #http_req{socket=Socket, transport=Transport}) ->
Transport:send(Socket, << 0, Data/binary, 255 >>).
-spec websocket_close(State::#state{}, Req::#http_req{},
HandlerState::term(), Reason::{atom(), atom()}) -> ok.
websocket_close(State, Req=#http_req{socket=Socket, transport=Transport},
HandlerState, Reason) ->
Transport:send(Socket, << 255, 0 >>),
Transport:close(Socket),
handler_terminate(State, Req, HandlerState, Reason).
-spec handler_terminate(State::#state{}, Req::#http_req{},
HandlerState::term(), Reason::atom() | {atom(), atom()}) -> ok.
handler_terminate(#state{handler=Handler}, Req, HandlerState, Reason) ->
Handler:websocket_terminate(Reason, Req, HandlerState).
