Initial draft-hixie-thewebsocketprotocol-76 support.

1 files changed, 183 insertions, 0 deletions

diff --git a/src/cowboy_http_websocket.erl b/src/cowboy_http_websocket.erl
new file mode 100644
index 0000000..46c2ffa
--- /dev/null
+++ b/src/cowboy_http_websocket.erl
@@ -0,0 +1,183 @@
+%% 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/types.hrl").
+-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).