Allow websocket handlers to reply more than one frame

Instead of returning {text, Data}, you can now return
[{text, Data}, {text, Data2}, ...].

src/cowboy_websocket.erl

@@ -450,11 +450,22 @@ handler_call(State=#state{handler=Handler, opts=Opts}, Req, HandlerState,
 		{ok, Req2, HandlerState2, hibernate} ->
 			NextState(State#state{hibernate=true},
 				Req2, HandlerState2, RemainingData);
-		{reply, Payload, Req2, HandlerState2} ->
-			websocket_send(Payload, State),
+		{reply, Payload, Req2, HandlerState2}
+				when is_tuple(Payload) ->
+			ok = websocket_send(Payload, State),
 			NextState(State, Req2, HandlerState2, RemainingData);
-		{reply, Payload, Req2, HandlerState2, hibernate} ->
-			websocket_send(Payload, State),
+		{reply, Payload, Req2, HandlerState2, hibernate}
+				when is_tuple(Payload) ->
+			ok = websocket_send(Payload, State),
+			NextState(State#state{hibernate=true},
+				Req2, HandlerState2, RemainingData);
+		{reply, Payload, Req2, HandlerState2}
+				when is_list(Payload) ->
+			ok = websocket_send_many(Payload, State),
+			NextState(State, Req2, HandlerState2, RemainingData);
+		{reply, Payload, Req2, HandlerState2, hibernate}
+				when is_list(Payload) ->
+			ok = websocket_send_many(Payload, State),
 			NextState(State#state{hibernate=true},
 				Req2, HandlerState2, RemainingData);
 		{shutdown, Req2, HandlerState2} ->
@@ -471,14 +482,15 @@ handler_call(State=#state{handler=Handler, opts=Opts}, Req, HandlerState,
 		websocket_close(State, Req, HandlerState, {error, handler})
 	end.
 
--spec websocket_send(binary(), #state{}) -> closed | ignore.
+-spec websocket_send({text | binary | ping | pong, binary()}, #state{})
+	-> ok | {error, atom()}.
 %% hixie-76 text frame.
 websocket_send({text, Payload}, #state{
 		socket=Socket, transport=Transport, version=0}) ->
 	Transport:send(Socket, [0, Payload, 255]);
 %% Ignore all unknown frame types for compatibility with hixie 76.
 websocket_send(_Any, #state{version=0}) ->
-	ignore;
+	ok;
 websocket_send({Type, Payload}, #state{socket=Socket, transport=Transport}) ->
 	Opcode = case Type of
 		text -> 1;
@@ -490,6 +502,14 @@ websocket_send({Type, Payload}, #state{socket=Socket, transport=Transport}) ->
 	Transport:send(Socket, [<< 1:1, 0:3, Opcode:4, 0:1, Len/bits >>,
 		Payload]).
 
+-spec websocket_send_many([{text | binary | ping | pong, binary()}], #state{})
+	-> ok | {error, atom()}.
+websocket_send_many([], _) ->
+	ok;
+websocket_send_many([Frame|Tail], State) ->
+	ok = websocket_send(Frame, State),
+	websocket_send_many(Tail, State).
+
 -spec websocket_close(#state{}, cowboy_req:req(), any(), {atom(), atom()})
 	-> closed.
 websocket_close(State=#state{socket=Socket, transport=Transport, version=0},

test/ws_SUITE.erl

@@ -16,10 +16,23 @@
 
 -include_lib("common_test/include/ct.hrl").
 
--export([all/0, groups/0, init_per_suite/1, end_per_suite/1,
-	init_per_group/2, end_per_group/2]). %% ct.
--export([ws0/1, ws8/1, ws8_single_bytes/1, ws8_init_shutdown/1,
-	ws13/1, ws_timeout_hibernate/1, ws_text_fragments/1]). %% ws.
+%% ct.
+-export([all/0]).
+-export([groups/0]).
+-export([init_per_suite/1]).
+-export([end_per_suite/1]).
+-export([init_per_group/2]).
+-export([end_per_group/2]).
+
+%% Tests.
+-export([ws0/1]).
+-export([ws8/1]).
+-export([ws8_init_shutdown/1]).
+-export([ws8_single_bytes/1]).
+-export([ws13/1]).
+-export([ws_send_many/1]).
+-export([ws_text_fragments/1]).
+-export([ws_timeout_hibernate/1]).
 
 %% ct.
 
@@ -27,8 +40,16 @@ all() ->
 	[{group, ws}].
 
 groups() ->
-	BaseTests = [ws0, ws8, ws8_single_bytes, ws8_init_shutdown, ws13,
-		ws_timeout_hibernate, ws_text_fragments],
+	BaseTests = [
+		ws0,
+		ws8,
+		ws8_init_shutdown,
+		ws8_single_bytes,
+		ws13,
+		ws_send_many,
+		ws_text_fragments,
+		ws_timeout_hibernate
+	],
 	[{ws, [], BaseTests}].
 
 init_per_suite(Config) ->
@@ -62,9 +83,10 @@ init_dispatch() ->
 	[
 		{[<<"localhost">>], [
 			{[<<"websocket">>], websocket_handler, []},
-			{[<<"ws_timeout_hibernate">>], ws_timeout_hibernate_handler, []},
+			{[<<"ws_echo_handler">>], websocket_echo_handler, []},
 			{[<<"ws_init_shutdown">>], websocket_handler_init_shutdown, []},
-			{[<<"ws_echo_handler">>], websocket_echo_handler, []}
+			{[<<"ws_send_many">>], ws_send_many_handler, []},
+			{[<<"ws_timeout_hibernate">>], ws_timeout_hibernate_handler, []}
 		]}
 	].
 
@@ -158,6 +180,25 @@ ws8(Config) ->
 	{error, closed} = gen_tcp:recv(Socket, 0, 6000),
 	ok.
 
+ws8_init_shutdown(Config) ->
+	{port, Port} = lists:keyfind(port, 1, Config),
+	{ok, Socket} = gen_tcp:connect("localhost", Port,
+		[binary, {active, false}, {packet, raw}]),
+	ok = gen_tcp:send(Socket, [
+		"GET /ws_init_shutdown HTTP/1.1\r\n"
+		"Host: localhost\r\n"
+		"Connection: Upgrade\r\n"
+		"Upgrade: websocket\r\n"
+		"Sec-WebSocket-Origin: http://localhost\r\n"
+		"Sec-WebSocket-Version: 8\r\n"
+		"Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==\r\n"
+		"\r\n"]),
+	{ok, Handshake} = gen_tcp:recv(Socket, 0, 6000),
+	{ok, {http_response, {1, 1}, 403, "Forbidden"}, _Rest}
+		= erlang:decode_packet(http, Handshake, []),
+	{error, closed} = gen_tcp:recv(Socket, 0, 6000),
+	ok.
+
 ws8_single_bytes(Config) ->
 	{port, Port} = lists:keyfind(port, 1, Config),
 	{ok, Socket} = gen_tcp:connect("localhost", Port,
@@ -218,51 +259,6 @@ ws8_single_bytes(Config) ->
 	{error, closed} = gen_tcp:recv(Socket, 0, 6000),
 	ok.
 
-ws_timeout_hibernate(Config) ->
-	{port, Port} = lists:keyfind(port, 1, Config),
-	{ok, Socket} = gen_tcp:connect("localhost", Port,
-		[binary, {active, false}, {packet, raw}]),
-	ok = gen_tcp:send(Socket, [
-		"GET /ws_timeout_hibernate HTTP/1.1\r\n"
-		"Host: localhost\r\n"
-		"Connection: Upgrade\r\n"
-		"Upgrade: websocket\r\n"
-		"Sec-WebSocket-Origin: http://localhost\r\n"
-		"Sec-WebSocket-Version: 8\r\n"
-		"Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==\r\n"
-		"\r\n"]),
-	{ok, Handshake} = gen_tcp:recv(Socket, 0, 6000),
-	{ok, {http_response, {1, 1}, 101, "Switching Protocols"}, Rest}
-		= erlang:decode_packet(http, Handshake, []),
-	[Headers, <<>>] = websocket_headers(
-		erlang:decode_packet(httph, Rest, []), []),
-	{'Connection', "Upgrade"} = lists:keyfind('Connection', 1, Headers),
-	{'Upgrade', "websocket"} = lists:keyfind('Upgrade', 1, Headers),
-	{"sec-websocket-accept", "s3pPLMBiTxaQ9kYGzzhZRbK+xOo="}
-		= lists:keyfind("sec-websocket-accept", 1, Headers),
-	{ok, << 1:1, 0:3, 8:4, 0:8 >>} = gen_tcp:recv(Socket, 0, 6000),
-	{error, closed} = gen_tcp:recv(Socket, 0, 6000),
-	ok.
-
-ws8_init_shutdown(Config) ->
-	{port, Port} = lists:keyfind(port, 1, Config),
-	{ok, Socket} = gen_tcp:connect("localhost", Port,
-		[binary, {active, false}, {packet, raw}]),
-	ok = gen_tcp:send(Socket, [
-		"GET /ws_init_shutdown HTTP/1.1\r\n"
-		"Host: localhost\r\n"
-		"Connection: Upgrade\r\n"
-		"Upgrade: websocket\r\n"
-		"Sec-WebSocket-Origin: http://localhost\r\n"
-		"Sec-WebSocket-Version: 8\r\n"
-		"Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==\r\n"
-		"\r\n"]),
-	{ok, Handshake} = gen_tcp:recv(Socket, 0, 6000),
-	{ok, {http_response, {1, 1}, 403, "Forbidden"}, _Rest}
-		= erlang:decode_packet(http, Handshake, []),
-	{error, closed} = gen_tcp:recv(Socket, 0, 6000),
-	ok.
-
 ws13(Config) ->
 	{port, Port} = lists:keyfind(port, 1, Config),
 	{ok, Socket} = gen_tcp:connect("localhost", Port,
@@ -314,6 +310,39 @@ ws13(Config) ->
 	{error, closed} = gen_tcp:recv(Socket, 0, 6000),
 	ok.
 
+ws_send_many(Config) ->
+	{port, Port} = lists:keyfind(port, 1, Config),
+	{ok, Socket} = gen_tcp:connect("localhost", Port,
+		[binary, {active, false}, {packet, raw}]),
+	ok = gen_tcp:send(Socket, [
+		"GET /ws_send_many HTTP/1.1\r\n"
+		"Host: localhost\r\n"
+		"Connection: Upgrade\r\n"
+		"Upgrade: websocket\r\n"
+		"Sec-WebSocket-Origin: http://localhost\r\n"
+		"Sec-WebSocket-Version: 8\r\n"
+		"Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==\r\n"
+		"\r\n"]),
+	{ok, Handshake} = gen_tcp:recv(Socket, 0, 6000),
+	{ok, {http_response, {1, 1}, 101, "Switching Protocols"}, Rest}
+		= erlang:decode_packet(http, Handshake, []),
+	[Headers, <<>>] = websocket_headers(
+		erlang:decode_packet(httph, Rest, []), []),
+	{'Connection', "Upgrade"} = lists:keyfind('Connection', 1, Headers),
+	{'Upgrade', "websocket"} = lists:keyfind('Upgrade', 1, Headers),
+	{"sec-websocket-accept", "s3pPLMBiTxaQ9kYGzzhZRbK+xOo="}
+		= lists:keyfind("sec-websocket-accept", 1, Headers),
+	{ok, << 1:1, 0:3, 1:4, 0:1, 3:7, "one" >>}
+		= gen_tcp:recv(Socket, 0, 6000),
+	{ok, << 1:1, 0:3, 1:4, 0:1, 3:7, "two" >>}
+		= gen_tcp:recv(Socket, 0, 6000),
+	{ok, << 1:1, 0:3, 1:4, 0:1, 6:7, "seven!" >>}
+		= gen_tcp:recv(Socket, 0, 6000),
+	ok = gen_tcp:send(Socket, << 1:1, 0:3, 8:4, 0:8 >>), %% close
+	{ok, << 1:1, 0:3, 8:4, 0:8 >>} = gen_tcp:recv(Socket, 0, 6000),
+	{error, closed} = gen_tcp:recv(Socket, 0, 6000),
+	ok.
+
 ws_text_fragments(Config) ->
 	{port, Port} = lists:keyfind(port, 1, Config),
 	{ok, Socket} = gen_tcp:connect("localhost", Port,
@@ -369,6 +398,33 @@ ws_text_fragments(Config) ->
 	{error, closed} = gen_tcp:recv(Socket, 0, 6000),
 	ok.
 
+ws_timeout_hibernate(Config) ->
+	{port, Port} = lists:keyfind(port, 1, Config),
+	{ok, Socket} = gen_tcp:connect("localhost", Port,
+		[binary, {active, false}, {packet, raw}]),
+	ok = gen_tcp:send(Socket, [
+		"GET /ws_timeout_hibernate HTTP/1.1\r\n"
+		"Host: localhost\r\n"
+		"Connection: Upgrade\r\n"
+		"Upgrade: websocket\r\n"
+		"Sec-WebSocket-Origin: http://localhost\r\n"
+		"Sec-WebSocket-Version: 8\r\n"
+		"Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==\r\n"
+		"\r\n"]),
+	{ok, Handshake} = gen_tcp:recv(Socket, 0, 6000),
+	{ok, {http_response, {1, 1}, 101, "Switching Protocols"}, Rest}
+		= erlang:decode_packet(http, Handshake, []),
+	[Headers, <<>>] = websocket_headers(
+		erlang:decode_packet(httph, Rest, []), []),
+	{'Connection', "Upgrade"} = lists:keyfind('Connection', 1, Headers),
+	{'Upgrade', "websocket"} = lists:keyfind('Upgrade', 1, Headers),
+	{"sec-websocket-accept", "s3pPLMBiTxaQ9kYGzzhZRbK+xOo="}
+		= lists:keyfind("sec-websocket-accept", 1, Headers),
+	{ok, << 1:1, 0:3, 8:4, 0:8 >>} = gen_tcp:recv(Socket, 0, 6000),
+	{error, closed} = gen_tcp:recv(Socket, 0, 6000),
+	ok.
+
+%% Internal.
 
 websocket_headers({ok, http_eoh, Rest}, Acc) ->
 	[Acc, Rest];

test/ws_send_many_handler.erl

@@ -0,0 +1,31 @@
+%% Feel free to use, reuse and abuse the code in this file.
+
+-module(ws_send_many_handler).
+-behaviour(cowboy_websocket_handler).
+
+-export([init/3]).
+-export([websocket_init/3]).
+-export([websocket_handle/3]).
+-export([websocket_info/3]).
+-export([websocket_terminate/3]).
+
+init(_Any, _Req, _Opts) ->
+	{upgrade, protocol, cowboy_websocket}.
+
+websocket_init(_TransportName, Req, _Opts) ->
+	Req2 = cowboy_req:compact(Req),
+	erlang:send_after(10, self(), send_many),
+	{ok, Req2, undefined}.
+
+websocket_handle(_Frame, Req, State) ->
+	{ok, Req, State}.
+
+websocket_info(send_many, Req, State) ->
+	{reply, [
+		{text, <<"one">>},
+		{text, <<"two">>},
+		{text, <<"seven!">>}
+	], Req, State}.
+
+websocket_terminate(_Reason, _Req, _State) ->
+	ok.