Allow passing options to sub protocols

Before this commit we had an issue where configuring a
Websocket connection was simply not possible without
doing magic, adding callbacks or extra return values.
The init/2 function only allowed setting hibernate
and timeout options.

After this commit, when switching to a different
type of handler you can either return

  {module, Req, State}

or

  {module, Req, State, Opts}

where Opts is any value (as far as the sub protocol
interface is concerned) and is ultimately checked
by the custom handlers.

A large protocol like Websocket would accept only
a map there, with many different options, while a
small interface like loop handlers would allow
passing hibernate and nothing else.

For Websocket, hibernate must be set from the
websocket_init/1 callback, because init/2 executes
in a separate process.

Sub protocols now have two callbacks: one with the
Opts value, one without.

The loop handler code was largely reworked and
simplified. It does not need to manage a timeout
or read from the socket anymore, it's the job of
the protocol code. A lot of unnecessary stuff was
therefore removed.

Websocket compression must now be enabled from
the handler options instead of per listener. This
means that a project can have two separate Websocket
handlers with different options. Compression is
still disabled by default, and the idle_timeout
value was changed from inifnity to 60000 (60 seconds),
as that's safer and is also a good value for mobile
devices.

src/cowboy_handler.erl

@@ -25,9 +25,7 @@
 
 -callback init(Req, any())
 	-> {ok | module(), Req, any()}
-	| {module(), Req, any(), hibernate}
-	| {module(), Req, any(), timeout()}
-	| {module(), Req, any(), timeout(), hibernate}
+	| {module(), Req, any(), any()}
 	when Req::cowboy_req:req().
 
 -callback terminate(any(), cowboy_req:req(), any()) -> ok.
@@ -41,13 +39,9 @@ execute(Req, Env=#{handler := Handler, handler_opts := HandlerOpts}) ->
 			Result = terminate(normal, Req2, State, Handler),
 			{ok, Req2, Env#{result => Result}};
 		{Mod, Req2, State} ->
-			Mod:upgrade(Req2, Env, Handler, State, infinity, run);
-		{Mod, Req2, State, hibernate} ->
-			Mod:upgrade(Req2, Env, Handler, State, infinity, hibernate);
-		{Mod, Req2, State, Timeout} ->
-			Mod:upgrade(Req2, Env, Handler, State, Timeout, run);
-		{Mod, Req2, State, Timeout, hibernate} ->
-			Mod:upgrade(Req2, Env, Handler, State, Timeout, hibernate)
+			Mod:upgrade(Req2, Env, Handler, State);
+		{Mod, Req2, State, Opts} ->
+			Mod:upgrade(Req2, Env, Handler, State, Opts)
 	catch Class:Reason ->
 		terminate({crash, Class, Reason}, Req, HandlerOpts, Handler),
 		erlang:raise(Class, Reason, erlang:get_stacktrace())

src/cowboy_http.erl

@@ -136,11 +136,10 @@ init(Parent, Ref, Socket, Transport, Opts) ->
 %% Timeouts:
 %% - waiting for new request (if no stream is currently running)
 %%   -> request_timeout: for whole request/headers, set at init/when we set ps_request_line{} state
-%% - waiting for body (if a stream requested the body to be read)
-%%   -> read_body_timeout: amount of time we wait without receiving any data when reading the body
+%% - waiting for new request, or body (when a stream is currently running)
+%%   -> idle_timeout: amount of time we wait without receiving any data
 %% - if we skip the body, skip only for a specific duration
 %%   -> skip_body_timeout: also have a skip_body_length
-%% - none if we have a stream running and it didn't request the body to be read
 %% - global
 %%   -> inactivity_timeout: max time to wait without anything happening before giving up
 

src/cowboy_loop.erl

@@ -12,27 +12,18 @@
 %% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 %% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
-%% When using loop handlers, we are receiving data from the socket because we
-%% want to know when the socket gets closed. This is generally not an issue
-%% because these kinds of requests are generally not pipelined, and don't have
-%% a body. If they do have a body, this body is often read in the
-%% <em>init/2</em> callback and this is no problem. Otherwise, this data
-%% accumulates in a buffer until we reach a certain threshold of 5000 bytes
-%% by default. This can be configured through the <em>loop_max_buffer</em>
-%% environment value. The request will be terminated with an
-%% <em>{error, overflow}</em> reason if this threshold is reached.
 -module(cowboy_loop).
 -behaviour(cowboy_sub_protocol).
 
--export([upgrade/6]).
+-export([upgrade/4]).
+-export([upgrade/5]).
 -export([loop/4]).
 
 -callback init(Req, any())
 	-> {ok | module(), Req, any()}
-	| {module(), Req, any(), hibernate}
-	| {module(), Req, any(), timeout()}
-	| {module(), Req, any(), timeout(), hibernate}
+	| {module(), Req, any(), any()}
 	when Req::cowboy_req:req().
+
 -callback info(any(), Req, State)
 	-> {ok, Req, State}
 	| {ok, Req, State, hibernate}
@@ -42,97 +33,44 @@
 -callback terminate(any(), cowboy_req:req(), any()) -> ok.
 -optional_callbacks([terminate/3]).
 
--record(state, {
-	env :: cowboy_middleware:env(),
-	hibernate = false :: boolean(),
-	buffer_size = 0 :: non_neg_integer(),
-	max_buffer = 5000 :: non_neg_integer() | infinity,
-	timeout = infinity :: timeout(),
-	timeout_ref = undefined :: undefined | reference()
-}).
-
--spec upgrade(Req, Env, module(), any(), timeout(), run | hibernate)
-	-> {ok, Req, Env} | {suspend, module(), atom(), [any()]}
+-spec upgrade(Req, Env, module(), any())
+	-> {ok, Req, Env} | {suspend, ?MODULE, loop, [any()]}
 	when Req::cowboy_req:req(), Env::cowboy_middleware:env().
-upgrade(Req, Env, Handler, HandlerState, Timeout, Hibernate) ->
-	State = #state{env=Env, max_buffer=get_max_buffer(Env), timeout=Timeout,
-		hibernate=Hibernate =:= hibernate},
-	State2 = timeout(State),
-	before_loop(Req, State2, Handler, HandlerState).
+upgrade(Req, Env, Handler, HandlerState) ->
+	loop(Req, Env, Handler, HandlerState).
 
-get_max_buffer(#{loop_max_buffer := MaxBuffer}) -> MaxBuffer;
-get_max_buffer(_) -> 5000.
+-spec upgrade(Req, Env, module(), any(), hibernate)
+	-> {suspend, ?MODULE, loop, [any()]}
+	when Req::cowboy_req:req(), Env::cowboy_middleware:env().
+upgrade(Req, Env, Handler, HandlerState, hibernate) ->
+	suspend(Req, Env, Handler, HandlerState).
 
-before_loop(Req, State=#state{hibernate=true}, Handler, HandlerState) ->
-
-	%% @todo Yeah we can't get the socket anymore.
-	%% Everything changes since we are a separate process now.
-	%% Proper flow control at the connection level should be implemented
-	%% instead of what we have here.
-
-%	[Socket, Transport] = cowboy_req:get([socket, transport], Req),
-%	Transport:setopts(Socket, [{active, once}]),
-	{suspend, ?MODULE, loop, [Req, State#state{hibernate=false}, Handler, HandlerState]};
-before_loop(Req, State, Handler, HandlerState) ->
-
-	%% Same here.
-
-%	[Socket, Transport] = cowboy_req:get([socket, transport], Req),
-%	Transport:setopts(Socket, [{active, once}]),
-	loop(Req, State, Handler, HandlerState).
-
-%% Almost the same code can be found in cowboy_websocket.
-timeout(State=#state{timeout=infinity}) ->
-	State#state{timeout_ref=undefined};
-timeout(State=#state{timeout=Timeout,
-		timeout_ref=PrevRef}) ->
-	_ = case PrevRef of
-		undefined -> ignore%;
-% @todo		PrevRef -> erlang:cancel_timer(PrevRef)
-	end,
-	TRef = erlang:start_timer(Timeout, self(), ?MODULE),
-	State#state{timeout_ref=TRef}.
-
--spec loop(Req, #state{}, module(), any())
-	-> {ok, Req, cowboy_middleware:env()} | {suspend, module(), atom(), [any()]}
-	when Req::cowboy_req:req().
-loop(Req, State=#state{timeout_ref=TRef}, Handler, HandlerState) ->
+-spec loop(Req, Env, module(), any())
+	-> {ok, Req, Env} | {suspend, ?MODULE, loop, [any()]}
+	when Req::cowboy_req:req(), Env::cowboy_middleware:env().
+%% @todo Handle system messages.
+loop(Req, Env, Handler, HandlerState) ->
 	receive
-		{timeout, TRef, ?MODULE} ->
-			terminate(Req, State, Handler, HandlerState, timeout);
-		{timeout, OlderTRef, ?MODULE} when is_reference(OlderTRef) ->
-			loop(Req, State, Handler, HandlerState);
 		Message ->
-			call(Req, State, Handler, HandlerState, Message)
+			call(Req, Env, Handler, HandlerState, Message)
 	end.
 
-call(Req, State, Handler, HandlerState, Message) ->
-	try Handler:info(Message, Req, HandlerState) of
-		{ok, Req2, HandlerState2} ->
-			before_loop(Req2, State, Handler, HandlerState2);
-		{ok, Req2, HandlerState2, hibernate} ->
-			before_loop(Req2, State#state{hibernate=true}, Handler, HandlerState2);
-		{stop, Req2, HandlerState2} ->
-			terminate(Req2, State, Handler, HandlerState2, stop)
+call(Req0, Env, Handler, HandlerState0, Message) ->
+	try Handler:info(Message, Req0, HandlerState0) of
+		{ok, Req, HandlerState} ->
+			loop(Req, Env, Handler, HandlerState);
+		{ok, Req, HandlerState, hibernate} ->
+			suspend(Req, Env, Handler, HandlerState);
+		{stop, Req, HandlerState} ->
+			terminate(Req, Env, Handler, HandlerState, stop)
 	catch Class:Reason ->
-		cowboy_handler:terminate({crash, Class, Reason}, Req, HandlerState, Handler),
+		cowboy_handler:terminate({crash, Class, Reason}, Req0, HandlerState0, Handler),
 		erlang:raise(Class, Reason, erlang:get_stacktrace())
 	end.
 
-terminate(Req, #state{env=Env, timeout_ref=TRef},
-		Handler, HandlerState, Reason) ->
-	_ = case TRef of
-		undefined -> ignore;
-		TRef -> erlang:cancel_timer(TRef)
-	end,
-	flush_timeouts(),
+suspend(Req, Env, Handler, HandlerState) ->
+	{suspend, ?MODULE, loop, [Req, Env, Handler, HandlerState]}.
+
+terminate(Req, Env, Handler, HandlerState, Reason) ->
 	Result = cowboy_handler:terminate(Reason, Req, HandlerState, Handler),
 	{ok, Req, Env#{result => Result}}.
-
-flush_timeouts() ->
-	receive
-		{timeout, TRef, ?MODULE} when is_reference(TRef) ->
-			flush_timeouts()
-	after 0 ->
-		ok
-	end.

src/cowboy_rest.erl

@@ -17,15 +17,14 @@
 -module(cowboy_rest).
 -behaviour(cowboy_sub_protocol).
 
--export([upgrade/6]).
+-export([upgrade/4]).
+-export([upgrade/5]).
 
 %% Common handler callbacks.
 
 -callback init(Req, any())
 	-> {ok | module(), Req, any()}
-	| {module(), Req, any(), hibernate}
-	| {module(), Req, any(), timeout()}
-	| {module(), Req, any(), timeout(), hibernate}
+	| {module(), Req, any(), any()}
 	when Req::cowboy_req:req().
 
 -callback terminate(any(), cowboy_req:req(), any()) -> ok.
@@ -232,14 +231,20 @@
 	expires :: undefined | no_call | calendar:datetime() | binary()
 }).
 
--spec upgrade(Req, Env, module(), any(), infinity, run)
+-spec upgrade(Req, Env, module(), any())
 	-> {ok, Req, Env} when Req::cowboy_req:req(), Env::cowboy_middleware:env().
-upgrade(Req0, Env, Handler, HandlerState, infinity, run) ->
+upgrade(Req0, Env, Handler, HandlerState) ->
 	Method = cowboy_req:method(Req0),
 	{ok, Req, Result} = service_available(Req0, #state{method=Method,
 		handler=Handler, handler_state=HandlerState}),
 	{ok, Req, Env#{result => Result}}.
 
+-spec upgrade(Req, Env, module(), any(), any())
+	-> {ok, Req, Env} when Req::cowboy_req:req(), Env::cowboy_middleware:env().
+%% cowboy_rest takes no options.
+upgrade(Req, Env, Handler, HandlerState, _Opts) ->
+	upgrade(Req, Env, Handler, HandlerState).
+
 service_available(Req, State) ->
 	expect(Req, State, service_available, true, fun known_methods/2, 503).
 

src/cowboy_sub_protocol.erl

@@ -15,6 +15,10 @@
 
 -module(cowboy_sub_protocol).
 
--callback upgrade(Req, Env, module(), any(), timeout(), run | hibernate)
+-callback upgrade(Req, Env, module(), any())
+	-> {ok, Req, Env} | {suspend, module(), atom(), [any()]} | {stop, Req}
+	when Req::cowboy_req:req(), Env::cowboy_middleware:env().
+
+-callback upgrade(Req, Env, module(), any(), any())
 	-> {ok, Req, Env} | {suspend, module(), atom(), [any()]} | {stop, Req}
 	when Req::cowboy_req:req(), Env::cowboy_middleware:env().

src/cowboy_websocket.erl

@@ -17,7 +17,8 @@
 -module(cowboy_websocket).
 -behaviour(cowboy_sub_protocol).
 
--export([upgrade/6]).
+-export([upgrade/4]).
+-export([upgrade/5]).
 -export([takeover/7]).
 -export([handler_loop/3]).
 
@@ -34,9 +35,7 @@
 
 -callback init(Req, any())
 	-> {ok | module(), Req, any()}
-	| {module(), Req, any(), hibernate}
-	| {module(), Req, any(), timeout()}
-	| {module(), Req, any(), timeout(), hibernate}
+	| {module(), Req, any(), any()}
 	when Req::cowboy_req:req().
 
 -callback websocket_init(State)
@@ -53,6 +52,12 @@
 -callback terminate(any(), cowboy_req:req(), any()) -> ok.
 -optional_callbacks([terminate/3]).
 
+-type opts() :: #{
+	idle_timeout => timeout(),
+	compress => boolean()
+}.
+-export_type([opts/0]).
+
 -record(state, {
 	socket = undefined :: inet:socket() | undefined,
 	transport = undefined :: module(),
@@ -60,6 +65,7 @@
 	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(),
@@ -70,14 +76,22 @@
 
 %% Stream process.
 
--spec upgrade(Req, Env, module(), any(), timeout(), run | hibernate)
+-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, Timeout, Hibernate) ->
-	try websocket_upgrade(#state{handler=Handler, timeout=Timeout,
-			hibernate=Hibernate =:= hibernate}, Req0) of
+upgrade(Req0, Env, Handler, HandlerState, Opts) ->
+	Timeout = maps:get(idle_timeout, Opts, 60000),
+	Compress = maps:get(compress, Opts, false),
+	State0 = #state{handler=Handler, timeout=Timeout, compress=Compress},
+	try websocket_upgrade(State0, Req0) of
 		{ok, State, Req} ->
 			websocket_handshake(State, Req, HandlerState, Env)
 	catch _:_ ->
@@ -104,14 +118,13 @@ websocket_upgrade(State, Req) ->
 
 -spec websocket_extensions(#state{}, Req)
 	-> {ok, #state{}, Req} when Req::cowboy_req:req().
-websocket_extensions(State, Req=#{ref := Ref}) ->
+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
-	Compress = maps:get(websocket_compress, ranch:get_protocol_options(Ref), false),
 	case {Compress, cowboy_req:parse_header(<<"sec-websocket-extensions">>, Req)} of
 		{true, Extensions} when Extensions =/= undefined ->
 			websocket_extensions(State, Req, Extensions, []);
@@ -170,6 +183,7 @@ websocket_handshake(State=#state{key=Key},
 	{#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()},