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authorLoïc Hoguin <[email protected]>2011-07-19 12:12:25 +0200
committerLoïc Hoguin <[email protected]>2011-07-19 12:20:16 +0200
commit293cf33702c8cad471989c1e08ce05323baadaf7 (patch)
tree737b0fdf40b69b5a5b47a8241ee3be9a455df85c
parentd363f914107d156f52ad73bf6bc3afcf0b1db701 (diff)
downloadcowboy-293cf33702c8cad471989c1e08ce05323baadaf7.tar.gz
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cowboy-293cf33702c8cad471989c1e08ce05323baadaf7.zip
Separate message and packet handling for websockets
Improves the readability of websocket handler code by having two functions: websocket_handle/3 handles the packets received from the socket, removing the tuple construct that was otherwise needed, so only websocket_handle(Data, Req, State) is needed now; websocket_info/3 handles the messages that the websocket handler process received, as websocket_info(Info, Req, State). Both functions return values are handled identically by Cowboy so nothing changes on that end.
-rw-r--r--README.md12
-rw-r--r--src/cowboy_http_websocket.erl28
-rw-r--r--src/cowboy_http_websocket_handler.erl35
-rw-r--r--test/websocket_handler.erl12
4 files changed, 53 insertions, 34 deletions
diff --git a/README.md b/README.md
index f9fb6ec..5933481 100644
--- a/README.md
+++ b/README.md
@@ -179,7 +179,8 @@ Websocket would look like this:
-behaviour(cowboy_http_handler).
-behaviour(cowboy_http_websocket_handler).
-export([init/3, handle/2, terminate/2]).
--export([websocket_init/3, websocket_handle/3, websocket_terminate/3]).
+-export([websocket_init/3, websocket_handle/3,
+ websocket_info/3, websocket_terminate/3]).
init({tcp, http}, Req, Opts) ->
{upgrade, protocol, cowboy_http_websocket}.
@@ -194,11 +195,14 @@ websocket_init(TransportName, Req, _Opts) ->
erlang:start_timer(1000, self(), <<"Hello!">>),
{ok, Req, undefined_state}.
-websocket_handle({timeout, _Ref, Msg}, Req, State) ->
+websocket_handle(Msg, Req, State) ->
+ {reply, << "That's what she said! ", Msg/binary >>, Req, State}.
+
+websocket_info({timeout, _Ref, Msg}, Req, State) ->
erlang:start_timer(1000, self(), <<"How' you doin'?">>),
{reply, Msg, Req, State};
-websocket_handle({websocket, Msg}, Req, State) ->
- {reply, << "That's what she said! ", Msg/binary >>, Req, State}.
+websocket_info(_Info, Req, State) ->
+ {ok, Req, State}.
websocket_terminate(_Reason, _Req, _State) ->
ok.
diff --git a/src/cowboy_http_websocket.erl b/src/cowboy_http_websocket.erl
index fa3e50f..66187f0 100644
--- a/src/cowboy_http_websocket.erl
+++ b/src/cowboy_http_websocket.erl
@@ -157,7 +157,7 @@ handler_loop(State=#state{messages={OK, Closed, Error}, timeout=Timeout},
handler_terminate(State, Req, HandlerState, {error, Reason});
Message ->
handler_call(State, Req, HandlerState,
- SoFar, Message, fun handler_before_loop/4)
+ SoFar, websocket_info, Message, fun handler_before_loop/4)
after Timeout ->
websocket_close(State, Req, HandlerState, {normal, timeout})
end.
@@ -178,7 +178,7 @@ websocket_frame(State=#state{eop=EOP}, Req, HandlerState, Data, 0) ->
Pos2 = Pos - 1,
<< 0, Frame:Pos2/binary, 255, Rest/bits >> = Data,
handler_call(State, Req, HandlerState,
- Rest, {websocket, Frame}, fun websocket_data/4);
+ Rest, websocket_handle, Frame, fun websocket_data/4);
nomatch ->
%% @todo We probably should allow limiting frame length.
handler_before_loop(State, Req, HandlerState, Data)
@@ -186,10 +186,11 @@ websocket_frame(State=#state{eop=EOP}, Req, HandlerState, Data, 0) ->
websocket_frame(State, Req, HandlerState, _Data, _FrameType) ->
websocket_close(State, Req, HandlerState, {error, badframe}).
--spec handler_call(#state{}, #http_req{}, any(), binary(), any(), fun()) -> ok.
+-spec handler_call(#state{}, #http_req{}, any(), binary(),
+ atom(), any(), fun()) -> ok.
handler_call(State=#state{handler=Handler, opts=Opts}, Req, HandlerState,
- RemainingData, Message, NextState) ->
- try Handler:websocket_handle(Message, Req, HandlerState) of
+ RemainingData, Callback, Message, NextState) ->
+ try Handler:Callback(Message, Req, HandlerState) of
{ok, Req2, HandlerState2} ->
NextState(State, Req2, HandlerState2, RemainingData);
{ok, Req2, HandlerState2, hibernate} ->
@@ -242,16 +243,19 @@ handler_terminate(#state{handler=Handler, opts=Opts},
HandlerState, Req, erlang:get_stacktrace()])
end.
-%% eunit
+%% Tests.
-ifdef(TEST).
websocket_location_test() ->
- ?assertEqual(<<"ws://localhost/path">>, websocket_location(other, <<"localhost">>, 80, <<"/path">>)),
- ?assertEqual(<<"ws://localhost:8080/path">>, websocket_location(other, <<"localhost">>, 8080, <<"/path">>)),
- ?assertEqual(<<"wss://localhost/path">>, websocket_location(ssl, <<"localhost">>, 443, <<"/path">>)),
- ?assertEqual(<<"wss://localhost:8443/path">>, websocket_location(ssl, <<"localhost">>, 8443, <<"/path">>)),
- ok.
+ ?assertEqual(<<"ws://localhost/path">>,
+ websocket_location(other, <<"localhost">>, 80, <<"/path">>)),
+ ?assertEqual(<<"ws://localhost:8080/path">>,
+ websocket_location(other, <<"localhost">>, 8080, <<"/path">>)),
+ ?assertEqual(<<"wss://localhost/path">>,
+ websocket_location(ssl, <<"localhost">>, 443, <<"/path">>)),
+ ?assertEqual(<<"wss://localhost:8443/path">>,
+ websocket_location(ssl, <<"localhost">>, 8443, <<"/path">>)),
+ ok.
-endif.
-
diff --git a/src/cowboy_http_websocket_handler.erl b/src/cowboy_http_websocket_handler.erl
index b02c28d..90cf7ac 100644
--- a/src/cowboy_http_websocket_handler.erl
+++ b/src/cowboy_http_websocket_handler.erl
@@ -14,12 +14,13 @@
%% @doc Handler for HTTP WebSocket requests.
%%
-%% WebSocket handlers must implement three callbacks: <em>websocket_init/3</em>,
-%% <em>websocket_handle/3</em> and <em>websocket_terminate/3</em>. These
-%% callbacks will only be called if the connection is upgraded to WebSocket
-%% in the HTTP handler's <em>init/3</em> callback. They are then called in that
-%% order, although <em>websocket_handle/3</em> will be called multiple time,
-%% one time for each message or packet received.
+%% WebSocket handlers must implement four callbacks: <em>websocket_init/3</em>,
+%% <em>websocket_handle/3</em>, <em>websocket_info/3</em> and
+%% <em>websocket_terminate/3</em>. These callbacks will only be called if the
+%% connection is upgraded to WebSocket in the HTTP handler's <em>init/3</em>
+%% callback. They are then called in that order, although
+%% <em>websocket_handle/3</em> will be called for each packet received,
+%% and <em>websocket_info</em> for each message received.
%%
%% <em>websocket_init/3</em> is meant for initialization. It receives
%% information about the transport and protocol used, along with the handler
@@ -27,11 +28,15 @@
%% If you are going to want to compact the request, you should probably do it
%% here.
%%
-%% <em>websocket_handle/3</em> receives messages sent to the process and
-%% also the data sent to the socket. In the later case the information is
-%% given as a tuple <em>{websocket, Data}</em>. It can reply something, do
-%% nothing or close the connection. You can choose to hibernate the process
-%% by returning <em>hibernate</em> to save memory and CPU.
+%% <em>websocket_handle/3</em> receives the data from the socket. It can reply
+%% something, do nothing or close the connection. You can choose to hibernate
+%% the process by returning <em>hibernate</em> to save memory and CPU.
+%%
+%% <em>websocket_info/3</em> receives messages sent to the process. It has
+%% the same reply format as <em>websocket_handle/3</em> described above. Note
+%% that unlike in a <em>gen_server</em>, when <em>websocket_info/3</em>
+%% replies something, it is always to the socket, not to the process that
+%% originated the message.
%%
%% <em>websocket_terminate/3</em> is meant for cleaning up. It also receives
%% the request and the state previously defined, along with a reason for
@@ -41,9 +46,11 @@
-export([behaviour_info/1]).
%% @private
--spec behaviour_info(_) -> undefined | [{websocket_handle, 3}
- | {websocket_init, 3} | {websocket_terminate, 3}, ...].
+-spec behaviour_info(_)
+ -> undefined | [{websocket_handle, 3} | {websocket_info, 3}
+ | {websocket_init, 3} | {websocket_terminate, 3}, ...].
behaviour_info(callbacks) ->
- [{websocket_init, 3}, {websocket_handle, 3}, {websocket_terminate, 3}];
+ [{websocket_init, 3}, {websocket_handle, 3},
+ {websocket_info, 3}, {websocket_terminate, 3}];
behaviour_info(_Other) ->
undefined.
diff --git a/test/websocket_handler.erl b/test/websocket_handler.erl
index 8e6915b..d06bfee 100644
--- a/test/websocket_handler.erl
+++ b/test/websocket_handler.erl
@@ -4,7 +4,8 @@
-behaviour(cowboy_http_handler).
-behaviour(cowboy_http_websocket_handler).
-export([init/3, handle/2, terminate/2]).
--export([websocket_init/3, websocket_handle/3, websocket_terminate/3]).
+-export([websocket_init/3, websocket_handle/3,
+ websocket_info/3, websocket_terminate/3]).
init(_Any, _Req, _Opts) ->
{upgrade, protocol, cowboy_http_websocket}.
@@ -19,11 +20,14 @@ websocket_init(_TransportName, Req, _Opts) ->
erlang:start_timer(1000, self(), <<"websocket_init">>),
{ok, Req, undefined}.
-websocket_handle({timeout, _Ref, Msg}, Req, State) ->
+websocket_handle(Data, Req, State) ->
+ {reply, Data, Req, State}.
+
+websocket_info({timeout, _Ref, Msg}, Req, State) ->
erlang:start_timer(1000, self(), <<"websocket_handle">>),
{reply, Msg, Req, State};
-websocket_handle({websocket, Data}, Req, State) ->
- {reply, Data, Req, State}.
+websocket_info(_Info, Req, State) ->
+ {ok, Req, State}.
websocket_terminate(_Reason, _Req, _State) ->
ok.