From a45813c60f0f983a24ea29d491b37f0590fdd087 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Lo=C3=AFc=20Hoguin?= Date: Sat, 18 Feb 2017 18:26:20 +0100 Subject: 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. --- doc/src/guide/ws_handlers.asciidoc | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'doc/src/guide/ws_handlers.asciidoc') diff --git a/doc/src/guide/ws_handlers.asciidoc b/doc/src/guide/ws_handlers.asciidoc index 011aa31..2c38b87 100644 --- a/doc/src/guide/ws_handlers.asciidoc +++ b/doc/src/guide/ws_handlers.asciidoc @@ -60,13 +60,13 @@ be: init(Req, State) -> case cowboy_req:parse_header(<<"sec-websocket-protocol">>, Req) of undefined -> - {ok, Req, State}; + {cowboy_websocket, Req, State}; Subprotocols -> case lists:keymember(<<"mqtt">>, 1, Subprotocols) of true -> Req2 = cowboy_req:set_resp_header(<<"sec-websocket-protocol">>, <<"mqtt">>, Req), - {ok, Req2, State}; + {cowboy_websocket, Req2, State}; false -> {stop, Req, State} end @@ -210,12 +210,13 @@ than needed. The `init/2` callback can set the timeout to be used for the connection. For example, this would make Cowboy -close connections idle for more than 60 seconds: +close connections idle for more than 30 seconds: [source,erlang] ---- init(Req, State) -> - {cowboy_websocket, Req, State, 60000}. + {cowboy_websocket, Req, State, #{ + idle_timeout => 30000}}. ---- This value cannot be changed once it is set. It defaults to -- cgit v1.2.3