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author | Loïc Hoguin <[email protected]> | 2017-02-18 18:26:20 +0100 |
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committer | Loïc Hoguin <[email protected]> | 2017-02-18 18:26:20 +0100 |
commit | a45813c60f0f983a24ea29d491b37f0590fdd087 (patch) | |
tree | c7e741ac4a684b365e70f7ff73d0c4b6e34232a7 /doc/src/guide/ws_handlers.asciidoc | |
parent | 80f8cda7ff8fe6a575b4c2eaedd8451acf4fcef3 (diff) | |
download | cowboy-a45813c60f0f983a24ea29d491b37f0590fdd087.tar.gz cowboy-a45813c60f0f983a24ea29d491b37f0590fdd087.tar.bz2 cowboy-a45813c60f0f983a24ea29d491b37f0590fdd087.zip |
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.
Diffstat (limited to 'doc/src/guide/ws_handlers.asciidoc')
-rw-r--r-- | doc/src/guide/ws_handlers.asciidoc | 9 |
1 files changed, 5 insertions, 4 deletions
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 |