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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/manual/cowboy_websocket.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/manual/cowboy_websocket.asciidoc')
-rw-r--r-- | doc/src/manual/cowboy_websocket.asciidoc | 66 |
1 files changed, 38 insertions, 28 deletions
diff --git a/doc/src/manual/cowboy_websocket.asciidoc b/doc/src/manual/cowboy_websocket.asciidoc index 73f5e72..b728edf 100644 --- a/doc/src/manual/cowboy_websocket.asciidoc +++ b/doc/src/manual/cowboy_websocket.asciidoc @@ -10,31 +10,6 @@ The module `cowboy_websocket` implements Websocket as a Ranch protocol. It also defines a callback interface for handling Websocket connections. -== Options - -[source,erlang] ----- -opts() :: #{ - websocket_compress := boolean() -} ----- - -Configuration for the Websocket protocol. - -This configuration is passed to Cowboy when starting listeners -using `cowboy:start_clear/4` or `cowboy:start_tls/4` functions. - -It can be updated without restarting listeners using the -Ranch functions `ranch:get_protocol_options/1` and -`ranch:set_protocol_options/2`. - -The default value is given next to the option name: - -websocket_compress (false):: - Whether to enable the Websocket frame compression - extension. Frames will only be compressed for the - clients that support this extension. - == Callbacks Websocket handlers must implement the following callback @@ -44,9 +19,7 @@ interface: ---- init(Req, State) -> {cowboy_websocket, Req, State} - | {cowboy_websocket, Req, State, hibernate} - | {cowboy_websocket, Req, State, timeout()} - | {cowboy_websocket, Req, State, timeout(), hibernate} + | {cowboy_websocket, Req, State, Opts} websocket_init(State) -> CallResult %% optional websocket_handle(InFrame, State) -> CallResult @@ -56,6 +29,7 @@ terminate(Reason, undefined, State) -> ok %% optional Req :: cowboy_req:req() State :: any() +Opts :: cowboy_websocket:opts() InFrame :: {text | binary | ping | pong, binary()} OutFrame :: cow_ws:frame() Info :: any() @@ -152,6 +126,42 @@ timeout:: {error, Reason}:: A socket error ocurred. +== Types + +=== opts() + +[source,erlang] +---- +opts() :: #{ + compress => boolean(), + idle_timeout => timeout() +} +---- + +Websocket handler options. + +This configuration is passed to Cowboy from the `init/2` +function: + +[source,erlang] +---- +init(Req, State) -> + Opts = #{compress => true}, + {cowboy_websocket, Req, State, Opts}. +---- + +The default value is given next to the option name: + +compress (false):: + Whether to enable the Websocket frame compression + extension. Frames will only be compressed for the + clients that support this extension. + +idle_timeout (60000):: + Time in milliseconds that Cowboy will keep the + connection open without receiving anything from + the client. + == Changelog * *2.0*: The Req object is no longer passed to Websocket callbacks. |