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|
= gun_ws_protocol(3)
== Name
gun_ws_protocol - Websocket subprotocols
== Description
The `gun_ws_protocol` module provides the callback interface
and types for implementing Websocket subprotocols.
== Callbacks
Websocket subprotocols implement the following interface.
=== init
[source,erlang]
----
init(ReplyTo, StreamRef, Headers, Opts) -> {ok, State}
ReplyTo :: pid()
StreamRef :: reference()
Headers :: cow_http:headers()
Opts :: gun:ws_opts()
State :: protocol_state()
----
Initialize the Websocket protocol.
ReplyTo::
The pid of the process that owns the stream and to
which messages will be sent to.
StreamRef::
The reference for the stream. Must be sent in messages
to distinguish between different streams.
Headers::
Headers that were sent in the response establishing
the Websocket connection.
Opts::
Websocket options. Custom options can be provided in
the `user_opts` key.
State::
State for the protocol.
=== handle
[source,erlang]
----
handle(Frame, State) -> {ok, FlowDec, State}
Frame :: cow_ws:frame()
State :: protocol_state()
FlowDec :: non_neg_integer()
----
Handle a Websocket frame.
This callback may receive fragmented frames depending
on the protocol and may need to rebuild the full
frame to process it.
Frame::
Websocket frame.
State::
State for the protocol.
FlowDec::
How many messages were sent. Used to update the flow
control state when the feature is enabled.
== Types
=== protocol_state()
[source,erlang]
----
protocol_state() :: any()
----
State for the protocol.
As this part of the implementation of the protocol
the type may differ between different Websocket
protocol modules.
== Changelog
* *2.0*: Module introduced.
== See also
link:man:gun(7)[gun(7)],
link:man:gun(3)[gun(3)],
link:man:gun:ws_upgrade(3)[gun:ws_upgrade(3)]
|
