From 136d443b5c38bee96f5d995dfea3629ef07564c3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lo=C3=AFc=20Hoguin?= <essen@ninenines.eu>
Date: Thu, 18 Jul 2019 09:59:28 +0200
Subject: Announce Ranch 2.0.0-rc.1

Adds Ranch 2.0 documentation and removes documentation for
very old Cowboy and Ranch, along with Erlang.mk documentation
which is available on its own website.
---
 docs/en/cowboy/2.0/guide/ws_handlers.asciidoc | 268 --------------------------
 1 file changed, 268 deletions(-)
 delete mode 100644 docs/en/cowboy/2.0/guide/ws_handlers.asciidoc

(limited to 'docs/en/cowboy/2.0/guide/ws_handlers.asciidoc')

diff --git a/docs/en/cowboy/2.0/guide/ws_handlers.asciidoc b/docs/en/cowboy/2.0/guide/ws_handlers.asciidoc
deleted file mode 100644
index 84dfb9bc..00000000
--- a/docs/en/cowboy/2.0/guide/ws_handlers.asciidoc
+++ /dev/null
@@ -1,268 +0,0 @@
-[[ws_handlers]]
-== Websocket handlers
-
-Websocket handlers provide an interface for upgrading HTTP/1.1
-connections to Websocket and sending or receiving frames on
-the Websocket connection.
-
-As Websocket connections are established through the HTTP/1.1
-upgrade mechanism, Websocket handlers need to be able to first
-receive the HTTP request for the upgrade, before switching to
-Websocket and taking over the connection. They can then receive
-or send Websocket frames, handle incoming Erlang messages or
-close the connection.
-
-=== Upgrade
-
-The `init/2` callback is called when the request is received.
-To establish a Websocket connection, you must switch to the
-`cowboy_websocket` module:
-
-[source,erlang]
-----
-init(Req, State) ->
-    {cowboy_websocket, Req, State}.
-----
-
-Cowboy will perform the Websocket handshake immediately. Note
-that the handshake will fail if the client did not request an
-upgrade to Websocket.
-
-The Req object becomes unavailable after this function returns.
-Any information required for proper execution of the Websocket
-handler must be saved in the state.
-
-=== Subprotocol
-
-The client may provide a list of Websocket subprotocols it
-supports in the sec-websocket-protocol header. The server *must*
-select one of them and send it back to the client or the
-handshake will fail.
-
-For example, a client could understand both STOMP and MQTT over
-Websocket, and provide the header:
-
-----
-sec-websocket-protocol: v12.stomp, mqtt
-----
-
-If the server only understands MQTT it can return:
-
-----
-sec-websocket-protocol: mqtt
-----
-
-This selection must be done in `init/2`. An example usage could
-be:
-
-[source,erlang]
-----
-init(Req, State) ->
-    case cowboy_req:parse_header(<<"sec-websocket-protocol">>, Req) of
-        undefined ->
-            {cowboy_websocket, Req, State};
-        Subprotocols ->
-            case lists:keymember(<<"mqtt">>, 1, Subprotocols) of
-                true ->
-                    Req2 = cowboy_req:set_resp_header(<<"sec-websocket-protocol">>,
-                        <<"mqtt">>, Req),
-                    {cowboy_websocket, Req2, State};
-                false ->
-                    {stop, Req, State}
-            end
-    end.
-----
-
-=== Post-upgrade initialization
-
-Cowboy has separate processes for handling the connection
-and requests. Because Websocket takes over the connection,
-the Websocket protocol handling occurs in a different
-process than the request handling.
-
-This is reflected in the different callbacks Websocket
-handlers have. The `init/2` callback is called from the
-temporary request process and the `websocket_` callbacks
-from the connection process.
-
-This means that some initialization cannot be done from
-`init/2`. Anything that would require the current pid,
-or be tied to the current pid, will not work as intended.
-The optional `websocket_init/1` can be used instead:
-
-[source,erlang]
-----
-websocket_init(State) ->
-    erlang:start_timer(1000, self(), <<"Hello!">>),
-    {ok, State}.
-----
-
-All Websocket callbacks share the same return values. This
-means that we can send frames to the client right after
-the upgrade:
-
-[source,erlang]
-----
-websocket_init(State) ->
-    {reply, {text, <<"Hello!">>}, State}.
-----
-
-=== Receiving frames
-
-Cowboy will call `websocket_handle/2` whenever a text, binary,
-ping or pong frame arrives from the client.
-
-The handler can handle or ignore the frames. It can also
-send frames back to the client or stop the connection.
-
-The following snippet echoes back any text frame received and
-ignores all others:
-
-[source,erlang]
-----
-websocket_handle(Frame = {text, _}, State) ->
-    {reply, Frame, State};
-websocket_handle(_Frame, State) ->
-    {ok, State}.
-----
-
-Note that ping and pong frames require no action from the
-handler as Cowboy will automatically reply to ping frames.
-They are provided for informative purposes only.
-
-=== Receiving Erlang messages
-
-Cowboy will call `websocket_info/2` whenever an Erlang message
-arrives.
-
-The handler can handle or ignore the messages. It can also
-send frames to the client or stop the connection.
-
-The following snippet forwards log messages to the client
-and ignores all others:
-
-[source,erlang]
-----
-websocket_info({log, Text}, State) ->
-    {reply, {text, Text}, State};
-websocket_info(_Info, State) ->
-    {ok, State}.
-----
-
-=== Sending frames
-
-// @todo This will be deprecated and eventually replaced with a
-// {Commands, State} interface that allows providing more
-// functionality easily.
-
-All `websocket_` callbacks share return values. They may
-send zero, one or many frames to the client.
-
-To send nothing, just return an ok tuple:
-
-[source,erlang]
-----
-websocket_info(_Info, State) ->
-    {ok, State}.
-----
-
-To send one frame, return a reply tuple with the frame to send:
-
-[source,erlang]
-----
-websocket_info(_Info, State) ->
-    {reply, {text, <<"Hello!">>}, State}.
-----
-
-You can send frames of any type: text, binary, ping, pong
-or close frames.
-
-To send many frames at once, return a reply tuple with the
-list of frames to send:
-
-[source,erlang]
-----
-websocket_info(_Info, State) ->
-    {reply, [
-        {text, "Hello"},
-        {text, <<"world!">>},
-        {binary, <<0:8000>>}
-    ], State}.
-----
-
-They are sent in the given order.
-
-=== Keeping the connection alive
-
-Cowboy will automatically respond to ping frames sent by
-the client. They are still forwarded to the handler for
-informative purposes, but no further action is required.
-
-Cowboy does not send ping frames itself. The handler can
-do it if required. A better solution in most cases is to
-let the client handle pings. Doing it from the handler
-would imply having an additional timer per connection and
-this can be a considerable cost for servers that need to
-handle large numbers of connections.
-
-Cowboy can be configured to close idle connections
-automatically. It is highly recommended to configure
-a timeout here, to avoid having processes linger longer
-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 30 seconds:
-
-[source,erlang]
-----
-init(Req, State) ->
-    {cowboy_websocket, Req, State, #{
-        idle_timeout => 30000}}.
-----
-
-This value cannot be changed once it is set. It defaults to
-`60000`.
-
-=== Saving memory
-
-The Websocket connection process can be set to hibernate
-after the callback returns.
-
-Simply add an `hibernate` field to the ok or reply tuples:
-
-[source,erlang]
-----
-websocket_init(State) ->
-    {ok, State, hibernate}.
-
-websocket_handle(_Frame, State) ->
-    {ok, State, hibernate}.
-
-websocket_info(_Info, State) ->
-    {reply, {text, <<"Hello!">>}, State, hibernate}.
-----
-
-It is highly recommended to write your handlers with
-hibernate enabled, as this allows to greatly reduce the
-memory usage. Do note however that an increase in the
-CPU usage or latency can be observed instead, in particular
-for the more busy connections.
-
-=== Closing the connection
-
-The connection can be closed at any time, either by telling
-Cowboy to stop it or by sending a close frame.
-
-To tell Cowboy to close the connection, use a stop tuple:
-
-[source,erlang]
-----
-websocket_info(_Info, State) ->
-    {stop, State}.
-----
-
-Sending a `close` frame will immediately initiate the closing
-of the Websocket connection. Note that when sending a list of
-frames that include a close frame, any frame found after the
-close frame will not be sent.
-- 
cgit v1.2.3

