From d5f1a47e9ab758a51b23440eb72a0251527f3f7b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lo=C3=AFc=20Hoguin?= <essen@ninenines.eu>
Date: Thu, 22 Oct 2020 18:48:06 +0200
Subject: Initial implementation of Websocket over HTTP/2

---
 src/gun_ws.erl | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

(limited to 'src/gun_ws.erl')

diff --git a/src/gun_ws.erl b/src/gun_ws.erl
index f413f94..a1fdfae 100644
--- a/src/gun_ws.erl
+++ b/src/gun_ws.erl
@@ -15,12 +15,15 @@
 -module(gun_ws).
 
 -export([check_options/1]).
+-export([select_extensions/3]).
+-export([select_protocol/2]).
 -export([name/0]).
 -export([opts_name/0]).
 -export([has_keepalive/0]).
 -export([default_keepalive/0]).
 -export([init/4]).
 -export([handle/5]).
+-export([handle_continue/6]).
 -export([update_flow/4]).
 -export([closing/4]).
 -export([close/4]).
@@ -89,6 +92,47 @@ do_check_options([{user_opts, _}|Opts]) ->
 do_check_options([Opt|_]) ->
 	{error, {options, {ws, Opt}}}.
 
+select_extensions(Headers, Extensions0, Opts) ->
+	case lists:keyfind(<<"sec-websocket-extensions">>, 1, Headers) of
+		false ->
+			#{};
+		{_, ExtHd} ->
+			ParsedExtHd = cow_http_hd:parse_sec_websocket_extensions(ExtHd),
+			validate_extensions(ParsedExtHd, Extensions0, Opts, #{})
+	end.
+
+validate_extensions([], _, _, Acc) ->
+	Acc;
+validate_extensions([{Name = <<"permessage-deflate">>, Params}|Tail], Extensions, Opts, Acc0) ->
+	case lists:member(Name, Extensions) of
+		true ->
+			case cow_ws:validate_permessage_deflate(Params, Acc0, Opts) of
+				{ok, Acc} -> validate_extensions(Tail, Extensions, Opts, Acc);
+				error -> close
+			end;
+		%% Fail the connection if extension was not requested.
+		false ->
+			close
+	end;
+%% Fail the connection on unknown extension.
+validate_extensions(_, _, _, _) ->
+	close.
+
+%% @todo Validate protocols.
+select_protocol(Headers, Opts) ->
+	case lists:keyfind(<<"sec-websocket-protocol">>, 1, Headers) of
+		false ->
+			maps:get(default_protocol, Opts, gun_ws_h);
+		{_, Proto} ->
+			ProtoOpt = maps:get(protocols, Opts, []),
+			case lists:keyfind(Proto, 1, ProtoOpt) of
+				{_, Handler} ->
+					Handler;
+				false ->
+					close
+			end
+	end.
+
 name() -> ws.
 opts_name() -> ws_opts.
 has_keepalive() -> true.
@@ -176,6 +220,11 @@ handle(Data, State=#ws_state{in=In=#payload{type=Type, rsv=Rsv, len=Len, mask_ke
 			closing(Error, State, EvHandler, EvHandlerState)
 	end.
 
+handle_continue(ContinueStreamRef, {data, _ReplyTo, _StreamRef, IsFin, Data},
+		#ws_state{}, CookieStore, _EvHandler, EvHandlerState)
+		when is_reference(ContinueStreamRef) ->
+	{{send, IsFin, Data}, CookieStore, EvHandlerState}.
+
 maybe_active(State=#ws_state{flow=Flow}, EvHandlerState) ->
 	{[
 		{state, State},
-- 
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