From 8d920f3db97067159fcf6ca497979f8e063986dc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lo=C3=AFc=20Hoguin?= <essen@ninenines.eu>
Date: Tue, 13 Nov 2018 15:55:09 +0100
Subject: Add the {deflate, boolean()} Websocket command

It allows to temporarily disable Websocket compression
when it was negotiated. It's ignored otherwise. This
can be used as fine-grained control when some frames
do not compress well.
---
 test/handlers/ws_active_commands_h.erl  |  4 ++--
 test/handlers/ws_deflate_commands_h.erl | 24 +++++++++++++++++++
 test/ws_handler_SUITE.erl               | 42 ++++++++++++++++++++++++++++++++-
 3 files changed, 67 insertions(+), 3 deletions(-)
 create mode 100644 test/handlers/ws_deflate_commands_h.erl

(limited to 'test')

diff --git a/test/handlers/ws_active_commands_h.erl b/test/handlers/ws_active_commands_h.erl
index 4cdb3b1..1c615e3 100644
--- a/test/handlers/ws_active_commands_h.erl
+++ b/test/handlers/ws_active_commands_h.erl
@@ -1,5 +1,5 @@
-%% This module takes commands from the x-commands header
-%% and returns them in the websocket_init/1 callback.
+%% This module starts with active mode disabled
+%% and enables it again once a timeout is triggered.
 
 -module(ws_active_commands_h).
 -behavior(cowboy_websocket).
diff --git a/test/handlers/ws_deflate_commands_h.erl b/test/handlers/ws_deflate_commands_h.erl
new file mode 100644
index 0000000..14236bc
--- /dev/null
+++ b/test/handlers/ws_deflate_commands_h.erl
@@ -0,0 +1,24 @@
+%% This module enables/disables compression
+%% every time it echoes a frame.
+
+-module(ws_deflate_commands_h).
+-behavior(cowboy_websocket).
+
+-export([init/2]).
+-export([websocket_handle/2]).
+-export([websocket_info/2]).
+
+init(Req, RunOrHibernate) ->
+	{cowboy_websocket, Req,
+		#{deflate => true, hibernate => RunOrHibernate},
+		#{compress => true}}.
+
+websocket_handle(Frame, State=#{deflate := Deflate0, hibernate := run}) ->
+	Deflate = not Deflate0,
+	{[Frame, {deflate, Deflate}], State#{deflate => Deflate}};
+websocket_handle(Frame, State=#{deflate := Deflate0, hibernate := hibernate}) ->
+	Deflate = not Deflate0,
+	{[Frame, {deflate, Deflate}], State#{deflate => Deflate}, hibernate}.
+
+websocket_info(_Info, State) ->
+	{[], State}.
diff --git a/test/ws_handler_SUITE.erl b/test/ws_handler_SUITE.erl
index 2caacca..6e2bb41 100644
--- a/test/ws_handler_SUITE.erl
+++ b/test/ws_handler_SUITE.erl
@@ -50,7 +50,8 @@ init_dispatch(Name) ->
 		{"/init", ws_init_commands_h, RunOrHibernate},
 		{"/handle", ws_handle_commands_h, RunOrHibernate},
 		{"/info", ws_info_commands_h, RunOrHibernate},
-		{"/active", ws_active_commands_h, RunOrHibernate}
+		{"/active", ws_active_commands_h, RunOrHibernate},
+		{"/deflate", ws_deflate_commands_h, RunOrHibernate}
 	]}]).
 
 %% Support functions for testing using Gun.
@@ -217,3 +218,42 @@ websocket_active_false(Config) ->
 	{ok, {text, <<"Not received until the handler enables active again.">>}}
 		= receive_ws(ConnPid, StreamRef),
 	ok.
+
+websocket_deflate_false(Config) ->
+	doc("The {deflate, false} command temporarily disables compression. "
+		"The {deflate, true} command reenables it."),
+	%% We disable context takeover so that the compressed data
+	%% does not change across all frames.
+	{ok, Socket, Headers} = ws_SUITE:do_handshake("/deflate",
+		"Sec-WebSocket-Extensions: permessage-deflate; server_no_context_takeover\r\n", Config),
+	{_, "permessage-deflate; server_no_context_takeover"}
+		= lists:keyfind("sec-websocket-extensions", 1, Headers),
+	%% The handler receives a compressed "Hello" frame and
+	%% sends back a compressed or uncompressed echo intermittently.
+	Mask = 16#11223344,
+	CompressedHello = <<242, 72, 205, 201, 201, 7, 0>>,
+	MaskedHello = ws_SUITE:do_mask(CompressedHello, Mask, <<>>),
+	%% First echo is compressed.
+	ok = gen_tcp:send(Socket, <<1:1, 1:1, 0:2, 1:4, 1:1, 7:7, Mask:32, MaskedHello/binary>>),
+	{ok, <<1:1, 1:1, 0:2, 1:4, 0:1, 7:7, CompressedHello/binary>>} = gen_tcp:recv(Socket, 0, 6000),
+	%% Second echo is not compressed when it is received back.
+	ok = gen_tcp:send(Socket, <<1:1, 1:1, 0:2, 1:4, 1:1, 7:7, Mask:32, MaskedHello/binary>>),
+	{ok, <<1:1, 0:3, 1:4, 0:1, 5:7, "Hello">>} = gen_tcp:recv(Socket, 0, 6000),
+	%% Third echo is compressed again.
+	ok = gen_tcp:send(Socket, <<1:1, 1:1, 0:2, 1:4, 1:1, 7:7, Mask:32, MaskedHello/binary>>),
+	{ok, <<1:1, 1:1, 0:2, 1:4, 0:1, 7:7, CompressedHello/binary>>} = gen_tcp:recv(Socket, 0, 6000),
+	%% Client-initiated close.
+	ok = gen_tcp:send(Socket, << 1:1, 0:3, 8:4, 1:1, 0:7, 0:32 >>),
+	{ok, << 1:1, 0:3, 8:4, 0:8 >>} = gen_tcp:recv(Socket, 0, 6000),
+	{error, closed} = gen_tcp:recv(Socket, 0, 6000),
+	ok.
+
+websocket_deflate_ignore_if_not_negotiated(Config) ->
+	doc("The {deflate, boolean()} commands are ignored "
+		"when compression was not negotiated."),
+	{ok, ConnPid, StreamRef} = gun_open_ws(Config, "/deflate", []),
+	_ = [begin
+		gun:ws_send(ConnPid, {text, <<"Hello.">>}),
+		{ok, {text, <<"Hello.">>}} = receive_ws(ConnPid, StreamRef)
+	end || _ <- lists:seq(1, 10)],
+	ok.
-- 
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