# HG changeset patch
# User Matthew Wild <mwild1@gmail.com>
# Date 1275085659 -3600
# Node ID 5b74d155036dfd680bf685e6f90480a1ee82f147
# Parent  36d113fb0f3c5101ddcccff7c49d51753e50fe58
verse.plugins.compression: Support for stream compression (requires brimworks lua-zlib)

diff -r 36d113fb0f3c -r 5b74d155036d plugins/compression.lua
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/plugins/compression.lua	Fri May 28 23:27:39 2010 +0100
@@ -0,0 +1,123 @@
+-- Copyright (C) 2009-2010 Matthew Wild
+-- Copyright (C) 2009-2010 Tobias Markmann
+-- 
+-- This project is MIT/X11 licensed. Please see the
+-- COPYING file in the source package for more information.
+--
+
+local st = require "util.stanza";
+local zlib = require "zlib";
+
+local xmlns_compression_feature = "http://jabber.org/features/compress"
+local xmlns_compression_protocol = "http://jabber.org/protocol/compress"
+local xmlns_stream = "http://etherx.jabber.org/streams";
+
+local compression_level = 9;
+
+-- returns either nil or a fully functional ready to use inflate stream
+local function get_deflate_stream(session)
+	local status, deflate_stream = pcall(zlib.deflate, compression_level);
+	if status == false then
+		local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed");
+		session:send(error_st);
+		session:error("Failed to create zlib.deflate filter: %s", tostring(deflate_stream));
+		return
+	end
+	return deflate_stream
+end
+
+-- returns either nil or a fully functional ready to use inflate stream
+local function get_inflate_stream(session)
+	local status, inflate_stream = pcall(zlib.inflate);
+	if status == false then
+		local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed");
+		session:send(error_st);
+		session:error("Failed to create zlib.inflate filter: %s", tostring(inflate_stream));
+		return
+	end
+	return inflate_stream
+end
+
+-- setup compression for a stream
+local function setup_compression(session, deflate_stream)
+	function session:send(t)
+			--TODO: Better code injection in the sending process
+			local status, compressed, eof = pcall(deflate_stream, tostring(t), 'sync');
+			if status == false then
+				session:close({
+					condition = "undefined-condition";
+					text = compressed;
+					extra = st.stanza("failure", {xmlns="http://jabber.org/protocol/compress"}):tag("processing-failed");
+				});
+				session:warn("Compressed send failed: %s", tostring(compressed));
+				return;
+			end
+			session.conn:write(compressed);
+		end;	
+end
+
+-- setup decompression for a stream
+local function setup_decompression(session, inflate_stream)
+	local old_data = session.data
+	session.data = function(conn, data)
+			session:debug("Decompressing data...");
+			local status, decompressed, eof = pcall(inflate_stream, data);
+			if status == false then
+				session:close({
+					condition = "undefined-condition";
+					text = decompressed;
+					extra = st.stanza("failure", {xmlns="http://jabber.org/protocol/compress"}):tag("processing-failed");
+				});
+				stream:warn("%s", tostring(decompressed));
+				return;
+			end
+			return old_data(conn, decompressed);
+		end;
+	session:debug("Replaced session.data %s with %s", old_data, session.data);
+end
+
+function verse.plugins.compression(stream)
+	local function handle_features(features)
+		if not stream.compressed then
+			-- does remote server support compression?
+			local comp_st = features:child_with_name("compression");
+			if comp_st then
+				-- do we support the mechanism
+				for a in comp_st:children() do
+					local algorithm = a[1]
+					if algorithm == "zlib" then
+						stream:send(st.stanza("compress", {xmlns=xmlns_compression_protocol}):tag("method"):text("zlib"))
+						stream:debug("Enabled compression using zlib.")
+						return true;
+					end
+				end
+				session:debug("Remote server supports no compression algorithm we support.")
+			end
+		end
+	end
+	local function handle_compressed(stanza)
+		if stanza.name == "compressed" then
+			stream:debug("Activating compression...")
+
+			-- create deflate and inflate streams
+			local deflate_stream = get_deflate_stream(stream);
+			if not deflate_stream then return end
+			
+			local inflate_stream = get_inflate_stream(stream);
+			if not inflate_stream then return end
+			
+			-- setup compression for stream.w
+			setup_compression(stream, deflate_stream);
+				
+			-- setup decompression for stream.data
+			setup_decompression(stream, inflate_stream);
+			
+			stream.compressed = true;
+			stream:reopen();
+		elseif stanza.name == "failure" then
+			stream:warn("Failed to establish compression");
+		end
+	end
+	stream:hook("stream-features", handle_features, 200);
+	stream:hook("stream/"..xmlns_compression_protocol, handle_compressed);
+end
\ No newline at end of file
diff -r 36d113fb0f3c -r 5b74d155036d squishy
--- a/squishy	Fri May 28 23:26:31 2010 +0100
+++ b/squishy	Fri May 28 23:27:39 2010 +0100
@@ -19,12 +19,13 @@
 Module "util.sha1"		"util/sha1.lua"
 
 -- Verse plugins
-Module "verse.plugins.tls"      "plugins/tls.lua"
-Module "verse.plugins.sasl"	"plugins/sasl.lua"
-Module "verse.plugins.bind"	"plugins/bind.lua"
-Module "verse.plugins.version"	"plugins/version.lua"
-Module "verse.plugins.ping"	"plugins/ping.lua"
-Module "verse.plugins.session"  "plugins/session.lua"
+Module "verse.plugins.tls"         "plugins/tls.lua"
+Module "verse.plugins.sasl"	   "plugins/sasl.lua"
+Module "verse.plugins.bind"	   "plugins/bind.lua"
+Module "verse.plugins.version"	   "plugins/version.lua"
+Module "verse.plugins.ping"	   "plugins/ping.lua"
+Module "verse.plugins.session"     "plugins/session.lua"
+Module "verse.plugins.compression" "plugins/compression.lua"
 
 Module "verse.client" "client.lua"