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-- Prosody IM
-- Copyright (C) 2009 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 pcall = pcall;
local tostring = tostring;
local xmlns_compression_feature = "http://jabber.org/features/compress"
local xmlns_compression_protocol = "http://jabber.org/protocol/compress"
local compression_stream_feature = st.stanza("compression", {xmlns=xmlns_compression_feature}):tag("method"):text("zlib"):up();
local compression_level = module:get_option("compression_level");
-- if not defined assume admin wants best compression
if compression_level == nil then compression_level = 9 end;
compression_level = tonumber(compression_level);
if not compression_level or compression_level < 1 or compression_level > 9 then
module:log("warn", "Invalid compression level in config: %s", tostring(compression_level));
module:log("warn", "Module loading aborted. Compression won't be available.");
return;
end
module:add_event_hook("stream-features",
function (session, features)
if not session.compressed then
-- FIXME only advertise compression support when TLS layer has no compression enabled
features:add_child(compression_stream_feature);
end
end
);
-- TODO Support compression on S2S level too.
module:add_handler({"c2s_unauthed", "c2s"}, "compress", xmlns_compression_protocol,
function(session, stanza)
-- fail if we are already compressed
if session.compressed then
local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed");
session.send(error_st);
session.log("debug", "Client tried to establish another compression layer.");
return;
end
-- checking if the compression method is supported
local method = stanza:child_with_name("method");
method = method and (method[1] or "");
if method == "zlib" then
-- create deflate and inflate streams
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.log("error", "Failed to create zlib.deflate filter.");
module:log("error", "%s", tostring(deflate_stream));
return
end
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.log("error", "Failed to create zlib.inflate filter.");
module:log("error", "%s", tostring(inflate_stream));
return
end
session.log("debug", "zlib compression enabled.");
session.send(st.stanza("compressed", {xmlns=xmlns_compression_protocol}));
session:reset_stream();
-- setup compression for session.w
local old_send = session.send;
session.send = function(t)
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");
});
module:log("warn", "%s", tostring(compressed));
return;
end
old_send(compressed);
end;
-- setup decompression for session.data
local function setup_decompression(session)
local old_data = session.data
session.data = function(conn, 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");
});
module:log("warn", "%s", tostring(decompressed));
return;
end
old_data(conn, decompressed);
end;
end
setup_decompression(session);
local session_reset_stream = session.reset_stream;
session.reset_stream = function(session)
session_reset_stream(session);
setup_decompression(session);
return true;
end;
session.compressed = true;
elseif method then
session.log("debug", "%s compression selected, but we don't support it.", tostring(method));
local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("unsupported-method");
session.send(error_st);
else
session.send(st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed"));
end
end
);
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