2 -- Copyright (C) 2009 Tobias Markmann
4 -- This project is MIT/X11 licensed. Please see the
5 -- COPYING file in the source package for more information.
8 local st = require "util.stanza";
9 local zlib = require "zlib";
12 local xmlns_compression_feature = "http://jabber.org/features/compress"
13 local xmlns_compression_protocol = "http://jabber.org/protocol/compress"
14 local compression_stream_feature = st.stanza("compression", {xmlns=xmlns_compression_feature}):tag("method"):text("zlib"):up();
16 local compression_level = module:get_option("compression_level");
18 -- if not defined assume admin wants best compression
19 if compression_level == nil then compression_level = 9 end;
21 compression_level = tonumber(compression_level);
22 if not compression_level or compression_level < 1 or compression_level > 9 then
23 module:log("warn", "Invalid compression level in config: %s", tostring(compression_level));
24 module:log("warn", "Module loading aborted. Compression won't be available.");
28 module:add_event_hook("stream-features",
29 function (session, features)
30 if not session.compressed then
31 -- FIXME only advertise compression support when TLS layer has no compression enabled
32 features:add_child(compression_stream_feature);
37 -- TODO Support compression on S2S level too.
38 module:add_handler("c2s_unauthed", "compress", xmlns_compression_protocol,
39 function(session, stanza)
40 -- checking if the compression method is supported
41 local method = stanza:child_with_name("method")[1];
42 if method == "zlib" then
43 session.log("info", method.." compression selected.");
44 session.send(st.stanza("compressed", {xmlns=xmlns_compression_protocol}));
45 session:reset_stream();
47 -- create deflate and inflate streams
48 local deflate_stream = zlib.deflate(9);
49 local inflate_stream = zlib.inflate();
51 -- setup compression for session.w
52 local old_send = session.send;
54 session.send = function(t)
55 local compressed, eof = deflate_stream(tostring(t), 'sync');
59 -- setup decompression for session.data
60 local function setup_decompression(session)
61 local old_data = session.data
62 session.data = function(conn, data)
63 local decompressed, eof = inflate_stream(data);
64 old_data(conn, decompressed);
67 setup_decompression(session);
69 local session_reset_stream = session.reset_stream;
70 session.reset_stream = function(session)
71 session_reset_stream(session);
72 setup_decompression(session);
75 session.compressed = true;
77 session.log("info", method.." compression selected. But we don't support it.");
78 local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("unsupported-method");
79 session.send(error_st);