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", "c2s"}, "compress", xmlns_compression_protocol,
39 function(session, stanza)
40 -- fail if we are already compressed
41 if session.compressed then
42 local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("unsupported-method");
43 session.send(error_st);
44 session:log("warn", "Tried to establish another compression layer.");
47 -- checking if the compression method is supported
48 local method = stanza:child_with_name("method")[1];
49 if method == "zlib" then
50 session.log("info", method.." compression selected.");
51 session.send(st.stanza("compressed", {xmlns=xmlns_compression_protocol}));
52 session:reset_stream();
54 -- create deflate and inflate streams
55 local status, deflate_stream = pcall(zlib.deflate, compression_level);
56 if status == false then
57 local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed");
58 session.send(error_st);
59 session:log("error", "Failed to create zlib.deflate filter.");
60 module:log("error", deflate_stream);
64 local status, inflate_stream = pcall(zlib.inflate);
65 if status == false then
66 local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed");
67 session.send(error_st);
68 session:log("error", "Failed to create zlib.deflate filter.");
69 module:log("error", inflate_stream);
73 -- setup compression for session.w
74 local old_send = session.send;
76 session.send = function(t)
77 local status, compressed, eof = pcall(deflate_stream, tostring(t), 'sync');
78 if status == false then
80 condition = "undefined-condition";
82 extra = st.stanza("failure", {xmlns="http://jabber.org/protocol/compress"}):tag("processing-failed");
84 module:log("warn", compressed);
90 -- setup decompression for session.data
91 local function setup_decompression(session)
92 local old_data = session.data
93 session.data = function(conn, data)
94 local status, decompressed, eof = pcall(inflate_stream, data);
95 if status == false then
97 condition = "undefined-condition";
99 extra = st.stanza("failure", {xmlns="http://jabber.org/protocol/compress"}):tag("processing-failed");
101 module:log("warn", decompressed);
104 old_data(conn, decompressed);
107 setup_decompression(session);
109 local session_reset_stream = session.reset_stream;
110 session.reset_stream = function(session)
111 session_reset_stream(session);
112 setup_decompression(session);
115 session.compressed = true;
117 session.log("info", method.." compression selected. But we don't support it.");
118 local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("unsupported-method");
119 session.send(error_st);